Twin Scroll Turbos?? Monster Spool.. FACT or FICTION???
warning!!!
FYI, that's about 50whp more than what becomes particularly risky with a stock block, especially if one is dealing with a higher mileage, tired block.
The smart move is to keep torque limited to no more than 400ft/lb, and power under 550whp. That keeps the forces of stress and heat somewhat in check, especially in the higher gears. And while there are zero guarantees by any stretch of the imagination, if you are fortunate, you won't have to add a block, crank, and possibly a head to your shopping list.
As the old saying goes, an ounce of prevention is worth a pound of cure, and we've seen plenty of a need for stock block 'cure' here over the years.
The smart move is to keep torque limited to no more than 400ft/lb, and power under 550whp. That keeps the forces of stress and heat somewhat in check, especially in the higher gears. And while there are zero guarantees by any stretch of the imagination, if you are fortunate, you won't have to add a block, crank, and possibly a head to your shopping list.
As the old saying goes, an ounce of prevention is worth a pound of cure, and we've seen plenty of a need for stock block 'cure' here over the years.
Wow I was way off. No more drinking and posting.
20psi by 4900 on a Non MIVEC 2.2 on E85. 42psi by 6300, all pulls in 3rd gear.
For giggles here is that turbo vs a 6262 in a 0.82 on a 2.0L with otherwise the same mods-
20psi by 4900 on a Non MIVEC 2.2 on E85. 42psi by 6300, all pulls in 3rd gear.
For giggles here is that turbo vs a 6262 in a 0.82 on a 2.0L with otherwise the same mods-
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From: Welly NZ
Wow that puts things into perspective, they really still don't like nice street setups - I had been wondering (given how many people seem to be going for 62-64mm turbos on road cars) until seeing that.
After reading a bit of this thread, it is interesting to see both sides of the spectrum. At any rate different setups and conditions will net different results.
One thing that is interesting though is the fact that Sierra Sierra and Nemo evos both run a TS setup for the following reasons:
In a twin scroll turbo, cylinders 1-4 are paired into one side of the turbine housing and cylinders 2-3 are paired into the other. That way the exhaust pulses are kept 180 crank degrees apart. This helps volumetric efficiency by keeping backpressure in check, gives the turbine discreet pulses for better efficiency and reduces overlap charge contamination.
Twin scroll manifolds pair cylinders 1-4 with 2-3 feeding into opposite sides of a divided turbine housing. The twin scroll utilizes the engine's pulse energy of the engine to spool the turbo faster. With the divided housing the turbine wheel is hit with 4 sequential discrete pulses, this transfers more exhaust energy to the wheel helping it spin up faster. The divided housing also improves volumetric efficiency as the overall pressure in the exhaust and turbine housing is less due to the pulses being evenly spaced out in timing. There is also less opportunity for charge contamination due to reversion because the pulses are kept separate so a pressure pulse from a cylinder on the exhaust stroke cannot back flow and contaminate a cylinder on overlap. This allows the cams to be run on a tighter lobe center which helps the engine have a broader powerband. The divided housing turbo and a twin scroll exhaust manifold can improve turbine efficiency by around 15% which can speed spool by around 1000 rpm or make up for a 25% gain in rotating mass, like some of the lag caused by a larger turbo. The twin scroll manifold is kept fully divided by running two independent Tial 38mm MSV wastegates.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno. I am sure that acute attention to detail in all aspects of the build and tune will be needed in netting those kind of results.
One thing that is interesting though is the fact that Sierra Sierra and Nemo evos both run a TS setup for the following reasons:
In a twin scroll turbo, cylinders 1-4 are paired into one side of the turbine housing and cylinders 2-3 are paired into the other. That way the exhaust pulses are kept 180 crank degrees apart. This helps volumetric efficiency by keeping backpressure in check, gives the turbine discreet pulses for better efficiency and reduces overlap charge contamination.
Twin scroll manifolds pair cylinders 1-4 with 2-3 feeding into opposite sides of a divided turbine housing. The twin scroll utilizes the engine's pulse energy of the engine to spool the turbo faster. With the divided housing the turbine wheel is hit with 4 sequential discrete pulses, this transfers more exhaust energy to the wheel helping it spin up faster. The divided housing also improves volumetric efficiency as the overall pressure in the exhaust and turbine housing is less due to the pulses being evenly spaced out in timing. There is also less opportunity for charge contamination due to reversion because the pulses are kept separate so a pressure pulse from a cylinder on the exhaust stroke cannot back flow and contaminate a cylinder on overlap. This allows the cams to be run on a tighter lobe center which helps the engine have a broader powerband. The divided housing turbo and a twin scroll exhaust manifold can improve turbine efficiency by around 15% which can speed spool by around 1000 rpm or make up for a 25% gain in rotating mass, like some of the lag caused by a larger turbo. The twin scroll manifold is kept fully divided by running two independent Tial 38mm MSV wastegates.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno. I am sure that acute attention to detail in all aspects of the build and tune will be needed in netting those kind of results.
