Boost at idle is common on supercharged diesel engines. 15 years ago or so, I built a twin turbo + whipple 24V Cummins pickup. It made 8PSI at idle. The idle boost is a non-issue. If the boost while revving get's into an uncomforable zone, a pulley change is likely the best and easiest solution. If you can't figure out the crank situation, maybe you can change the pulley on the stupidcharger.
Diesels really dont require bov's/ dumps to atmosphere. i work as a diesel semi truck mechanic and they dont use them. boost at idle is not necessarily ideal per se but not the end of the world either. as long as your EGT's are stable, cylinder pressure is in safe range, and you have enough fuel its not a problem. Diesels LOVE extra oxygen.
My BMW m57 makes a few psi of boost at idle it's not an issue imho, arguably it's desirable as your Increasing the compression ratio and giving more oxygen to boot. Will make for better emission at idle.
The only thing that can happen is if you really crank the boost is you end up too lean at idle and have a misfire. That's at the edge of what can happen but it is possible.
Don't fear the boost. I'd leave the pullies alone but only make fuel adjustments from this point forward to achieve whatever results you're after. But I am just a random guy from the Internet.
If I'm thinking right, won't the boost be dependent mainly on RPM and not load for the s/c? So, the max boost could be checked revving while stationary, and it should actually drop some under load at the same RPM due to increased volume consumed by engine? All that to say that I think the boost will actually drop under load vs while parked, unlike a turbo, but I could be wrong.
@@smokesandalloy9487 for the most part you're correct. This supercharger is positive displacement meaning it can only push X amount of CFM per rotor rotation, and an engine's cylinder can consume only Y amount of air per stroke. So once you're off idle with this diesel, boost should remain the same up to redline, barring things like cam overlap or something of that nature that probably doesnt apply here. So the 10 or 11psi we saw when he revved it should be the same up to redline, regardless of engine load. Boost is a waste value, a measurement of the air the engine cannot consume.
@@bobirving6052 that makes sense, although I don't expect the dip to be drastic. Hopefully Jimbo will split screen boost to RPM and do a thorough pull though the rev range so we can see
@GTkyle At peak torque, intake manifold pressure should be it’s lowest. The supercharger should increase output almost linearly, but the intake’s inertial mechanism will get the air into the cylinders more efficiently at the sweet spot where you get most torque. Edit: I realized this theory is not true. The supercharger’s output can increase faster than the engine’s intake, depending on pulley size. So pressure could increase or decrease as rpm increases. There will just be a pressure drop around peak torque.
Its funny how being around the channel long enough makes unique statements sound normal "you may recall how I installed a stupidcharger on a twostoke leafblower motor and used it to power a.... "
From my experience Kabota (well, most manufacturers of) diesels have sturdy block and head construction and I’d keep a close eye on the EGTs since heat will likely destroy the engine before cylinder pressure will. Oh and I guessed 5psi at idle but the was just a guess based off your comment after squeezing the charge pipe. No math, just lucky lol.
My understanding is egts and cylinder head temps are the point where when they get too hot they like to drop valve seats. But beyond that I've seen plenty of em with thousands of hours of abuse, I assume it would be fine for quite some time if pushed a little
I hope *Future Jimbo* sees this. You should be able to get rid of the *Flutter* in the boost gauge needle by adding a type of inline restriction. Basically slowing the boost down to the gauge. This "should" work. Cool project.
@@somedude2492 A lot of electric welders are essentially standalone generators with live wires you handle. This is to avoid needing to put in a heavy duty fuse in the building it's in. He turboed the generator for the welder.
@@MyLonewolf25 Without a blow off or recirculation valve a positive displacement blower builds pressure in the charge pipe before the throttle body which will heat soak the blower and intercooler if it has one. source: my eaton m90 supercharged rx7
I'm one of your less technical RUclips channel followers, so I'm going to have to give you the "Send it as is, YOLO!" response that you're probably not looking for. But, seriously, it's time to embrace your inner Cleetus McFarland. Give it ALL the boost, if it blows, it blows!
As much as I want him to Do it for Dale, ole Cleet has a budget to work with, that a lot of folks don't. A replacement d722 last I seen for a decent unit was at least a couple grand.
Queen said it best- "Pressure pushin' down on me Pressin' down on you, no man ask for Under pressure that brings a building down Splits a family in two, puts people on streets Mm-ba-ba-beh, mm-ba-ba-beh Dee-day-da, ee-day-da That's okay" Send the pressure and don't worry about the family of parts getting split in two. it's OK.
Awesome work as usual. Thanks for the entertainment. The gauge is fluttering with the pulse of the supercharger lobes and the intake valves. Roots blowers by design have a high and low output as the lobes cover the suction and discharge during each displacement event, similar to a workshop air compressor. To even out the pulse, the only option is to install a large plenum. This will absorb the fluctuations, but it's really not going to make a world of difference. These little kubota engines don't flow much air, so 10psi is showing you the restriction. If the engine had improved breathing, the pressure would drop. The other consideration is after adding an intercooler, the pressure will drop again once passed through the heat exchanger.
Man! These big budget shows always leave you on the edge of your seat wanting more! That’s how they keep you coming back! I was not expecting 6 psi at idle. But I also don’t know much about superchargers either. Can’t wait for the test drive!
For the lost gauge fluctuations. You can rip the cotton off a cotton swab. Jam it in the line close to your gauge. Not block it but put a decent amount in. Helps with the flutter.
Jimbo, opposite to a gasser, excess air is not a problem for a diesel. Over fueling (rich) cooks the oil motor, under fueling (lean) cooks a gasser. Your extra boost at idle might increase NOX output (not enough carbon for the oxygen, so it bonds to nitrogen instead), but it wont damage the mill. Btw, i guessed 7 psi at idle, lol. I also saw your old "launch" vids showed "coal" at launch and first shift, so id say send her as she lies now, then worry about adding fuel if you need it. She may well surprise ya! Sweet mod job, just add a tin firewall between the blower and exhaust downpipe, just like a 22ga panel to reflect radiant heat (could even glue alum foil shiney side out on the pipe side for style points, lol)
I'd leave the boost as is. Maybe put an intake temp sensor in there to see if you need an intercooler. The gauge moving around was from the intake valves closing, BTW. Keep up the great work. This is fascinating. I used to work on these diesel generators all the time, in large light-alls. I always wondered what it would be like in a go cart or something.
As a keyboard warrior and expert in things not automotive engineering related, I say you send it! You have a spare engine and that's what spares are for, right?
My recommendation would be to try a 1:1 pulley ratio or even a slight underdrive. Also, maybe you can use that electric dump valve to vent boost at zero throttle using a normally closed switch that opens when the throttle is depressed.
The only bad thing about making boost at idle on a diesel is the heat generated. On a gas engine it would be generating even more boost in the charge pipe before the throttle body
@@Mrshotshell agreed. I'm just thinking about during times when the engines idling and it's putting needless stress on the supercharger it might be beneficial to allow the engine to just idle it atmospheric pressure and vent the Boost that the compressor is making.
