I go back and forth on this. I had an 80mm on my Supra for a few months last year and it was nostalgically fun. My kid referred to the car as a "roller coaster" because there was soo much build up to it coming online and making power! I'm now back to a 7275 and it's much more responsive. I don't know that I would complain about a little smaller turbo but than again, lag is part of the Supra's character. Thanks
@@jaymeagher1510 i am NOT a lag person, i want instant spool and power and i am NOT a top end hwy fan either. My 240sx is instant spool and jnstant power ... My Genesis coupe is the same way, hit the gas and it goes .. My 98 Supra is still on stock twins and they responded descent when it was stock but now with the full exhaust, no cats, and no clutch fan drag, they respond MUCH faster ... If and when i decide to remove the stock twins, i may stick with a mid size turbo to maintain the quick low end spool, because when i hit that gas pedal, i want it to respond then and there ...
@@ACommenterOnRUclips If you decide to go single on the Supra I'd suggest a 6466 with a 1.0 housing. It's really a hard combination to beat and will enough airflow to make over 900whp without drama with supporting mods. You won't have the power you have now at 2,700-2,800rpm but it will more than make up for it once it's online. Thanks
@@jaymeagher1510 i think that 1 ar is going to me too big for my taste especially when the stock twins kick on almost instant and still give me good mid range. I can care less about top end as i dont do hwy pulls ever, most of my power pulls are going to be from a stop light launch or over taking someone from a ~45 mph stroll up to ~80mph ... So i will need something to mimic the stock twins quick response ...
Love this Jay!!! And as expected only you I’d expect to talk about “transient” response as I always mention it but I see others don’t really bring that up Very nice video here! :)
@@BrettObie oh I see! well I hear less of that word actually but that could mostly be because all the ones I know are too busy in “drag” not the clothing though lol
Jay knows “More” than what’s he is talking about. His voice is perfectly tuned for all listeners :)) I have always wondered if he had a background in engineering.
Thank you! Very informative. I have a GM 6.5TD 1999 and want to maximize the performance of said design. It has High compression ratio so boost will be limited to 1BAR for longevity. But a higher volumetric efficiency and intercooler should net usable results.
Always appreciate your explanations! I've never run into A/R being described as the flange opening footprint vs the nozzle/volute size, and it would make the A/R disparity between T3 and T4 more intuitive, but as I've understood it is more related the radius and turbine wheel? There are some things, like T3 and T4 despite the same turbine wheels that is inconsistent there too, unless its just an artifact of old info when there where "T3" and "T4" turbine wheels
Thanks for the informative video. I recently acquired an A91 Toyota Supra in manual. Coming from the WRX platform I like the responsiveness of the twin scroll setup. I'm not really a fan of turbo setups due to turbo lag so it's always interesting hearing about different types of turbo configurations.
My fix to twinscroll gasket Using a tungsten-scriber i scratch three (1”) vertical lines on the centre divider. This holds the centre “weakest” part without sacrificing seal on the rest
Twin pulse has it's uses in the low to mid range power and torque increase as the volume is less thus the velocity per pulse of exhaust energy, from the cylinder, is higher and more efficient through pulse-firing organization. A Split T4 will flow less mass at a given pressure ratio than an open V-Band of the exact same A/R. Garrett Documentation and graphs show this, but it's around 2-3 lb/min difference across the graph. A Split T4 may assist the in getting more torque, through efficiency increase, at lower RPM speeds to get the torque converter ready for launch, without NOS. In a 1500+hp application split pulse is likely a hindrance due to lack of housing options available - however you can always use a split pulse manifold with an Open T4 or T4 to V-Band adaptor, but not the other way around, as the divider melts with high EGTs. On a drag car, it's not much of an issue which setup you go for as the working RPM is in the top half to third of the range. In a circuit car, it's very important as you have a much more dynamic rev range where torque is required on tap, out of corners, as soon as possible. V-Band certainly makes it a lot easier to do turbo swaps and carriage changes, however a pro tip would be to ditch the factory cutter style nut that always damages the thread when removing and use copper nuts instead or double regular stainless nuts to prevent backing out under vibration / heat cycling, along with the addition of copper paste anti-seize. The nuts that Garrett Supply for all their v-bands are terrible and the thread is way too fine for the application. Always have a spare v-band on hand when removing a V-Band based turbo Inlet or Outlet. A/R is also dependent on fuel choice. If you're running E85 or E98-100 or Methanol - you need to up at least 1-2 sizes higher due to a 40+% increase in exhaust mass flow VS petrol, so you don't choke the exhaust side and have excessive exhaust pressure than boost pressure. This is where EMAP datalogging plays a key role. Lastly, A/R is not valid across different turbine sizes and frames of turbo. A 1.21 A/R on a G35 is much smaller than a 1.21 A/R on a G42, by a considerable amount. Use the mass flow graphs to determine the peak flow you need or run a range of different housings and dyno/road test with EMAP vs BOOST logging. Non genuine housings are much cheaper than genuine nowadays so you can easily tune in your response or even have different housings for different race conditions. What housing your choose depends on what you want optimised and how efficient you want your turbo system to run and where you want the boost to come in by. Having a 0.63 housing on a GTX35 will bring in the boost as soon as possible, but your peak power will be severely limited. A 1.21 housing on the same turbo - your boost will be 1000rpm + laggier, but your top end power band may increase by 2500rpm as you're not choking it out with excessive EMAP / restriction. If you have a 4000rpm stall converter for example - you match your housing to where you will make your launch boost. No point getting some 1.44 housing that's 1000 rpm laggier than your stall instead of a 1.00 and you can't get it on the converter until the middle of next month if you're not spraying it with NOS. Turbo choice plays a role here as well.
There is not a 40% increase on exhaust mass with the use of alcohol fuels at all. The whole 14.7:1 or 9.7:1 etc stoichiometric ratios of fuel are a hint to this. By far the majority of the exhaust mass comes from the air that's going in, even with methanol fuel. E85 is going to be far closer to around 3% more mass flow, and this arms you with choices in regards to how you want to make power. Going to E85 on a knock limited setup can often gain a lot more than 3% more power with the same airflow so the power gains you get are significantly more than the increase in exhaust mass flow would suggest. If you happen to be pushing the turbo hard enough that 3% more mass flow means EMAP is bad enough that the housing is too small you often can decide whether you want the extra response and reliability offered with E85 and just adjust boost targeting to sacrifice a bit of the power gains to bring EMAP back into check, or go up a housing size and really go for the moon. I personally have not seen a bigger housing being necessary purely from going E85, it's been more where you can go boost wise meaning a lot more flow capacity is required when you can push the turbo much harder where tuning was stopped on pump gas due to octane reasons.
