twin scroll hype?
Sep 30, 2007, 02:15 PM
#17
I realize that a dynograph isn't going to demonstrate partial throttle response, but I feel like a good part of a turbo's transient response can be shown by taking note of the degree of slope of the initial torque curve upon going WOT on the dyno...
Of course, this doesn't measure from the time the gas pedal was pressed, but it should tell some of the story.
correct me if I'm wrong...
Of course, this doesn't measure from the time the gas pedal was pressed, but it should tell some of the story.
correct me if I'm wrong...
Sep 30, 2007, 04:35 PM
#18
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If I'm following what Ted's getting at it won't.
It'll only show up in varying throttle conditions more experienced by your *** in a d/d situation. Or like a road course.
It'll only show up in varying throttle conditions more experienced by your *** in a d/d situation. Or like a road course.
Sep 30, 2007, 07:12 PM
#19
I've said this maybe a dozen times before, and I'll say it again for the benefit of those who haven't seen it . . .
Unless or until one has an opportunity to drive a properly equipped, properly tuned TS setup, he will be in the dark to some extent. No amount of posted dyno sheets (not even the dozen or so that Geoff has presented) can replace this type of experience. And where dyno charts are concerned, they don't (typically) show spool time, transient response, or what happens for the remaining 99% of throttle position, which more or less constitutes 90+% of driving time. These things just cannot be relayed through a keyboard or screen, so until one has the opportunity to test a familiar configuration in TS, he'll just have to be patient until he can. There's no way around it.
That's all (from someone with first-hand experience and nothing to sell).
Unless or until one has an opportunity to drive a properly equipped, properly tuned TS setup, he will be in the dark to some extent. No amount of posted dyno sheets (not even the dozen or so that Geoff has presented) can replace this type of experience. And where dyno charts are concerned, they don't (typically) show spool time, transient response, or what happens for the remaining 99% of throttle position, which more or less constitutes 90+% of driving time. These things just cannot be relayed through a keyboard or screen, so until one has the opportunity to test a familiar configuration in TS, he'll just have to be patient until he can. There's no way around it.
That's all (from someone with first-hand experience and nothing to sell).
I also disagree with not being able to see turbo response on a dyno pull. I drove half of those cars on my my spreadsheet.. The first three boxes tell you how responsive the setup is.
The simple fact is when you switch to twin scroll the biggest thing that happens is you change the a/r. And since there is no way to tell which direction you are actually changing it (bigger or smaller) back to backs at this point aren't telling us much. In the case of this 3071 swap. The 78 divided was likely just a smaller a/r than the open 63. The open 63 worked better. No amount of off boost feel, or transient response makes up for 400rpm loss in spool.
As I haver said before. When you switch to twin scroll and pick up performance it likely due to finding the ideal a/r for the turbine and not because the twin scroll itself made the difference.
Sep 30, 2007, 07:51 PM
#22
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If you were to find a better match for either housing, both would respond better.
Like which is better for a FP red, a 7cm or 8 cm housing? Going to an 8cm housing made the car a little laggier but more top end.
My take on this is that if you compare a DSM with 16g and an Evo, which would win in a race? They both have similar output, but the Evo has way more fun factor getting off it's own face.
Sep 30, 2007, 08:21 PM
#23
There is no difference in what you are saying between a TS and a SS. Switch a 9.8 TS to a 10.5 and what do you get?
If you were to find a better match for either housing, both would respond better.
Like which is better for a FP red, a 7cm or 8 cm housing? Going to an 8cm housing made the car a little laggier but more top end.
My take on this is that if you compare a DSM with 16g and an Evo, which would win in a race? They both have similar output, but the Evo has way more fun factor getting off it's own face.
If you were to find a better match for either housing, both would respond better.
Like which is better for a FP red, a 7cm or 8 cm housing? Going to an 8cm housing made the car a little laggier but more top end.
My take on this is that if you compare a DSM with 16g and an Evo, which would win in a race? They both have similar output, but the Evo has way more fun factor getting off it's own face.
I have driven a galant with evo 3 16g that made 411/433 on mustang dyno. I have yet to drive an evo8/9 that made that much power on stock turbo. curt brown recently built a talon with evo3 turbo. he made 455whp on E85. theres not any evidence that suggests the evo8 turbo is much better than an evo3 turbo. at full song they both move the same air. the evo8/9 is more efficient but max power potential is actually the same.
I have not yet seen any proof that twinscroll is worth it. I'll standby till someone proves otherwise.
Sep 30, 2007, 09:07 PM
#24
The fastest FP red time was done on the 7cm.. 143mph.
I have driven a galant with evo 3 16g that made 411/433 on mustang dyno. I have yet to drive an evo8/9 that made that much power on stock turbo. curt brown recently built a talon with evo3 turbo. he made 455whp on E85. theres not any evidence that suggests the evo8 turbo is much better than an evo3 turbo. at full song they both move the same air. the evo8/9 is more efficient but max power potential is actually the same.
I have not yet seen any proof that twinscroll is worth it. I'll standby till someone proves otherwise.
I have driven a galant with evo 3 16g that made 411/433 on mustang dyno. I have yet to drive an evo8/9 that made that much power on stock turbo. curt brown recently built a talon with evo3 turbo. he made 455whp on E85. theres not any evidence that suggests the evo8 turbo is much better than an evo3 turbo. at full song they both move the same air. the evo8/9 is more efficient but max power potential is actually the same.
I have not yet seen any proof that twinscroll is worth it. I'll standby till someone proves otherwise.
