35 replies to this topic

[stuart bowes]

Someone who I trust to know what they're talking about with these things once told me that their van / estate engines always seemed to run a little better than the saloons, and his thinking on it was that the only real difference was the exhaust being a little bit longer 

 

that's just something I head one time, I don't have any evidence to back it up .. does that ring true with anyone else

 

we're not talking extra horsepower or anything obviously I figured he just meant a little more responsive, smoother tickover or whatever 

 

So I guess my question is, how much does the center exit reduce the length from standard, without having the bend (i.e. maybe there's a reason they did it like that)

Edited by stuart bowes, 10 July 2023 - 10:41 AM.

[Cooperman]

 

Side Exit = Classic
Centre Exit = Boy Racer

Boy racer? Erm... no. Works rally cars had centre exits

 

Rally Minis have centre exit exhausts for two reasons. 

The first is that when the sliencer box is positioned diagonally across the rear sub-frame it presents a larger item to hit on the ground on rough roads. The front of the box is fited with a welded on skid plate which reduces shock loading when it hits the ground.

Secondly, the up-sweep of the final exit means that if the car spins off backwards, the pipe is less likely to get blocked with earth and mud or otherwise damaged.

there is also the fact that if electric fuel pumps are mounted under the rear seat base on the LHS inside the sub-frame, a centre-exit means access to the pump(s) is easier. It is also possible to fit a cover plate to shield the pumps. In fact, if a centre exit pipe is fitted, with a battery box shield on the RHs ad a fuel pump shield on the LHS, the aerodynamics is certainly improved a bit.

Centre-exit exhausts are really a competition thing.

[greenwheels]

Someone who I trust to know what they're talking about with these things once told me that their van / estate engines always seemed to run a little better than the saloons, and his thinking on it was that the only real difference was the exhaust being a little bit longer 

 

that's just something I head one time, I don't have any evidence to back it up .. does that ring true with anyone else

 

we're not talking extra horsepower or anything obviously I figured he just meant a little more responsive, smoother tickover or whatever 

 

So I guess my question is, how much does the center exit reduce the length from standard, without having the bend (i.e. maybe there's a reason they did it like that)

I recall being told that the side exit on the saloon is the best tuned length exhaust. On estates the length may be better tuned length. What the hp or torque output difference is I have no idea. Perhaps a rolling road test with side/centre/estate exhausts would be interesting if someone has the time/facilities/exhausts available.

[GT Jimmy]

I have a centre exit only for the reason I think they look cool. Didn't notice any performance change after fitting it

[StefanMini]

I have a side exit, this because I wanted a towbar on my Mini. But if there was no reason for a towbar I also fitted a centre exit exhaust.

[Cooperman]

Having just had to remove and refit an engine in one day, I just realised another benefit of a centre exit if you have an LCB manifold. When re-fitting the exhaust you can just locate the Y-piece onto the manifold ends, then go around the back and give the end of the exhaust pipe a few quick thumps with a wooden mallet.