Tsi_Xtreme

I did a search but couldn't find the answer I was looking for.

I'm wondering if I cut my cats off my 85 GSL-SE if it will hurt performance or make it better. Where I live I don't have emissions so not worried about it. Plus this is mostly autocross car anyways.

I'm wanting to put a 2.5" from the header to a magnaflow muffler out.

Discuss...

HighwayRacer

u will increase performance and your noise level. be careful of the exhaust pieces u put on an rx-7. the exhaust is 3 times as hot as conventional. I have melted glass packs and turbo pulse mufflers. check mazdatrix.com for compatable replacements for performance based issues.

vipernicus42

iTrader: (4)

HighwayRacer speaks the truth

Cats restrict the exhaust gas ALOT and thus decrease your HP. The only thing you have to worry about is that with a GSL-SE, you have 6th ports which are actuated by exhaust back-pressure. RB's exhaust system is built to deal with that (as long as you get the GSL-SE specific one).

Conventional exhaust WILL deteriorate faster on a rotary due to the extreme heat and pulsing cycles. Check out www.racingbeat.com . They're a little more expensive, but definitely worth it. Get the GSL-SE specific exhaust package. You only need the headers and presilencer to be able to do the back-pressure activated 6th ports, but the muffler is awesome. If you want/like loud, you can go with another muffler.

Jon

The_Dude

I personnally recommend getting the muffler too.. I had a normal stock one ( not the ordiginial, but still a stock ) and it's now shot , I'm gessing because of the bigger backpressur ... BUT, I did notice a gain in power so ... up to you ! ... ohh yeah, I'm getting my muffler within 2-3 weeks from RB, thus completing my complete RB exhaust .. NA NA NA NA NA NA !! :P

jkjk

thricerx7

i heard that rotaries run like 2200 degrees and normal conventional cars are around 1600-1800 degrees to the headers and exhaust. is this true?

thricerx7

but hell i wouldn't know. my cats are clogged and i live in CA so emissions is all up my @$$. haha. damn pollution *****. once i pass smog somehow, then my rex will breathe! without cats. muhahahahaha!!!!!

Snapshot

Get a Racing Beat presilencer to replace cat. Heavy duty for rotary engin & runs free. Don't know about CA emissions but RB is in CA so just call. RB is the industry standard for performance & fuction.

mazdaverx713b

iTrader: (91)

that is nearly true. the exhaust temp can get up there but usually stays between 16-1900 degrees. so i am told. lets put it this way, i wouldnt want to have my have on any of the exhaust even 15 mins after the car was shut off.

Tsi_Xtreme

thanks guys, I think I'm just going to go with the Racebeat exhaust. Its damn expensive! It better be worth it...

twigg

just buy the racing beat headers, and get a shop to weld all the way back to a RB Muffler, RB whole system package is good but it will damn better sounding this way and cheaper

Tanjo

How do you get a shop to weld your exhasut and not put a cat back on?

GavinJuice

If you don't have a cat to begin with then it's no problem, ie. custom, if you're taking one out and replacing it with a straight pipe thats when they're going to bitch.

thricerx7

yeah the only prob about the RB presilencer is the money. I am too poor to afford that at the moment. CA emissions are a bitch, and I cannot drive without a catalytic converter on my car. I am lucky b/c I live here, not lucky b/c of emissions. Luckily I am getting a free cat from my friend's shop and having a straight pipe hopefully made, not installed though. The same shop who is giving me the cat will install the straight pipe for me. it's going to be a straight pipe/ cat bolt on conversion. it's going to be sweet. then to top it off, because of the CA emissions *****, if i have my straight pipe in, I will have a catalytic converter cover covering the pipe so it looks like my cats are on. TRICKY TRICKY!