3D Printed Velocity stacks - Dyno tested - Round 2
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- Опубликовано: 10 ноя 2023
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Test engine spec:
Modified smallport head w/ oversized valves
kelford beehive valve springs
shimless buckets
oversize toda pistons (1627cc)
bc rods
approx 12.5:1 compression
arp hardware throughout
toda oil pump gears
toda 3.7kg flywheel
52mm itb's
Garage4age Header and 3" exhaust
Link g4 ecu
Kelford 300 deg camshafts + VVTi 
Авто/Мото
If you haven't seen the first round here it is : ruclips.net/video/G8L9_XO3iCw/видео.html different engine so cant compare to the numbers here
It’s spelt stax not stack
@@garage4k989 hika bro
Maybe try a 3d printed design with a Sharrow Propeller inspired design this is really trending at the moment hahah
Or maybe a double stacked design with Sharrow Propeller on the external or maybe on the internal or maybe try both hahah
@@mitchellpaterson7062 What for? There is a wonderful article by professor, motorcyclist Gordon Blair, “The Best Bell.” In the article, Blair compares round, aerodynamic and elliptical bells. A bell with an elliptical profile gives a mass air flow rate of 17% more than a conventional pipe.
Usually we see intakes that point up, but in some ocasions there are some that are plenum down like on SR20det, does this curve alters power in any means? only one way to find out
I can't believe you're basically doing the Fan Showdown with ITB runners on a dyno. Amazing stuff.
ah a fellow fan fan
@@TheUltimateRanger89lol
Hi fellow fan fan
@@Draecko 🪭🤝🪭
It’s amazing, isn’t it.
I wrote a wikipedia page on Velocity stacks. Read that and you'll know the results of this without doing all the work(although it has been vandalized by a velocity stack manufacturer). There is almost nothing to be had from velocity stacks beyond the length, diameter and some kind of radius.
Golf ball dimples are widely misunderstood. They work PARTIALLY on a golf ball under golf conditions. They can be of use on some aircraft wings under certain conditions but they do NOT increase flow what so ever. In fact they can only reduce flow but they alter the downstream conditions that MIGHT be advantageous in SOME situations, like a golf ball in full flight. They are only effective over a small range of speeds even on golf balls(roughly 125mph-250mph) which happens to coincide with the speed of a drive. Above and below that speed range dimples cause MORE drag.
Hey thanks for making these dyno comparison videos. Your hard work is much appreciated by many people!
Try a flat plate in front of the trumpets that you can adjust closer and further away and see what happens if you reflect some of the wave energy back down the trumpets it used to work great on twin sidedrafts
Conical satelites with the focus point inside the trumpet.
I'd be surprised if that reflected anything back down the trumpet. I'd guess that it would behave like a marginally longer tube...
Really interesting to see the Golf Ball and Dimples. Was surprised at how the golfball was more even between 3500RPM and 5500RPM than the others. Thanks for another great video.
They were a little shorter than the rest. which is most likely the reason for the change in the curve
@@Garage4age right I compared side by side, on the Dyno for a motorcycle, the exact same size, dimensions, etc. velocity stack that had dimples and one without. They performed identical. Well, actually the smooth performed approx. 0.5 better in hp and torque, but I chalk that up to the usual deviation from run to run. I only did two pulls each, comparing the two back to back (4 pulls total)
@@boxcrashmfg9420 yeah that looks to be the same as what happened here. when you compare the red to black. which are the same but red is dimpled. the blue ones where the shorter ones, and different shape to the others so cant really be directly compared. just testing what i've been sent
Dimples create vortices that reduce the boundary layer and keep the airflow attached longer.
On a surface where the flow cannot detach no matter what you do, like an inlet trumpet, dimples are pointless and merely add flow resistance that goes up exponentially with velocity, as the high rpm numbers show nicely.
Great stuff 👍🏻
I wish for a compairson between 4-1 and 4-2-1 header, in best case different diameter and lengh 😁
Yeah Id like to see how much you can move the engines peak torque rpm up or down between a short 4-1 and a very long 4-1 or 4-2-1 manifold. Maybe even try an EXUP valve from a Yamaha FZR/R1?
