Twin-scroll skeptics...
every turbo is different and every engine is different. 2 things dont change tho -- twinscroll improves turbine efficiency. and bigger compressor wheels (aka hta) decrease turbine efficiency. both can work great and make great power, and both can work poorly and make pisspoor power. its all in the setup. if there were more engineers actually *engineering* headers maybe we'd have something to talk about
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
Last edited by Geoff Raicer; May 13, 2008 at 12:37 PM.
Split-Inlet Exhaust Housings known as "Twin Scroll" permit the exhaust pulses to be grouped (or separated) by cylinder all the way to the turbine. The reason for doing this in keeping the individual package of energy, an exhaust pulse, intact and undisturbed by other pulses, all the way to the turbine. This in turn can give the turbine a better kick to get it moving. This is specifically useful in four-cylinder engines. Because a four-cylinder only sees one pulse every 180 degrees of crank rotation, it needs all the energy it can get from each pulse. Keeping them separate and undisturbed will therefore pay back some dividends. "Maximum Boost" by Corky Bell.
Some really informative reply's being made.
FYI
I will be testing the ETS Twin-scroll HTA35R (.78 AR) to the limit later this year after my car is built. So hopefully I can give the EvoM community some hard data and find the truth in the process.
FYI
I will be testing the ETS Twin-scroll HTA35R (.78 AR) to the limit later this year after my car is built. So hopefully I can give the EvoM community some hard data and find the truth in the process.
Last edited by weap0n; May 13, 2008 at 03:19 PM. Reason: spelling
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With the big power HTAs running an .82, the ideally sized T3 TS housing to compare would be a 1.06, but I'm not sure where you would get one. I've come to the conclusion that the T4 TS may be the better option because of the greater number of TS housing choices and look forward to seeing some results with a T4.
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every turbo is different and every engine is different. 2 things dont change tho -- twinscroll improves turbine efficiency. and bigger compressor wheels (aka hta) decrease turbine efficiency. both can work great and make great power, and both can work poorly and make pisspoor power. its all in the setup. if there were more engineers actually *engineering* headers maybe we'd have something to talk about
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
What i would love to see is a car like Dave Buschur's RS or one of their customer cars do a back to back test with a TS manifold. Something like 30psi on the Buschur 35r T3 0.82 kit VS the full race or ETS 35rTS 1.01 T3 or T4.
every turbo is different and every engine is different. 2 things dont change tho -- twinscroll improves turbine efficiency. and bigger compressor wheels (aka hta) decrease turbine efficiency. both can work great and make great power, and both can work poorly and make pisspoor power. its all in the setup. if there were more engineers actually *engineering* headers maybe we'd have something to talk about
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
btw sean ivey said the twinscroll T4 35R on the STOCK evo9 motor was very fast, in his words "feels like a perfect powerband, the best road race setup I've ever driven"
... no hta, and 2 wastegates.
I think people need to get the T4 is too big thing out of there heads. On the TS if I were to do one I would do a T4 35r as it will make great power, with great spool and you have more of an option on housings and less restriction.
I for one have tested a lot of turbo set-ups on a lot of different displacement cars and I can tell you for a street car there is no doubt TS is the way to go. SS is good but you just cannot get the same spool out of it I dont care what anyone says.
I also have talked with Geoff a lot on this and the amount of engineering that goes into there manifolds is unreal. I have had the pleasure of working with these guys directly and I have learned a great deal.
Sorry for the long reply,
Mitch M
Last edited by Magnumpsi; May 14, 2008 at 12:04 AM.
This is no different than the thread I posted. More comments by more guys vouching for both sides and I'm still stuck on what I want to do.....well I'm leaning one way but that can change.