The engine is a big restriction to the supercharger and why the boost is so high at idle The Subaru engine even if it's 660cc like the Kubota engine make 3x as much power so it way more efficient and less restrictions on the supercharger if the supercharger make 1000cc every rotation and the engine need 500cc the engine would be in boost vs a engine that need 2000cc of air would be in vacuum at idle With a 1:1 pulley you can see the second example would never make boost if the engine need 2000cc per rev and the supercharger give 1000cc per rev plus volumetric efficiency vary with rpm/engine design Root type supercharger are constant displacement and rated by how many liter per rev they displace Boost is complicated lol
Lol. 6 psi at idle. The little engine has so little flow. Diesels are great for playing with boost. They just perform better without any tuning when boost is added.
Hi Robot. I should have said that long ago: I had this silly challenge when I was younger of making as much distance as possible with a stock old 206 peugeot with a 1.4l HDI motor. I did 1300km with 45liters of fuel. For conversion that's like 68 mpg, the car already had 125 000km on it at the time (or 77 700 miles) the tires were over inflated and it was a company car so no backseat. The car was from 2003 maybe I was a bit reckless at times to brake as little as possible and accelerating slowly.
I got 1200 km's from the south of France to Luxembourg (where fuel is cheap ;)), with the same car model and engine. We took the all toll-free road, so a lot of 80 km/h driving with a hot engine, which turned out to be very efficient. No modifications to the car were needed.
This, as a fuel consumption number aficionado, is the kind of story I like to hear. Well done. Most small-ish diesel cars can get about 3.5l/100km when driven at their most economical speed on favorable roads. I have never owned such a small diesel car to be involved in pushing for great numbers, though I have driven my larger cars quite a bit under their "extra-urban" EU fuel rating.
If you could engineer a suitable leak you would reduce boost pressure, just not sure if you can engineer a precise enough and consistent leak. Maybe just add pinholes until you get the desired boost.
Jim- I think a useful metric for this process would be a thermocouple placed after the charger. You get a really effective cooling and atomization effect from the gasoline on the carburetor application, but superchargers make a ton of heat themselves, even before the heat gain from compression. With no evaporative cooling on the diesel, I'd theorize you're getting a decent amount of boost only from expansion, but the actual density of the charge is far from that of ambient air at ambient temperatures. I think you're seeing at least 60 degrees of temp rise between ambient and after the charger, so that shoud account for roughly 2psig by itself. Venting would disproportionately reduce your efficency, as you're still paying the price to compress and heat the air, to then dump it overboard. Solutions may include an aftercooler, water meth, and reducing the drive speed of the charger to better match the air requirements of the engine. I recommend caution going above 10psi on this, as factory turbo kubotas dont run much more pressure than that sustained, and those are built for it. So, how are you going to get that 10psig to be as cold and dense as possible?
We made a second video on the DIY brake booster system and we eliminated the chatter with a programmable delay relay. After shooting that video we found a compact programmable delay relay that completely simplifies the whole system. we will do another update soon.
What most people don't understand is that boost is a measure of restriction. If you have a turbo or supercharger that is producing 8 lbs of boost, then you change the heads, intake, or anything else in the system, your boost will likely not be the same after, because you are changing the amount of air in/out in some way. If your boost drops, that is because it is better flowing, and you can then change your pulley to increase it back up to your previous amount, basically increasing the overall power at the "same" boost level
Jimbo, I am sure, will heed your comment - its looking at the issue from another perpective and that usually produces a deeper understanding and better solutions.
Your boost can also drop simply by adding an intercooler which will reduce the air pressure while increasing the manifold air density and power. The restriction isn't the only factor in that number. Banks goes on and on about manifold air density, and it makes a lot of sense.
@@Sevalecan Obviously, there are other factors than *just* restriction, but it is the largest one. I was keeping it simple. There are engine builders on RUclips you can learn more about it from them. Steve Morris or Pete Harrell for example have some good videos on it, that cover quite a bit about turbo & supercharger builds
Exaxctly! Up to a limit, and that's usually the mass flow limit of the compressor, no matter if it's a supercharger or a turbocharger. On a crappy flowing 2.0L engine, one compressor may produce 1 bar of boost and not heat up, while on another 2.0 properly flowing engine, it may barely produce 0.5 bar of boost and heat up.
Sunday morning is now complete. The experiments are the best part, I am not addicted to Robot Cantina at all....☕️. Now that I have watched another great episode, I can head out to the shop and work on my project. Great work. Waiting (patiently) for the test drive.
I'm making this comment about 4 minutes in, so sorry if you cover it later in the video. This is how I equate it. The old saying "there is no replacement for displacement" still stands true in a sense. This is because by bosting engines, we are in effect increasing the amount of air and fuel that engine can displace into an engine on every intake stroke. The more fuel air/fuel we can et in, the more power we can get out. Turbocharging and supercharging are using devices that allow us to squeeze more bang into every revolution. Turbocharging and supercharging are how we increase the fuel displacement of an engine. What this has done to my thinking is changed how I calculate engines in my mind. A naturally aspirated engine us under the force of ambient barometric pressure, which is 14.7psi. 14.7psi 1 1 bar, or 1 atmosphere. If you have 21 atmospheres, you have double the volume of air in the same space. Metric makes so much more sense in this case. When you put 14.7psi of boost to an engine, you have the 14.7psi (1 atmosphere) from ambient pressure, and another one from the boost. You are doubling the volume of the air, and when air/fuel ratios are correct, you have double the air/fuel mixture. You are in in effect turning a 731cc diesel engine into a 1462cc engine that weighs less than a typical 1462cc engine. 14.7psi of with no adjustment for intake and exhaust restrictions, is doubling the power that can be generated from that air/fuel mixture charge. The difference is, you don't have the additional rotating mass and other factors that rob power in an engine that has a physical cylinder displacement of 1462cc. Boost makes engines have a higher displacement, but don't have a heavier engine mass that they have to rotate, and they don't have to carry that extra weight. With that, boosting an engine can be more efficient at generating power. You can calculate if it's more efficient by calculating the fuel consumption against the horsepower, and comparing the result of the naturally aspirated engine against the result of the boosted engine. I find this way of looking at engines helps me wrap my head around the expected torque and horsepower values. It makes more sense in my mind, I hope it maybe helps some other people visualize it too.
Banks "lockjaw" build is a Whipple supercharged duramax so it's a bit similar. They had to run a bypass valve for idle because it was building up way too much heat. Any time you have pressure in the intake work is being done to compress the air and adding heat.
@@kd5inm The intercooler would cool the intake charge going into the engine, but it wouldn't stop the supercharger from overheating. In fact the added restriction woukd exacerbate the problem at idle/low load. He could try water injection pre-supercharger. But, he would be better off reducing the output of the supercharger. Or bypassing excess air to keep the supercharger from overheating due to the excess pressure/restriction at idle.
@@jjsledneck Sure the water temperature, but the temperature of the supercharger itself may become a problem, especially if it continues to make more boost (due to the lack of flow) through the rev range. Without a Compressor Map we dont know how far outside its efficiency range it would be. It might see 15+ psi at higher rpm without making changes.