@@stevenbusk539 about 14" shorter intake tract on my 2.0 Alfa Romeo JTS moved the torque band about 1000 rpm higher and also peak power.
@@projector7141Where does it peak now?
'Compairson' ??? 'Lengh' ???
7600-7700 rpm @@Callagwhan
Another superb video from you, congrats. That engine won the heaven!!!!! That sound .......
Wow, great stuff as usual man. Well done!
Cool to see the dimple and golfball actually smooth out the curve
I like how your runners were the best. Keep up with the awesome work 👍🇭🇲
New wheels on the testcar! Nice job, thanks for sharing! Please try to place some solid full size vertical dividers between the horns. As CFD suggests the cylinders will not interfere.
Respect for taking the effort of fabrication & testing. the science stuff. Cheers
You have no clue how much I LOVE this channel
I love the craziness and variation of the designs. Working or not it's nice to see what people create. The stupid Golfball texture, i've seen many ITBs on sale with that.
That was very interesting! Thanks for do this!
Well good to see the expected dimple doing nothing for performance… and shutting some people up. Keep it up 👍 another good session of dyno talk
It was worse than stock!! 🤣☠
Your eyes not work bro? The gains were all there for everybody to see
@@garage4k989 What gains? I see a barely perceptible change, with (if anything) a loss of top end power.
Probably above your pay grade mate
@@garage4k989 you just being silly now…
This is actually the coolest channel on youtube. Project Farm and Torque Test Channel have nothing on the testing you do!
The sound changes are crazy!
Great video thanks for testing all those.
This is pretty cool. Alot of work to find out different designs have such little different.
Vraiment intéressant toutes ces courbes et tests. Merci.
Very interesting results!
Dimples only work on round balls to reduce drag on the tail end.Double work to make a stronger vacuum for more fuel intake .I found the Velocity stack design worked on the air intake of my 10kg thrust Pulse Jet engine.Its holds the strength of shock waves & still guides the air in as smooth as possible
Thanks for your job!
Awesome video. Great work. Original is best in the end.
Good video broski!
Increase I.d. as close to the head as you can. Simulate an engine dyno air hat in shape. Keep the trumpet entrance but keep a devider between each port. And last, give the entire port run a slight turn up from the short side of the intake port. 13" rule from valve to opening. This will give you the greatest overall power. A shorter runner will favor peak redline, while an 18" will favor the bottom 50%.
The hissing sound at the top end is a tell tale sign the port is hitting exstream velocity. The air needs more room.
Wow! This is kinda research! Well done!
Thanks !! great video!!
love your vids
Sounded like the double stack was noticeably raspier than the others. I liked that one.
Great video with the best symphony 💪 👌 wouldn't mind a set to suit my 45s on my 1700 Ford Xflow one day 💪 cheers for your efforts
Man go buy that car a drink after a day on the treadmill like that. Really cool video!
after watching a lot of your videos, i think its safe to say your intake is not a limiting factor in your engines performance. but fun to watch n learn nonetheless.
Love watching these and the side by side comparisons! Would really appreciate seeing a comparison of different filtration options for standard or typical velocity stacks and the impact on hp... single/individual foam socks, dual socks, large single foam filter with a backing plate, gauze dual filters, velocity stack "screens" or covers... that would be very helpful! People make all kinds of claims, but nothing beats objective third party data!
For now i can say the big single filter this engine usually runs has no measurable effect on power, Pretty sure i have a video where i tested it. have personally seen individual socks loose a lot of power on dyno. avoid
totally agree socks kill power@@Garage4age
@@Garage4age thanks for the quick response and info! I currently use foam filters that fit over the two stacks on each TB (Jenvey Heritage EFI TBs that mimic Weber sidedrafts on a 7000rpm Datsun Roadster U20). They do touch the sides of the stack on the outside edges but for the most part are "free" with plenty of room in front. They are very convenient but if they are significantly restrictive then I would likely switch to a "Piper Cross" or "ITG" type set up. Some claim foam is restrictive, others say anything touching the edges of the stack interferes and that things like stack screens are horrible, and other filters are only effective if they are lightly oiled but then become very restrictive... I have not yet found a great, objective side by side test like what you do... I really appreciate whatever info you have or future testing you do!
