Im in the process of making my own custom 3 in exhaust all the way back, but today I was having second thoughts. 2.5 is usually big enough for a turbo set up, which is in the near future. I'm finishing the 3 but I just wanted to know what you guys thought and why. Pros cons, you know. Thanks a lot.

 

Most will say 3". But honestly on a NA car I kind of regret going with a 3", my car always ran stronger with the stock exhaust than it has with my HKS and now with the Turbo XS 3". But I'm installing a turbo kit so I will utilize the 3" now. I personally thin the engine needs the smaller diameter piping. I also have the BHR midpipe.

 

That's what I've heard but I've never felt it. My s13 na 3 in straight back I felt more power. But I wasn't sure on this 8. I think I'm going to do it anyway though. It's almost made up and it will get utilized within the year, if stuff goes as planned

 

Do you like the sound though? What's under there for the turbo xs? One resonator and muffler? What I'm fabing up will be straight all the way back..I know it's goin to be loud. If I don't like it what's the best sounding resonator or cutback I guess to tone it down a bit?

 

I loved the HKS (single side, one muffler) with the SR motorsports midpipe and the BHR. The Turbo XS is too loud, it has two mufflers in it. I am getting a resonator welded in before the turbo build is done.

If you are doing straight back you are nuts. The HKS was loud but sounded great, the Turbo XS is loud in another way and doesn't sound great. Every muffler and resonator will sound different.

 

Nuts yes, it will be done and I know it's gunna be crazy but after it's done I'll weld what I need to underneath till I have the sound I like. I get exactly what I want and it's cheaper then an exhaust kit.

 

3 inch for turbo applications, 2.5 for NA, you lose low end a little but you gain it up top I believe. Complete straight pipe is like open header. Crazy loud. Im running a single exit with a test pipe, its loud but not too loud to me.

 

I have a feeling that you have no idea what you are getting into.

 

I acually have it done now. thanks for your concern. just ordered an turbo xs dual resonated midpipe and exotic speed rear muffler. ill have to refab some of what i have now but i think ill like it. midpipe 3 in to the exotic speed rear R1-T muffler.

 

Bigger is always better, zoom zoom!

 

Wrong (as usual). An exhaust that is too large can hurt performance.

 

God damn you fill every thread with nonsense ... do us a favor and stfu...

While you are doing that read up on the importance of flow capacity and its relation to velocity. I am not talking about car velocity, but the velocity of the exhaust.

In a perfect world an exhaust would be engineered to fit the power band of the vehicle. Most cars utilize a midrange power band, therefore the exhaust is sized to that spec. One could ideally increase the affect of their low range power band (1k - 3k) by opting for a smaller exhaust diameter, however, as you approach midrange to high range, the backpressure created by the lack of flow and the increase velocity would cause you to lose power

If you get too large of an exhaust, the velocity would decrease at a lower rpm band as your flow diameter has increased greatly...sort of like having a large diameter garden hose vs a small one. In retrospect, the higher end rpm range would "benefit" due to the increased flow capability at that velocity.

 

2.5" is ideal and still plenty large for an RX8, 3" is a bit excessive unless you are making pretty good numbers.

 

Settle down settle down. Thanks though good ****