I have a fully built t3/t4 turbo s2k, after building the motor with a revhard kit. I learned on the dyno of bad back pressure, due to my multiple exhaust issues. I had cast iron manifold, 2.5dp, 2.5 test pipe & 2.5 hks high power (which has 2.5 pipe to split to 2 by 2.25 inch pipes to mufflers, also includes a one way air tank between mufflers) exhaust. Could only tune at 17psi with no vtec to get rid of back pressure. Temporary of course, I ordered steed speed manifold, 2.75 test pipe & straight back single 2.75 invidia exhaust. Now my problem is downpipe, i can't find any thing bigger than what i have with out customizing. Will i be okay with the new exhaust set up with same downpipe? I truely think the problem was a combination of cast iron manifold with N/A exhaust. Looking to make 450-600whp. What to do, and advise would be appreciated. Just to note that the exhaust side of turbo is only 2.5inches. thx

 

The steed speed manifold won't be that much better than the Rev Hard. They are both log manifolds.

The 2.5" downpipe won't help, but if it is short, it shouldn't hurt too much.

What type of T3/T04E do you have? The 60 trim T04E may make 450 whp, but that will be its limit. This turbo could be a limiting factor. What is the turbine housing's A/R ratio?

Tim

 

New manifold, turbo, and downpipe will fix it. The downpipe isnt so bad, but the other two just wont cut it.

 

for 600 your gonna want at least 3 inch piping