@misterlith I must have glossed over that number in his comment, because you are definitely correct on that. It's definitely more with ethanol or methanol, but not much more.
@@misterlith Nonsense. E85, for example, has a density of 773kg/m3. Gasoline is 716kg/m3 , Ethanol 100% is 784 kg/m3 and Methanol 792 kg/m3. E85 is ~8% more dense than Gasoline, right off the bat, so that throws your 3% theory on these 2 facts alone. -1. The chemical reaction that takes place in the combustion chamber is based on a fuel mass flow, primarily. Gasoline - to completely burn 1kg of gasoline in a perfect molecular reaction, you need 14.7kg of air. Ethanol E85 - 1KG of E85 9.7kg of air is required. The power output is much less than Gasoline if you're just burning at stoich. To burn the same 14.7kg of air, you need 34% more ethanol fuel by weight. This where the extra mass flow comes from. -1. using methanol, Stoich is 6.5:1 - you need 56% more Methanol Weight to burn 14.7kg of air. Thus approx. 34% more fuel is required than gasoline to burn the same quantity of air compared to that of gasoline. Because we are injecting such a large amount of ethanol to reach Lambda 1 in this case, more molecules exist in the combustion chamber, compared to that of gasoline, by weight and thus mass flow increase over that of gasoline. That is why a 2JZ will pickup approx. 400-700 more RPM spool response and hit boost earlier on a 2JZ with just Ethanol E85 vs Gasoline 93 or Petrol 98 on the same housing. It will also choke a smaller housing and increase EMAP sooner at lower boost levels, compared to Gasoline. This is why a housing increase may be recommended depending on the power goals. To put it simply, E85 has less thermal energy per kg (which is why it burns cooler) and because such a greater volume of E85 is required to burn the same quantity of air, compared to gasoline, that's where you get a much higher energy output compared to gasoline. If you have actually tuned a car, you need approx. 35-40% more injector flow / pulse width to reach the same Lambda level as Petrol/Gasoline in a performance application with headroom. That's why you need to upgrade the injectors and fuel pumps when running E85 or E100 by a considerable amount to flow more. Fuel consumption is down by approx. 40% as well compared to gasoline. You'll be lucky to get 200-250km/s to a tank in a JZA80 supra with spirited street driving, vs 400kms on gasoline. I have witnessed this in my own cars, side by side, same routes and turbo setup, different fuels, same races. This doesn't take into consideration any timing advantages that you gain from running E85, where you can easily tune up to and beyond MBT to increase the combustion pressure and thus exhaust gas velocity, compared to petrol, which further aids in a mass flow increase. -1 point to you again. All of these are needed in a quantities far more than 3% mass flow. You're way out by a factor of 10. Please humor me how you got to 3%, which cars you have tuned and how much your fuel map has changed between Petrol and E85. Then tell me why everyone that goes E85 runs 50% lager injectors and pump flow as a mere necessity to run E85 at high performance levels. when your claimed 3% will do the same job with no upgrades. Hint - it doesn't. -100. In Australia we had locally built Flex Fuel cars that ran on E85 and Petrol 98, namely the LS based SS commodore, et al. On my dyno with an OTR and exhaust it made 275rwkw Stock on Petrol. With E85 - it made the same power - it was tuned not to take advantage of e85 at all - just to run it as an alternative and then cheaper fuel available the the pump. When E85 was cheaper than Petrol - it was a good deal - you could get E85 for 20-30c per liter less than Petrol. However the fuel consumption of E85 used 25-30% more fuel according to the customers. When E85 got more expensive - it wasn't worth losing the range per tank compared to that of gasoline. If you want to make the same power as a gasoline engine - you need to burn more ethanol to do so, and thus increase the exhaust mass flow in the process. In addition the benefits of the extra fuel is better cylinder cooling, higher octane to push more timing and better boost response as the mass flow is increased earlier on, spooling the turbo sooner and improving volumetric efficiency. When you're talking 7-9 second cars - it's all about exhaust mass flow not choking the turbo to the point where high EMAPs and EGTs are a hindrance. This is why most turbo drag cars have a larger turbine inducer than compressor inducer and that's evident in the precision nomenclature. PTE 7576 / 8385 / Promod 98-103. Thus I'm not convinced by your 3%. I haven't seen it in real life on basic fuel consumption, it doesn't math out and I don't believe you have tuned a vehicle for flex fuel, as you would know that by virtue of a fuel temp vs ethanol % there's different densities that are required for the VE calculation as well as a fuel composition scaler that is based on the stoich differences at each ethanol % , to start with. -9k. There is a considerable increase in exhaust mass flow, in the the order of 30-40% depending on how rich you run your mixtures and what blend, which is responsible for the spool increase and response when using E85 vs Gasoline and can create choking issues when EMAP rises beyond an acceptable level, thus you must increase your housing size. This was done with a customer car that went from 1.01 A/R to 1.21 and gained nearly 6mph on the 1/4 mile, chopped 0.3s off the time and could run more boost before the EMAP became a limiting factor again. I don't see this 3% increase approximation to exhaust mass flow mathematically on all the chemical equations or physically in the real world. It's false. Your math is backwards based on the stoich values which means you're not qualified to even understand combustion and how an engine makes power. The more fuel weight you can burn per unit quantity of air, the more thermal energy will be released from the chemical reaction and thus the more power there is to be gained. This is the premise you don't understand and that's why you're categorically wrong.
