proof needed! - A/M dumps needed to run upgraded turbos!?

[archaeic_bloke]

im really looking for proof of the often heard claim that when you upgrade the twins to GT2860R-5's you also really need aftermarket turbo outlet pipes lake those Tomei or HKS ones or they lag terribly!

is this true? does anyone have any dyno graphs of the comparisons? can anyone contribue a dyno graph? or even some knowledge?

please!

im basically just trying to decide wether i should install these while the engine is out (even though i don't have any aftermarket turbo outlets yet) or wait because the car would be too laggy and not fun to drive?

[BenC]

From what I understand you're letting the exhaust out of the turbine side quicker with larger outlets. So you should see some decent gains. It's probably a good idea to swap those out while the motors out. Looks like a pita while its in

[Skym]

Stock dumppipe is ok to a certain boost level / hp. Then you upgrade, as the diameter of stock dumppipe becomes a restriction.

Should notice torque increase at a lower rpm, increase in response, increase in hp with aftermarket single dumppipes like HPI or TOMEI. Some notice a increase in boost level (0.08bar or so on a Silvia), which is a result of engine / turbo breathing better.

For example with a S15 2 litre SR20DET and stock turbo with intake, full 3" exhaust from stock dumppipe, FMIC, FPR, fuelpump, PowerFC ECU + boost control solenoid option, Z32 MAF, you could run 1.2bar for 198rwkw with stock dumppipe vs 1bar for 200rwkw with aftermarket dumppipe. R32 RB20DET is similar with stock turbo and same mods.

But on GTR dumppipes are best done with a cam upgrade (Poncams), ECU retune, etc, that can take full advantage of the bigger diameter dumppipes. Nismo do this with S -tune R32GTR (stock R34 GTR turbo's, Nismo dumppipes, Stune cams, stock ECU retune, upgraded (colder heat range) NGK sparkplugs, metal headgasket -

http://www.nismo.co.jp/omori_factory/original_menu/engine_m/s1/index.html

[Daryl @ RightDrive]

Short answer, you don't need to, but it's a better to. I use the Trust extension front pipe with my HKS turbos.

[GTRADDICT]

From what I understand you're letting the exhaust out of the turbine side quicker with larger outlets. So you should see some decent gains. It's probably a good idea to swap those out while the motors out. Looks like a pita while its in

+1...

[malibusst]

in a clean running car, you can see 33+hp gains. depending on past modifications,

[archaeic_bloke]

hrm... do you think its a waste to install the turbos without doing dump pipes too tho?

[CelicaKidd_205]

Yeah probably. If you already have it apart, you might as well. Maybe not as extreme but it's kind of like changing your timing belt without doing the water pump too.

[falcon]

no, not a waste. And you can pop on new dumps when you get them pretty easily.