Straight through exhaust

[Paul C]

i have just recently had a new exhaust fitted ( about 3 month ago been busy so haven't got round to taking pictures). It is a 2 1/2 inch cat back center box and back box setup. I was wondering if i removed the center box for more sound/rumble would it compromise performance in anyway. Am i right in thinking that if i do this it will sound a bit louder?

Thanks

Paul C

[BraindG]

it will deffo sound louder!.. im not expert, but the freer the exit, the better it will perform.. which is why some of the evo guys have their exhaust coming out of the side of the engine, through the front panels.

[Paul C]

it will deffo sound louder!.. im not expert, but the freer the exit, the better it will perform.. which is why some of the evo guys have their exhaust coming out of the side of the engine, through the front panels.

is back pressure not important with a turbo car, i wouldn't know myself not mechanically minded

[SGHOM]

Mine is a cat back straight through 3" system. :afro: & It's pretty quick ........ or was ! /help

[Wodjno]

As far as i know, an exhaust is only as restrictive as it's smallest part :thinking:
So if there isn't any more restrictive part in the exhaust than the downpipes then it shouldn't make any difference to the power output. :inquisiti

In theory :scholar:

[chris g]

Turbo engined cars, and perhaps n/a cars, can change performance for the worse when exhaust systems/components changed

I think H.7 has posted a few comments about this IIRC in relation to a Legacy but check/do a search

[Kieran]

General rule of thumb without getting snarled up in exhaust theory is this, at least for a VR-4.... In my experience.


De-Cat on a standard exhaust = Not much difference - Feels stock untill about ~4500 rpm where the engine starts to pull a little harder.

Straight through exhaust on a catted car = Not much difference from stock either. It seems that the cat and the stock exhaust are as restrictive as each other.

De-cat + Quality straight -through system* = Significant difference. Feels slightly 'flat' on part throttle or low revs, and it's much louder. However... Huff it and especially as you go past ~4000rpm, it will pull a lot harder!!

* = In this instance, a quality straight through system is a Blitz Realize-TT. This is a 3" straight through to the backbox - the backbox is a 'refector' design rather than a straight through, but appears to be very free flowing. I like it anyway!

[bradc]

With my car on stock boost the exhaust only gave the car more power at about 5000rpm. It gave it 6kw more at max power, from 153kw to 159kw at the wheels, but when the power started to fall off there was a difference of about 12kw at one point, around about 6000rpm.

[Paul C]

Thanks for the response, i will get round to getting the center box removed when i get 5 minutes.