If you dont want to watch the explanation of the flex fuel in the AEM Series 2 (worth the watch though) FFWD to 10:51 or so.
6466 with the 1.15 twin.
After reading a bit of this thread, it is interesting to see both sides of the spectrum. At any rate different setups and conditions will net different results.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno.
What Twin scroll setups can do on the street/track/moon far outweigh what you see in a dynograph. There isnt much science to it really, its a little bit of reading and then ALOT of doing. What we do doesnt look like it should be right, but it feels right when you are in the car.
Last edited by JohnBradley; Sep 10, 2013 at 07:38 PM.
A dyno chart represents only a static run in a single gear. It doesn't illustrate how TS quickens transient response. That's the first difference one notices with TS in real world driving.
@JB,
What I meant was the optimum results you will see on a TS won't be seen unless you:
I guess I should have explained a bit more. At any rate my butt dyno>everything else 
Sounds like an impressive build though. I haven't seen the vid yet due to work computers. But will check it out when I get a chance.
What I meant was the optimum results you will see on a TS won't be seen unless you:
I am sure that acute attention to detail in all aspects of the build and tune will be needed in netting those kind of results.
Sounds like an impressive build though. I haven't seen the vid yet due to work computers. But will check it out when I get a chance.
i totally agree and would like to thank you because you were the reason i went with a TS set up and the difference in response is night and day compared to my previous t3 singlescroll. my car is a lot more fun to drive and it is all due to the twinscroll set up.
Its not as bad as it looks actually. Here is the vid-
http://youtu.be/xjPZbwfItVQ
If you dont want to watch the explanation of the flex fuel in the AEM Series 2 (worth the watch though) FFWD to 10:51 or so.
6466 with the 1.15 twin.
Our Eclipse that runs 8.20@176.6 on E98 runs an HTA105 (42R) with a 1.44 Twin scroll. Properly loaded up against the converter it has made boost far lower than anyone would suspect or even guess based on a dyno sheet.
What Twin scroll setups can do on the street/track/moon far outweigh what you see in a dynograph. There isnt much science to it really, its a little bit of reading and then ALOT of doing. What we do doesnt look like it should be right, but it feels right when you are in the car.
http://youtu.be/xjPZbwfItVQ
If you dont want to watch the explanation of the flex fuel in the AEM Series 2 (worth the watch though) FFWD to 10:51 or so.
6466 with the 1.15 twin.
Our Eclipse that runs 8.20@176.6 on E98 runs an HTA105 (42R) with a 1.44 Twin scroll. Properly loaded up against the converter it has made boost far lower than anyone would suspect or even guess based on a dyno sheet.
What Twin scroll setups can do on the street/track/moon far outweigh what you see in a dynograph. There isnt much science to it really, its a little bit of reading and then ALOT of doing. What we do doesnt look like it should be right, but it feels right when you are in the car.
That was a sick video, I learned alot on how the aem can be tuned by e-content. Ideally its what every e85 user would want with their oem ecu dual maps. If I had the money I would def swtich over for those extra failsafes aem can provide!
I still find it interesting that buschur doesn't offer twin scroll.
After reading a bit of this thread, it is interesting to see both sides of the spectrum. At any rate different setups and conditions will net different results.
One thing that is interesting though is the fact that Sierra Sierra and Nemo evos both run a TS setup for the following reasons:
In a twin scroll turbo, cylinders 1-4 are paired into one side of the turbine housing and cylinders 2-3 are paired into the other. That way the exhaust pulses are kept 180 crank degrees apart. This helps volumetric efficiency by keeping backpressure in check, gives the turbine discreet pulses for better efficiency and reduces overlap charge contamination.
Twin scroll manifolds pair cylinders 1-4 with 2-3 feeding into opposite sides of a divided turbine housing. The twin scroll utilizes the engine's pulse energy of the engine to spool the turbo faster. With the divided housing the turbine wheel is hit with 4 sequential discrete pulses, this transfers more exhaust energy to the wheel helping it spin up faster. The divided housing also improves volumetric efficiency as the overall pressure in the exhaust and turbine housing is less due to the pulses being evenly spaced out in timing. There is also less opportunity for charge contamination due to reversion because the pulses are kept separate so a pressure pulse from a cylinder on the exhaust stroke cannot back flow and contaminate a cylinder on overlap. This allows the cams to be run on a tighter lobe center which helps the engine have a broader powerband. The divided housing turbo and a twin scroll exhaust manifold can improve turbine efficiency by around 15% which can speed spool by around 1000 rpm or make up for a 25% gain in rotating mass, like some of the lag caused by a larger turbo. The twin scroll manifold is kept fully divided by running two independent Tial 38mm MSV wastegates.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno. I am sure that acute attention to detail in all aspects of the build and tune will be needed in netting those kind of results.
