Fenris Ulf

iTrader: (-1)

Actually on their website it says they are high temp coated, explaining the non-stainless look....

TurboMaestro

iTrader: (2)

OK does anyone think a tubular manifold would help with low end power/launches? Less manifold pressure due to larger runners?

MalibuJack

iTrader: (5)

It should help low end torque a little, but only if its tuned as such, where it will help a little (assuming the tubular manifold is high-temp coated) is exhaust velocity and expanding gasses should lower the spool RPM's slightly, that in turn should boost power a little at lower RPM..

EVOeight

I kept the factory exhaust manifold. I have ported, polished, and ceramic coated it. Just another option for those who don't want the header. Check it out here: http://users2.ev1.net/~subaru/evo_web/evo_exhaust.htm

Huscroft6

iTrader: (2)

Quick question, I actually just ordered the DNP manifold from Lancer Shop as well as a few other things, Studs, injectors etc. But Im not upgradng my O2 housing quite yet. Would that be any kind of problem not upgrading the O2 while upgrading to a tubular manifold?? Most people Ive talked to personally say no problem but I sa this thread and figured to throw it out there......

EVOeight

You will not have any kind of problems with the stock O2 housing. You could get a slight improvement going with an aftermarket one, or even porting the stock one but neither are neccessary. The stock piece is very good...

Fenris Ulf

iTrader: (-1)

A tubular manifold will generally have longer runners which will improve lowend torque and and time to spool through the helmhertz effect. So yes it will help in launches somewhat.

Guack007

RNR racing has a sweet manifold for around $1000 it comes coated and is guarenteed to never crack.

alleggerita

Unless the volume is less or the same as the stock manifold I would not expect improvement in spool (assuming same heat retention within the manifold). However, less interference between cylinders may improve low end torque unless the length and/or volume of the manifold go up too much. In a turbo engine, in comparison to normally aspirated, the shorter path and retention of heat energy is much more important than the theoretically ideal length of the manifold with regard to gasflow interference.

Fenris Ulf

iTrader: (-1)

I agree, but the exhaust for a turbo engine pre-spool is treated as an NA engine with a dynamic restriction, the turbine. Thus longer runners that are equal length will improve the strength of the twin scroll design, improving time to full boost. Once the turbo has spooled, the shorter runner and larger pipes will offer the least restrictive path to the blades and improve power in boost.

EVOeight

The way I understand it:
Smaller runners increase exhaust gas velocity and will increase low-end torque and help the turbo spool faster, but becomes a restriction at higher RPM's.
Larger runners decrease the exhasut gas velocity hindering low-end torque and causes the turbo to spool a little slower but increases the high RPM power...

MrBubbler

iTrader: (8)

well i have run the JIC manifold for about 10k miles of hard canyon driving and the hot cali heat to boot and i have had no problems with it at all exept i went with a gt35r and a RnR equal length tubular manifold = X if anyone is looking for a JIC headers with 2000 degree thermal coating lemme know = )

Fenris Ulf

iTrader: (-1)

Right, that is a generalization about runner cross-sectional area, but there are other factors at play. A longer runner will improve low end torque production because pulses traveling near the speed of sound reflect back through the runner once it meets the collector or a step in the runner. If timed right, these pulses will add their energy to the subsequent exhaust charge and thus cause an improvement in spool. Many factors going on here

evo400

2.4 bar held on a stock manifold !!! also apt kit here in the uk well over 500hp so far !
i have fitted so many stainless manifolds NONE have ever lasted more than a couple of months before cracking even the HKS kits CRACK !!!!!!! save money and stay stock !!!!! as all my customers do

Guack007

Have you tried the RNR manifold evo400. I think it was moses or someone over there in the UK that just loves it. It will never crack.