What is ideal exhaust?

[NewfieArcher]

Hey guys. I'm still new to tuning so I wanted to ask your opinions.

If I was to put a turbo on my 2 (where turbos cause minor increase in back pressure), what would the best performance exhaust be?

I also know CS has their full exhaust and combined with Andreas manifold I'd lose all cats. So would a larger custom exhaust like 2.5-3" improve power at all?

Lastly where do you get highflow cats? I'd like to put one into the exhaust so it's still legal.

Thanks for any information.

 

[Danielcut]

Andres manifold will not do you any good on a turbo set up as it would need to be replaced with a turbo manifold.

Generally with turbos, freer flowing is better so a larger exhaust would be better. I don't know for sure if 3" would be overkill but that's what I had on my Spec v and it made a difference over 2.5"

 

[chumlet]

2.5-3in piping with a custom turbo mani... I have not been able to find a turbo manifold for the mazda2 the system will be fully custom as for cats the exhaust shop can help you out along with your custom piping

 

[Racebrewer]

Magnaflow has high flow cats. I have had a couple on my Integra along with their stainless steel mufflers and resonators.

 

[Racebrewer]

Might depend upon the turbo you end up with.

Isn't the stock exhaust closer to 2"? I'd think that fully 2.25" would be good for N/A. 2.5" sufficient for small turbo and 3" for large turbo.

 

[NewfieArcher]

Go big or go home. Probably go with the biggest turbo that will fit in it.

 

[NewfieArcher]

Maybe twin turbo

 

[Danielcut]

A big turbo will probably be fairly useless on this small engine. It's important to properly size the turbo you use.

 

[CorkSport]

The stock exhaust is under 2 inches....

 

[deadlydave]

Generally with turbos, freer flowing is better so a larger exhaust would be better. I don't know for sure if 3" would be overkill but that's what I had on my Spec v and it made a difference over 2.5"

This is the great rule of thumb for turbo applications. A freer-flowing exhaust is almost never a bad thing, once the ECU is adjusted for it.

Others have mentioned that a large turbo for our little 1.5's will suck to drive. The engines may not be able to move enough exhaust gas to spool such a turbo until near-readline. A small/moderate turbo with mild/moderate boost and the correct tuning would provide a solid kick in the pants at more useful RPM's. A supercharger would actually be great, since you wouldn't have to change much plumbing upstream of the engine.

Any turbo company worth their salt will do this: if you are doing a custom or 1-off install, they will give you advice for exhaust requirements, and can help you figure out what turbo will work best with your application.