One thing that is interesting though is the fact that Sierra Sierra and Nemo evos both run a TS setup for the following reasons:
In a twin scroll turbo, cylinders 1-4 are paired into one side of the turbine housing and cylinders 2-3 are paired into the other. That way the exhaust pulses are kept 180 crank degrees apart. This helps volumetric efficiency by keeping backpressure in check, gives the turbine discreet pulses for better efficiency and reduces overlap charge contamination.
Twin scroll manifolds pair cylinders 1-4 with 2-3 feeding into opposite sides of a divided turbine housing. The twin scroll utilizes the engine's pulse energy of the engine to spool the turbo faster. With the divided housing the turbine wheel is hit with 4 sequential discrete pulses, this transfers more exhaust energy to the wheel helping it spin up faster. The divided housing also improves volumetric efficiency as the overall pressure in the exhaust and turbine housing is less due to the pulses being evenly spaced out in timing. There is also less opportunity for charge contamination due to reversion because the pulses are kept separate so a pressure pulse from a cylinder on the exhaust stroke cannot back flow and contaminate a cylinder on overlap. This allows the cams to be run on a tighter lobe center which helps the engine have a broader powerband. The divided housing turbo and a twin scroll exhaust manifold can improve turbine efficiency by around 15% which can speed spool by around 1000 rpm or make up for a 25% gain in rotating mass, like some of the lag caused by a larger turbo. The twin scroll manifold is kept fully divided by running two independent Tial 38mm MSV wastegates.
Now these cars are at the pinnacle of their class and I would like to think that if a TS design did nothing for them why would they utilize such a setup? It begs the question why? At any rate, I will continue to do more research as turbo technology continues to exponentially advance. It is an interesting topic to say the least.
I would imagine these results aren't created by simply just bolting a TS setup on and throwing it on the dyno. I am sure that acute attention to detail in all aspects of the build and tune will be needed in netting those kind of results.
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From: Raleigh, Transplanted from Toronto, Canada
BR doesn't believe in it and he's been doing it for a while. Why would he change. I don't think TS matters for drag racing which seemed to be his main focus.
I have an oddball TS setup but it works really well on the street. Most people who drive the car comment on how quick it spools and how hard it hits and stays there.
I have an oddball TS setup but it works really well on the street. Most people who drive the car comment on how quick it spools and how hard it hits and stays there.
Can't teach an old dog new tricks?
Even drag racing though, TS is still better. Sure, if everything works out perfect, the SS setup will be on boost off the line from anti-lag and you'll hook up just right where it doesn't blow the tires off or bog, hit every gear perfectly without lifting...then, yeah the SS works as well as the TS setup. Record runs, sure, they are going to be about equal.
Have to pedal the car though? TS power delivery is more linear and will be easier to modulate torque on.
Bog it or miss a gear? TS will be back on boost WAY sooner.
Sure, you won't set a personal record in these situations. But for the sportsman type classes, being able to recover from these issues and only lose a fraction of a second will likely mean the difference between a win and a loss.
Then again, does anybody actually drag race competitively in heads up sportsman classes anymore? It’s not something I really follow.
As TedB an Aaron have said, it's more then a dynosheet. GT42R setups are crazy responsive on the street when done right. You would expect miles of lag with them, but any where over 4000 RPM, they rip to crazy acceleration rates instantly. They might not be at full boost until 5500+, but they'll be over 500ft-lbs LONG before then.
Even drag racing though, TS is still better. Sure, if everything works out perfect, the SS setup will be on boost off the line from anti-lag and you'll hook up just right where it doesn't blow the tires off or bog, hit every gear perfectly without lifting...then, yeah the SS works as well as the TS setup. Record runs, sure, they are going to be about equal.
Have to pedal the car though? TS power delivery is more linear and will be easier to modulate torque on.
Bog it or miss a gear? TS will be back on boost WAY sooner.
Sure, you won't set a personal record in these situations. But for the sportsman type classes, being able to recover from these issues and only lose a fraction of a second will likely mean the difference between a win and a loss.
Then again, does anybody actually drag race competitively in heads up sportsman classes anymore? It’s not something I really follow.
As TedB an Aaron have said, it's more then a dynosheet. GT42R setups are crazy responsive on the street when done right. You would expect miles of lag with them, but any where over 4000 RPM, they rip to crazy acceleration rates instantly. They might not be at full boost until 5500+, but they'll be over 500ft-lbs LONG before then.
Last edited by 03whitegsr; Sep 11, 2013 at 08:39 AM.
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From: Raleigh, Transplanted from Toronto, Canada
Can't teach an old dog new tricks?