@@racetunecalm down bud, I didn't mean offense. I enjoy learning and I've done a lot, so am also into sharing what I've learned so far and figure there is no harm in one or the other of us being wrong here. We don't agree, we clearly want to share knowledge, so this is an opportunity do suss out where things aren't adding up and both feeling like we've got something from the convo. If we push ego aside one of us will realise what we've missed, I don't feel compelled to try and willy wave about what I've done in the past to try and gain credibility and you shouldn't need to as well. The concepts we are discussing should be the truth of the matter so let's find that truth. Firstly, because I assumed you understood the fundamentals and had just missed something I didn't go max effort breaking down everything to precision or treating you like a child so my numbers were and will be loose. I'm trying to help people understand stuff, not prove how big a nerd dick I have. So here is how I came to my loose numbers. For this I'll keep it simple and say I'm going to compare two cars running .78lambda, same air mass, and that petrol stoich is 14.7:1 and E85 is 9.8. With that I'm gonna say the equivalence ratios we are working with are: Petrol: 1 / (.78 * 14.7) = 0.0872 E85: 1 / (.78 * 9.8) = 0.1308 Any further calculation on top of that for the "fuel" share of the mass going through the engine is pretty academic as air/fuel ratios are discussing the air and fuel mass ratio - I don't need to go into fuel density or anything because we are assuming that has been worked out earlier on and we are hitting our target mass ratios. What does need to be added here is the air mass, seeing as I used "1" as the reference point for mass ratios I can just go 1.0872 (adding 1 for the air mass involved in this combustion) for petrol and 1.1308 for the E85 combustion. So, those are the relative masses of air and fuel that will be going through the engine during combustion, the only way either of them change is if someone adds or removes some of it somewhere along the line. So as long as some strange shenanigans aren't afoot we should be able to go 1.1308 / 1.0872 = 1.040. So, admittedly my thumb suck of "around 3%" was looser then I expected... Unless I missed something in that there is actually 4% more exhaust mass flow with E85 vs petrol, I was wrong on that part (or just relied a bit too much on the accuracy of my thumb suck maths haha. Trust me I am more pedantic when tuning than I am when walking with my cellphone). But yeah, that's the gist of where I was coming from. Let me know if there is a glaring step I missed in the above
great information, I have a 2014 Ram 3500 6.7l with some mods, primary use is towing a 40 ft 5th wheel and tractors to get maintenance and such. Can you do a video that is more specific to this type of set-up, thanks Mike P.
Exactly what I was looking for. Ideally I'd like to make 550 with my 1jz I know the stock twins are tuned at 2,400 and 3,600rpm for peak torque and hp so I'd like quicker spool but I also don't ever really shift must past 4k so when the rpms drop there they are right in the sweet spot. What if I wanted to change that curve to more like 4,000-5,500 rpm that sounds about right like twice as much and if I shift at 6,300 way closer to 7,200 red line it'll fall right back down to 5,000 and that's twice the rpm as stock so right when it would be done pulling at stock is really where I want that single turbo to start building boost
Love it Jay you guys are the best, please do an Sr20det complete build guide 🙏🏽🙏🏽🙏🏽🙏🏽 trying to build the most responsive and reliable engine possible at 450hp
Nice one man. Same good level info, only one area I'm gonna be picky about: A/r = area / radius, not aspect ratio. It defines the area of the volute vs the radius of the housing. This is pretty relevant because it means the .8x a/r you mentioned as being a golden rule of being a nice mix of response vs flow, which IS true for a lot of turbine housing and wheel combinations however with things like Borg Warner EFR turbos the 1.0x area is the holy grail area, if you go .8x with those you're likely to choke most typical setups and even 1.05 is semi response orientated. A 1.45a/r EFR would be like the parallel for 1.0x-1.1 from other brands
I went back and forth on the terminology and assumed someone would chime in. When you look up calculating the area of odd shapes it seemed like aspect ratio was the right word. We also have to face that some brands don't account for the divider in "twin scroll" housings so we get what you mentioned with larger numerical values just to get back to the same place a "1.0" housing would be. Thanks for your feedback!
Man I wanted to go G30-900 divided 1.06 A/R W/ Twinscroll Tubular manifold. BUT now I have to consider a G30-900 1.01 Vband with single scroll tubular mani
If you have creep, yes a bigger wastegate will help control boost, but my experience has shown a larger housing is the better option. If you have a reasonable turbo/wastegate setup, and are still experiencing creep, a larger turbine housing may give you a nice bump in power without much if any loss in response, plus control of the boost.
What about different frame sized turbos, or different brands. Like a t25 frame .64 housing compared to a .63 t3 housing compared to a .68 t4 housing? Is .80-1.00 a good range no matter the turbo or are you being specific to a certain frame size
Which is better for 4.3L Syclone 500 whp range 66mm compressor wheel with P trim turbine wheel .82 T3 a/r or divided T4 .81 70mm compressor wheel ball bearing Q trim turbine wheel?
man i wanted to ask about holset turbine housing since they are designated as cm^2 like mitsubishi .... but thanks for this info, everything i know i learned on superstreet (turbo edition) :) honda-tech helped
Because holsets are for diesels would they require a naturally larger turbine to perform as well as a precision or garret equivalent? If I used an 8cm housing would it spool as quickly as it should or would it need to be 14cm because holsets are designed on diesels like that
can a turbo T4 open be connected with a manifold that has a T4 twin scroll or the opposite?can a turbo t4 twin scroll be connected to a T4 manifold open? will it have its cons and pros?
As wheel size (MASS) increases the turbos loose transient response. A larger wheel with a smaller housing isn't ideal. It's about a balanced approach and then operating the system at a desirable pressure ratio. Ideally you want to make the power you'd like while having less pressure in the exhaust side of the engine than the inlet side. Thanks
Hold my beer) Twinscroll spins the turbo earlier, which widens the operation engine range. If you're into drag racing then this probably won't matter much to you. But if you're drifting, it's important to have high turbo RPM in the low to mid range engine RPM. The turbine spins up earlier due to the fact that the cylinders are connected in the correct order and do not have a stray influence (pressure pulsation during valves operation) on each other. I think it would be great if you made a practical video on the topic, where you showed the difference in numbers. And then they would give the followers the opportunity to make an independent decision
@@ohhman9400 That's easy, call Real St. Depending on how long the turbo's been in service you may struggle to remove the housing. If it's been a couple years I'd remove the turbo off the car and place it on a bench EX housing down. Soak the hardware with PB blaster overnight. From there it's just working the hardware out and using a rubber mallet to break the housing free of the turbo's heat shield. Thanks
My turbo used come on boost at 1800rpm and peak at 3000rpm I noticed my map filter is cracked and has oil now the car is surging in power. No boost at 1800 comes in very very hard and late at 2000rpm and peaks around the same 3000ish rpm.
