I'm wondering whether it's worth replacing my 2.5" Afterburner exhaust system with the newly available 3" system. Does anybody know just how much difference the extra 0.5" will make? Both sizes will be fully decatted!

I can't ever see my wanting to take my car beyond 350-400bhp but I guess who knows in the future!

Any opinions appreciated.

Rich

 

I've got 353/335 with a 2.5" exhaust (inc prodrive sports cat, though). Having said that, I don't know what the figures would be like with a 3" exhaust, obviously

 

I had the AB decat setup when at 315, but was then advised to upgrade to 3" when changing the turbo.

I noticed that the spool was very good on the 18g, expected it to be slower, which was commented on possibly going to 3", because less restrictive.

If that's any help. I think it was Scoobymania who gave me the figures for the differences between flow rate. Could check their site.

 

Thanks! Checked the scoobymania website and they claim 30% extra gas flow compared to 2.5". Thats sounds an awful, just don't know what that means in the real world!

 

I wouldn't bother at that power level. Not worth it for the extra expense/hassle involved.

Dave

 

I'm running a fully decatted 2.5" H&S system with an 18g and get around 370bhp/350ftlbs. I doubt a 3" would give me any more as the turbo would be struggling above 380bhp.

James.

 

Remember there is a difference between what an exhaust CAN flow and what it actaually needs to flow for a particular power output. Flow is related to cross sectional area and a 3" pipe is more than 50% greater than a 2.5" in terms of CSA.
Your 2.5" system, if it is well designed, is perfectly capable of producing a lot more power than your 350-360 bhp target.
If I had the choice between the systems 3" and 2.5", I would go for the 3" but mainly to allow for "project creep"
Some exhausts seem to perform far better than others so it is more important to choose one known to give good results.