Even drag racing though, TS is still better. Sure, if everything works out perfect, the SS setup will be on boost off the line from anti-lag and you'll hook up just right where it doesn't blow the tires off or bog, hit every gear perfectly without lifting...then, yeah the SS works as well as the TS setup. Record runs, sure, they are going to be about equal.
Have to pedal the car though? TS power delivery is more linear and will be easier to modulate torque on.
Bog it or miss a gear? TS will be back on boost WAY sooner.
Sure, you won't set a personal record in these situations. But for the sportsman type classes, being able to recover from these issues and only lose a fraction of a second will likely mean the difference between a win and a loss.
Then again, does anybody actually drag race competitively in heads up sportsman classes anymore? It’s not something I really follow.
As TedB an Aaron have said, it's more then a dynosheet. GT42R setups are crazy responsive on the street when done right. You would expect miles of lag with them, but any where over 4000 RPM, they rip to crazy acceleration rates instantly. They might not be at full boost until 5500+, but they'll be over 500ft-lbs LONG before then.
Even drag racing though, TS is still better. Sure, if everything works out perfect, the SS setup will be on boost off the line from anti-lag and you'll hook up just right where it doesn't blow the tires off or bog, hit every gear perfectly without lifting...then, yeah the SS works as well as the TS setup. Record runs, sure, they are going to be about equal.
Have to pedal the car though? TS power delivery is more linear and will be easier to modulate torque on.
Bog it or miss a gear? TS will be back on boost WAY sooner.
Sure, you won't set a personal record in these situations. But for the sportsman type classes, being able to recover from these issues and only lose a fraction of a second will likely mean the difference between a win and a loss.
Then again, does anybody actually drag race competitively in heads up sportsman classes anymore? It’s not something I really follow.
As TedB an Aaron have said, it's more then a dynosheet. GT42R setups are crazy responsive on the street when done right. You would expect miles of lag with them, but any where over 4000 RPM, they rip to crazy acceleration rates instantly. They might not be at full boost until 5500+, but they'll be over 500ft-lbs LONG before then.
The issue with twin scroll has been, historically, trying to run to small of a housing because the A/r sounds WAY TOO CRAZY. News flash, they do sound crazy, but thats how they work. Despite the Garrett white paper that is oft quoted (spools 60% of its size, 5/6 the power potential) it seems that many people were trying to run a big compressor with a small turbine and it wouldnt DO anything.
Case in point an Evo IX with an HTA 35R came in with a twin scroll 0.78 T3 diesel housing for us to install and tune on a 2.0L motor. I told the owner that there was no way it was going to work properly and that the housing was too small. He had the misguided notion it would spool at 2000rpm or something and drive like a big block.
Here is the initial result -
Spooled extremely horrible, was VERY knock prone, and really all in all didnt satisfy anyone. In fact for a long time I thought that it meant twin scroll didnt work and teamed up on the "other side" in this thread in fact. Keep in mind this before we started doing a bunch of testing on street cars and got a feel for what it needed to be to work right.
FFWD
Customer ran the car out of oil and wants a 2.4 now but doesnt want to swap the housing. He is convinced the car will work WAY better now with a 2.4L. Okay sure-
Same boost level but same problems. Its better but no where near where it should be of course. Again same result more or less, no one is really happy, he isnt interested in putting a 1.06 T3 on it.
For giggles here is my car as a 2.0L vs his, single scroll to twin scroll-
Now FFWD again to us testing a proper twin scroll, mod to mod other than it was an VIII vs my IX. Twin scroll 1.06 T4 vs my 0.82 T3-
Case in point an Evo IX with an HTA 35R came in with a twin scroll 0.78 T3 diesel housing for us to install and tune on a 2.0L motor. I told the owner that there was no way it was going to work properly and that the housing was too small. He had the misguided notion it would spool at 2000rpm or something and drive like a big block.
Here is the initial result -
Spooled extremely horrible, was VERY knock prone, and really all in all didnt satisfy anyone. In fact for a long time I thought that it meant twin scroll didnt work and teamed up on the "other side" in this thread in fact. Keep in mind this before we started doing a bunch of testing on street cars and got a feel for what it needed to be to work right.
FFWD
Customer ran the car out of oil and wants a 2.4 now but doesnt want to swap the housing. He is convinced the car will work WAY better now with a 2.4L. Okay sure-
Same boost level but same problems. Its better but no where near where it should be of course. Again same result more or less, no one is really happy, he isnt interested in putting a 1.06 T3 on it.
For giggles here is my car as a 2.0L vs his, single scroll to twin scroll-
Now FFWD again to us testing a proper twin scroll, mod to mod other than it was an VIII vs my IX. Twin scroll 1.06 T4 vs my 0.82 T3-
Last edited by JohnBradley; Sep 11, 2013 at 11:02 AM.