[VitZook]

Anybody had experience with aftermarket units ? I am about to replace my muffler and was told to replace the original Cat (140,000K's) with a hi flow one... Unsure if its worth doing ...?

[royce]

I guess it would depend if the original was choking it or not

lots of people grab one from a v8 commodore that has been replaced by a bigger one, works well on a little engine

[TZAR]

I talked to a few exhaust shops before I got my exhaust for the swift and they all said the same thing. Not any extra benefit on small engines UNLESS yoiu have some seroius air going through the engine

IE turbo supercharger etc

But if the price isn't to much higher then I couldn't see any harm in fitting it. Yours is the 2,5 V6 isn't it Dick??

[Bruce]

no Tzar it's a 2lt V6 but it is chipped

[cj_zuki]

Dick,

I did the exhaust on my old 1.6 lwb with headers, high flow muffler and 2" pipe and it was good but not as good as I was hoping for. I then did the cat and that gave it what I thought it should have had all along. Now in general most cats shouldn't really pose much of a restriction but I suppose every little bit counts and it did make the difference. I was talking with somebody who builds a few street/strip type cars and what he had found (and what I had done) was that going one size larger with the cat than the pipework seemed to be the optimum so if for example you have 2" pipes then use a 2 &1/4 cat.