exhaust/cat question

[twilightprotege]

hey all you exhaust nuts. as you may or may not know, i will be getting a full 2.5" mandrel bent exhaust system shortly....anyway, i've can get a really good deal for a 3" carsound cat converter.

would it be better to try and find a 2.5" in/outlet cat converter or would the 3" one actually be better?

a mate of mine is going to do the exact same system as me but 2.25". would a 3" cat converter work better or worse with it???

 

[twilightprotege]

anyone??????

 

[PaulMP3]

i remember a thread from before where spoolinmp3 mentioned use a cat off an old covette which is 3" and reduce it to your prefrence as a price alternitive to a highflow cat.. Sounds like the same idea

 

[twilightprotege]

i can get a carsound (ie magnaflow) brand new 3" in/out high flow cat for pretty cheap. i cant see it being a problem really. the exhaust ppl would just make a small merge out part before the cat and after to fit the 2.5" piping for the rest of the system.

i spose the only problem could be if the in/out was smaller than the piping i'll run.

 

[PaulMP3]

yea it wont be a problem... my muffler inlet is over 3" 80mm an i just have a reducer made to match up to the 2.5"

 

[twilightprotege]

sweet. yeah thats what i thought you could do, but i thought i'd just double check.

thanks!

 

[PaulMP3]

here is a photo

 

[twilightprotege]

cool. thanks.

i was actually just thinking that having a 3" inlet to a cat would be better than 2.5" so that way the gases have more time to spread out over the surface of the cat stuff and therefore be less of a restriction. sound logical???

 

[PaulMP3]

yea sounds good to me... i think that is the deal with most high flow cats.. they dont flow much more, there is just a larger area then stock.. (correct me if im wrong)

 

[twilightprotege]

yeah i've got no idea how the flow more etc...

ok den, 3" in/out cat is it then

 

[thewrench]

From what I can tell, the Random Tech cats (at least the bullet ones) all use the same body and they just weld on different inlets/outlets. The inside is basically a square honeycomb, if that makes sense, tiny little square channels that run straight through. The difference I can see between it and the stock main/pre cat is the size of the "grid". Ie, the channels are larger on the highflow cat.

 

[twilightprotege]

fairy nuff.

so my theory of having a larger inlet diameter on the cat would be better so the gases had more time to move out to the outer channels in the cat?

 

[thewrench]

Not sure how much it'd help, don't see how it could possibly hurt. Hehe, how's that for definitive answer?

 

[twilightprotege]

hehehehe....

that's basically what i thought...it cant hurt