High flow cat install

[99camaro-3.8]

i just bought a 2.5" high flow cat. i already have a 2.5" flowmaster cat back on there so the whole exhaust will be 2.5". my question is about the s-pipe. how much and where can i get a 2.5" s-pipe? could i also just take a u-pipe and cut it in half and weld it together as a s-pipe since im sure thats cheaper?

[lookout4theyeti]

Re: High flow cat install

before you do anything with the s-pipe, i would check the diameter of the flowmaster where it meets the s-pipe. If i remember correctly, it was an odd size so as to fit over the s-pipe... Your new 2.5" s-pipe might have to go over the flowmaster, instead of inside. I could be wrong, just something for you to double check before you get everything.

BTW im gonna be doing the same thing when i get my new cat this summer

[BLLDOGG]

Re: High flow cat install

yes you can just take a u-bend pipe. this has been discussed before and I did it back in the day.

first things first though, i though the flowmaster system came with the s pipe?

[99camaro-3.8]

Re: High flow cat install

no it didnt come with an s-pipe. what they actually do is have a pipe that fits the stock s-pipe and welded into the resonator and then its 2.5" from there on back. im just chopping the small pipe off before the resonator and having them weld on a new 2.5" one with the new s-pipe. what size diameter u-pipe do i need? http://www.jegs.com/webapp/wcs/store...0263&langId=-1

i found a lot of them on there what one do i need to get?

[lookout4theyeti]

Re: High flow cat install

the flowmaster is 2.5" all the way back from the s-pipe. It just has a small end to fit the s pipe. I know for a fact that it is 2.5" up to the resonator because i cut my resonator off and replaced it with a straight 2.5" pipe

[BLLDOGG]

Re: High flow cat install

sorry, i was thinking of the 3.4 kit

i would just get a 2.5" u-bend pipe

[99camaro-3.8]

Re: High flow cat install

sorry, i was thinking of the 3.4 kit

i would just get a 2.5" u-bend pipe

which size width though? the diameter of the u-pipe. they sell them in a 2.5" pipe in a 4" diameter and a 5" diameter. anyone know what one i need so the s-pipe ends up being the right size?

[BLLDOGG]

Re: High flow cat install

I used the 5" and it worked well for me.

[99camaro-3.8]

Re: High flow cat install

ok just ordered that u-pipe from jegs. looks like the last thing i need is an o2 sim. i found one on ftpp.net for $44. anyone know if i can get it cheaper anywhere else?

[BLLDOGG]

Re: High flow cat install

I only trust the casper electronic ones. the one on ftpp.net for 44 is the same one.

https://www.casperselectronics.com/M...camaro1996upv6

[Tom Rs]

Re: High flow cat install

old thread, but how did this go ? i am still confused as if i need a 3" in/out cat and 3" s-pipe for my 2.5 catback ??

[RicE-ter]

Re: High flow cat install

well either way ur gunna need a 3" to 2.5" adapter either infront or behind the cat. i welded a 3/2.5 adapter infront of my 2.5/2.5 magnaflow cat, got a 2.5" u-pipe 5"bend radius from summit. since the, now s-pipe wouldnt slip on the 2.5 flowmaster, with the 2.25 part on the i-pipe for the stock s-pipe, i just cut of the slightly non straight part in the i pipe and replaced it with the extra long leg of the s-pipe.

or if u get the 3" cat and 3" s-pipe, to which i dont know the proper bend radius(presumably something close to 5"), then put the reducer there after the s.

or maybe after the cat into a 2.5 s-pipe, up to u.

u could actually use the stock s and stuff, like stock manifold to 3/3 cat to 3/2.25 reducer will have to weld it all, so may as well change that stuff too. layed my s-pipe on the stock one, way less angle on it more free flowing

[99camaro-3.8]

Re: High flow cat install

what i did was go with a 2.5" high flow cat since i got a good deal on it and then ordered a 2.5" u-bend. made that into an S-pipe. i went to meinike and had them make me a custome 3"-2.5" reducer for coming from the y-pipe into the cat. i cut off the pipe leading into the resonatore and just used one of the extended legs of the s-pipe and welded it all together.

[Tom Rs]

Re: High flow cat install

i see. i already ordered the 3 in u bend so i am getting the 3in cat and then put the reducer after the s-pipe.