The crack it makes as it crosses over sounds fantastic
Cool stuff. Thanks
Great video!
It would have been interesting to see what happens with none.
There is another detail, at least 2 of the intakes are very close to the suspension support panel, so I think that avoiding that somehow (curved pipes in-between) could change the result of this test.
I also think that having a collector would benefit more from the usage of those technics, because the air intake flow would have a better continuity since four cylinders instead of a single one would contribute to the air suction in the same period of time.
I've got one for you. Ok well, you're gonna need a length of stack that would allow you to turn them up away from the shock tower. But I've always wanted to see if we could adjust the frequency of a large woofer 280-300-350 Hertz, something like that for this engine and see if it either disrupts or enhances power at a resonant frequency. Point it right at the stacks. you've gotta try it!
I’m not going to try it
That's very cool...
Great video. I'd like to see a test of barrel valve throttles against your current setup. I could imagine better fuel atomization and higher airspeed at part throttle and a slight increase in maximum airflow at full throttle. Keep the good work up 🎉
I am probably really late to the party here, but I have an idea that should (in theory, at least) work.
Use a Y pipe (one straight leg with the branch pipe coming off at an angle) oriented with the Y branch coming upward and outward (towards the strut tower in your case). The inlet trumpets will be affixed to the Y branch. The end of the straight pipe closest to the engine will attach like the trumpet would normally, the trumpet goes on the Y branch, and the other end is where things get interesting.
As the intake valve closes and the pressure wave is formed and "bounces" off the back of the closed intake valve, it would normally travel back up the runner, out of the trumpet, and "bounce" off of the atmosphere- with each time it does this, it loses some pressure (1st, 2nd, and 3rd harmonics)- for two reasons, 1) the atmosphere is not very bouncy, and 2) that's how physics works in this galaxy.
We can alleviate one of those issues to some extent by taking advantage of the 1st law of motion ( An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a STRAIGHT LINE unless acted on by an unbalanced force)- the pressure wave which normally travels out to atmosphere will want to travel in a straight line. It will then be directed to the capped end where it should retain more of its initial velocity when it bounces off (think throwing a bouncy ball at a concrete floor vs throwing it at a pillow).
In theory this should work, and all it would require to test is 4 of something like this:www.amazon.com/POWERTEC-70228-Y-Fitting-Clear-Color/dp/B07NC6KBQT/ref=pd_lpo_sccl_1/137-6445067-9242329?pd_rd_w=LuuTk&content-id=amzn1.sym.1ad2066f-97d2-4731-9356-36b3edf1ae04&pf_rd_p=1ad2066f-97d2-4731-9356-36b3edf1ae04&pf_rd_r=26BGB0CW7AYEN2VBW244&pd_rd_wg=LW6Yk&pd_rd_r=d0952c71-7d9b-466f-9995-47ff50cc67d3&pd_rd_i=B07NC6KBQT&psc=1
or PVC plumbing
Well firstly your setup is unbelievably well sorted.
Secondly, I really love that you're product testing for people. It is great to see.
I must admit I was surprised the tapered dimple was worse than just the plain taper but you'd never know unless some real world testing confirmed it. Even a homemade flow bench might show the dimples performing better but there's nothing like the real world. I wonder if there's gains in throttle response with the dimples that can't be picked up on the dyno? Great idea dimpling the intake even if it doesn't work but perhaps it needs more or less cross sectional area to realize the benefits. Those dimples have really sparked my curiosity.
Dimples have already been beaten to death in the cylinder head community, and flow benches all consistently reflect poorer airflow with a dimpled surface. What works on a ball doesn't necessarily work on a tube. The ONLY reason to dimple is that it takes considerably more time and you can charge the customer a WHOLE LOT more.
the dimples create a thicker boundary layer effectively reducing the cross sectional area of the trumpet, meaning it can't move as much air through it.
