Catco ...2.5" or 3"??

[tkoforpresident]

hey guys, i'm going to purchase a catco high flow cat and i was wondering if i should get the 2.5" or the 3"....i have a stock manifold but a 2.5" flowmaster cat back exhaust...what would be the best size for my catco cat and why? also it's a 93 firebird 3.4l if that helps, thanx

[00 Silver 6]

Re: Catco ...2.5" or 3"??

i'd go with the 2.5", id assume it would weld up better to your exhaust

[badinfluenceRS]

Re: Catco ...2.5" or 3"??

I'd go 3" just incase you ever upgrade to a 3" catback...you can always get a 3" to 2.5" adapter...your y-pipe outlet is 3" right?

[tkoforpresident]

Re: Catco ...2.5" or 3"??

I'd go 3" just incase you ever upgrade to a 3" catback...you can always get a 3" to 2.5" adapter...your y-pipe outlet is 3" right?

i don't know about my y pipe thats why i was wondering what to get...i don't think i'll ever upgrade to a 3" cat back honestly...but i heard getting a large cat and having a smaller exhaust you create a bottleneck

[badinfluenceRS]

Re: Catco ...2.5" or 3"??

well if you y-pipe is 3" your gonna have to reduce down to 2.5" anyways...

[tkoforpresident]

Re: Catco ...2.5" or 3"??

well if you y-pipe is 3" your gonna have to reduce down to 2.5" anyways...

oh i didn't know that, i'm a noob and i noobishly figured if your y pipe is 3" then it just continues to 3" on your cat... is it not like that then??

[badinfluenceRS]

Re: Catco ...2.5" or 3"??

oh i didn't know that, i'm a noob and i noobishly figured if your y pipe is 3" then it just continues to 3" on your cat... is it not like that then??

my bad...you can get a 3" inlet/2.5" outlet cat


I'm gonna have a 3" Y-Pipe outlet, so I just got a 3" in/out cat...but I'm gonna run a 3" catback too

I don't kno if the 3.4 Y-pipe is 3" outlet or not...

[tkoforpresident]

Re: Catco ...2.5" or 3"??

my bad...you can get a 3" inlet/2.5" outlet cat


I'm gonna have a 3" Y-Pipe outlet, so I just got a 3" in/out cat...but I'm gonna run a 3" catback too

I don't kno if the 3.4 Y-pipe is 3" outlet or not...

aight, well should i just go with the 3" in 2.5" out cat then?

[badinfluenceRS]

Re: Catco ...2.5" or 3"??

yea...if your not 'planning' on getting a 3" catback (and that's if your Y-pipe outlet is 3")

[tkoforpresident]

Re: Catco ...2.5" or 3"??

yea...if your not 'planning' on getting a 3" catback (and that's if your Y-pipe outlet is 3")

heres the prob i can only find a catco cat thats 2.5 in and out or 3" in and out...not both..i'm seriously on summitracing.com ready to buy one or the other right now but i don't know which one to buy! can anyone help??

[Fbody3400]

Re: Catco ...2.5" or 3"??

Its not a huge ordeal man, don't stress. If you get the 3" in/out, you'll have to buy a 3" to 2 1/2" reducer. If you buy the 2 1/2" in/out, you'll have to buy the same thing. The only difference is if its going before, or after the new cat.

Who is going to be installing it?

[tkoforpresident]

Re: Catco ...2.5" or 3"??

Its not a huge ordeal man, don't stress. If you get the 3" in/out, you'll have to buy a 3" to 2 1/2" reducer. If you buy the 2 1/2" in/out, you'll have to buy the same thing. The only difference is if its going before, or after the new cat.

Who is going to be installing it?

an auto shop, do you think they will be able to order it and install it(the reducer)? (by the way i did just buy the 2.5/2.5 catco cat) I am having them put on my 2.5" flowmaster 80 series cat back and figured to upgrade my cat to a high flow one while i was under there.

[FireBird_Fr3ak]

Re: Catco ...2.5" or 3"??

I thought that 3.4's ypipe was smaller than 3"?

[tkoforpresident]

Re: Catco ...2.5" or 3"??

I thought that 3.4's ypipe was smaller than 3"?

yeah... i've got no idea...does anybody know the diamater for the 3.4 y pipe???

[BLLDOGG]

Re: Catco ...2.5" or 3"??

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