Maggie with Stock Mufflers?

[Boss Hogg]

My current exhaust is 1 3/4" JBA headers, 2 1/2" High Flow cats, 2 1/2" Summit X Pipe (Replaced the mid-muffler), & stock mufflers. I like this setup because it's quiet under light throttle and has no rasp.

With a blower (6 lb), how much more horsepower would I get with a pair of Dynomax bullet mufflers?

Has anyone dynoed with the stock mufflers and then dynoed without the mufflers for a comparison?

[G8GT594]

Swapping out the stock muffs isn't going to net you a huge gain in HP. Most change them out purely for sound.

[norm8332]

My current exhaust is 1 3/4" JBA headers, 2 1/2" High Flow cats, 2 1/2" Summit X Pipe (Replaced the mid-muffler), & stock mufflers. I like this setup because it's quiet under light throttle and has no rasp.

With a blower (6 lb), how much more horsepower would I get with a pair of Dynomax bullet mufflers?

Has anyone dynoed with the stock mufflers and then dynoed without the mufflers for a comparison?


Livernois pulled my stock axle backs off my fully stock exhaust during dyno testing after my Magnacharger install and the difference from just the axle backs was 19 rwhp. This was with the stock 3.3" pulley.

[Jaysin]

Livernois pulled my stock axle backs off my fully stock exhaust during dyno testing after my Magnacharger install and the difference from just the axle backs was 19 rwhp. This was with the stock 3.3" pulley.

WOW, that's huge. What mufflers did you end up going with?

[norm8332]

I just ordered some stuff here:


http://forum.grrrr8.net/showthread.php?t=5835

[Livernois Motorsports]

Livernois pulled my stock axle backs off my fully stock exhaust during dyno testing after my Magnacharger install and the difference from just the axle backs was 19 rwhp. This was with the stock 3.3" pulley.

I know every car is different, so without doing the test on the same car it's hard to tell, but Norm's car made 423 RWHP / 401 RWTQ with the stock catback and we did another car with the identical mods and added a Corsa catback and it made 438 RWHP / 425 RWTQ.

Regards,

Rick LeBlanc
Livernois Motorsports

[Boss Hogg]

Just to confirm, the results on Norms car were 423rwhp with the stock mufflers and 442rwhp with no muffler behind the axle back and no other changes?

So the small 3-5 rwhp difference on a stock G8 becomes a large 15-20 rwhp difference on a blown G8?

[Livernois Motorsports]

Just to confirm, the results on Norms car were 423rwhp with the stock mufflers and 442rwhp with no muffler behind the axle back and no other changes?

So the small 3-5 rwhp difference on a stock G8 becomes a large 15-20 rwhp difference on a blown G8?

You are correct. With Norm's car that was the difference between stock and no muffler behind the axle back. I also think that the difference on a bone stock car vs. a Maggie car with a catback is substantial.

-Rick

[MtbDoc]

I am going to be installing 1 7/8" headers + X-pipe, smaller pulley, injectors, voltage booster. My intent had been to leave the stock mufflers...perhaps we'll see what we see at the dyno. Data is needed!!!

[BoostedToy]

I'll let you all know how my setup does. TVS1900/60lb injectors/BAP/3.1 pulley. Stock headers/cat-back/cam/heads...etc. I'll let you know how it does. I'll probably be putting it on in 2-3 weeks.

[JMorris]

Boss, can you tell me about our hi-flow cats? I'm tired of waiting for the Magnaflows or Random tech to come out with there bolt on kit. Did you go with the cats that are on the headers? I'm looking to do some bolt on cats with stock exhaust manifolds.

[Boss Hogg]

I bought aftermarket metallic cats. It threw a code after a couple of days, but I turned it off with EFI Live.