Next step is to test drive as is and then do an intercooler. No need to turn boost down. Motor can handle it. Absolute worse case is you nip the head gasket but honestly if was me I’d absolutely test drive it. I build Harley motors daily so diesels are not my wheel house but I still understand enough about engines to know you have very little risk here. A head gasket is a small price. If you do nip a head gasket just know one thing do not try to start the engine after you shut it off or high risk of bending a connecting rod. Other then that. Watch your EGTS and let er eat
Do they make high volume whoopee cushions that actuate at a calibrated 15psi? That could be a good way of venting excess boost. Maybe back-bending a single-v belt is worse for it than a poly-v belt, but I've worked on everything from Pontiacs to elliptical machines that regularly have very tight bends on poly-v belts and it never seems to do them a lick of harm. As long as you're not loading the alternator so much it slips I expect the belt will hold up well enough for your purposes.
Poly Vs don't mind it at all, it's just single V belts that prefer not to be bent backwards. Even then you can get V belts that are designed to handle it, in fact they even make double sided ones that fit V-pulleys on both sides.
With the drive belt I would look to see if there was one in the same size for running lawnmower blades. Those are v-belts and they run on the back side of the idler. The idler pulley does also have flanges to keep from throwing the belt off.
If you still have the stock intake of the supercharger they are crap... hella restrictive, i don't know if it will really change something at your power level but yeah just let you know it! For reference we made 140hp on 1.3L micra here with this supercharger, not a lot but yeah it can pump
What about an external waste gate? My thinking here is you can dump the excess boost at idle to atmosphere and have it controlled by a Arduino using a pressure sender, RPM and solenoid using vacuum from the vacuum pump? If you wanted to be really fly you could even throw a throttle position sensor in the mix!
I was thinking the electronic "roboot" throttle body from the saturn project. Use the throttle body to bypass the supercharger. Could be simple on/off based on throttle position, or fancy with a feedback loop and controlling boost.
Toyota previas use a clutch on their supercharger. Perhaps you can find a beefy ac compressor clutch and Have it hooked up to a relay normally off at idle position.
I would't worry about the blow off valve unless you are trying to get all the mpgs. Props for acually describing the role of the blower in gm two cycle diesels (51,53,71,92,110[some of them],149,567,645)
The belt shouldn't be an issue, Dodge put a v belt with a similar idler on a 1976-1978 Plymouth Volare/Dodge Aspen Slant 6 AC system. So I converted my friend's slant 6 with a similar AC setup I made myself. To be fair, Chrysler DID change it by the time the car was done with in 1980.
With a 1:1 ratio you'd have about 5.1 lb of boost with that setup (at speed). Expect around 3lb at low speed due to the additional parasitic blowby. Back-calculating I'd say you are currently running a 1:1.25 overdrive ratio. Needle bouncing is expected since the plenum chamber volume is quite low in your setup. Did a lot of these calculations when I put an Eaton M45 on my 800cc Suzuki, also ethanol efi. Let me know if you want numbers done. 👍
Wow that's way more boost than I expected too. Don't think it would hurt anything as diesels like to run lean. It would sure help keep the EGT's and soot down at the same time. All-in-all, I think it would work out fine. Hopefully, you can sneak the intercooler in somehow. Can't wait to see how she'll run. Nice work Jimbo!! 💪🔥
From what I've seen, tubing is a better choice than hose for your application. I watch your channel on a homemade cash register t-71 thinkcentre with a 4th gen I7 (instead of a 'energy saver' I3) and 16GB of ram instead of 4. I use Ubuntu Linux 23.10, and love it. #ComputerNerdsUnite
Jimbo.. You need to put some safety tethers on that charger. When it blows off the side of the block. Like a top fuel dragster. 🤣🤣 But seriously. Your pully size, looks about right. The boost will be fairly flat through the rev range. Superchargers do not tend to spike like turbos.
You have an interesting situation, two positive displacement devices, engine and blower, butting heads. The manifold pressure is only function of rpm, independent of the load. That is, it will be increasing proportional with rpm no risk of runaway boost. Pressure will likely drop with the addition of an intercooler. For now I would install an EGT sensor and boost gauge and do some testing
If it's a concern... I'd swap the pulley on the supercharger for something a little larger... But as long as blower rpm is in the safe limits for the unit, I wouldn't worry about it. As you said.. diesels are controlled by fuel.. not air. Can't have too much air... Only too little. Cylinder pressure is created by fuel and timing. The little bit of pressure added to the cylinder by the supercharger won't hurt anything... even at idle.
I think a mini CVT drive for the stupidcharger so that it boosts low at idle but also can do 45psi at top speed. Variable drive ratios fix everything, and that belt isn't abused enough yet.
Banks Power has a series of videos that goes into great depth how supercharging a 4 stroke diesel works. Like SUPER depth like measuring combustion chamber pressure and in/out heat etc. It can work great, but you will want good intercooling.
Actually, I wouldn’t worry too much about that idler that you added . Back idlers are commonly used on several automotive applications and have been for years so it’s nothing new and shouldn’t hurt the belt providing the Bell tension is tolerable.
let'er rip the way she is! Extra air doesn't hurt a diesel engine. It puts a slightly higher load on the internal engine components when under no load, but that's still vastly less than what the components see when the engine is loaded. Just monitor the boost during your test run - if it gets out of control let off the throttle. There isn't much of an advantage to dumping the boost to atmosphere under low engine load conditions other than fuel economy. But you can totally get fancy with an electric butterfly dump valve, and use an arduino to close that only when above x% throttle or something
Perhaps some sort of one way valve to even out the pressure at idle, and as the throttle increases, the valve will close as it builds pressure? That's the only thing I can think of as a mechanical solution. I am no expert or keyboard mechanic either.
You could be the Tesla Gastown in a bad pandemic.. love these videos. Just because it has enough engineering and not too much. Not that I can’t understand too much but I like to relax when I watch the Internet.
Diesel does not care that you’re putting in extra air. It won’t make any extra power until you add fuel. It’s possible that the leaner condition will increase efficiency. I would say test drive it and keep an eye on it.
Re: Future grade 8 bolt on your supercharger mount. A grade 8 is hard, but can be brittle, like glass. A softer bolt will deform but hang together. Test? Put a 1/4"-20 grade 8 in a vise and smack it from the side with a hammer. If you do the same with a grade 5, you can probably bend it 90 degrees and it will stay together. Good luck and let me know what happens if you try the test. I always enjoy your videos.
There's places where manufacturers spec grade 5 bolts over grade 8 for that reason. Really for what it's being used for it's not going to matter but in places like a suspension you don't want to replace grade 5 with grade 8 unless you know what you are doing. The same is true for the metric equivalents.
@@edwardscott3262 lol there no suspension that use grade 5 bolt hell you won't find a single grade 5 bolt on a car Higher bolt grade doesn't mean more brittle that just stupid but the opposite is true a low grades bolt will shear easily vs a higher graded one than will bend We use grade 5 bolt as safety bolt on street diesel snowblower To op a grade 8 bolt wil bend no problem it not a drill bit And we not talking critical bolt like a conrod bolt or head stud You all got no clue what grade mean A grade 5 bolt is maybe good for 80k psi grade 8 is rated 120kpsi ARP2000 headstud are rated at 220kpsi L19 at 260kpsi (L19 can be subject to hydrogen embrittlement This material is easily contaminated by sweat and could cause failure if not handled with glove or covered in oil before handling but that beyond this conversation) When the bolt clamping force taper off(bolt stretch) at the elastic deformation(regain is original form) when plastic deformation(permanent deformation) occurs the clamping force decrease until failure point 99% of the time a bolt will break at the last engaged thread where the plastic deformation occurs at the weakest spot on the bolt(less material)
How could you calculate the boost? Boost is just a measurement of the restriction point of the engine. You could take some educated guesses but hard to be right
Have a look at the Sporlan/Parker stepper motor regulator. "Electric Regulator Valve - CDS Series" You can get one and a control board that will take 4-20 mA for a control signal and a motor that will run on 12V. These are used in refrigeration. With one of these and you're control skills you can do whatever you want with the boost. There are mechanical options in the refrigeration world but they don't offer the easy to change capabilities electronics offer.
