TD in DC

I blew out my old three-chamber flowmaster on my '44 track car, so I need to replace it. This is a track car, so my primary concern is maximizing reliability and performance. Is there any muffler out there that is the "favorite" of the track guys, or are most pretty universal.

TD in DC

P.S. How far away from the block can a crack in an exhaust pipe still lead to backfiring issues?

Campeck

where does backpressure play into this? (cause you dont want any)

TD in DC

Are you 100% certain about this? Nearly every motor with which I am familiar benefits from some backpressure.

Geo

Todd, get a muffler with a straight-through perforated core. They will be the most efficient. Avoid louvered mufflers as they generate a good deal of backpressure. The so-called "turbo" mufflers also generate a fair amount of backpressure.

Campeck, backpressure on an NA is not really the big deal if the system is sized properly. What is really the issue is maintaining gas velocity. Gas velocity is the reason you don't want to go too large on an NA because if you go too large the velocity drops off and you don't maintain as much flow.

TD in DC

Geo . . . any brand names come to mind?

Geo

Todd, backpressure is not really the issue. It some cars with lots of overlap in the cam(s) you might want a little to resist the intake charge seeping out the exhaust, however with the 944 there is no valve overlap so the issue is simply maintaining gas velocity for scavenging.

Geo

There are several. We ran a Dynomax on our ITS Sentra SE-R. I don't know what I'm going to run just yet. I have friends who swear by the exhaust/mufflers that Mario Andretti pitches (or used to). The name escapes me at the moment.

JR944

I had good luck with a 951 muffler on my former 944 I-class race car.
Joe

Campeck

geos right. with overlap it might be ok to have some. but lets say you design the exhaust to have some backpressure at lower rpm to keep the misxture in. then at higher rpm (where you benefit from overlap) theres more backpressure.

on the 944. backpressure will just keep exhaust from coming out. i dont see how anything resiting free flow of gases can benefit anything. ide bet alot that freeing up a stock na exhaust will gain hp.

someone needs to put a pressure sensor on a stock na exhaust. then put a striaght pipe and free flow muffler and remeasure. with dyno results as well.

hacker-pschorr

My 928 has an adjustable muffler - either through a chamber that makes it somewhat louder than stock, or 100% straight through. This is with long tube headers, and a custom Y collector before the muffler.

On the dyno, my car lost 5.7hp and 7ftlbs of torque with the muffler in the "closed" (quiet) position.

I doubt a less restrictive exhaust could be made over this one. Currently there are many in the 928 forum questioning my results since a stock engine 79 928 with headers making 285ft-lbs of torque at the wheels is very high.

Laust Pedersen

I am going to try one of these . More about that later.

87_944s

Magnaflow, I have a Wideopen performance muffler from Magnaflow i like the sound and it is straight through with the perfortated holes like you had mentioned Geo. The quality is exellent it is polishe stainless so no rusting and it looks nice lol

Eon S.

bleucamaro

I'm planning on getting a Spintech to replace the Borla thats currently on the S2. The car has a cat still, so I'm not worried about a lack of backpressure.

RMills944

The magnaflow just didn't have a deep enough sound for me so I got rid of mine. I have a Borla XR-1 muffler on it now(SFR System) and it has an awesome burble to it - right on the edge of backfiring, but never does.

Mongo

Get another Flowmaster. The Super 40 I have is holding up fairly well. What series did you have that failed on you?