do you need new housings for a exhaust porting? Thats what RB site says
 

I want to streetport my 12a. I have the Racing beat Streetport exhaust system with the RB rear muffler swaped for a canister muffler. I also plan to get the holley street port intake.

The RB site mentions that Exhaust porting can only be done on new housings. But I hear people on this site talk of exhaust porting, I cant believe they all have new housings.

Plus-would pluging the fresh air port in the exhaust cut down on backfires. My car tends to backfire when I shift high in the RPMs.

What year is your RX7? And I do not think that you have to have new housings to get a exhaust porting... I believe that they just enlarge the existing hole there... Am I right? :confused:

I dunno why the RB site says that. As long as the old housing is in good shape I don't see any reason why you would need to replace it?

Do you mean the fresh air hose that goes to the catalytic converter? Cutting off the fresh air supply to the cat would only make backfiring worse I think...

backfires and housings
 

You DO NOT need new housings, just inspect and measure your housings and if they appear ok then port and reassemble. You have a 12a so there will be some horrible discoloration on your hosings, doesn't matter clean them, check for huge gouges, if they are badly gouged then, boat anchors. Pay no mid to a little bit chrome flaking by the edges this is normal. RB just wants to seel you 900$$ worth of rotor housings. the motor will run great for the street and track.

Guru

I think they are trying to say they only port new housings, they will not port Yours. I could be wrong.:D

Yeah thats what they are saying, they WONT port used housings.

Most people wont do used ones, but if the housing is in PERFECT shape I dont see why not?

Turns out i wasn't pulling crap from my ass :)

It's more of a warranty issue for RB. they don't want to do all that work and have a problem with it later.

Yeah that whole warranty issue... Used housings are a crapshoot, and given that when you port the housing you're doing it because you want more power, you're more likely than most people to wring that power out of the engine...