Thanks for another great video Jimbo! Don't mind any critics you're doing great. Personally I'd say take it for a drive. As long as your egt stays low it should be fine.
How about using a throttle by wire throttle body and gas pedal but flip flop the position sensor out put so when not pressed it's wide open and as the pedal is pressed it closes to build full boost.
Howdy Jimbo! I ain't an expert on this particular engine, but if you wanted the belt to have more contact with the alternator pulley, how about adding another idler pulley at the bolt where the turn buckles are?
Hey Jimbo. The boost needle jumps with the pulsing of the supercharge/ intake opening and closing.. you can choke it with a little valve they use for fish tank bubblers and adjust it till it's relatively stable😊
Not sure why people insist on pointing out stuff they THINK is wrong when it takes a two second google search to see that in reality they are the ones that are wrong. It’s totally fine to use a tensioner on a v belt to have the belt bend backwards some. It’s been implemented on many designs in the past.
Jimbo, never boosted an N/A diesel this small but even the smaller Turbo models can handle 20psi no problem. Bigger issue is going to be you have the wrong pistons for boost or constant boost. I wouldn't change anything myself @jake20479 is correct. Watch your EGT like a hawk. Also in the summer if you don't have the intercooler in you will need to watch intake air heat. Boost generally doesn't kill diesels it's cylinder pressure and heat. Diesel generally don't need wastegates or blow off valves. Might save you some headaches seeing how it all works and also so you don't limit out your pump and injectors, but it's not really needed.
A lot of older cars and trucks that used v-belts and had a bunch of accessories that need belt drive often had two pulleys on one or more of those accessories. That way you had one belt with good engagement on the crank and one drive pulley, then another belt drives another accessory off of the first one, ensuring positive belt engagement for all drive pulleys, and no need for idlers pushing the v-belts in the wrong direction. As for the boost at idle, I don't know if a blow off is really necessary being that it's a diesel, but it may be possible to electronically actuate one using something simple like a switch on the gas pedal.
A blow off would be more to protect the supercharged than the engine lot of heat at idle making that much boost The engine seem to be a big restriction for the supercharged and the reason the boost is so high at idle More restrictions equal more boost at the same air volume The original Subaru engine may be the same 660cc size but is clearly way more efficient/less restrictive And make 3x as much as this 20 HP engine
3:59 I got my self a 4.236 Perkins in my fishing boat, and thinking about given the ol' girl some boostyness. It only makes 60 odd HP but a 100 would be nice 😅
6psi on idle, thats HUGE definetely need lower ratio, something like 1.2-1.4 maybe? i always thought that if SC pumping 500cc/rev, then for 700cc it would require more then 1:2 ratio to make any boost, but i guess i am wrong
too much boost at idle should be close to 0 , the boost gauge is shaking like that because is a cheap one and will be very noise , u need to put a restriction in the vacuum house to make it stop , good luck
I gotta ask, I have the same diesel engine in my UTV project, and I cant find the oil pan gasket anywhere! Checked online and called all my local Kubota dealers(boy are they a sorry sort around here). Any thoughts? It needs to be replaced due to a nasty leak(the "automatic oil change" kind). I am considering using RTV, but I am worried even if it seals it will alter the clearance in a negative way or not last very long at all. I found one online in the UK, but the shipping for a $10 gasket is $35 to get it over here. If thats my only option Ill do it, but I imagine there has to be a more local source. Anyones input is appreciated! :)
Keep it around 14.5 psi for the stock block. Then pull the crank bearings after a few test drives. Soft and hard driving. Check the clearances, and then check the head for any damage. If it’s all still within spec, add some slightly bigger injectors. 100-150cc larger, and keep the boost at the same level. Fuel is a great way to keep the engine cool under boost.
Boost at idle is common on supercharged diesel engines. 15 years ago or so, I built a twin turbo + whipple 24V Cummins pickup. It made 8PSI at idle. The idle boost is a non-issue. If the boost while revving get's into an uncomforable zone, a pulley change is likely the best and easiest solution. If you can't figure out the crank situation, maybe you can change the pulley on the stupidcharger.
I think I've seen that truck. Was it white?
@@KRRZ350 nah mate, it was red with hello kitty stickers all over. It also was rolling on thirteen inch gold Dayton's.
Diesels really dont require bov's/ dumps to atmosphere. i work as a diesel semi truck mechanic and they dont use them. boost at idle is not necessarily ideal per se but not the end of the world either. as long as your EGT's are stable, cylinder pressure is in safe range, and you have enough fuel its not a problem. Diesels LOVE extra oxygen.
I got the feeling he wants to bleed off an excess of boost, not to blow off spikes or whatever it is called.
My BMW m57 makes a few psi of boost at idle it's not an issue imho, arguably it's desirable as your Increasing the compression ratio and giving more oxygen to boot. Will make for better emission at idle.
I would say his ultimate fear is blowing a head gasket. Which would be anyone's concern with too much boost.
The only thing that can happen is if you really crank the boost is you end up too lean at idle and have a misfire. That's at the edge of what can happen but it is possible.
Timothybayliss6680, please refresh your knowledge on diesels. They can safely run very lean. 80:1 is ok for an air:fuel ratio.
Don't fear the boost. I'd leave the pullies alone but only make fuel adjustments from this point forward to achieve whatever results you're after. But I am just a random guy from the Internet.
If I'm thinking right, won't the boost be dependent mainly on RPM and not load for the s/c? So, the max boost could be checked revving while stationary, and it should actually drop some under load at the same RPM due to increased volume consumed by engine? All that to say that I think the boost will actually drop under load vs while parked, unlike a turbo, but I could be wrong.
@@smokesandalloy9487 for the most part you're correct. This supercharger is positive displacement meaning it can only push X amount of CFM per rotor rotation, and an engine's cylinder can consume only Y amount of air per stroke. So once you're off idle with this diesel, boost should remain the same up to redline, barring things like cam overlap or something of that nature that probably doesnt apply here. So the 10 or 11psi we saw when he revved it should be the same up to redline, regardless of engine load. Boost is a waste value, a measurement of the air the engine cannot consume.
@@bobirving6052 that makes sense, although I don't expect the dip to be drastic. Hopefully Jimbo will split screen boost to RPM and do a thorough pull though the rev range so we can see
@GTkyle
At peak torque, intake manifold pressure should be it’s lowest. The supercharger should increase output almost linearly, but the intake’s inertial mechanism will get the air into the cylinders more efficiently at the sweet spot where you get most torque.
Edit: I realized this theory is not true. The supercharger’s output can increase faster than the engine’s intake, depending on pulley size. So pressure could increase or decrease as rpm increases. There will just be a pressure drop around peak torque.
Boost could be a problem at higher rpms, one, for the afr, but more so two, for the skinny belt. You don't want that belt under too much tension.
my favorite part of the weekend! Thanks for the fun videos Jimbo!
