Fingers

What would you guys use for a high-flow cat, if you have a racingbeat downpipe? I need to remain smog legal, but i want to stick with the racingbeat downpipe that i bought. That means that i'll be selling my presilencer i guess :P

Thanks
-Ross

Scott 89t2

do you have the 2.5" or 3" racing beat down pipe??...

if you are lucky the bonez one might bolt to the 2.5" but don't know.

for the 3" you gota make your own.

Icemark

The downpipe and Pre-silencer are supposed to be as long as all the cats on the car and bolt onto the cat back, so you would probably have to have a custom cat made up that just replaced the pre-silencer.

fcturbo2

Can you have both a cat and a presilenser???... LIke bolt the cat on the DP. And why cant some cat handle the heat on the rotaries. Is this true????..

Icemark

According to RB, no.

, yep most cats die from the high temp and unburned mixture.

fcturbo2

sucks..hmmm..what im trying to do is have a cat and im also trying to lower down the noise level that my RB full turboback produces. Will replacing the RB presilenser with a high flow cat lower down the noise???..

flying taco

Call up RB and the the length specs for the pre-silencer. Check this place out -> http://www.testpipe.com/htmlsite/pro...5&pstring=1,15 for 3" cats. $59.95... can't beat that.

Aaron

Scott 89t2

yes a little. I have one.

fastrotaries

random technologies will make a cat that will work for a rotary. you could also get your hands on a FD high flow cat. you're going to have to visit a muffler shop and have them weld some stuff for you.

Kelimutu

I have the Bonez "Turboflo" from RX7.com and i t works great, much more power and still silent (alot of bass in idle but its cozy!) It consists of a 2,5" DP and Hi-flow cat. You can buy wach separet or as a kit. This togehter with MazdaSPeed 3" catback is great, pass emissions, not too loud (but not silent) and with a lot pf power... Im happy!

dad4ever

I have the RB 2.5" downpipe (thanks Chris) and Bonez converter. It appears to be a perfect fit but I won't know for sure until I install it in a few days. I am still waiting on the y-pipe for the RB catback system. The RX-7 store forgot to ship the second box that contains the y-pipe.
I was a little disappointed with the looks of the Bonez converter. It is very lightweight compared to the stock converter and reminds me of a standard generic aftermarket cat.
By the way, the mufflers with the RB cat back system are awesome!! A real work of art.

Fingers

dad4ever, i'd be very interested to find out whether or not the bonez converter bolts up.

If it does, i'll have a RacingBeat presilencer with 2 hours of use for sale very soon

My second option is to buy a generic cat and have my buddy (has a tig and an arc welder) weld it all up for me.

dad4ever

I did a trial fit of the exhaust parts last night and the RB downpipe is about 3.5 inches too short to use it with a stock replacement cat. The Bonez converter is 17.5 inches long (same as the stock cat). I do not have a pre-siliencer but I am guessing that it must be about 21 inches long. After considering my options, I have decided to fabricate a 3.5 inch pipe with a flange on each end. I salvaged two flanges from my old exhaust parts.
fingers, I would be curious to know exactly how long the pre-silencer is as that would tell me exactly how long to make my extension pipe.

Fingers

Sure i'll get you those measurements by tomorrow.

I think I'll be getting a universal 2600 series Catco high flow cat. (its what bonez uses anyway)... and hopefully that will work out well

dad4ever

I installed my system yesterday. Ended up making a short pipe with a flange on each end to make up the 3.5" difference. Here is a picture, mostly to see if I can post a picture!

Still interrested in knowing the length of the RB pre-silencer.

Icemark

5 stars for Dad4ever's contribution

Fingers

**** sorry forgot!! 20.75"

Hope that helps

Fingers

While we're on the topic of measurements, can anyone tell me how far the o2 pipe stops from the cat-back junction? I want to get a cat replacement built, and possibly start selling them, but I need to know some measurements.

-Ross

Icemark

a pre-cat replacement down pipe? Now there's something someone should make and sell.

ERAUMAZDA

dad4ever

Looks like the 3.5" that I added is about right since that comes within a quarter inch of the pre-silencer. My cat plus extension measures 21".

The o2 pipe junction is 12" from the RB downpipe and 9" from the cat-back junction. The Bonez converter comes with the o2 pipe parallel with the cat and I had to cut some off the end and bend it before welding on the flange frrom the old cat to get it to be a perfect fit. You can see from the picture that it is at a compound angle. BTW the pipe is difficult to bend without kinking. I heated it red hot with a propane torch while bending and had a minimum of kinking. For the price of the Bonez, I expected the o2 flange to be on the air pipe. I guess that most people cut the flange off the o2 pipe from the car and use a high temperature hose to make the connection.

Fingers

Interesting indeed. So it looks like i'll have to get me a 20.75" long cat from flange to flange. I want to keep the cutting to a minimum, so i'll try to arrange it so the o2 pipe lines up. thanks for the measurements!!

fastrotaries

what the hell was the purpose of that flange up there? You should have just welded some extra piping and at LEAST broke it down to one flange.

jgrts20

my CAT that was on the 7 before i replaced it with a presilincer was 18" so i did not have to do any of that stuff(dont ask me why cos i dont know) i think the header made up for the extra!! (shurges shoulders)

Fingers

i think what he's saying is, why didnt you just cut off the flange and add 3.5" of piping instead? Would have saved you a weld, and two flanges