Custom Turbo Exhaust

[SonicStangGT]

Well I'm still running stock catback with weld in flowmasters(2 1/4). My tuner told me its holding me back at least 10-15 hp. So I've bought a slp catback minus the mufflers nd want to put 2 1/2 race flowmasters. But this is my question, would it be better since I'm have a turbo with a 3'' downpipe to run a 3 '' race muffler with a turndown and no tailpipes. Car is not daily driven and 1/8 mile racing is what I'm building for. Yes want to still drive on street but just to cruise in and such. Thanks for any input.

 

[Mattstang04]

I always thought a little back pressure was good for turbo cars. I have the weld in Flows as well. Didn't know that set up could hold you back that much, horsepower wise.

 

[Noobz347]

I always thought a little back pressure was good for turbo cars. I have the weld in Flows as well. Didn't know that set up could hold you back that much, horsepower wise.

How can back pressure, down-stream from a turbo, be a good thing?

 

[SonicStangGT]

also, future wise, gonna build bottom end and full port heads and turbo cams. Right now my winter build includes temp comp cam 270's, stealth fuel pump upgrade, exhaust setup and tune. Also thought of using slp with race mufflers and doing a 3'' electric cutout for the track. Just don't wanna blow money on exhaust but one more time, I hope.

 

[Mattstang04]

Let me preface by stating that I don't know about turbos (which is probably evident). But I thought some back pressure may help route more exhaust air through the turbocharger. I am likely wrong.

 

[Noobz347]

also, future wise, gonna build bottom end and full port heads and turbo cams. Right now my winter build includes temp comp cam 270's, stealth fuel pump upgrade, exhaust setup and tune. Also thought of using slp with race mufflers and doing a 3'' electric cutout for the track. Just don't wanna blow money on exhaust but one more time, I hope.

I don't think you need a cut-out but I'd def go with the 3 inch. An exhaust restriction or "back pressure" is never a good thing in an exhaust.

Make the exhaust on an N/A car TOO large, and you get poor exhaust scavenging. With a turbo car, that's kind of a moot point. The turbo itself is going to be the biggest restriction is an exhaust system. Any help you can give it on the back end, will be GOOD thing. Scavenging is not really a consideration anymore because the turbo is already serving as a restriction but also a vac (of sorts).

 

[Mattstang04]

Gotcha. Writing that down.

 

[SonicStangGT]

Thanks for the info.