4 replies to this topic

[XTT]

I was wondering what would be the advantages and/or disadvantages of an A-series running a 3 into 2 setup instead of a 3 into 2 into 1. In other words seperate exhaust systems for the outer cylinders and the inner cylinders.

(The engine rebuilt I'm carrying on at the moment has destroyed my drive for rational thinking) :fear:

[Wil_h]

So you are saying run two exhausts on two seperate manifolds?

For this to work you would need to use smaller bore exhaust pipes to keep the velocity up.

There might be an advantage to it, but for all the cost and hassle it would cause it's probably not worth it. It might also be a disadvantage.


Wil

[The Matt]

So you could retain the LCB and do away with th 'Y' piece? Running two seperate pipes under the car you mean? I guess it would work OK, but there would have to be alot of expensive development and testing.

I don't know if ultimately you would gain any power through it?

[XTT]

So you are saying run two exhausts on two seperate manifolds?

For this to work you would need to use smaller bore exhaust pipes to keep the velocity up.

There might be an advantage to it, but for all the cost and hassle it would cause it's probably not worth it.  It might also be a disadvantage.


Wil

Exactly,

pipe 1 = cyls 1 and 4

pipe 2 = cyls 2 and 3


I don't really think it would necessarily be a disadvantage otherwise all engines would have a single line exhaust system(think of several V engines, two seperate systems.) (by the way, I know that there is no comparison between the A-series and a V layout) . The problem is that i don't know the principles on how to make it work properly :smartass: If I knew some basic stuff about exhaust designing, testing would be reduced.
It's not so much about power gains as it is for achieving a nice exhaust burble without losing any power.

Cost and hassle are not really a problem. IMHO its all about having enough pipe lengths(can get them vey cheap), a MIG welder(got that) and an exhaust pipe bender machine thingy(a friend has that) and loads of spare time :wink:

[Philtrum]

I've had a few v8's and if there is not a balance pipe (which joins the two exhaust systems) then they sound pants .... no burble, sounds like a 4 cylinder

put a pipe in and its great !!

the balance pipe makes the 2 exhaust under the car into a H shape .... hope that explains it

also you need to bear in mind the purge effects from the other cylinders, the manifold helps this, which is why an LCB is much better than a non-LCB on the mini, otherwise all tuning/performance exhausts would use a 4 into 1 manifold as its cheaper to make

also ... if you took it to the extreame ... 4 exhausts ... or 3 in case of the mini, would it burble .... no it would sound like 4 low cc single pot engines running at about the same speed (or 2 mopeds and a twin cylinder moped in the case of the mini)

hope that made some sense

Cheers
Phil