Glad you enjoy it!
Install your intercooler. It will drop the boost a tiny bit and cool the charge, making it safer all around. Then SEND IT!
Agreed. I am sure it would be the "Banks Power" recommendation as well.
Its funny how being around the channel long enough makes unique statements sound normal "you may recall how I installed a stupidcharger on a twostoke leafblower motor and used it to power a.... "
I once had a side hole. Then my main hole found out. Didn't turn out well.
lol... :)
From my experience Kabota (well, most manufacturers of) diesels have sturdy block and head construction and I’d keep a close eye on the EGTs since heat will likely destroy the engine before cylinder pressure will. Oh and I guessed 5psi at idle but the was just a guess based off your comment after squeezing the charge pipe. No math, just lucky lol.
My understanding is egts and cylinder head temps are the point where when they get too hot they like to drop valve seats. But beyond that I've seen plenty of em with thousands of hours of abuse, I assume it would be fine for quite some time if pushed a little
I hope *Future Jimbo* sees this. You should be able to get rid of the *Flutter* in the boost gauge needle by adding a type of inline restriction. Basically slowing the boost down to the gauge. This "should" work. Cool project.
Also known as a gauge snubber, for easier researching
Yep, Optimal Welding did this when he turbo’d his welder and it fixed it
@@davismccoy77when he turbo'ed his what?
I had success with a DIY dampener that was just a plug of loose cotton pulled from a Q tip and stuffed in the line behind the manual boost gauge.
@@somedude2492 A lot of electric welders are essentially standalone generators with live wires you handle. This is to avoid needing to put in a heavy duty fuse in the building it's in. He turboed the generator for the welder.
Send it! Blow-off valves are overrated.
Gasoline engines need it
@@juhomaki-petajano they don’t
@@MyLonewolf25 study some more and understand what is happening in blower gas engines...
@@MyLonewolf25 Without a blow off or recirculation valve a positive displacement blower builds pressure in the charge pipe before the throttle body which will heat soak the blower and intercooler if it has one.
source: my eaton m90 supercharged rx7
@@Mrshotshell heat soak?, pfff. 10psi is for rookies, and Jimbo is not a rookie.
The suspense. KILLING ME !!
DRIVE IT. Lol. pleESE.
I'm one of your less technical RUclips channel followers, so I'm going to have to give you the "Send it as is, YOLO!" response that you're probably not looking for.
But, seriously, it's time to embrace your inner Cleetus McFarland. Give it ALL the boost, if it blows, it blows!
Since he got another engine 😂
As much as I want him to Do it for Dale, ole Cleet has a budget to work with, that a lot of folks don't. A replacement d722 last I seen for a decent unit was at least a couple grand.
@@goosenotmaverick1156 Good point, it'd be different if we could donate/join a channel membership to support some crazier projects.
Believe it or not these Kubota diesels are a lot more expensive than a junk yard 5.3. Like many multiples we're talking.
For context I just found a new reman unit for sale in Texas for $4500.
Note to Present Jimbo, please buy Future Jimbo a cool beverage. Your tenacity, attention to detail and knowledge is superlative.
At last, the Mazda 626 Comprex has finally got a spiritual offspring ^^
Like the profile picture
@@kansasadventure1831 Thanks, it's the cover of Iron Butterfly's first LP "Heavy" released 4 months before In A Gadda Da Vida.
Simple fix for the boost meter. Put a restrictor with a hole of approx 2 mm in the hose. It evens out the pressure fluctuations.
I think your work is very impressive , heck i figured you were a mechanical engineer. i love these projects
that thing is already running so fast there appeared to be doppler distortion around the license plate. 10 psi & you're going into orbit.
Queen said it best-
"Pressure pushin' down on me
Pressin' down on you, no man ask for
Under pressure that brings a building down
Splits a family in two, puts people on streets
Mm-ba-ba-beh, mm-ba-ba-beh
Dee-day-da, ee-day-da
That's okay"
Send the pressure and don't worry about the family of parts getting split in two. it's OK.
Awesome work as usual. Thanks for the entertainment. The gauge is fluttering with the pulse of the supercharger lobes and the intake valves. Roots blowers by design have a high and low output as the lobes cover the suction and discharge during each displacement event, similar to a workshop air compressor. To even out the pulse, the only option is to install a large plenum. This will absorb the fluctuations, but it's really not going to make a world of difference.
These little kubota engines don't flow much air, so 10psi is showing you the restriction. If the engine had improved breathing, the pressure would drop. The other consideration is after adding an intercooler, the pressure will drop again once passed through the heat exchanger.
Man! These big budget shows always leave you on the edge of your seat wanting more! That’s how they keep you coming back! I was not expecting 6 psi at idle. But I also don’t know much about superchargers either.
Can’t wait for the test drive!
For the lost gauge fluctuations. You can rip the cotton off a cotton swab. Jam it in the line close to your gauge. Not block it but put a decent amount in. Helps with the flutter.
Is this a permafix or just a bodge job?
Jimbo, opposite to a gasser, excess air is not a problem for a diesel. Over fueling (rich) cooks the oil motor, under fueling (lean) cooks a gasser. Your extra boost at idle might increase NOX output (not enough carbon for the oxygen, so it bonds to nitrogen instead), but it wont damage the mill. Btw, i guessed 7 psi at idle, lol. I also saw your old "launch" vids showed "coal" at launch and first shift, so id say send her as she lies now, then worry about adding fuel if you need it. She may well surprise ya! Sweet mod job, just add a tin firewall between the blower and exhaust downpipe, just like a 22ga panel to reflect radiant heat (could even glue alum foil shiney side out on the pipe side for style points, lol)
I'd leave the boost as is. Maybe put an intake temp sensor in there to see if you need an intercooler. The gauge moving around was from the intake valves closing, BTW. Keep up the great work. This is fascinating. I used to work on these diesel generators all the time, in large light-alls. I always wondered what it would be like in a go cart or something.
As a keyboard warrior and expert in things not automotive engineering related, I say you send it! You have a spare engine and that's what spares are for, right?
My recommendation would be to try a 1:1 pulley ratio or even a slight underdrive. Also, maybe you can use that electric dump valve to vent boost at zero throttle using a normally closed switch that opens when the throttle is depressed.
The only bad thing about making boost at idle on a diesel is the heat generated. On a gas engine it would be generating even more boost in the charge pipe before the throttle body
@@Mrshotshell agreed. I'm just thinking about during times when the engines idling and it's putting needless stress on the supercharger it might be beneficial to allow the engine to just idle it atmospheric pressure and vent the Boost that the compressor is making.
The engine is a big restriction to the supercharger and why the boost is so high at idle
The Subaru engine even if it's 660cc like the Kubota engine make 3x as much power so it way more efficient and less restrictions on the supercharger
if the supercharger make 1000cc every rotation and the engine need 500cc the engine would be in boost vs a engine that need 2000cc of air would be in vacuum at idle
With a 1:1 pulley you can see the second example would never make boost if the engine need 2000cc per rev and the supercharger give 1000cc per rev plus volumetric efficiency vary with rpm/engine design
Root type supercharger are constant displacement and rated by how many liter per rev they displace
Boost is complicated lol
Lol. 6 psi at idle. The little engine has so little flow. Diesels are great for playing with boost. They just perform better without any tuning when boost is added.
