HTA 35R VS 35R Twin Scroll Pump Gas on both
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From: Australia
Well said Ted B, its all about the area under the curve and the usable powerband...
On the 30R vs. the Green, most people over look the PSi vs. PSi side of the debate.
the Stock frame Turbo has a smaller Turbine side and a smaller Compressor side that a 30R...
At 23psi the Evo 9 Turbo is a 400HP Turbo and the 30R is a 500HP Turbo...
.
On the 30R vs. the Green, most people over look the PSi vs. PSi side of the debate.
the Stock frame Turbo has a smaller Turbine side and a smaller Compressor side that a 30R...
At 23psi the Evo 9 Turbo is a 400HP Turbo and the 30R is a 500HP Turbo...
.
Just because we haven't seen it (yet) doesn't mean that it cannot or will not happen. Like the others, it just requires the right hardware and a suitably twisted individual.
(corrected)
Last edited by Ted B; Apr 29, 2008 at 10:19 AM.
Evolutionboy67 I'm quoting Tom@ETS
To benefit in spool from the twin scroll package, you'll need both the equal length manifold and twin wastegates to keep the pulses separate all the way into the turbine. Using one wastegate combines the pulses thus negating the twin scroll effect and using an unequal length manifold puts the pulses at the collector on either side at different times, again negating the benefits of a twin scroll design.
To benefit in spool from the twin scroll package, you'll need both the equal length manifold and twin wastegates to keep the pulses separate all the way into the turbine. Using one wastegate combines the pulses thus negating the twin scroll effect and using an unequal length manifold puts the pulses at the collector on either side at different times, again negating the benefits of a twin scroll design.
There is absolutely no reason to use two wastegates in a twin scroll set-up, unless dictated by packaging or ease of integration on the manifold.
A single wastegate simply requires that the flow paths from both "sides" of the exhaust manifold remain divided all the way up to the wastegate valve. This requires careful fabrication of the wastegate feeder tubes, but little more.
Again, on a twin scroll setup, there is ZERO inherent performance advantage to running two gates.
Also, the comment that: "an unequal length manifold puts the pulses at the collector on either side at different times, again negating the benefits of a twin scroll design" is nonsensical. There is, by design, no collector in a twin scroll setup.
The theory behind twin scroll and how/why it works is based around keeping the pulses separate into the turbine. Using a common wastegate negates that benefit as the pulses are combined and can cancel each other out in that case. If we were talking simply about flow, sure that would work, but we're talking about sound waves.
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
The theory behind twin scroll and how/why it works is based around keeping the pulses separate into the turbine. Using a common wastegate negates that benefit as the pulses are combined and can cancel each other out in that case. If we were talking simply about flow, sure that would work, but we're talking about sound waves.
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
This means that running two is not necessary or that the gains from running a truely divided wastegate setup is not that advantageous(esp considering cost) vs a divided runner single wastegated setup.
Scorke
I talk to Nick from DTM on a pretty regular basis and those guys are doing a great job with their testing! This is another of those theory vs. practice situations where the established hardcore theory may not translate to performance as much as it might seem it should. It's something we experience pretty regularly, and the end resuilt of testing those theories is a great power/dollar ratio for everyone! 
Tom
Tom
The theory behind twin scroll and how/why it works is based around keeping the pulses separate into the turbine. Using a common wastegate negates that benefit as the pulses are combined and can cancel each other out in that case. If we were talking simply about flow, sure that would work, but we're talking about sound waves.
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
There is also significant removal of context with regard to the latter statement. When trying to explain the basics of the twin scroll principle and manifold design in general, basic description of the process and why equal length, merge collectors, etc. are used is what was being explained
Tom
This is the wastegate feed of a properly integrated single gate on a twin scroll app. It achieves the exact same degree of pulse separation as using two gates.
I don't have the sheet right now, since I am at home, but I do have the TQ curve.
Some quick math at 6650 rpm we are making about ~380 wtq. that is about 474 whp, if i have my basic arithmetic right.
Last edited by EFIxMR; Apr 29, 2008 at 11:57 PM.
To put theory to the test, Nick from DTM will be doing two tests with two different manifold designs: one with a single wastegate and the other with two. I'm really looking forward to the results. 
Stayed tuned...
Stayed tuned...
It IS usually easier to achieve an appropriate wastegate orientation using two gates (since the feed tubes are more of a straight shot to each wg valve). With a single gate, the feed tube that "wraps around" poses integration challenges. But this has no effect on pulse conversion.
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