So after debating for a couple of months on going for a midpipe or hi-flow, I have decided to stick with a cat. I suppose I could say that I am doing it as a responsible citizen, which truly is part of it being in CA, but even more than that the thought of getting caught without one makes my wallet feel lighter already. So all that aside the only thing holding me back is the cost of the damn things.. $500 for Bonez, $350 for N-tech, even more for one from Tri-Point. After taking a look at what Summit has to offer I have picked out a 3" SS Catco unit with an air pipe to hook up to the air pump, and for under $100! I can get a midpipe for a shade over $100-120 and get one of these suckers welded in. Has anyone used this brand of cat on any of their own cars? I'd imagine even this would flow much better than the stock unit.

Matt
93 SSM

 

check out this link www.xtremeflow.com
ive been very interested in trying one of their cats out.

 

i ahve heard of catco before, they seem to be pretty reputable

 

You better make sure any cat NOT sold by a rotary dealer can put up with our exhaust temps of 1500-1700F or so. Uf the cat can't resist this amount of heat, it will quickly clog, and you will find yourself a bit irritated.

 

but I was disconected while on hold when he was gettin info on whether it was considered hi-flow or not.

Anyhow the only thing I think everyone is worried about is how long will it last from the turbo rotary's extreme heat and how moch more flow.

I even thought of cutting off the cat and welding in a hi-flow one in it's place but I beleive the stocker is mild steel and have no idea if you can weld stainless to it.

I looked at Dynomax but they don't list Mazda. Then I looked http://www.xtremeflow.com/ which claims higher flow than Random Technology? http://www.xtremeflow.com/catalyticconverters.htm
but their chart is wrong and you need part #XF607 (3" dia not 2.5")and you need to specify over the phone that it needs the O2 fitting.

So I haven't done it yet for the RX7. The only thing I can sugest is buy the part first. When I had the Dynomax done for the CRX, the muffler shop said they had it in stock but they never even checked part #'s. They just go to the shelf and get the box, then eyeball the length. What F'n morans, how do they know if it will handle my size engine!

I did a poll and out of the people that actually bothered to answer, Bonez was the most popular. I wish there was some kind of comparison as to which flowed the most and which lasted the longest.

 

I purchased a R.T. hi-flo cat off the net last year and it ended up being gutted (got shafted) - I did get some money out of the guy since he claimed he didn't know it was gutted. Anyway I took it to Meineke and had them weld on one of their performance cats for $150 installed. I've been running it for a year now with no airpump and it's been fine. If it lasts me another year or 2 I'll be happy. Supposedly the number off the cat is the same as off Bonez's cat......hmmm

 

Barry:

Exactly my thoughts, if one thinks about this it seems very unlikely that all of these rotary shops are fabricating their own catalytic converters. So where the heck are they coming from? They must be outsourcing them from somewhere, welding them into a midpipe, and then jacking the price up. Now Random Tech, yes, they make their cats.. but N-tech? Bonez? They don't seem like the type of places that would have the resources to do so since they focus on many other areas of performance as well.

Matt
93 SSM

 

I bought a custom Hi-Flo from twstd rx that uses a Catco Cat. I LOVE IT!!! Made a world of difference!! Quite a bit louder under WOT, but not unbearable...

 

Do you happen to know the part # that was on the cat?

Matt

 

Sure don't, but I'll see if I can get it for you..

 

Can some one post the part #'s for:

Bonez hi-flow Cat'
N-Tech hi-flow Cat'

 

I will be cutting out the cat and welding in a XR-1 muffler in it's place. This will keep the air pump fitting. And if by chance it doesn't pass...connections

 

If you are curious, here is what an FD sounds like with just an XR-1 in place...

FD with XR-1

 

eeeewwwww......that sounds gross!

 

A few years ago, I called Random Tech. regarding a replacement cat for the FD. When I told him it was for a RX-7, the guy said, "Oh yeah, we call rotarys cat-killers because the heat is so extreme that it causes the converters to fail. We will give you one replacement under warranty, but that's it."

Now this was a few years ago, and Random may be different now, but after hearing that I decided to get a Bonez if I was going to replace the main cat. Of course, if you can keep getting $100 cats that last a decent amount of time, maybe that's a better buy...

 

I had to download it to my HD and play it from there to make it sound better. I like the sound but it's alot louder than I expected!

Thanks for the tip on Random Tech. I called them also but they wouldn't comment on how it would hold up with a rotary, much less a turbo rotary. Bonez is the only brand that claims it can hold up to the heat. Although, Petit and Tri-Point make them for the FD as well. When I called both, they both said they had never heard of the other brands and Tri-Point will "NOT" install a cat' made by another company.