[Healeys] IS Bigger exhaust better

[E.A. Driver]

Hi Kees

You might find "The Sports Car Engine: its tuning and modification" by 
Colin Campbell an interesting read.

Kind regards
Ed
Historian, AHCUSA

Oudesluys wrote:
> Smaller resistance in the exhaust can be a factor in increasing the 
> power output but is not always so, certainly not on small well 
> designed engines with tuned exhausts.  Tuning the exhaust instead of 
> only increasing the bore is a far better idea. This way you create 
> certain resonances in the system at specific rpm bands by playing 
> around (calculating) with the exhaust manifold (length, collector, 
> bore etc) bore of the various components, capacity of the exhaust  
> boxes, number of exhaust boxes, distance between the various exhaust 
> boxes, number of pipes, crossovers or not and a few other things. A 
> well trained automotive engine designer should be able to do this.
> However by just only doing that, you will not gain much if anything at 
> all. It will also mean you have to make changes in the induction (e.g. 
> length), jetting and ignition, compression ratio, not to mention 
> camshafts if you want to extract the most of these tuned exhausts on 
> carboretted engines.
>
> Kees Oudesluijs
> NL