We have played with a few T3 twin scroll set-ups and have decided to sell what we currently offer since we feel it performs the best just the way it is. I’m not one to jump on the latest bandwagon or trend to sell parts but rather try to offer parts that are proven to work and work well. Sometimes I feel like I am the jackass since most of our money is made on labor and the Twin Scroll units do take a bit more labor to produce. Keep this in mind as one of the companies currently selling the Twin Scroll units were very vocal in speaking out against them just a few years ago. You can look at it two ways. Have they found new parts to make these TS units work well? Or is it a steam engine to propel their latest marketing scheme into public eyes to make a bunch of extra money? As a manufacturer, producing solid data to show these supposed gains would be a VERY key point in my marketing campaign and would be the first thing that would have been presented to the public to get ahead of the competition while you can. With the extreme lack of data to back up the manufacturers claims it has to make you wonder.
In a T3 platform with smaller sized turbos (gt30 - gt35), on an engine of this size, I have not seen any noticeable gain or benefit in the few combinations that we have put together. With as much kept the same as possible (ie. primary diameter) we have noticed some decreased spool time with them but that was negated by a loss, sometimes a significant loss depending on turbine choice, in top end power. Not an acceptable trade off, in my opinion, as we could always reduce the size of the open inlet turbine housing and see similar results.
The biggest gains that I have seen in decreasing spool time and increasing transient response is simply by reducing the primary size of the header. With some simple on road tests with a ~500hp car we have seen some pretty significant decreases in spool time and moving torque peak down in RPM’s quite a bit. The use of pipe elbows in our production headers makes primary sizing somewhat limited and I do not feel that the smaller pipe size is ideal by any means. But there are a niche of people out there whose purpose it will fit very nicely. I do not want to start blabbing that by reducing primary size you are going to see significant gains as I do not have any rock hard data numbers YET. After the tax season rush is over I will finish up some of these test pieces and off to a brake dyno they will be going for some solid numbers. Hopefully then we will have some solid data to compare our standard T3 header to the small runner t3 header. And with any luck we will be able to compare those to some twin scroll data if there is any by then.
Am I saying that twin scroll doesn’t work? No, but currently I am not a fan of it with the smaller turbos. Turbocharging technology is in its infancy and constantly evolving for the better and in a couple years time we may have parts that work significantly better for this application. With the current parts available, in and outside the US, I do not feel it is the best choice and the performance does not add up.
In a T3 platform with smaller sized turbos (gt30 - gt35), on an engine of this size, I have not seen any noticeable gain or benefit in the few combinations that we have put together. With as much kept the same as possible (ie. primary diameter) we have noticed some decreased spool time with them but that was negated by a loss, sometimes a significant loss depending on turbine choice, in top end power. Not an acceptable trade off, in my opinion, as we could always reduce the size of the open inlet turbine housing and see similar results.
The biggest gains that I have seen in decreasing spool time and increasing transient response is simply by reducing the primary size of the header. With some simple on road tests with a ~500hp car we have seen some pretty significant decreases in spool time and moving torque peak down in RPM’s quite a bit. The use of pipe elbows in our production headers makes primary sizing somewhat limited and I do not feel that the smaller pipe size is ideal by any means. But there are a niche of people out there whose purpose it will fit very nicely. I do not want to start blabbing that by reducing primary size you are going to see significant gains as I do not have any rock hard data numbers YET. After the tax season rush is over I will finish up some of these test pieces and off to a brake dyno they will be going for some solid numbers. Hopefully then we will have some solid data to compare our standard T3 header to the small runner t3 header. And with any luck we will be able to compare those to some twin scroll data if there is any by then.
Am I saying that twin scroll doesn’t work? No, but currently I am not a fan of it with the smaller turbos. Turbocharging technology is in its infancy and constantly evolving for the better and in a couple years time we may have parts that work significantly better for this application. With the current parts available, in and outside the US, I do not feel it is the best choice and the performance does not add up.
I run a custom TS setup and I love it. I see 25lbs@4500 rpm. Ran an 11.4@125 on pump gas@ 25lbs, not 28 and the spool up is amazing. Low and mid power are awesome and Compared to my old GT40R setup top end is the same or even better. The most I ever trapped on the GT40R on pump was 124. I trapped 125 on the first pass with the TS Setup. I have a "hybrid" turbo which is smaller than the gt40r, but larger tan a gt35r on a single wastegate T4 Manifold. I absolutely recommend the the TS setup. That's just my opinion.
