stock7

OK, so I got the whole racing beat header back exhaust for my 89 GTU. I got the header on there.... a pain in the ***, but it's on there, and then I ran the cat back and it didn't line up?? this really confused me, the header is specifically for my car ( NA by the way) and the cat ( High flow) and the cat back came off an 88. why doesn't it line up? it is a bit too long. But that's not the biggest point of concern, I see a lot on this forum about the 5th and 6th port actuators? do I need that little metal pipe that runs back from the stock cat? and if not what do I do with the hose cap it off? some advise would be greatly appreciated...

1987RX7guy

iTrader: (3)

As far as I can remember RB headers WILL NOT bolt up with a cat.

stock7

It is a racing beat High flow cat! and the header and the cat both have like a 2 1/2" inlet. there is no way the cat would line up with the stock header.

1987RX7guy

iTrader: (3)

Like I already said they are not meant to go with a cat.

SDrotary

I have the RB headers to a bonez cat, with custom piping to a apexi N1, you need to hook up the pipe to the actuators if you want them to work right. If you don't use the pipe you can cap it and wire open you 5th and 6th ports .

ilike2eatricers

You need to look up the high flow cat part number on the mazdatrix website that goes with the racing beat header you got. Either that or have a custom cat made. There are several different high flow cats all with different dimensions you need to find out which one you need.

stock7

A haaa that makes more sense.. ok another question. what if I take off the cat, and get the RB pre - silencer, is there a difference between the turbo and the NA? 'cause from rxecret I can get the turbo pre silencer for about half of what I can get the NA one for??
still same question with 5th and 6th port, will I notice much differnence with the hose just capped off, and no pipe run?

Cory Simpson

If you just leave the auxilary ports closed you will notice a loss of power above 3500 RPM's (about 20 HP or so), and it you wire them open, or just take the sleeves out, you will notice the same power loss it will just be below 3500 RPM's.

But if you get a RB presilencer, it has the hookup for the backpressure like that the 5th and 6th ports use. So if you do that you don't have to worry about it.

jcaldwell

I thought that in s5's Mazda changed the actuation to something other than using exhaust backpressure, changed it to use the air pump maybe? Please correct me if I am wrong though.

stock7

That's why I asked, I was under the impresion that it used the air pump as well, but it has the pipe.....

stock7

ok, so let me ask this, does anybody know where i can get the pre-silencer with the back pressure 5th and 6th port accuater for not too incredibley much? or does anybody want to trade for the USED RB high flow cat?

ilike2eatricers

I would search the mazdatrix page either under exhaust systems or the race section for what you want.

Jumbogumbp

I got an idea, give me your cat back you can have my stock setup and it should work fine if not I'll just go to your house and steal it. now that I know where you live.

stock7

Jumbo wha.....?
sure you don't want a high flow ... It would prob make it past emisions? and it costs almost twice that of a pre - silencer.

Jumbogumbp

heh, your a little slow arn't you. I already have the rb header and pre silencer, I need your cat back. You will give me it NOW. or you can take your exhaust to noone in town, midas is full of suck, I'm just post whoreing right now anyway bump, for your problems, and if you can't figure out who this is by tomorrow i'll just steal your cat-back