I paired a GTX3076r with a .64 a/r to my SR20 but the exhaust choked out at 20lbs of boost at 6800 rpm. I’ll be installing a .86 turbine housing shortly. Do any of you guys have any advice for the swap?
I understand how thw turbo can choke the exhaust at hight boost levels, but how dies it at high RPM? Shouldn't the wastegate be able to flow the eccess gas flow?
You just lose efficiency as the exhaust is trapped in the system. Remember it's just an air pump. The wastegate is there trying to maintain a user prescribed manifold pressure value. Thanks
I have the on3 n54 “ t4 “ vband turbo manifold .. it has the single round vband hole . Not the 4 bolt t4 flange … I’m confused on what turbine housing fits mine . Can anyone help me please
"That .8 to 1.0 range is a very organic position to be and it will compliment the size of the wheels well..." "...you just want to get as close as possible, that .8 to 1.0 range won't do you wrong..." Uncle Jay, does this also apply if you are twin turbo instead of single turbo? 🤔
In the examples I've been around we've just stuck to the same approach. I had a 2jz with twin 6466 and .82 housings and it was making good boost by 6,000 and ran extremely well. On the Coyote engines it's the same routine, we're running close to 1.0 and they spool and perform very well. I'd venture to say the guys that have been immersed in the R35 community can chime in. It really comes down to the powerlevel and the pressure ratio that's required to make it. If you can keep the back pressure down the engines are less knock prone and live longer.
@@jaymeagher1510Thanks Uncle Jay. 👍 I'm using two T25 flanged GT2860RS turbos with .86 A/R on a 1JZ, so the goal was power (600hp-700hp using 108RON Unleaded jungle juice) but more importantly, response across a wide rpm range. The build has been catered for response and building boost as soon as possible, hence the small turbos and using not as wild cams (264s) to keep that response. 😎
Prolly, buuut u just said u like top end power. Get the .82 you will definitely have power where the k series likes to make power vs the .63. K series have alot of headflow, so the .63 would just hold you back.
Don’t agree at all about twin scroll only helping at low rpm. It’s less about transient response and simply where in the rev range the turbo spools. That’s just simple fact.
I prefaced with the OEM approach where twin scroll has the largest impact. The aftermarket is muddy at best on the subject. I'm not saying there's "nothing to be gained" but will take the position that there's way more opinions surrounding the subject than data. Thanks
Any one in the comment wanna inform me on A/R ? I'm looking for best response and lowest backpressure for a 2jz not interested in going over 500HP Happy with 400HP
You can do that easily with the factory turbos on a 2JZ-GTE and have better response than 90% of aftermarket turbos. Just exhaust, intercooler and boost rise and voila.
@@streetinfamy GE head peasant. 😛🤣 To be honest, a G25-660 might be your best option there. Available as T25 flange or V-band. 👍 As Jay said, lower A/R means better response but the turbo itself will choke out at higher rpm. Also factor in manifold runner sizing for this as that can also affect how the turbo absorbs the exhaust gases to turn in the first place. 👍
@@MafiaboysWorld aye, it's a hard life, the life of a pirate, yeah ive looked into those $$$$, there is the option to swap a 1JZGTE head on since the 1J block froze but man what a hassle after finally getting the NA going... thanks for the scoop
@@streetinfamy in reality, both heads are awesome. Some argue the GE is better than the GTE. I totally agree that the GE is much better than the SMALL PORT vvt-i versions of the 1JZ/2JZ but the BIG PORT Non-VVTI? Hell no and I'll die on this hill fighting anyone over it! 😂👍
Got to disagree with cross plane cannot be the best ever, it's just not engineered that well. Best cheap engine maybe but anything better balanced is nicer IMO
Really though I like my k20s with NOS and any 2jz or RB's get supercharged and any V8 loke the coyote or ls gets the N/A treatment. Turbos run too hot.
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Jay talks ... I immediately like 👍 and listen 👂
If only my wife were so in tune! Thanks!
More engine rebuilds/tear downs PLEASSSE!!
Once again Awesome stuff Jay… this helps a lot for most that are starting and I do hope they check this out! hopefully this spreads out more!
Great information thanks for sharing
The ONLY thing good about a LARGE turbo is giving the other guy the impression he is winning the race ....
Lmao
I go back and forth on this. I had an 80mm on my Supra for a few months last year and it was nostalgically fun. My kid referred to the car as a "roller coaster" because there was soo much build up to it coming online and making power! I'm now back to a 7275 and it's much more responsive. I don't know that I would complain about a little smaller turbo but than again, lag is part of the Supra's character. Thanks
@@jaymeagher1510 i am NOT a lag person, i want instant spool and power and i am NOT a top end hwy fan either.
My 240sx is instant spool and jnstant power ...
My Genesis coupe is the same way, hit the gas and it goes ..
My 98 Supra is still on stock twins and they responded descent when it was stock but now with the full exhaust, no cats, and no clutch fan drag, they respond MUCH faster ...
If and when i decide to remove the stock twins, i may stick with a mid size turbo to maintain the quick low end spool, because when i hit that gas pedal, i want it to respond then and there ...
@@ACommenterOnRUclips If you decide to go single on the Supra I'd suggest a 6466 with a 1.0 housing. It's really a hard combination to beat and will enough airflow to make over 900whp without drama with supporting mods. You won't have the power you have now at 2,700-2,800rpm but it will more than make up for it once it's online. Thanks
@@jaymeagher1510 i think that 1 ar is going to me too big for my taste especially when the stock twins kick on almost instant and still give me good mid range. I can care less about top end as i dont do hwy pulls ever, most of my power pulls are going to be from a stop light launch or over taking someone from a ~45 mph stroll up to ~80mph ... So i will need something to mimic the stock twins quick response ...
that turbo cut open up in the background is sooooo COOL :)
Love this Jay!!! And as expected only you I’d expect to talk about “transient” response as I always mention it but I see others don’t really bring that up
Very nice video here! :)
Anyone who suggests a twin-scroll setup will say transient response is the main benefit though
@@BrettObie oh I see! well I hear less of that word actually but that could mostly be because all the ones I know are too busy in “drag” not the clothing though lol
I was given a free turbo off a 2018 Cummins turbo diesel and the exhaust side is funky.
Jay being the GOAT as usual.
