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?

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.

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)

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.

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.

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

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.

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.

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.

Bloody double post :(

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 :)

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

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.

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

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.

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

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:

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.

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.......

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.

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

-John

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

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.

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

I didn't know that. There are FD's running in SS with no precat. Would someone confirm this.:confused:

What is the point in cheating to win in something that the only reward is your own self satisfaction of a good job done and maybe a few handshakes from some friends at the event?

Sure he could gut both of his cats, install a PFC (no commander), port his engine, upgrade injectors & fuel pump, etc, and still have a visibly "stock" looking car but what sense of satisfaction would you get knowing you just cheated to win?

For good or ill, amateur motorsports rely on policing by the participants. Tech inspection is primarily for safety, not compliance with class specs. If you suspect a competitor is cheating, you must file a complaint or challenge (and frequently post a bond to cover the tear-down and rebuilding costs if you are wrong). If you are only competing locally, you're no threat to the class winners, and your class competitors know you are not strictly legal and are ok with that (not uncommon with non-performance-enhancing deviations), I suppose there's no harm, no foul. If you win, however, it's really easy for someone to complain after the fact and strip your trophy from you (and get you banned from future competition in some venues).

Now, realistically, all high-end motorsports (amateur and professional) tend to live on the bleeding edge of the rules, and creative interpretations are sometimes necessary to be competetive.

In my case, all I have at stake in competition is my own satisfaction - winning with an illegal car is like shooting fish in a barrel - what's the point?

Here in Washoe county in Nevada the smog tests are pretty stringent, as bad as California I would imagine since most of the new cars sold here come with California smog equipment. My FD passes now with all the factory smog equipment, but barely. Sometimes it will fail the first time and the machine runs a second test which it will pass (not enough warmup time usually). Fail twice and you're parked until you make repairs.

I agree with MacDaddy, it would be like cheating at solitaire. Everyone trusts that you'll play by the rules - to the absolute limit of the rules for sure - but within their limits. It's ultimately the driver's talent that wins in autox, if I wanted to beat my competitors with my credit card and tool box I'd take up drag racing or road racing where you can spend your way to the podium. At the end of the day I want to feel I'm a faster driver than the guy who finishes behind me, not a sneakier mechanic.

In any stock class you may only alter the exhaust after the main cat. For the FD in SS this means the stock downpipe must be left in place to remain legal.

Catback legal in stock, downpipe or gutted precat illegal.

I agree with the others that going to all that trouble to cheat in SS is pointless. One point to consider though is the reliability value of removing the precat, especially on a car that's pushed hard and not allowed to get out in the wind and cool down ... even more so in your hot climate. My advice would be to see if you can borrow a DP from someone and try emissions and if it passes move to ASP or maybe even just put the precat back on once a year. The DP was all that ever put me in ASP before I completely gutted my car and installed a cage, putting me in AP. Now I have a gutted car with race cage racing in AP ... still no other mods than a DP LOL

Anyhow, the race preparations have begun. It will be a full-bore race car within two years.

Tubbs

Thats very nice =P
Not even a radiator?
Im sorry but a cat in that location, is another reason why I wouldnt race SS, not because of the class and where the FD is, but because my motor will bake after the first few track days in 95+ degree wheather here in South Fla.

My car has done quite a few track days with the stock plastic radiator in 90+ degree heat.

Have you used a digital or analog aftermarket guage to see where your numbers hover at?

Also youve done this with the precat?

Water temps stay around 225F when running hard. If it's 100F out then I can make it overheat if I try, but that's only at the racetrack at full boost the entire time.

Engine is completely stock other than downpipe and catback. 80% water / 20% coolant mix, Miata thermoswitch and baffles on the sides of the radiator air inlet.

Damon have you tried Water Wetter? Does it help?

Thats what Im saying. I wasnt really talking about the stock radiator (even though a better one helps) I was more talking about trying doing track with the stock pre-cat, I bet your temps will be a bit higher, probably overheat.

Haven't tried that yet but I'm planning to soon. I plan to spend a weekend within the next few weeks doing a bunch of little things and water wetter is on the list.