@@seanb250 And this effect is good on a golf ball, because the turbulent boundary layer is more resistant to separation resulting in less drag. But it is not applicable to an intake
@@dannyb9083 correct, the dimple in ports thing has been beaten to death and disproven as a performance gain for a long time, but every 6 months or so it pops up again as some new discovery 😂
Just curious, but what is the rough thermal efficiency of this engine if you have any idea? Has all these mods translated into efficiency gains as well?
Wonderful as usual... Continuously variable is the trick... motor controlled... You might shorten them at certain higher revs just to flatten the torque due to the resonances. keep up the amazing work. You are literally killing many people's suppositions with real data.
I made some variable stacks on my motorcycle. Check out the video on my channel. They're not continuously variable, but two step. Determined it needs to move at 9k. Still working on the electronics to have them move at exact rpm.
@@gogocro1 We use an emtron to control all of that on our 24V S38 motor.. Kinsler also makes a high torque radial motor.. But for simplicity the linear motor or motors work best. ruclips.net/video/YZhSgwYs08k/видео.html
Keep up the great work!
No you didnt
Great content. Hopefully someone can one day make a comparison between a metal intake manifold with and without velocity stacks.
Спасибо за твой труд.Удачи и добра.
This is what i would like to see tested; a custom manifold with long thin tubes that goes all the way into intake port to one side of the valve stem, hopefully creating swirl. Then at a higher rpm, 4 throttle bodies, close to ports, open a larger passage from manifold to port.
Muchas gracias. Sin entender una palabra de tu idioma gracias x los gráficos , Esos gracias me lo Explican todo en un idioma universal. muy buen video y q BUENO el Toyota tremendo motor. Desde argentina un Saludo enorme 🇦🇷👍
I love this channel! 👍👍👍💪💪💪🖤🖤🖤
Such a cool experiment and well made video thanks. Wounder if you made a good radius bellmouth but with extra large flat 'flange' surface for moving air to creat low pressure over. Obviously witj a large flat area they would merge but still shouls be possible to print
The taper seems to have more flow right at the top. I wonder if the taper was slightly narrower bore (so faster air speed), what the midrange would do.
Great job and thanks again for your hard work in making a pretty cool vid. Others have mentioned a couple of interesting things.
1. Dave walker done an article 25yrs ago on roller barrel itb’s vs normal butterfly itb’s. I’d like to see that revisited but costly exercise. Lol.
2. Does stand off injectors affect the intake runner length and shape?
Few vids back I tested stand off injection. It looked as tho it effectively made the runner longer
I think the length and diameter are really what's going to effect the way the air bounces back into the cylinder. An interconnected series of intake runners would be interesting.
*affect
you're talking about fuel stand off?
I think you need to go online and read Professor Gordon Blair's article "The Best Bell"
When the bonus title came up I thought it would be the peach cans. But we all know they are king of power delivery.
Tall taper with elliptical opening with dimples throughout the whole opening plus length of the tube. The elliptical opening seems to smooth entry and the dimples will smooth the pathway.
Would be nice to try and stick with the best design of those tested, and try and find out narrowest runner with dimples... perhaps if you ended with more narrow runner that flows similar, you would get more velocity and maybe more power? Then compare the new found one to same size but no dimples.
Can a velocity stack applied directly on the OEM intake result in the same gain? (Not like individual per cylinder)?
What if you added Pc fans infront of the intakes or mini water cooled radiators with Pc fans infront? Ball shaped mini radiators?
The Golf ball seems to have some advantages with a smoother curve. Would be good to see it with different tapers. Have you ever thought of trying one with a bit of a Venturi ?
Is it possible to compare individual throttle for each cylinder vs 4 in 1 with only one trottle ?
would u try what effect to connect a high vacuum source in exhaust?
Did some sotp dyno bellmouth testing in the 80's, on a Ducati 900SS. It was length more than anything else that influenced engine characteristics, even then it was response and power band that were the noticable effects, power was little affected. Short gave better response at top end, long better midrange. SOTP dyno, seat of the pants.
yeah length has the most affect by far, unless i undersized to start with.