Jay knows “More” than what’s he is talking about. His voice is perfectly tuned for all listeners :)) I have always wondered if he had a background in engineering.
Best video i've seen explaining this stuff...thanks man.
I know I can trust every bit of his advice without question. Time to listen up and take notes.
Can you share some knowledge on big turbine with small a/r vs smaller turbine with larger a/r?
Dang amazing!!! Can we get a podcast soon!!!!🎉
Thank you! Very informative. I have a GM 6.5TD 1999 and want to maximize the performance of said design. It has High compression ratio so boost will be limited to 1BAR for longevity. But a higher volumetric efficiency and intercooler should net usable results.
Always appreciate your explanations!
I've never run into A/R being described as the flange opening footprint vs the nozzle/volute size, and it would make the A/R disparity between T3 and T4 more intuitive, but as I've understood it is more related the radius and turbine wheel? There are some things, like T3 and T4 despite the same turbine wheels that is inconsistent there too, unless its just an artifact of old info when there where "T3" and "T4" turbine wheels
Thanks for the informative video. I recently acquired an A91 Toyota Supra in manual. Coming from the WRX platform I like the responsiveness of the twin scroll setup. I'm not really a fan of turbo setups due to turbo lag so it's always interesting hearing about different types of turbo configurations.
Hello from Australia Jay told a few people at the pub yesterday to contact your business
I always buy the smallest turbo to meet my power goal with the largest housing in it's range to keep the flow up
God bless you senpai Jay!
My fix to twinscroll gasket
Using a tungsten-scriber i scratch three (1”) vertical lines on the centre divider. This holds the centre “weakest” part without sacrificing seal on the rest
Great insight as always Jay
Twin pulse has it's uses in the low to mid range power and torque increase as the volume is less thus the velocity per pulse of exhaust energy, from the cylinder, is higher and more efficient through pulse-firing organization. A Split T4 will flow less mass at a given pressure ratio than an open V-Band of the exact same A/R. Garrett Documentation and graphs show this, but it's around 2-3 lb/min difference across the graph.
A Split T4 may assist the in getting more torque, through efficiency increase, at lower RPM speeds to get the torque converter ready for launch, without NOS. In a 1500+hp application split pulse is likely a hindrance due to lack of housing options available - however you can always use a split pulse manifold with an Open T4 or T4 to V-Band adaptor, but not the other way around, as the divider melts with high EGTs. On a drag car, it's not much of an issue which setup you go for as the working RPM is in the top half to third of the range. In a circuit car, it's very important as you have a much more dynamic rev range where torque is required on tap, out of corners, as soon as possible.
V-Band certainly makes it a lot easier to do turbo swaps and carriage changes, however a pro tip would be to ditch the factory cutter style nut that always damages the thread when removing and use copper nuts instead or double regular stainless nuts to prevent backing out under vibration / heat cycling, along with the addition of copper paste anti-seize. The nuts that Garrett Supply for all their v-bands are terrible and the thread is way too fine for the application. Always have a spare v-band on hand when removing a V-Band based turbo Inlet or Outlet.
A/R is also dependent on fuel choice. If you're running E85 or E98-100 or Methanol - you need to up at least 1-2 sizes higher due to a 40+% increase in exhaust mass flow VS petrol, so you don't choke the exhaust side and have excessive exhaust pressure than boost pressure. This is where EMAP datalogging plays a key role.
Lastly, A/R is not valid across different turbine sizes and frames of turbo.
A 1.21 A/R on a G35 is much smaller than a 1.21 A/R on a G42, by a considerable amount. Use the mass flow graphs to determine the peak flow you need or run a range of different housings and dyno/road test with EMAP vs BOOST logging. Non genuine housings are much cheaper than genuine nowadays so you can easily tune in your response or even have different housings for different race conditions.
What housing your choose depends on what you want optimised and how efficient you want your turbo system to run and where you want the boost to come in by. Having a 0.63 housing on a GTX35 will bring in the boost as soon as possible, but your peak power will be severely limited. A 1.21 housing on the same turbo - your boost will be 1000rpm + laggier, but your top end power band may increase by 2500rpm as you're not choking it out with excessive EMAP / restriction.
If you have a 4000rpm stall converter for example - you match your housing to where you will make your launch boost. No point getting some 1.44 housing that's 1000 rpm laggier than your stall instead of a 1.00 and you can't get it on the converter until the middle of next month if you're not spraying it with NOS. Turbo choice plays a role here as well.
This was an excellent addition to the comments section and you saved me a lot of time typing lol. Good stuff.
There is not a 40% increase on exhaust mass with the use of alcohol fuels at all. The whole 14.7:1 or 9.7:1 etc stoichiometric ratios of fuel are a hint to this. By far the majority of the exhaust mass comes from the air that's going in, even with methanol fuel.
E85 is going to be far closer to around 3% more mass flow, and this arms you with choices in regards to how you want to make power.
Going to E85 on a knock limited setup can often gain a lot more than 3% more power with the same airflow so the power gains you get are significantly more than the increase in exhaust mass flow would suggest. If you happen to be pushing the turbo hard enough that 3% more mass flow means EMAP is bad enough that the housing is too small you often can decide whether you want the extra response and reliability offered with E85 and just adjust boost targeting to sacrifice a bit of the power gains to bring EMAP back into check, or go up a housing size and really go for the moon.
I personally have not seen a bigger housing being necessary purely from going E85, it's been more where you can go boost wise meaning a lot more flow capacity is required when you can push the turbo much harder where tuning was stopped on pump gas due to octane reasons.
@misterlith I must have glossed over that number in his comment, because you are definitely correct on that. It's definitely more with ethanol or methanol, but not much more.
@@misterlith Nonsense. E85, for example, has a density of 773kg/m3. Gasoline is 716kg/m3 , Ethanol 100% is 784 kg/m3 and Methanol 792 kg/m3.
E85 is ~8% more dense than Gasoline, right off the bat, so that throws your 3% theory on these 2 facts alone. -1.
The chemical reaction that takes place in the combustion chamber is based on a fuel mass flow, primarily.
Gasoline - to completely burn 1kg of gasoline in a perfect molecular reaction, you need 14.7kg of air.
Ethanol E85 - 1KG of E85 9.7kg of air is required. The power output is much less than Gasoline if you're just burning at stoich.
