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-   -   Catback exhaust really help? (https://www.rx7club.com/race-car-tech-103/catback-exhaust-really-help-300093/)

RenoCYM 04-28-04 04:10 AM

Catback exhaust really help?
 
I've been thinking about putting a catback on my bone stock 93 FD in hopes of getting a little more midrange torque; but am getting different opions on it. I run SS so there's no hope of matching it with some intake punch, and I really don't want the Suzuki in a garbage can sound in my daily driver - so is it really worth it? Have any of you noticed a appreciable difference?

Fatman0203 04-28-04 07:33 AM

I will let you know in a week or two. Currently Im running non-seq with a downpipe and gutted cat and Im having high-rpm boost lost probably being restricted by the muffler since thats the only thing left. Im getting the racing beat which nearly looks identical to stock.
[EDIT] Sounds GREAT too.

RenoCYM 04-28-04 03:41 PM

I'd like to know if it helps, and just how loud is it? (Shatter windows, makes dogs bark, sounds like a Harley, or just rumbles)

DamonB 04-28-04 03:59 PM

You'll certainly notice a difference by going to some sort of high flow catback. I love my M2 dual but the Racing Beat dual is another great choice for a performance exhaust that doesn't sound like a fart can or get very loud until you're really on it.

TracyRX7 04-28-04 04:41 PM

Any chance you're heading to the national event in Atwater, CA this weekend? If so I can drive out my FD that is stock + 3" catback exhaust.

I can't stand the "rice" sounding exhausts either. The exhaust sound is a nice deep rumble at idle and not too loud when you're on it. I'm not really sure what the power difference is in reality. Most of the advertising claims say it makes a 6-15HP gain.

RenoCYM 04-29-04 01:19 AM

I won't be able to go to Atwater. What brand is your catback?

DamonB 04-29-04 09:48 AM

Big difference I notice with catback and/or downpipe is the turbos spool faster. The peak horsepower doesn't change much but there is more power before peak because boost can build quicker. You will certainly notice.

TracyRX7 04-29-04 11:31 AM

It is a Dynomax Ultra Flo muffler with a stainless pipe and tip. It was on the car prior to my purchase so I'm not sure if it is a 'kit' or if the piping and tip are custom.

It has a Racing Sports Akimoto sticker on the side of the muffler by the heat shield to the gas tank. I haven't been able to find anything about them offering an exhaust kit though.

One thing you might like as well is the Ultra Flo muffler weighs a lot less than the stock (not sure exactly what the stock FD muffler weighs but the Ultra Flo is around 9lbs).

I'll see if I can take some audio of my exhaust today or tomorrow and post it up.

adam c 04-29-04 02:58 PM

I added a RB catback after having the downpipe in the car for a couple of months. I did notice a difference, but it was not as much as I had expected.

The RB, and M2 are both very good quality catbacks that look pretty stock, and don't sound like fart cans. I don't think you can go wrong by buying either one of those.

TracyRX7 04-29-04 09:55 PM

Bloody double post :(

TracyRX7 04-29-04 09:56 PM

My wife is out tonight so I've got the kids meaning no driving around to get decent audio but here is a picture of what the exhaust looks like (looks bigger than I'd like really but doesn't sound bad which is a bigger concern to me).

http://deathincarnate.game-host.org/...-ultra-flo.JPG

Audio tomorrow :)

adam c 04-29-04 10:22 PM

M2 is in Concord, which is not far from you.

TracyRX7 04-29-04 10:45 PM

Yeah I may be heading over there at some point in the future for some of their suspension parts :) NorCal is really a great place to be for somebody with a rotary. We have Rick's Rotary in Pleasanton/Livermore, SR Motorsports in Brentwood, M2 in Concord, C2 in Hayward and those are all within 45 miles of me. I'm sure down in San Jose or over in SF/Berkley area there are bound to be a few more.

tpdrx7 05-11-04 08:41 PM

Why a muffler at all?
 
I run SS in NC and looked at a couple of catbacks before I aquired a straight pipe from GH Sharp who used to autocross FD's. The sound is actually quite nice - not too loud at all. Don't get me wrong, it is louder than the stock muffler, but with the standard precat, cat and twins, there really isn't much 'un-muffled' exhaust left. I'm sure if you were running a down pipe and a high flow cat, you'd need the muffler, but if you're planning on staying in SS you won't be doing that. The straight pipe looks good, sounds great and weighs considerable less than any muffler you can buy.

Tomas

John Magnuson 05-11-04 09:22 PM

M2 is really slow lately... it's almost like they don't do stuff for the FD anymore...

I have a racing beat dual tip exhaust. The quality is very nice. I have no precat but the stock main cat and it's not loud. Has a nice mellow note and I was the only FD at Laguna Seca that didn't have to make some modications to get by the silly track 92 decible limit.

As far as performance I can't really tell you because I did an intake, intercooler and ECU at the same time.

The fact is that you won't be very loud if you have both stock cats in place. I know a guy who autocrosses his totally stock R1 model and the only modification he has done is a straight pipe (no muffler at all) from the cat back. It's not really very loud.

If you take both cats off... that's another story... both in terms of noise and in not blowning up your car from boost creep or being out of tune.

RenoCYM 05-19-04 01:07 AM

I've got a RB dual tip on the way, thanks for the advise.

cruiser 05-19-04 01:39 AM

I think you gain more with high-flow muffler if you already run DP and MP like me. I'll dyno my car when I get one and let you know. But I think it will be more then 10HP :p:

SpeedKing 05-22-04 11:02 PM


Originally posted by TracyRX7

...C2 in Hayward and those are all within 45 miles of me. I'm sure down in San Jose or over in SF/Berkley area there are bound to be a few more.
C2 is actually in Oakland. Going down south, there's K2RD in San Jose, Rotorsport in Santa Clara, and PR Motorsports in Hayward.

If you need anything from M2, make sure they have it in stock, as their parts are on perennial backorder.

MrZUMZUM 06-09-04 06:43 PM

I have a RB dual tip. Looks good. Sounds good. Daddy like..............

Someone started a group buy on them here about a year ago and we all got them for $420. Daddy also like.......

RenoCYM 06-10-04 08:15 PM

I put on the Racing Beat dual tip, very easy install, and it looks great, sounds nice (low rumble) and does seem to let her breath a bit easier. I'm a happy camper.

John Magnuson 06-11-04 12:53 PM

Good to hear! Now if you haven't already get a downpipe to remove that precat aka nuclear reactor/ engine baker.

-John

TracyRX7 06-11-04 02:03 PM

He can't if he wants to stay in SS class :(

RenoCYM 06-11-04 02:43 PM

Can't mess with the precat as TracyRX7 says 'cuz it's not allowed in the rules for SS, and the car won't smog here in my county without it.

Fatman0203 06-11-04 11:44 PM


Originally posted by RenoCYM
Can't mess with the precat as TracyRX7 says 'cuz it's not allowed in the rules for SS, and the car won't smog here in my county without it.
How strict is smog there? From my understanding smog can still be passed with a removed pre-cat.

John Magnuson 06-13-04 07:20 PM

Then gut the precat! You'll still pass at the tailpipe and the inspectors won't know... and probably neither will the autocross folks... unless they test the temperature of BOTH your cats to see if they're hollow.

-John


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