This is a good thread
Sep 30, 2007, 09:38 PM
#25
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The simple fact is when you switch to twin scroll the biggest thing that happens is you change the a/r. And since there is no way to tell which direction you are actually changing it (bigger or smaller) back to backs at this point aren't telling us much. In the case of this 3071 swap. The 78 divided was likely just a smaller a/r than the open 63. The open 63 worked better. No amount of off boost feel, or transient response makes up for 400rpm loss in spool.
I have driven a galant with evo 3 16g that made 411/433 on mustang dyno. I have yet to drive an evo8/9 that made that much power on stock turbo. curt brown recently built a talon with evo3 turbo. he made 455whp on E85. theres not any evidence that suggests the evo8 turbo is much better than an evo3 turbo. at full song they both move the same air. the evo8/9 is more efficient but max power potential is actually the same.
I have not yet seen any proof that twinscroll is worth it. I'll standby till someone proves otherwise.
you cannot compare an E3 16g on a DSM to an evo with a stock turbo. first off, people have been tuning DSM's since the 80's here in the states. we have had 4 years of the evo. give it some time, I guarantee people will be pulling rediculous numbers off the stock turbo's. I believe theres someone locally who is close to 400 wheel with bolt-ons and a flash. thats a stock turbo car. and they will drive far better than any DSM.
Sep 30, 2007, 09:56 PM
#26
A "back-to-back" test between the two is a waste. The twin scroll setup will prefer bigger cams, higher compression, and larger turbos while still offering awesome response. Building a twin scroll setup and not taking advantage of these benefits is a waste of time and money.
I have a dyno plot of a TS vs. undivided GT42 car though and the divided setup KICKS THE **** out of the undivided setup in every respect. On the time scale, it gets to 600+ HP a LOT sooner. It also made almost 130 WHP more up top too. RPM wise, it more then made up for a larger compressor wheel and a lack of BB center section. But hey, it was a 4% bigger motor with a larger compressor wheel, so it's not a direct comparison.
The difference in feel between the cars was astonishing. One felt like a 700HP turbo 4-cylinder (laggy). The other felt like a big block chevy with boost on top. Take a wild guess as to which is which.
*** Honestly people, how is this stuff a "good read" though? Everything posted (including my own post) is merely opinion.***
I have a dyno plot of a TS vs. undivided GT42 car though and the divided setup KICKS THE **** out of the undivided setup in every respect. On the time scale, it gets to 600+ HP a LOT sooner. It also made almost 130 WHP more up top too. RPM wise, it more then made up for a larger compressor wheel and a lack of BB center section. But hey, it was a 4% bigger motor with a larger compressor wheel, so it's not a direct comparison.
The difference in feel between the cars was astonishing. One felt like a 700HP turbo 4-cylinder (laggy). The other felt like a big block chevy with boost on top. Take a wild guess as to which is which.
*** Honestly people, how is this stuff a "good read" though? Everything posted (including my own post) is merely opinion.***
Last edited by 03whitegsr; Sep 30, 2007 at 10:01 PM. Reason: Added some
Sep 30, 2007, 10:09 PM
#27
Several of us here have first-hand, real world driving experience in similarly prepared 3076R EVOs with both .63 A/R open and .78 A/R TS setups. The TS cars are much more responsive and spool faster 100% of the time, and one doesn't need a dyno to know the difference (it's rather stark). Just ask Sean Ivey, Drifto, or Evodan if additional first-hand observations are desired.
The physical design difference of a TS housing reveals a much less abrupt transition between primary and 'collector', and the length of the division into the turbine housing reduces the possibilty of reversion between adjacently firing cylinders. The physical differences are obvious. The actual differences can only be resolved through real world experiences, not speculation.
Last edited by Ted B; Sep 30, 2007 at 10:13 PM.
Oct 1, 2007, 05:23 AM
#28
Ted, I am on here 4 times a day. I have read all the posts on TS. Nothing you just said refutes any of my observations. My opinion is unchanged.
One question for you. How much experience do you have swapped a/r on single scroll setups? Untill you have had that experience you cant relate to what I am saying either. And switching to 10.5 form a 9.5 is a joke. No real difference there. Switching to 82 from a 63, or 48 from 63 is on the other hand huge by comparison.
EVERYONE who promotes TS simply ignores that A/R changes on the exhaust side make huge difference is spool/feel/transients. Regardless of whether its TS or open scroll.
One question for you. How much experience do you have swapped a/r on single scroll setups? Untill you have had that experience you cant relate to what I am saying either. And switching to 10.5 form a 9.5 is a joke. No real difference there. Switching to 82 from a 63, or 48 from 63 is on the other hand huge by comparison.
EVERYONE who promotes TS simply ignores that A/R changes on the exhaust side make huge difference is spool/feel/transients. Regardless of whether its TS or open scroll.
Oct 1, 2007, 06:16 AM
#29
One of my oldest observations about twin scroll. 20 years ago I asked the local go fast guys if twin scroll is worth it. One response came from someone who builds turbos for a living. His knowledge says it helps a little with spool but hurts top end. Likely the best synopsis for TS in a nut shell.
Another came from a 10 flat VW drag car owner. He switched to a t4 .70 open to a t4 .84 divided. He picked up 700 rpm spool with no loss in power. But heres the part you need to pay attention to. This car had an open header and one waste gate off the collector. NO TS MANIFOLD . The swap to the housing simply PROVES what I have been trying to tell everyone here. This car had a large increase in response from an A/R change. TS design had NOTHING to do with it.
Another came from a 10 flat VW drag car owner. He switched to a t4 .70 open to a t4 .84 divided. He picked up 700 rpm spool with no loss in power. But heres the part you need to pay attention to. This car had an open header and one waste gate off the collector. NO TS MANIFOLD . The swap to the housing simply PROVES what I have been trying to tell everyone here. This car had a large increase in response from an A/R change. TS design had NOTHING to do with it.