COOL VIDEO MAN! Really interesting seeing the differences. Btw, looks like you have ignition miss at high rpm.
no ign problems. just what the dyno does when power rolls over
have you tried taking the Double one a few steps further and making a Louvered trumpet?
Mythbusters did not create a myth, they explained how dimples keep flow attached on situations where it wouldn't be. A sphere is a terrible shape aerodynamically, that why it could use dimples to improve its aero wake. People just didn't understand that explanation 😉
It is useless to use dimples on surfaces where the flow would have been attached in the first place.
Thanks mate! do tests and spare long theory and discussions.
You should try different methods of creating vaccume pressure in the crank case. I've always been interested in those little exhaust gas scavenger fittings, would be interesting. Cheers
have you tried a grid of air straighteners inside the stacks?
Is there a time element to the graph, like are they all automatically overlayed or is there a way of seeing which one pulled through the curve the fastest? I know the double stack didnt perform as well as the others but it seemed the most agressive on throttle?
its a braked dyno, not inertia. so all the runs are the same length. the more power you throw at it the more it will brake to keep the ramp rate the same. is lots going on, but the bark where its a bit all over the shop in lower rpm, is a bit of reversion. its pretty hard to eliminate with the aggressive cams. if you watch the latest video, with the small diameter trumpets. it does it even less, as its increasing the intake pressure.
Those golfball runners REALLY flatten that torque curve
they r all so equal. is there a other problem? to large TB's? exhaust?
Haven't watched it all yet but Suzuki used 2 short stacks and 2 longer stacks in their 1000cc engines which produced a broader curve. You could swap to all long/short depending on your track and they were cheaper then aftermarket. Food for though
How about a trumpet with a ventury in the middle, like a carb throat. The air should speed up but it may ice if cold weather?
I like how smooth the golfball intake was.
I wonder if it would be worth making a telescopic variable length set like the 787b or the two stage r6 stacks, I'm planning an itb build on my 2jz and I've been contemplating making something like that to go with.
I'm currently designing a continuously variable intake for a 2 cylinder engine in a motorbike, made a prototype and its working great
when i get time i will post a video simulating a variable length setup.
Could you print the tapered one and use fuzzy skin settings in the 3d printer slicer? Both Cura and Prusaslicer has the setting. Seeing how smooth the curve is with both the golfball and dimpled one I think using fuzzy skin would introduce a lot of surface turbulence and therefore minimize the pressure drag.
Hey! Do bends end up restricting air flow? could you do a normal length runner but with a 180 degree bend that hangs over the engine cover? My current D17a2 has the intake facing the firewall, and I'd like to do a hood vent or in bay air box.
Hey, bends are fine long as they aren't too tight.
@@Garage4age Thank you for the response man! Appreciate the information as always, just this time I can thank you! haha.. can't wait to see more content. Keep it up!
because it's ITB intake, the flow is close to maximum for what it needs. make them smaller version of all the different shape intake, that will show up a bigger different.
Conclusion for me - eat noodles and your engine will be happy. In my ride i use audio speaker box tubes. They get the job done. I see performance dont goes up with the price. Thanks for the video 👍
interestingly i think the mouth design is way more important than initialy thought. The dimples do seem to smooth the overall curve, so if you want the power to come on very linear I feel like these would help
Likely find the blue ones changed the power curve, as they were sightly shorter. the red and black were the same
Could you try off senter trumpets, so you do not have the trumpets interact with each other. Similar ideas was done in Canam. Uneven length runners as well to avoid interference of each other. @@Garage4age
@@MatsNorway ruclips.net/video/nqYkmCLrlEo/видео.html
Looks like Golfball normalized midrange the best due to a bit more boundary layer. Looks like a slightly smaller ITB is what this engine is asking for to net area under the curve.
How many degrees taper are your own OG ones?
This car must be so much fun to drive.
That took a lot of effort. It is greatly appreciated. Can you enclose the stacks in a pressurized box (a scoop)?