Excellent video!!! Can't wait for the final results on this once everything is sorted.🆒😎💪!
Hi Robot. I should have said that long ago:
I had this silly challenge when I was younger of making as much distance as possible with a stock old 206 peugeot with a 1.4l HDI motor. I did 1300km with 45liters of fuel.
For conversion that's like 68 mpg, the car already had 125 000km on it at the time (or 77 700 miles) the tires were over inflated and it was a company car so no backseat. The car was from 2003 maybe
I was a bit reckless at times to brake as little as possible and accelerating slowly.
I got 1200 km's from the south of France to Luxembourg (where fuel is cheap ;)), with the same car model and engine. We took the all toll-free road, so a lot of 80 km/h driving with a hot engine, which turned out to be very efficient. No modifications to the car were needed.
This, as a fuel consumption number aficionado, is the kind of story I like to hear. Well done.
Most small-ish diesel cars can get about 3.5l/100km when driven at their most economical speed on favorable roads.
I have never owned such a small diesel car to be involved in pushing for great numbers, though I have driven my larger cars quite a bit under their "extra-urban" EU fuel rating.
my 1.4L D-4d toyota gets approx 72mpg so 68 on a 1.6L is solid
I have no idea what you should do. Jimbo, but I can tell you that you are my hero.
Really enjoy the series
Twincharge ?
If you could engineer a suitable leak you would reduce boost pressure, just not sure if you can engineer a precise enough and consistent leak. Maybe just add pinholes until you get the desired boost.
Jim- I think a useful metric for this process would be a thermocouple placed after the charger. You get a really effective cooling and atomization effect from the gasoline on the carburetor application, but superchargers make a ton of heat themselves, even before the heat gain from compression. With no evaporative cooling on the diesel, I'd theorize you're getting a decent amount of boost only from expansion, but the actual density of the charge is far from that of ambient air at ambient temperatures.
I think you're seeing at least 60 degrees of temp rise between ambient and after the charger, so that shoud account for roughly 2psig by itself. Venting would disproportionately reduce your efficency, as you're still paying the price to compress and heat the air, to then dump it overboard.
Solutions may include an aftercooler, water meth, and reducing the drive speed of the charger to better match the air requirements of the engine.
I recommend caution going above 10psi on this, as factory turbo kubotas dont run much more pressure than that sustained, and those are built for it.
So, how are you going to get that 10psig to be as cold and dense as possible?
more power, you need to get boost at idol to at least 20PSI 🤘🤣
I'm really curious on the next step of the DIY brake booster system. If it works, I'm going to copy it for my project.
We made a second video on the DIY brake booster system and we eliminated the chatter with a programmable delay relay. After shooting that video we found a compact programmable delay relay that completely simplifies the whole system. we will do another update soon.
What most people don't understand is that boost is a measure of restriction. If you have a turbo or supercharger that is producing 8 lbs of boost, then you change the heads, intake, or anything else in the system, your boost will likely not be the same after, because you are changing the amount of air in/out in some way. If your boost drops, that is because it is better flowing, and you can then change your pulley to increase it back up to your previous amount, basically increasing the overall power at the "same" boost level
Jimbo, I am sure, will heed your comment - its looking at the issue from another perpective and that usually produces a deeper understanding and better solutions.
Your boost can also drop simply by adding an intercooler which will reduce the air pressure while increasing the manifold air density and power. The restriction isn't the only factor in that number. Banks goes on and on about manifold air density, and it makes a lot of sense.
@@Sevalecan Obviously, there are other factors than *just* restriction, but it is the largest one. I was keeping it simple. There are engine builders on RUclips you can learn more about it from them. Steve Morris or Pete Harrell for example have some good videos on it, that cover quite a bit about turbo & supercharger builds
Exaxctly! Up to a limit, and that's usually the mass flow limit of the compressor, no matter if it's a supercharger or a turbocharger. On a crappy flowing 2.0L engine, one compressor may produce 1 bar of boost and not heat up, while on another 2.0 properly flowing engine, it may barely produce 0.5 bar of boost and heat up.
10:19- YES! THANK YOU!! My 4 year old and I giggle at it
You've got a spare motor, send it!
Don't worry about excessive boost. Just keep your fuel on the level you want to and extra air will give you less smoke.
Aside from afr, he needs to make sure the skinny belt doesn't get under too much tension.
Sunday morning is now complete. The experiments are the best part, I am not addicted to Robot Cantina at all....☕️. Now that I have watched another great episode, I can head out to the shop and work on my project. Great work. Waiting (patiently) for the test drive.
I'm making this comment about 4 minutes in, so sorry if you cover it later in the video. This is how I equate it. The old saying "there is no replacement for displacement" still stands true in a sense. This is because by bosting engines, we are in effect increasing the amount of air and fuel that engine can displace into an engine on every intake stroke. The more fuel air/fuel we can et in, the more power we can get out. Turbocharging and supercharging are using devices that allow us to squeeze more bang into every revolution. Turbocharging and supercharging are how we increase the fuel displacement of an engine. What this has done to my thinking is changed how I calculate engines in my mind. A naturally aspirated engine us under the force of ambient barometric pressure, which is 14.7psi. 14.7psi 1 1 bar, or 1 atmosphere. If you have 21 atmospheres, you have double the volume of air in the same space. Metric makes so much more sense in this case. When you put 14.7psi of boost to an engine, you have the 14.7psi (1 atmosphere) from ambient pressure, and another one from the boost. You are doubling the volume of the air, and when air/fuel ratios are correct, you have double the air/fuel mixture. You are in in effect turning a 731cc diesel engine into a 1462cc engine that weighs less than a typical 1462cc engine. 14.7psi of with no adjustment for intake and exhaust restrictions, is doubling the power that can be generated from that air/fuel mixture charge. The difference is, you don't have the additional rotating mass and other factors that rob power in an engine that has a physical cylinder displacement of 1462cc. Boost makes engines have a higher displacement, but don't have a heavier engine mass that they have to rotate, and they don't have to carry that extra weight. With that, boosting an engine can be more efficient at generating power. You can calculate if it's more efficient by calculating the fuel consumption against the horsepower, and comparing the result of the naturally aspirated engine against the result of the boosted engine.
I find this way of looking at engines helps me wrap my head around the expected torque and horsepower values. It makes more sense in my mind, I hope it maybe helps some other people visualize it too.
Banks "lockjaw" build is a Whipple supercharged duramax so it's a bit similar. They had to run a bypass valve for idle because it was building up way too much heat. Any time you have pressure in the intake work is being done to compress the air and adding heat.
Wouldn't an intercooler fix a bunch of that?
@@kd5inm The intercooler would cool the intake charge going into the engine, but it wouldn't stop the supercharger from overheating.
In fact the added restriction woukd exacerbate the problem at idle/low load.
He could try water injection pre-supercharger.
But, he would be better off reducing the output of the supercharger.
Or bypassing excess air to keep the supercharger from overheating due to the excess pressure/restriction at idle.
It’s probably not a problem. He’s been having trouble building enough heat to get the engine up to operating temperature.
@@jjsledneck Sure the water temperature, but the temperature of the supercharger itself may become a problem, especially if it continues to make more boost (due to the lack of flow) through the rev range.