To burn the same 14.7kg of air, you need 34% more ethanol fuel by weight. This where the extra mass flow comes from. -1.
using methanol, Stoich is 6.5:1 - you need 56% more Methanol Weight to burn 14.7kg of air.
Thus approx. 34% more fuel is required than gasoline to burn the same quantity of air compared to that of gasoline. Because we are injecting such a large amount of ethanol to reach Lambda 1 in this case, more molecules exist in the combustion chamber, compared to that of gasoline, by weight and thus mass flow increase over that of gasoline. That is why a 2JZ will pickup approx. 400-700 more RPM spool response and hit boost earlier on a 2JZ with just Ethanol E85 vs Gasoline 93 or Petrol 98 on the same housing. It will also choke a smaller housing and increase EMAP sooner at lower boost levels, compared to Gasoline. This is why a housing increase may be recommended depending on the power goals.
To put it simply, E85 has less thermal energy per kg (which is why it burns cooler) and because such a greater volume of E85 is required to burn the same quantity of air, compared to gasoline, that's where you get a much higher energy output compared to gasoline.
If you have actually tuned a car, you need approx. 35-40% more injector flow / pulse width to reach the same Lambda level as Petrol/Gasoline in a performance application with headroom. That's why you need to upgrade the injectors and fuel pumps when running E85 or E100 by a considerable amount to flow more. Fuel consumption is down by approx. 40% as well compared to gasoline. You'll be lucky to get 200-250km/s to a tank in a JZA80 supra with spirited street driving, vs 400kms on gasoline. I have witnessed this in my own cars, side by side, same routes and turbo setup, different fuels, same races.
This doesn't take into consideration any timing advantages that you gain from running E85, where you can easily tune up to and beyond MBT to increase the combustion pressure and thus exhaust gas velocity, compared to petrol, which further aids in a mass flow increase. -1 point to you again.
All of these are needed in a quantities far more than 3% mass flow. You're way out by a factor of 10. Please humor me how you got to 3%, which cars you have tuned and how much your fuel map has changed between Petrol and E85. Then tell me why everyone that goes E85 runs 50% lager injectors and pump flow as a mere necessity to run E85 at high performance levels. when your claimed 3% will do the same job with no upgrades. Hint - it doesn't. -100.
In Australia we had locally built Flex Fuel cars that ran on E85 and Petrol 98, namely the LS based SS commodore, et al. On my dyno with an OTR and exhaust it made 275rwkw Stock on Petrol. With E85 - it made the same power - it was tuned not to take advantage of e85 at all - just to run it as an alternative and then cheaper fuel available the the pump. When E85 was cheaper than Petrol - it was a good deal - you could get E85 for 20-30c per liter less than Petrol. However the fuel consumption of E85 used 25-30% more fuel according to the customers. When E85 got more expensive - it wasn't worth losing the range per tank compared to that of gasoline. If you want to make the same power as a gasoline engine - you need to burn more ethanol to do so, and thus increase the exhaust mass flow in the process. In addition the benefits of the extra fuel is better cylinder cooling, higher octane to push more timing and better boost response as the mass flow is increased earlier on, spooling the turbo sooner and improving volumetric efficiency.
When you're talking 7-9 second cars - it's all about exhaust mass flow not choking the turbo to the point where high EMAPs and EGTs are a hindrance. This is why most turbo drag cars have a larger turbine inducer than compressor inducer and that's evident in the precision nomenclature. PTE 7576 / 8385 / Promod 98-103.
Thus I'm not convinced by your 3%. I haven't seen it in real life on basic fuel consumption, it doesn't math out and I don't believe you have tuned a vehicle for flex fuel, as you would know that by virtue of a fuel temp vs ethanol % there's different densities that are required for the VE calculation as well as a fuel composition scaler that is based on the stoich differences at each ethanol % , to start with. -9k.
There is a considerable increase in exhaust mass flow, in the the order of 30-40% depending on how rich you run your mixtures and what blend, which is responsible for the spool increase and response when using E85 vs Gasoline and can create choking issues when EMAP rises beyond an acceptable level, thus you must increase your housing size. This was done with a customer car that went from 1.01 A/R to 1.21 and gained nearly 6mph on the 1/4 mile, chopped 0.3s off the time and could run more boost before the EMAP became a limiting factor again.
I don't see this 3% increase approximation to exhaust mass flow mathematically on all the chemical equations or physically in the real world. It's false. Your math is backwards based on the stoich values which means you're not qualified to even understand combustion and how an engine makes power. The more fuel weight you can burn per unit quantity of air, the more thermal energy will be released from the chemical reaction and thus the more power there is to be gained. This is the premise you don't understand and that's why you're categorically wrong.
@@racetunecalm down bud, I didn't mean offense. I enjoy learning and I've done a lot, so am also into sharing what I've learned so far and figure there is no harm in one or the other of us being wrong here. We don't agree, we clearly want to share knowledge, so this is an opportunity do suss out where things aren't adding up and both feeling like we've got something from the convo. If we push ego aside one of us will realise what we've missed, I don't feel compelled to try and willy wave about what I've done in the past to try and gain credibility and you shouldn't need to as well. The concepts we are discussing should be the truth of the matter so let's find that truth.
Firstly, because I assumed you understood the fundamentals and had just missed something I didn't go max effort breaking down everything to precision or treating you like a child so my numbers were and will be loose. I'm trying to help people understand stuff, not prove how big a nerd dick I have.
So here is how I came to my loose numbers. For this I'll keep it simple and say I'm going to compare two cars running .78lambda, same air mass, and that petrol stoich is 14.7:1 and E85 is 9.8.
With that I'm gonna say the equivalence ratios we are working with are:
Petrol: 1 / (.78 * 14.7) = 0.0872
E85: 1 / (.78 * 9.8) = 0.1308
Any further calculation on top of that for the "fuel" share of the mass going through the engine is pretty academic as air/fuel ratios are discussing the air and fuel mass ratio - I don't need to go into fuel density or anything because we are assuming that has been worked out earlier on and we are hitting our target mass ratios.
What does need to be added here is the air mass, seeing as I used "1" as the reference point for mass ratios I can just go 1.0872 (adding 1 for the air mass involved in this combustion) for petrol and 1.1308 for the E85 combustion.
