Exactly what the topic says. I was thinking about going Thermal 3 inch next year but I heard that it really won't benifit much at all unless I'm pushing more than 10 psi of boost. Is that true? Cuase if I dont' ahve to spend the money... ****.... I won't!

 

From my experience, having a 3" exhaust robs precious low end power but gives it back up top. If you are running only 6-8 psi, I would get a 2 1/2" exhaust and you may loose a little top end power. And if you go to the track, take the whole thing off and run open downpipe

 

I will take that into consideration.

But only one response?

 

better to get the 3 inch now instead of upgrading from a 2.5 to a 3 inch later. from personal experience im running a 3 inch crush bent exhaust with 7-8psi boost. i dont see the need to spend that much on a 3" thermal exhaust since it's just going under my car and im lowered... u get the picture.

 

I thought you want the biggest possible pipe after the turbo because you don't want any back pressure on the turbo as it causes wear and tear. Are you sure that you lose torque with a larger diameter exhaust on a turbo car?? I think that you should go 3" mandrel bent but custom, some local shops should be able to do it pretty cheap. I got mine done at Midas for ~$100 cat->axleback

 

With a turbo, there is no disadvantage to going to a 3" exhaust. You will get better boost repsonse, better wastegate control, a lower tone, and much better high rpm power.

Just get the 3" and don't waste time and money.

Randy

 

but if you want a 3" dp you cant have a/c

 

He said Thermal exhaust, not downpipe. I assume he has a 2.25" downpipe or a 2.5" downpipe max.

Randy

 

Get a 3" dude, faster spool and more top end power. With a turbo backpressure is the enemy!

 

yup, you want the least amount of back pressure possible.....even on 6 psi, with 2.25 exhuast, your car WILL be slower. ive seen it first hand numerous times. my friend ran a best of 13.5 (many times to the track) with 2.25 on his ls turbo hatch. switched to 3" and his first day at the track he ran 13.0, 13.0, and a 12.9. this was all on 7 psi, and the EXACT same setup and conditions both times to the track

 

I'm sold, I'm going 3" next year.

I just already have a 2.25 one right now that I have had on for the last 2 years. Just wanted to know if I should upgrade. Guess so. I will get it next spring. Can't wait to feel the difference.

Thanks for the input.

Oh, does anybody know if Thermal just bolt on up? I heard somethign about that they need some mod or some special pipe made or something.

 

On NA cars the backpressure is needed by the engine for low end response, which is why you don't see 3" exhausts on NA cars. However, on Turbo, the Turbo itself acts as a restriction itself and provides the backpressure. So go 3" and don't look back...

 

yo mskibbz - so you got MIDAS to make you a catback piping with axle back?? what muffler did you use???? cuz i got a APEX world sport and i love that quiet sound but its not giving me enough top end, so ill prolly try this 3" exhaust... can i use my axle back from teh apex world sport??? its about 2.25-2.5....

should i replace the down piping too???? someone mention that i can't have an AC with 3" DP.. why is that???? thanks

 

It's too thick and passes right next to the A/C unit. Tha'ts what somebody told me anyway.

 

the a/c compressor is in the way! a 2.5 dp just fits

 

3" dp is huge!

 

I got Midas to custom make the pipe from the cat back to my 5Zigen Fireball axleback, my current setup is 2.25" inch but 3" shouldn't be much more than $100. You can use your axleback but it will be the bottleneck on your exhaust, if you go 3" go 3" the whole way back otherwise its not worth doing. You can buy a 3" muffler and go custom piping to it, remember a resonator or you'll be sorry

 

thanks mskibbz....

 

2 resonators and I still don't feel a difference... not a big enough one anyways. Fug it and run open dp. Best tone, response and foot massager w/ heat.