Without a Compressor Map we dont know how far outside its efficiency range it would be.
It might see 15+ psi at higher rpm without making changes.
Next step is to test drive as is and then do an intercooler. No need to turn boost down. Motor can handle it. Absolute worse case is you nip the head gasket but honestly if was me I’d absolutely test drive it. I build Harley motors daily so diesels are not my wheel house but I still understand enough about engines to know you have very little risk here. A head gasket is a small price. If you do nip a head gasket just know one thing do not try to start the engine after you shut it off or high risk of bending a connecting rod. Other then that. Watch your EGTS and let er eat
Hip hip hooray for Robot cantina!! thank you sir
Do they make high volume whoopee cushions that actuate at a calibrated 15psi? That could be a good way of venting excess boost.
Maybe back-bending a single-v belt is worse for it than a poly-v belt, but I've worked on everything from Pontiacs to elliptical machines that regularly have very tight bends on poly-v belts and it never seems to do them a lick of harm. As long as you're not loading the alternator so much it slips I expect the belt will hold up well enough for your purposes.
Poly Vs don't mind it at all, it's just single V belts that prefer not to be bent backwards. Even then you can get V belts that are designed to handle it, in fact they even make double sided ones that fit V-pulleys on both sides.
As a big horsepower overcompensating track rat… God I just LOVE everything this channel stands for.
With the drive belt I would look to see if there was one in the same size for running lawnmower blades. Those are v-belts and they run on the back side of the idler. The idler pulley does also have flanges to keep from throwing the belt off.
If you still have the stock intake of the supercharger they are crap... hella restrictive, i don't know if it will really change something at your power level but yeah just let you know it!
For reference we made 140hp on 1.3L micra here with this supercharger, not a lot but yeah it can pump
My Sunday is great, thanks Jimbo!
That's boost baby 👍💪✌
My favorite episodes are adding the boost. Here we go. Great job, as always. 😎👍🏼
What about an external waste gate? My thinking here is you can dump the excess boost at idle to atmosphere and have it controlled by a Arduino using a pressure sender, RPM and solenoid using vacuum from the vacuum pump? If you wanted to be really fly you could even throw a throttle position sensor in the mix!
I was thinking the electronic "roboot" throttle body from the saturn project. Use the throttle body to bypass the supercharger. Could be simple on/off based on throttle position, or fancy with a feedback loop and controlling boost.
Your idler pulley design is the same as an R53 mini cooper S and that belt lasts me 5 years so you’ll be fine.
Thats a serpentine belt. The idler pulley might be the same, the belt isn't.
Serpentine belts have no issue bending backwards
Ah the Cooper S. I shudder everytime I hear it 😂 Oop, she heard me, now she is crying for her 5th high pressure pump 😂
Toyota previas use a clutch on their supercharger. Perhaps you can find a beefy ac compressor clutch and Have it hooked up to a relay normally off at idle position.
good thinking but you cant use gasoline thinking on diesel engines, sadly
I would't worry about the blow off valve unless you are trying to get all the mpgs. Props for acually describing the role of the blower in gm two cycle diesels (51,53,71,92,110[some of them],149,567,645)
The belt shouldn't be an issue, Dodge put a v belt with a similar idler on a 1976-1978 Plymouth Volare/Dodge Aspen Slant 6 AC system. So I converted my friend's slant 6 with a similar AC setup I made myself. To be fair, Chrysler DID change it by the time the car was done with in 1980.
With a 1:1 ratio you'd have about 5.1 lb of boost with that setup (at speed). Expect around 3lb at low speed due to the additional parasitic blowby.
Back-calculating I'd say you are currently running a 1:1.25 overdrive ratio.
Needle bouncing is expected since the plenum chamber volume is quite low in your setup.
Did a lot of these calculations when I put an Eaton M45 on my 800cc Suzuki, also ethanol efi. Let me know if you want numbers done. 👍
Wow that's way more boost than I expected too. Don't think it would hurt anything as diesels like to run lean. It would sure help keep the EGT's and soot down at the same time. All-in-all, I think it would work out fine. Hopefully, you can sneak the intercooler in somehow. Can't wait to see how she'll run. Nice work Jimbo!! 💪🔥
From what I've seen, tubing is a better choice than hose for your application.
I watch your channel on a homemade cash register t-71 thinkcentre with a 4th gen I7 (instead of a 'energy saver' I3) and 16GB of ram instead of 4. I use Ubuntu Linux 23.10, and love it.
#ComputerNerdsUnite
They make variable speed pullys, in the $120 range. Not cheap, but one might be useful for dialing in the right size and for the supercharger.
Jimbo.. You need to put some safety tethers on that charger. When it blows off the side of the block. Like a top fuel dragster. 🤣🤣
But seriously. Your pully size, looks about right. The boost will be fairly flat through the rev range. Superchargers do not tend to spike like turbos.
Very tight packaging, great work!
You have an interesting situation, two positive displacement devices, engine and blower, butting heads. The manifold pressure is only function of rpm, independent of the load. That is, it will be increasing proportional with rpm no risk of runaway boost. Pressure will likely drop with the addition of an intercooler. For now I would install an EGT sensor and boost gauge and do some testing
If it's a concern... I'd swap the pulley on the supercharger for something a little larger... But as long as blower rpm is in the safe limits for the unit, I wouldn't worry about it. As you said.. diesels are controlled by fuel.. not air. Can't have too much air... Only too little. Cylinder pressure is created by fuel and timing. The little bit of pressure added to the cylinder by the supercharger won't hurt anything... even at idle.
I think a mini CVT drive for the stupidcharger so that it boosts low at idle but also can do 45psi at top speed. Variable drive ratios fix everything, and that belt isn't abused enough yet.
Banks Power has a series of videos that goes into great depth how supercharging a 4 stroke diesel works. Like SUPER depth like measuring combustion chamber pressure and in/out heat etc. It can work great, but you will want good intercooling.
Actually, I wouldn’t worry too much about that idler that you added . Back idlers are commonly used on several automotive applications and have been for years so it’s nothing new and shouldn’t hurt the belt providing the Bell tension is tolerable.
I'd say to install a clutch on amr500 and any mechanism to engage it at X rpms.... Cheers from Brazil
let'er rip the way she is! Extra air doesn't hurt a diesel engine. It puts a slightly higher load on the internal engine components when under no load, but that's still vastly less than what the components see when the engine is loaded.
Just monitor the boost during your test run - if it gets out of control let off the throttle.
There isn't much of an advantage to dumping the boost to atmosphere under low engine load conditions other than fuel economy. But you can totally get fancy with an electric butterfly dump valve, and use an arduino to close that only when above x% throttle or something
Perhaps some sort of one way valve to even out the pressure at idle, and as the throttle increases, the valve will close as it builds pressure? That's the only thing I can think of as a mechanical solution. I am no expert or keyboard mechanic either.
You could be the Tesla Gastown in a bad pandemic.. love these videos. Just because it has enough engineering and not too much. Not that I can’t understand too much but I like to relax when I watch the Internet.
Diesel does not care that you’re putting in extra air. It won’t make any extra power until you add fuel. It’s possible that the leaner condition will increase efficiency. I would say test drive it and keep an eye on it.
FULL SEND
Here's a dumb idea (but I love it): install the second engine in the boot just to run the supercharger (which feeds the front engine)
Serpentine belts often bend backwards. Whoever said that it would be damaged was trippin.