So, those are the relative masses of air and fuel that will be going through the engine during combustion, the only way either of them change is if someone adds or removes some of it somewhere along the line. So as long as some strange shenanigans aren't afoot we should be able to go 1.1308 / 1.0872 = 1.040.
So, admittedly my thumb suck of "around 3%" was looser then I expected... Unless I missed something in that there is actually 4% more exhaust mass flow with E85 vs petrol, I was wrong on that part (or just relied a bit too much on the accuracy of my thumb suck maths haha. Trust me I am more pedantic when tuning than I am when walking with my cellphone).
But yeah, that's the gist of where I was coming from. Let me know if there is a glaring step I missed in the above
great information, I have a 2014 Ram 3500 6.7l with some mods, primary use is towing a 40 ft 5th wheel and tractors to get maintenance and such. Can you do a video that is more specific to this type of set-up, thanks Mike P.
Tremendos amounts of spectacular knowledge. I love this video very much.
Awesome video Jay, as always.
What about using copper antisieze on the hardware?
Exactly what I was looking for. Ideally I'd like to make 550 with my 1jz I know the stock twins are tuned at 2,400 and 3,600rpm for peak torque and hp so I'd like quicker spool but I also don't ever really shift must past 4k so when the rpms drop there they are right in the sweet spot. What if I wanted to change that curve to more like 4,000-5,500 rpm that sounds about right like twice as much and if I shift at 6,300 way closer to 7,200 red line it'll fall right back down to 5,000 and that's twice the rpm as stock so right when it would be done pulling at stock is really where I want that single turbo to start building boost
Jay know's his stuff. Good info!
Love it Jay you guys are the best, please do an Sr20det complete build guide 🙏🏽🙏🏽🙏🏽🙏🏽 trying to build the most responsive and reliable engine possible at 450hp
We're about to jump into some SR20 builds for the engine dyno so stick around! Thanks
@@jaymeagher1510 legend 🫶🏾
@@carllourenznaidoo2470 At least on the internet! 🤙 thanks for the kind words!
I'm currently using a vgt t6 unit but not a vane style like o.e. a aftermarket nozzle style. Its advertised a r is 65 to 1.45
Nice one man. Same good level info, only one area I'm gonna be picky about:
A/r = area / radius, not aspect ratio. It defines the area of the volute vs the radius of the housing. This is pretty relevant because it means the .8x a/r you mentioned as being a golden rule of being a nice mix of response vs flow, which IS true for a lot of turbine housing and wheel combinations however with things like Borg Warner EFR turbos the 1.0x area is the holy grail area, if you go .8x with those you're likely to choke most typical setups and even 1.05 is semi response orientated. A 1.45a/r EFR would be like the parallel for 1.0x-1.1 from other brands
I went back and forth on the terminology and assumed someone would chime in. When you look up calculating the area of odd shapes it seemed like aspect ratio was the right word. We also have to face that some brands don't account for the divider in "twin scroll" housings so we get what you mentioned with larger numerical values just to get back to the same place a "1.0" housing would be. Thanks for your feedback!
Man I wanted to go G30-900 divided 1.06 A/R W/ Twinscroll Tubular manifold. BUT now I have to consider a G30-900 1.01 Vband with single scroll tubular mani
Easy: Always go with the bigger option. 👍🏻
Awesome info this explains so much . Thanks 💪👊
@realstreetperformance if you don't mind, what are your thoughts on a divided 88/89 turbo with a .96 AR and a quick spool valve on a built LS3 motor?
dope stuff jay
Maybe a dumb question, but why do promod turbos have those 2 bolts in the exhaust housing. Is it for safety being larger??
So the turbine doesn't exit the down pipe at 100000rpms and kill someone in case of a failure.
Been wondering if I could cure my boost creep with a bigger housing
Bigger waste gate if the waste gate is too small it can't control boost.
If you have creep, yes a bigger wastegate will help control boost, but my experience has shown a larger housing is the better option. If you have a reasonable turbo/wastegate setup, and are still experiencing creep, a larger turbine housing may give you a nice bump in power without much if any loss in response, plus control of the boost.
Thanks Jay. Your knowledge and wisdom is priceless.. Love that you stay out of the unnecessary debates 😂
Superchargers are faster! /s
What about different frame sized turbos, or different brands. Like a t25 frame .64 housing compared to a .63 t3 housing compared to a .68 t4 housing? Is .80-1.00 a good range no matter the turbo or are you being specific to a certain frame size
Thanks lots learned here. Great vid
What I really want to know is what is Jay's "cold, cheap beer" preference?
Amazing video ! Please do a part 2 with some real examples !
We're working on it! Thanks
Why does the vband manifold make more power ?
Straight forward info...thanx!
Class video as always and technically mega ❤
Teacher Jay good morning.
Can u ise a twin scroll in drag racing ?
Which is better for 4.3L Syclone 500 whp range 66mm compressor wheel with P trim turbine wheel .82 T3 a/r or divided T4 .81 70mm compressor wheel ball bearing Q trim turbine wheel?
man i wanted to ask about holset turbine housing since they are designated as cm^2 like mitsubishi .... but thanks for this info, everything i know i learned on superstreet (turbo edition) :) honda-tech helped
You can calculate centimeter squared to A/R ..For example an A/R of 0.89 is 12 cm squared....
Because holsets are for diesels would they require a naturally larger turbine to perform as well as a precision or garret equivalent? If I used an 8cm housing would it spool as quickly as it should or would it need to be 14cm because holsets are designed on diesels like that
can a turbo T4 open be connected with a manifold that has a T4 twin scroll or the opposite?can a turbo t4 twin scroll be connected to a T4 manifold open? will it have its cons and pros?
Whats better for the same exhaust flow? Small a/r big exhaust impeller. Or the other way around ?
As wheel size (MASS) increases the turbos loose transient response. A larger wheel with a smaller housing isn't ideal. It's about a balanced approach and then operating the system at a desirable pressure ratio. Ideally you want to make the power you'd like while having less pressure in the exhaust side of the engine than the inlet side. Thanks
Hold my beer)
Twinscroll spins the turbo earlier, which widens the operation engine range. If you're into drag racing then this probably won't matter much to you. But if you're drifting, it's important to have high turbo RPM in the low to mid range engine RPM.
The turbine spins up earlier due to the fact that the cylinders are connected in the correct order and do not have a stray influence (pressure pulsation during valves operation) on each other.
