i currently have the 2.5' mandrel bent stans iszuzu performance piping but when i get the turbo on i was thinking of running 3'......
i only plan on making roughly 260ish hp at the most as im on a stock bottom end still and was wondering if going to 3' would be too big still
or i could run a 2.5inch downpipe to 3' exhaust... im stumped as to what will work out
You can also get an electric cut out! When you are planning on getting on it then you can open it in 5 seconds! close's in 5 seconds as well. Then you can run 2.5" and not have any problems!
We have instilled them on alot of SRT-4 which is the same size engine and we have seen 15-20 horse power gain. just a thought!
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3" turbo-back piping would be ideal. Using the 2.5" downpipe and 3" cat-back like you mentioned would work fine, but since you'll have to make a new downpipe and you're going to redo the whole exhaust anyway, why not just go all 3"?
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450WHP Turbo Ecotec swap in the works...
ive got a 2.5" downpipe with 3" exhaust with a side dump and it sound mean as he11 it doesnt have an import sound to it at all. but the bigger the exhaust the better for turbo applications.
12.7@110MPH with 10PSI.
the bigger the better with boost, i run 2 1/2 on my N/a motor, so it might be a little small for a turbo, my bro has 3.5 on his WRX, But he has 536 to the ground
fully built 2200-TO4E T3/T4-HP tuners-373hp @18psi
fatcavy04 wrote:but the bigger the exhaust the better for turbo applications.
HALF right. You can go too big with a turbo exhaust too and lose a lot of low end grunt. I ran 2.25in DP into a 3in side exit exhaust for 6 months. When we put the muffler on and finished the exhaust out the rear we picked up a TON of low end torque and a bit of high end HP as well. Just goes to show you that you need SOME resistance in the system. 3in will be fine but don't go crazy and think that just cause your turbo'd a 4 or 5in exhaust will be perfect for you. I wouldn't go bigger than 3in on any F/I J-Body application not pushing over 20PSI.
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Team Vision Racing (aka hypsy) wrote:fatcavy04 wrote:but the bigger the exhaust the better for turbo applications.
HALF right. You can go too big with a turbo exhaust too and lose a lot of low end grunt. I ran 2.25in DP into a 3in side exit exhaust for 6 months. When we put the muffler on and finished the exhaust out the rear we picked up a TON of low end torque and a bit of high end HP as well. Just goes to show you that you need SOME resistance in the system. 3in will be fine but don't go crazy and think that just cause your turbo'd a 4 or 5in exhaust will be perfect for you. I wouldn't go bigger than 3in on any F/I J-Body application not pushing over 20PSI.
Actually that is absolutely right that bigger is better for a turbo engine - assuming we're talking about turbo-back piping. You don't want ANY resistance anywhere in an exhaust system, especially on a turbo. I have seen some weird results with a small downpipe and large cat-back piping so it doesn't entirely surprise me seeing your gain. Had you swapped you're little 2.25" downpipe for a 3" pipe to match the rest of the exhaust, you would've noticed even more of a gain in low and high end power.
You don't need exhaust velocity on a turbo engine to make low end power. The bigger the piping, the less resistance there will be on the turbine, the qucker it will spool, and the more power it will make on the low end.
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450WHP Turbo Ecotec swap in the works...
