header/piping questions

[Taxi-R]

My current setup:
- short ram intake
- aftermarket b-pipe and muffler (dunno the pipe size tho)
- stock headers and cat
- besides strut bars and sussy mods, no other performance mods and don't really plan to do much else for performance

What i'm thinking about:
- 4-1 headers (i believe the collector size is 2.25" and it bolts onto stock cat)

Question:
- Now i understand that to get better results i should tack on a hi-flow cat. So i'm thinking about the Magnaflow/Carsound one. Do i say "i want a 2.25" cat please"? or is there sth else i need to take into account?
- Since i'm not really doin any more performance mods, 2.25" is ok?
- Do i need to get any other lil bits and pieces keeping in mind that the car doesn't really get pushed much hence wear and tear is less?

Thanks you guys!

[SKREMN]

you have to gat a cat the same size as your exhaust the collector is 2.25" but what is the rest of the exhaust? if it is 2.25" then thats all you need

[wynode]

From the collector back, the internal diameter should be the same size throughout.

[crx_boy7]

ull hav to pull ur D-pipe and cat apart and measue it - very ease
1jak car up
2get 12mm spanner or similar no open enders!
3 get sum multygrips for the other end
4 loosen 2 bolts and walla
5 now just pull them apart with ur hands and measure the inside
6 now put everything back were u got it
dont worry about the flange as if u get a new cat it will be replaced soon anyway
also make those bolts nice and tyte

[crx_boy7]

i hope that helps

dose anyone kno about ECUz im building a turbo b18c full internals 9,0compresion 1,9 stroker t3/4 and need help with finding a suitable ecu note i have no previous knowledge on ecus and need it to run at tymz 25psi and at others 6psi eficiently!!
i also need support with v-tec and no wasting feul at low boost plz anyone email me if u hav anz good surgestions of wat i should look for

[Taxi-R]

i think i'm gettin it now...

1. so is it possible to have diff dimensions on both sides of the cat? say a 2.25" collector and then a 2.5" b-pipe?
1. or you HAVE to have them both the same size as a cat is EITHER 2.25" or 2.5" on BOTH sides?
3. wouldn't my current aftermarket b-pipe have to b a particular size for it to fit my current OEM/stock cat?

thanks :wave:

[crx_boy7]

i think i'm gettin it now...

1. so is it possible to have diff dimensions on both sides of the cat? say a 2.25" collector and then a 2.5" b-pipe?
1. or you HAVE to have them both the same size as a cat is EITHER 2.25" or 2.5" on BOTH sides?
3. wouldn't my current aftermarket b-pipe have to b a particular size for it to fit my current OEM/stock cat?

thanks :wave:
well iv never seen or herd of a cat with a different size on either end. and in my opinion it would hurt performance because the velocity of the gas as it comes out would change half way through its hard to understand without a pic the best way is to stick to a desired size throughout ur exhaust depending on ur desired feul econmy, future and past mods, tone, performance, and engine size. wen in doubt ask an experianced person in a exhaust shop :thumbsup:

[crx_boy7]

if you measured one side of ur cat the rest of ur exaust should be the same diameter ie if ur cat is 2,25 ur extractors need to be 2,25 and so dose ur performance cat but the best way is to write ur questions down and call midas or someone trusted (quick and esy 5min call)