engine is a 100% stock f20c. The only thing that was changed was the turbo manifold. All manifolds are t3 single/open scroll. The turbo was a old school garrett ball bearing t3 50 trim with a 5 bolt .63 ar hotside. First manifold was a rev hard log. Second manifold was a mase tubular sidewinder. Third manifold was a trackforged tubular sidewinder eaqule length manifold.

First manifold is a rev hard log

blue line is the most boost I was able to run on 91 octane showing just under 10psi. Red line was e85.



second manifold is a mase manifold. This manifold along made 60whp more on 91 octane at almost the same boost level but spooled 800 rpm slower than the rev hard log manifold.


red line is 91 octane and blue line is e85


Third manifold is the trackforged. Notice the runners are much longer than the mase manifold and this manifold had all equal length runners. This manifold made all most the same exact power as the mase manifold but spool 200 rpm slower due to the longer runners.


This grap shows the spool of the trackforged vs the mase. This shows 200rpm slower spool of the trackforged manifold. Boost plots showing 91 octane and 11psi on both manifolds.


A picture of my current engine bay with the track forged manifold.



This tells my the ideal t3 single/opens open scroll manifold would have a merge collector with all the runners being as short as possible and that eaqule length does nothing for power production. The shorter the runners the faster the spool.

 

Good info

 

nice! been waiting for someone to do a test like this again. I always felt like that full race manifold test with the tubular log vs the ramhorn was a lil bias:p All in all which manifold setup was the most "fun" to drive around on the street with?

 

Glad you did the test, though this further validates the theory that was located in the FAQs entitled "which manifold is for me?"

 

The perpose of this thread is just to show the differents in spool with different manifolds. But I would not ever recommend a log manifold for a s2000 as the s2000 flows so well it holds back power a great deal. On straight 91 octane I was only able to make about 340whp with the log manifold. With the tubular manifolds I make almost 400whp on straight 91 octane. Although the log manifold spooled noticeable faster and made more power under 4k rpm, the car fell on its face and had no top end power. Sort of felt like an Evo with a stock turbo but not as bad.

With the tubular manifold the cars top end power was much much better as I gained 60whp on straight 91 octane. These results were only exaggerated even more on e85/race gas.

For a street car for a t3 undivided setup u want a quality manifold that wont crack with a 4-1 mearge coolecter with the shortest runners possible.

 

AKA InlinePro

 

Thanks for the info... It's really good to see this type of data especially on an F20

I've had many unofficial tests on spool, but the relationship is never a "one size fits all" type of scenario though.

With a small turbine wheel, it's easy to saturate the manifold full of exhaust gases and spool up the turbo quickly. A small turbo will spool quickly with a short runner manifold and when the engine size vs turbo sizing is within very streetable regions. e.g. GT30R on a 2.0L

With a larger turbo, like a GT42R or bigger, it demands exhaust velocity at the turbine wheel to spool up. Because the turbine wheel is so big, it doesn't fully rely on bulk exhaust flow and pressure to spool the turbo, but rather the high exhaust velocity and energy to "crash" into the wheel and get it going. This is when longer runners can allow exhaust gases to maintain velocity, and along with a nice merge collector, it can achieve highest velocity just before the turbine wheel. With equal length in mind, it keeps the pulses evenly spaced for best spool up and response.

You will quickly find that a log manifold with a massive turbo will never spool up properly and very slow to reach peak turbine speed. For example, a B18C with a 67mm T4 turbo will simply hate a log manifold or any type of short runner unequal length manifold.