Hi All:

I haven't weighed the stuff yet, but I have to say that I cannot believe how freakin heavy the stock downpipe/cat combo is. That stock cat is seriously the heaviest cat that I've ever had to mess with. I think Mazda used lead bricks as part of its construction.

Between using a replacement downpipe and a midpipe with a welded-in Carsound 3" cat, I'm thinking that it is easily possible to easily save 50 lbs, get a performance increase, stay legal, and be easy on the wallet. I know that the FD3 tends to roast 'conventional' cats pretty easily, so my plan is to weld it in as far back as possible. I'm not sure if anyone has tried this yet, but I have all of the parts to do it (downpipe, midpipe, cat, high temp hose, etc), so I'm gonna give it a go. I have a pyrometer so that I can monitor the pre-cat and post-cat temps to compare to stock and to also check on the life of the Carsound.

Sonny

 

The high temps of a rotary exhaust will destroy all but the most heat resistant materials. I don't know how your carsound cat is constructed, but don't be surprised if it doesn't last too long.

 

My high-flow cat lasted 5 years, until the bricks fell apart, and clogged my cat (keeping the turbos from boosting). I solved this problem by going with a midpipe.

 

Of all of the high flow cats out there, only the Bonez seems to last. Not personal experience...just a conclusion based on what I've found here. It's a nice piece, but damn, that core is expensive. The core alone is $250. A carsound core is $50.

If the Carsound fails me, I'll just cut it out and stick a Bonez core in there.

Sonny

 

Ok, weighed the stock parts.

Downpipe = 22 lbs
Cat = 32 lbs
Muffler = 34 lbs

That's 88 lbs under the car.

Sonny

 

Yes, Its quite a peice.

 

I have never seen a side by side comparison before.

 

Sonny, in about a week my 88lbs original stock exhaust will be replaced with a tad over 20lbs. Greddy ti, and stainless downpipe and midpipe. I think i'll feel the difference just from the weight

 

I removed all the covers and insulations on my cat and muffler to reduce some weight maybe saved 20lbs if that. I really need to get midpipe and catback already.

 

The pre-cat and cat should be the first things to go. Very good chance they are already shot if the car was stock for 10 years

 

i read something about metal cats working very well for the FD

 

The guy at Carsound that I talked to said that a metal core would be ideal for the turbo rotary. Unfortunately, Carsound does not have any metal core offerings. He did say that if the cat was far enough back in the exhaust stream, the ceramic core would survive.

Sonny