FLALS1

Well I had my SLP Loudmouth changed out for the Magnaflow exhaust system due to the noise and lost horsepower and torque (see results below).
I had Mike at Next Level Performance do the tuning and dyno. I really liked the LM but the police didn't.

RWHP Before = 385
RWHP After = 372
Total HP Loss = 13 HP

RWTQ Before = 385
RWTQ After = 360
Total TQ Loss = 25 LBS

Predatorbird

ouch. i didn't think there would be that much of a difference. you could always install a cutout to make up that loss. whats your opinion on sound? better/worse?

FLALS1

My car is to low for a cut out. I wish there was room though. The sound is much different. It seems to sound meaner at idle but the rasp and NASCAR sound at higher RPM's is gone. I used to love that sound. I could set off every alarm on one floor of the parking garage at Point Orlando just starting up the car. Now I might set off the on next to me. Going on I-4 at 60 MPH sounds better with out the rasp and drone. But again I would get looks and comments on the sound at high speed.

Overall its seems pretty good. It makes my car sound like it did stock with Loudmouth before headers but with a hint of cam. I will see how it does after a break in period. It might get better. If not I may put th LM back in. I'm sure the Orange County Sherriff's office is happy with the change. I accidentaly scared the crap out of one officer sitting next to me at 7-11 before the Magnaflow install. Luckly he didnt say anything. He did jump out of his seat though. Kind of funny.

86 IROC

Just out of curiostiy, what was the correction factor used in both instances? The weather might have been a lot better when you did 385/385. No doubt the Magnaflow is more restrictive, but I'm surprised your car is down on power that much.

Ws6Envy

yea, ls1+loudmouth = sounds like death

JimMueller

How about a custom exhaust dump after the axle but before the muffler inlet?

86 IROC

[QUOTE=JimMueller][QUOTE=FLALS1]My car is to low for a cut out. I wish there was room though. The sound is much different. It seems to sound meaner at idle but the rasp and NASCAR sound at higher RPM's is gone. Yeah, he could go w/ a Z'ed style cut out. Do a search on either LS1.com or LS1Tech for "Z'ed cut out."

The Vette Dr

Hi Russell,

Sorry I missed ya when you came to pick up the car. Wifes gotta eat I figured the Magnaflow may shgow a 5-8RWHP drop as I have seen in most cases compared to a cutout. We also installed the SLP ported TB and i am wondering if it had anything to do with the additional power loss. You know my opinion on ported TB's in some cases Just a thought and only on way to find out. And being the old guy who does not like loud, she does sound good though.

As far as the correction factors, with the Loudmouth and stock TB was a .97 at 75*F and with the Magnaflow and SLP TB it was .99 and 96*F if that helps. Definitely two different days weather wise. Talk to you soon.

Mike Norris

86 IROC

Roughly 20* hotter this last time you dyno'd the car. Attribute some of the loss due to the weather.

zeemadman

I love the way the Magnaflow sounds on my Z. I think the LM is too much for the peace of the neighborhood. Though it is a great system. How 'bout a test pipe instead of a C. Converter? Good luck...

Don