There are cars that do that. BMW, Ferrari, etc. The Hoonicorn before it went twin turbo was setup like that.
the shorter the better ? (maybe because of the wheel arch close to the input of the long ones ?)
What i learned is that these are changed out largely as one prefers for appearance or sound because overall performance is so similar
idk if this makes sense but, some maf sensors have that square mesh in front, would that make a small improvement on air flow if the trumpets had something like that?
would be worse
Spicy for sure 🥵😂
I think its pretty clear that you have enough intake already so trying a bunch of different stuff isint showing any big changes.
Id add some more displacement, no idea what your head/cam situation is but i would be going too a stroker and making sure the heads/cam situation is really good then try again.
Hey man,love the channel.Are you going to finish that 7A project?Last time I looked it ran a bearing.I would love to see the big valve head,cams etc from the good engine.Get a direct back to back comparison between the 1600 and the 1800 The suspense is killing me.
no more 1800 sorry. Its all been split up for other projects, some of it will likely be seen on here, but wont be 1800. I think it would likely just do the same thing as it did with the turd head. about the same power as 1600 just at lower rpm.
Only real difference will come with variable runner length as long as the general shape is sufficiently allowing the venturi effect to occur (at least the velocity-increase part of it).
Maybe try rigging up a pull-tie to make some motorcycle-style 2-stage variable runners that just stack on another trumpet onto the first one.
i always wondered what would happen if you make an intake like a equeal lenght header exhaust.. so 1 throttle body with equal lenght tubes going to each cilinder. or with ITB's
Yes, Chrysler slant 6 tried to get close to this with a longer manifold giving a more even result and it was a very fast motor for that reason.
That's why V8's are successful because the manifold can be easily made that way like a spider, so the result is smoother
even with a direct pipe setup there are only 2 different lengths that are not so different from each other.
It's a hard one because as the closer pipes get curled to make equal length then we are adding more corners.
Is the engine running so weird (in steps) or is the Dino doing some wierd break stuff?
can you make stack that has small pipes inside, like catalytic converter , to get laminar air flow, that principle is used in fountain where burst of water flies in one piece 5-10 meters away
hahaha i love this shit man! Would love to se what you could stretch out my ciompoound turbo settup lol
i have one fun thought but i dont know how much space there is or if it let itself be done, but like a 2 stroke having the exhaust pipe expand into a wide diameter and then shrink down to a very small diameter, what if the intake trumpet goes from throttle body size then out and taper back in to throttle body size? like it can catch the back pulse?
almost like each throttle got it's own pree ITB chamber?
That would lose flow and make a very messy wave. 2 stroke exhaust has nothing to do with that.
@@billshiff2060 yes, but in practise what would it do on a intake side would be fun to watch, i am not talking of making the smal diameters less than the ITB's but make a echo chamber of torts to see what happens on lower rpm
What is your tuned length for intake runners? Also what is your inatake cam duration @1mm
you can ask me anything else, but my total intake runner length and cam combo. sorry haha
The "golf ball phenomenon" does not occur because the ball moves uniformly, with the gas flow close to linear, while the air in the intake sometimes stands still, sometimes accelerates, and these changes occur at relatively high frequency.
The creating/stabilization of the "cushion" in the hole itself takes some time.
I was interested in this phenomenon before it was commonly known.
This myth was propagated on YT by the CNC company that works with the engine heads (i remember the name but I wont write it down).
Something else that is interesting - the flow bench test in this case will show false results, because the conditions of such a test (gas flow is unidirectional) do not reflect the actual conditions during engine operation.
If it made sense when gas flows in the conditions as in the intake duct - why doesnt any competition engine, including F1 engines, have it?
Thank You for antoher interesting video Garage 4AGE.
👍as usual.
Flow bench is a great tool, i'd like to have access too. More work to test things on a running engine, but the power numbers are the end game, so the dyno is the one
@@Garage4age
Ive been following Your channel for years and I know that building a DIY flowbech, with Your skills, is a piece of cake.
@@Garage4age Building a flow bench is not difficult as long as you understand the simple principals. It will be accurate and affordable.