I think it would be great if you made a practical video on the topic, where you showed the difference in numbers. And then they would give the followers the opportunity to make an independent decision
Hopefully you are enjoying your cold cheap beer 🤣🤣
the real question is where to you buy just the back housing only? currently with a t4 .83 A/R and want to go a tad over. thank you
That depends on the brand. We have the major brands within reach. Thanks
@@jaymeagher1510 precision 6266 t4
@@ohhman9400 That's easy, call Real St. Depending on how long the turbo's been in service you may struggle to remove the housing. If it's been a couple years I'd remove the turbo off the car and place it on a bench EX housing down. Soak the hardware with PB blaster overnight. From there it's just working the hardware out and using a rubber mallet to break the housing free of the turbo's heat shield. Thanks
Great video
5:25
Jay just INSULTED the stretched tire community 🤣
Why is everyone omitting VGT turbos lately? MotoIQ just did the same...
My turbo used come on boost at 1800rpm and peak at 3000rpm I noticed my map filter is cracked and has oil now the car is surging in power. No boost at 1800 comes in very very hard and late at 2000rpm and peaks around the same 3000ish rpm.
Can we get something on superchargers? Because I have zero interest in turbos
I paired a GTX3076r with a .64 a/r to my SR20 but the exhaust choked out at 20lbs of boost at 6800 rpm. I’ll be installing a .86 turbine housing shortly. Do any of you guys have any advice for the swap?
I understand how thw turbo can choke the exhaust at hight boost levels, but how dies it at high RPM? Shouldn't the wastegate be able to flow the eccess gas flow?
You just lose efficiency as the exhaust is trapped in the system. Remember it's just an air pump. The wastegate is there trying to maintain a user prescribed manifold pressure value. Thanks
I have the on3 n54 “ t4 “ vband turbo manifold .. it has the single round vband hole . Not the 4 bolt t4 flange … I’m confused on what turbine housing fits mine . Can anyone help me please
I’m Looking to run a garrett style “pulsar” turbo like a g35 or gtx35 and don’t want to order the wrong stuff 😅
"That .8 to 1.0 range is a very organic position to be and it will compliment the size of the wheels well..."
"...you just want to get as close as possible, that .8 to 1.0 range won't do you wrong..."
Uncle Jay, does this also apply if you are twin turbo instead of single turbo? 🤔
In the examples I've been around we've just stuck to the same approach. I had a 2jz with twin 6466 and .82 housings and it was making good boost by 6,000 and ran extremely well. On the Coyote engines it's the same routine, we're running close to 1.0 and they spool and perform very well. I'd venture to say the guys that have been immersed in the R35 community can chime in. It really comes down to the powerlevel and the pressure ratio that's required to make it. If you can keep the back pressure down the engines are less knock prone and live longer.
@@jaymeagher1510Thanks Uncle Jay. 👍 I'm using two T25 flanged GT2860RS turbos with .86 A/R on a 1JZ, so the goal was power (600hp-700hp using 108RON Unleaded jungle juice) but more importantly, response across a wide rpm range.
The build has been catered for response and building boost as soon as possible, hence the small turbos and using not as wild cams (264s) to keep that response. 😎
Can a T3 63.Ar GT35 gen 1 turbo handle 550 whp K20? I daily drive it but do like top end dragging on freeway lol
Prolly, buuut u just said u like top end power. Get the .82 you will definitely have power where the k series likes to make power vs the .63. K series have alot of headflow, so the .63 would just hold you back.
Interesting that v band inlets don't incorporate twin scroll variations, think it shows there not really effective.
Except for they do, Garrett offers split Vband setups
I've also seen late model Ferrari's with split round housings. They're effective at low engine speeds. Thanks
👍👍
So basically, I should buy the biggest turbo for my Altima and tune it up to 50 psi.
Jk jk awesome video
Big altima energy!
🍺
Don’t agree at all about twin scroll only helping at low rpm. It’s less about transient response and simply where in the rev range the turbo spools.
That’s just simple fact.
I prefaced with the OEM approach where twin scroll has the largest impact. The aftermarket is muddy at best on the subject. I'm not saying there's "nothing to be gained" but will take the position that there's way more opinions surrounding the subject than data. Thanks
keep simpel ,,,,,PROCHARGER for ever
Any one in the comment wanna inform me on A/R ? I'm looking for best response and lowest backpressure for a 2jz not interested in going over 500HP Happy with 400HP
You can do that easily with the factory turbos on a 2JZ-GTE and have better response than 90% of aftermarket turbos. Just exhaust, intercooler and boost rise and voila.
@@MafiaboysWorld Oh I know the USDM twins could but that is not at all what is available to me, its NA
@@streetinfamy GE head peasant. 😛🤣
To be honest, a G25-660 might be your best option there. Available as T25 flange or V-band. 👍
As Jay said, lower A/R means better response but the turbo itself will choke out at higher rpm. Also factor in manifold runner sizing for this as that can also affect how the turbo absorbs the exhaust gases to turn in the first place. 👍
@@MafiaboysWorld aye, it's a hard life, the life of a pirate, yeah ive looked into those $$$$, there is the option to swap a 1JZGTE head on since the 1J block froze but man what a hassle after finally getting the NA going... thanks for the scoop
@@streetinfamy in reality, both heads are awesome. Some argue the GE is better than the GTE. I totally agree that the GE is much better than the SMALL PORT vvt-i versions of the 1JZ/2JZ but the BIG PORT Non-VVTI? Hell no and I'll die on this hill fighting anyone over it! 😂👍
😂😂😂😂😂😂 @ 4:04 comment.
Joe Rogan as a mechanic lol
The Chevy 350 was the best engine ever built, change my mind.
Nah the Barra mate
Got to disagree with cross plane cannot be the best ever, it's just not engineered that well. Best cheap engine maybe but anything better balanced is nicer IMO
Superchargers are better
Only for V8s.
Incredibly subjective but okay.
Better at parasitic power loss sure. Trash in every other possible way
Really though I like my k20s with NOS and any 2jz or RB's get supercharged and any V8 loke the coyote or ls gets the N/A treatment. Turbos run too hot.
@@marcscarthingsandstuff then you're doing it wrong
I'll join you with another cheap beer jay 🤣🫡