MPM

On a mildly ported N/A engine with a header, will I hear much difference from running two mufflers after the presilencer in series or parallel? One setup will be two similiar sized mufflers inline as a single exit exhaust. The other will be two mufflers off a y-pipe config like a stock 2nd gen. I'm guessing the parallel setup will be a little quieter but not hugely as compared to a single exit with two good mufflers. All mufflers used will be magnaflow of the largest size that will fit the needed location.

Tom93R1

iTrader: (2)

My REPU has a 2.5" in/out Magnaflow 6"x27" round muffler and a RB header, thats it. The sound actually isnt too loud, it isnt quiet but the exhaust definately makes less noise than my Weber carb. How quiet are you going for?

MPM

My Weber is pretty loud also.

I'd love to put a 27" long muffler under my car but that would require a lift kit. The length of your muffler is the key to making it quiet.

I would like it to be as quiet as possible while using straight thru mufflers. I know thats asking alot. I just want to utilize what I'm going to purchase in the best possible way.

I've been trying to decide on this for many weeks. Knowing I want to make it quiet as possible with a straight thru muffler I'm going to end up doing the mufflers parallel in the factory location. Magnaflow makes a 5" x 8" oval muffler 18" long that is real close to the size of the racing beat or factory muffler. If that isin't enough I can always add the 4" round resonators 14" long just after the Y split. It will have a little bit of weight but this is a daily driver and I'd never notice the few extra pounds.

RETed

It depends on the muffler design.
Get an offset, straight-through like a Walker Dynomax UltraFLO, and it will give you the best flow with the least amount of noise.


-Ted

Jodeny

iTrader: (3)

The larger the muffler case is- the quieter it will be. Also the further back towards the bumper the muffler is the quieter the car will be. I would stay away from bullet type designs. Go with a straight through oval as it has more interior space on the inside to absorb sound.
John

MPM

Thanks everyone for your suggestions. I appreciate it.

Last nite I received my purchase order # from the financial dept.(wife) so I can place my order now. Still not sure what I'm going to get. Two Magnaflows to put in the stock location or a single Racing Beat turbo muffler and a Magnaflow resonator to put between the presilencer and RB muffler. No matter what I get it will be better than the factory mufflers I'm using now.

2Lucky2tha7

iTrader: (3)

Any type of muffler that uses a stainless steel mesh liner for baffling, not the fiberlass type. My brother just bought a Borla XR-1 muffler from Summit Racing or Jegs (oval shaped) with a 3" inlet/outlet for $125 to use as the presilencer/ resonator and bought a Greddy style muffler with a 3" inlet/ 4.5" outlet for the rear muffler for only $65 new (ebay). (The body of it looks to be about 8" in diameter). Racing Beat also uses stainless steel mesh for it's liner in it's presilencer, but they cost close to $200 and only are available in 2.5" inlet/ outlet.

MPM

I don't mind the 2.5" size. Its the same size as the presilencer so it will not be a restriction. If I were to loose any high RPM power due to the 2.5" pipe I'd most likely make it up in the midrange due to better exhaust gas velocity. But then I may not notice any difference at all. I'm going to find out eventually.

maxcooper

The December 2002 issue of 5.0 Mustang and Super Fords magazine did a big dyno shootout of lots of mufflers. They all made pretty similar power (and almost all of them made more power than stright pipes) on an NA 370 RWHP Mustang with dual exhaust (half the flow through each muffler). They also tested the noise level, and the Borla XS mufflers were the queitest and made within a few HP of the best of them (there was only a ~10HP difference from the best to worst, and the XS was among the best).

Here's the Borla ProXS web site, which I think is the same thing as the XS line of mufflers in the test: http://borla.com/proxs/ . All the mufflers seem to be straight-thru (as opposed to chambered), and they have center/offset configurations like Ted suggested to use. They are all T-304 stainless steel cases, and I think the packing is SS as well, so they should last (and they have the Borla 1,000,000-mile warranty if they do eventually burn/blow out).

Having said that, though, it is quite possible that a larger muffler from another manufacturer (e.g. Magnaflow) would end up being quieter, but the mufflers in the 5.0 shootout were all about the same size.

It was interesting how close they all were for power, but I am not sure the test really pushed the flow limits of the mufflers, since 370/2 = 185WHP of flow per muffler isn't all the much (for my own purposes, I was researching a single muffler for 400-500RWHP). But for duals on an NA rotary, the flow portion of the test is probably pretty valid and shows that there isn't much difference in flow among the various choices at that power level.

The noise test might not apply all that well to rotaries, either, but it should at least give some idea of the relative amounts of muffling. The different exhaust note of a rotary might still yield completely different results, though. I just don't know. And sound level doesn't directly relate to how "good" or tolerable the exhaust noise will be for any given engine, but it's still a useful metric.

-Max

RETed

Funny you mention the ProXS...

We actually got to try one (3" in/out) on our 20B NA, and it worked really well.
The downside is that it's pretty damn expensive - $200!

It's built really nice and with a lot of heft.
Rapping your knuckles against the can rewards you with a dead "thunk" - a quick-n-dirty test of how well the muffler will work (if it "tinks", it will likely emit a lot of noise).

Walker Dynomax UltraFLO offers a similar design for a little less money for those on a budget.
I think Magnaflow is the other company that offers a similar unit for a little less also.

Don't get me wrong - Borla makes great stuff, but Borla mufflers are usually pricey!


-Ted