I have an 84 GSL-SE that is otherwise stock. I removed the stock header and pre-cats. I bolted in the Racing Beat header with no problem, but there is a 3-4" gap from where the header ends and the cat begins.

I am not putting on a pre-silencer now (I have to pass inspection), the rest of the exhaust is stock.

My other GSL-SE had the same header when I bought it, but somebody had cut the header at the end and did a really sloppy job of adding about 2" to it. Until now, I didn't see why.

I thought this was a bolt on replacement...I hear about people switching out the pre-silencer for the cat for inspection all the time. What did I do wrong?

Thanks,
Brian T. Carter

 

You might have gotten the short primary header or road race header. You need the long one that collects at the end. Other than that, is the cat maybe a non-Mazda replacement? Wish I could help more, sorry.

Zac

 

there is a part that adapts the header from 2 pipes to one that is the same length as the presilencer. (assuming you got that header)

 

Why not buy a couple flanges, gaskets and some piping, cut it to the size you need, and take it someplace to get welded?

 

why not buy the correct part?

 

As I understand it, the Racing Beat header isn't designed to bolt up to the stock exhaust....

 

do you have this-



or this-
http://www.racingbeat.com/photos/16010.jpg



you may need this if you have the second one-
http://www.racingbeat.com/photos/16407.jpg



If you have the first one, well... you need the adapter, which, after looking, I couldn't find...

This would work, though, and you'd have a LOT better flow!!! (this is what I got)



Hope that helps

 

First, thanks for everyone's help.

I spoke to both Mazdatrix and Racing Beat. I have the correct header. It is not a straight replacement. They explain that in the section where they sell cats, which they state clearly are 'longer', but it is vague in the header section.

The cat I have is gutted (by previous owner), and since this part of Texas only has visual inspection, I want to use that cat. Also, I don't want a cheesy weld job, because then I could never use it with the pre-silencer if I bought one.

So, I am going to make a 3-4" section of pipe with flanges for between the cat and header. I am ticked off (mostly at myself) for not knowing about this earlier - but at lease I now have a use for part of those pre-cats I had - I will take the flanges.

FWIW, my pipe already includes the 'Y' and comes down to a single pipe flange. It is for the 13B.

Thanks again,
Brian T. Carter

 

Yes that's correct and should be a warning for anybody planning to do a similar setup. The RB header will not bolt to a stock cat. You will need RB's cat, which is slightly longer.

 

just a confirmation.
i've already started my racing beat setup, got the cat-backs and i was looking into the header.
so if i want to buy the header, the streetable cuz i cant go true dual right now, i have to buy the rb cat? no other way to do it without making a custom extension?
if that is the case could anyone suggest a header that will bolt up directly to my cat?
ty

 

Geoff at Mazdatrix revised the listing on the website so that it is clear, the header will not bolt up to the OEM cat without an extension. Kudos to them for quickly doing that and being open-minded to making it more 'idiot-proof' for people like myself.

Itaidoushin: Go ahead and get the RB header. Then, when you remove the pre-cats, cutoff the flanges off the pre-cats with enough pipe so that they can be welded together to make a short intermediate pipe. Having someone weld it up should only be a few bucks...but I guess I will find that out later today for sure. In any case, it is worthwhile for having an exhaust where I can easily swap the cat in or out.

Thanks,
Brian T. Carter

 

Why not buy a car that is already modified?
Not everyone has the money to buy bolt-ons, and not everyone has limited ability to do anything but bolt-ons.

 

Man this is so simple. Get the RB header. Get a CATCO high flow cat (I got one from summit for 66 bucks shipped). I got the 2.5 inch cat, I had a muffler shop weld the flange (u can get the RB flange from them) to a section of pipe that was on the cat. From the cat I got a mid pipe made up. The put a 2 1/4 to 2.5 sleeve (goes bigger to the cat) then from the cat back to the muffler (magnaflow straight thorough 2.5 inch can with 3 inch tip) I got the muffler from them, they made the pipe (mandrel bend over the rear axle) and I brought in my cat. Oh btw, I had to park my car over nite so I could remove the old exhaust man and place the header on the car before they started. Everything cost me 200 bucks (after purchasing my header, flange, and cat). I would say that is probably the 2nd best way to do this (I think the dual exhaust is the best for these cars, collecting back at the axle as far as torque). The 2.5 inch screams on top now, cant wait to get to the track to see if I get my 1/4 mile times down.

 

Sure, easy if I have tons of money and don't mind throwing away good components...

Seriously though, everyone has given good advice. In my case I wanted to minimize outlay, especially since there simply aren' tny cats that are higher flow than this one.

I cutoff two ends on one of the precats and had a muffler shop weld them together. Given that I supplied the parts, I think $36 was way too much, but it is in now and works fine.

The car hadn't been started in 6 months, but it came to life with some coaxing, lots of smoke (temporarily)...and everything started to work well (excpet the tranny plug was somehow sucked into the bell housing where is was promptly chewed to bits and spat out. Even my power antenna started working - it hadn't worked before.

Unfortunately, as day turned to dusk and I turned on the headlights, everything became very dim and then the car died -- the alternator was dead. So that is what I will be doing tomorow.

The exhaust is great though...no leaks, sounds good, street legal which much higher throughput than before.

Thanks again,
Brian T. Carter

 

Glad it worked for you. My RX7 Cat was plugged. The catco one I can actually see through, and had a larger inlet and outlet. Again, good luck!