hey guys my brother just got a gsl-se with a 3 inch exhaust , rb race headers , and a supertrap muffler off a formula mazda car. the car would not pull all the way up to 7k it would just stop at about 6k rpm. i checked everything from fuel to ignition system. finally i just decided to remove all the plates from the supertrap and run open exhaust. that was the problem. what do the formula mazda guys do to prevent this. i know this is not normal. i've never worked with a supertrap before and am wondering am i missing some parts. all i have is the bolts for the plates and about 10 plates and the end cap. should there be washers between each plate?
a little help please!!!!!

 

No washers between the plates, its just the nature of the muffler. The fewer the number of plates, the more back pressure. Formula Mazda cars are rev limited very low(6500rpm sticks in my head but I'm not positive). The thing is still technically a muffler without the plates just a loud one. I think the formula guys use the backpressure to tune the power band, its not the best way but its allowed within the tight rules of the class.

 

Ever wonder why the exhaust on a Formula Mazda rattles? Double nutted at the end of the stud (or with enough room to let the plates move... I never looked at one that close).

PS - get rid of the Supertrapp. If somebody brings me a car with a supertrapp, I go from providing them a 15HP gain to a 30HP gain.

 

what kind of muffler do you guys use / this car is driven on the street so i want to keep the noise level down to just loud not ear drum bursting. the pipe is 3 inch. tell me what to run.

 

Well on my street car I have some cheapy O'Reilly's muffler, but it's only 2.5 (I was desperate... just made an adapter from my 3"). On the racecars I run a Dynomax (not recommended for street) and a Flowmaster. Series 40 Flowmaster sounds pretty cool, but on a straight pipe it's pretty loud. One of their more restrictive mufflers might quiet it down. Just remember piston engine mufflers don't work the same on a rotary.

 

I have 2 Supertraps (2.25" x 16")on my 89NA and I have no problems reving up to 8k. 7 plates a side seems to affect the top end a little and I settled on 12 plates a side. Are you just running 1 muffler? Try adding addittional plates.

 

I'm with Chris, lose the supercrap, almost anything is better for these cars. Yes two of them would be an improvement but one Flowmaster would be better.

 

does the flowmaster quieten it down to a standable level? is there any flowmaster that works better or can i just go get one from advanced auto?

 

They have different 'Series' mufflers. I think the '40' series is the loudest and the higher the number the quieter the muffler. I've used the '40' on race cars and its kind of loud for the street, the '50 series' might be OK or check out their website and see what you can find. The '40' only has a single chamber, some others have two. I got mine from Summit Racing, if flowmaster makes it they have it even if its not in the catalog. I used a generic side in/center out because I ran the exhaust under the rear end (FB).

 

Dynotesting shows 21+ discs = no horsepower loss but is too loud for street.

I'd just add discs until it revs to 7k, that motor won't make power after that, they peak around 6500 anyways.

 

Having two Supertraps that are 16" long is not that loud but, I have a high flow cat with a pre-silencer. I would be interested in the dyno results I would get with adding and removing discs to see what is correct for my car. Seat of the pants tells me 10-12 a side is best.