Run it, the engine will only except air in or boost as vavles open. Us your dump valve on deceleration to keep from popping hoses.
Re: Future grade 8 bolt on your supercharger mount. A grade 8 is hard, but can be brittle, like glass. A softer bolt will deform but hang together. Test? Put a 1/4"-20 grade 8 in a vise and smack it from the side with a hammer. If you do the same with a grade 5, you can probably bend it 90 degrees and it will stay together. Good luck and let me know what happens if you try the test. I always enjoy your videos.
Really bad suggestions
Lol use cheese rated bolt lol
Ps don't do it
There's places where manufacturers spec grade 5 bolts over grade 8 for that reason.
Really for what it's being used for it's not going to matter but in places like a suspension you don't want to replace grade 5 with grade 8 unless you know what you are doing.
The same is true for the metric equivalents.
@@edwardscott3262 lol there no suspension that use grade 5 bolt hell you won't find a single grade 5 bolt on a car
Higher bolt grade doesn't mean more brittle that just stupid but the opposite is true a low grades bolt will shear easily vs a higher graded one than will bend
We use grade 5 bolt as safety bolt on street diesel snowblower
To op a grade 8 bolt wil bend no problem it not a drill bit
And we not talking critical bolt like a conrod bolt or head stud
You all got no clue what grade mean
A grade 5 bolt is maybe good for 80k psi grade 8 is rated 120kpsi
ARP2000 headstud are rated at 220kpsi L19 at 260kpsi (L19 can be subject to hydrogen embrittlement This material is easily contaminated by sweat and could cause failure if not handled with glove or covered in oil before handling but that beyond this conversation)
When the bolt clamping force taper off(bolt stretch) at the elastic deformation(regain is original form) when plastic deformation(permanent deformation) occurs the clamping force decrease until failure point
99% of the time a bolt will break at the last engaged thread where the plastic deformation occurs at the weakest spot on the bolt(less material)
How could you calculate the boost? Boost is just a measurement of the restriction point of the engine. You could take some educated guesses but hard to be right
Absolutely love your videos. Watching them makes my day
You are so kind
Have a look at the Sporlan/Parker stepper motor regulator. "Electric Regulator Valve - CDS Series" You can get one and a control board that will take 4-20 mA for a control signal and a motor that will run on 12V. These are used in refrigeration. With one of these and you're control skills you can do whatever you want with the boost. There are mechanical options in the refrigeration world but they don't offer the easy to change capabilities electronics offer.
Thanks for another great video Jimbo! Don't mind any critics you're doing great. Personally I'd say take it for a drive. As long as your egt stays low it should be fine.
You can get kevlar belts for snowblowers. They grip better, strech less and last longer :)
Not that much more expensive either
I can't believe it's time!!!!! I have waited to see this for ages!!!!!
How about using a throttle by wire throttle body and gas pedal but flip flop the position sensor out put so when not pressed it's wide open and as the pedal is pressed it closes to build full boost.
Over boost is far safer than over fuel on a diesel. I wouldn't worry about 6 psi at idle.
Howdy Jimbo! I ain't an expert on this particular engine, but if you wanted the belt to have more contact with the alternator pulley, how about adding another idler pulley at the bolt where the turn buckles are?
Hey Jimbo. The boost needle jumps with the pulsing of the supercharge/ intake opening and closing.. you can choke it with a little valve they use for fish tank bubblers and adjust it till it's relatively stable😊
I'll never get tired of STUPID CHARGER
As Men at Work might have said, you may be an idiot but indeed you are no fool.
8 to 10 PSI ~ 2/3rd atmosphere.
1 -----> 1.66 atm.
Not sure why people insist on pointing out stuff they THINK is wrong when it takes a two second google search to see that in reality they are the ones that are wrong. It’s totally fine to use a tensioner on a v belt to have the belt bend backwards some. It’s been implemented on many designs in the past.
I don't see anyone suggesting a adjustable waste gate,I guessed 5 psi🤗😎🤗😎
Jimbo, never boosted an N/A diesel this small but even the smaller Turbo models can handle 20psi no problem. Bigger issue is going to be you have the wrong pistons for boost or constant boost. I wouldn't change anything myself @jake20479 is correct. Watch your EGT like a hawk. Also in the summer if you don't have the intercooler in you will need to watch intake air heat. Boost generally doesn't kill diesels it's cylinder pressure and heat. Diesel generally don't need wastegates or blow off valves. Might save you some headaches seeing how it all works and also so you don't limit out your pump and injectors, but it's not really needed.
U make my weekend better
so glad this channel exists, this is the kinda stuff id like to be goofing around with if i had the means
A lot of older cars and trucks that used v-belts and had a bunch of accessories that need belt drive often had two pulleys on one or more of those accessories. That way you had one belt with good engagement on the crank and one drive pulley, then another belt drives another accessory off of the first one, ensuring positive belt engagement for all drive pulleys, and no need for idlers pushing the v-belts in the wrong direction. As for the boost at idle, I don't know if a blow off is really necessary being that it's a diesel, but it may be possible to electronically actuate one using something simple like a switch on the gas pedal.
A blow off would be more to protect the supercharged than the engine lot of heat at idle making that much boost
The engine seem to be a big restriction for the supercharged and the reason the boost is so high at idle
More restrictions equal more boost at the same air volume
The original Subaru engine may be the same 660cc size but is clearly way more efficient/less restrictive
And make 3x as much as this 20 HP engine
3:59 I got my self a 4.236 Perkins in my fishing boat, and thinking about given the ol' girl some boostyness.
It only makes 60 odd HP but a 100 would be nice 😅
And I find that this is actually very helpful upon my quest of a tad bit more power
6psi on idle, thats HUGE
definetely need lower ratio, something like 1.2-1.4 maybe? i always thought that if SC pumping 500cc/rev, then for 700cc it would require more then 1:2 ratio to make any boost, but i guess i am wrong
It is a four-stroke engine so it displaces 700cc every TWO revolutions.
The intake side of the supercharger will be your constant vacuum source
too much boost at idle should be close to 0 , the boost gauge is shaking like that because is a cheap one and will be very noise , u need to put a restriction in the vacuum house to make it stop , good luck
I gotta ask, I have the same diesel engine in my UTV project, and I cant find the oil pan gasket anywhere! Checked online and called all my local Kubota dealers(boy are they a sorry sort around here). Any thoughts? It needs to be replaced due to a nasty leak(the "automatic oil change" kind). I am considering using RTV, but I am worried even if it seals it will alter the clearance in a negative way or not last very long at all.
I found one online in the UK, but the shipping for a $10 gasket is $35 to get it over here. If thats my only option Ill do it, but I imagine there has to be a more local source.
Anyones input is appreciated! :)
As I recall, we got the oil pan gasket on ebay or Amazon Amazon actually sells a lot of parts for the Kubota D722 engine
Keep it around 14.5 psi for the stock block. Then pull the crank bearings after a few test drives. Soft and hard driving.
Check the clearances, and then check the head for any damage. If it’s all still within spec, add some slightly bigger injectors. 100-150cc larger, and keep the boost at the same level.
Fuel is a great way to keep the engine cool under boost.
Spark ignition runs cooler when it's richer, the opposite is true for diesels.