BillP

Well, after leaving my car with Flowmaster for a few days, I got it back.

WARNING, the results here are NOT what they are going to be offering as a kit!

Background: I contacted Flowmaster and they were interested in building an "American Thunder" system for this car, and wanted to use my car for R&D. "American Thunder" systems are fairly loud, but not obnoxiously so.

They tried many, MANY of their existing mufflers in order to try and get their sound. They tried the Super40 (too quiet, even though it's a very free-flowing muffler), and various Delta40's, and none of them got the right sound. The Delta's tended to drone too much in the interior of the car. The dynamics of the long tubes from cat-back, and the short tips (no tail pipe to speak of) made tuning the sound a completely new ball of wax.

The status on the R&D of their exhaust system KIT is that they are going to probably build an entirely new muffler (new part number) in order to get their "American Thunder" sound and sell it as a kit.

The system they left me with was axle-back (they didn't have time to do the pipes, they were too busy trying mufflers) Super40 system. Joe at Flowmaster said that if they decide to market a "Force II" exhaust system (one notch quieter than American Thunder), then this is the likely setup.

Mufflers: Flowmaster Super40 part# 952548
Tips: Flowmaster part# 15365

The tips are similar to the Magnaflow system seen here and elsewhere, with "Flowmaster" stamped into the body of the tip (sorry, it's out of focus):



View from the rear:


Larger photo, of the tip and muffler from underneath
http://www.squadengine.com/~bill/2005/flow...G_0208_1024.jpg

Here is the back, where it connects to the pipes:
http://www.squadengine.com/~bill/2005/flow...G_0209_1024.jpg

And finally the whole package from the rear, underneath:
http://www.squadengine.com/~bill/2005/flow...G_0212_1024.jpg

The Sound: This system moves the sound at idle down a couple of octaves, it now has that classic V8 rumble. It's a bit louder at most speeds, but is VERY liveable for those of you who, like me, are past the headers and glasspacks part of your life. In fact, if you want "Thunder", this isn't it. But it's got a growl that is deeper and in my opinion nicer than stock. There are only a couple of cases where you get some resonance in the cockpit, like flooring it WOT at 1900rpm in 5th gear (like 45-55 mph). But you should be downshifting it anyhow, and it's not bad, just a bit boomier than stock in that one situation.

Flowmaster mentioned that the stock exhaust ROCKS, it really flows well. So nobody sweat it if you are keeping it stock!


Dyno runs, before and after, available as soon as they forward them to me!

BillP

modified the original post to include the sound quality.

freebass55

Nice.

Like I said before, free stuff rocks.

Dyno runs, huh. Yeah i'd like to see those.

BillP

I still haven't gotten the dyno runs from Flowmaster. I did hear back today that they had zero gains from this muffler system. They are going to have to build a special muffler for it to get the combination of breathing and sound they want.

That's a bummer.

I'm going to get it dyno'd myself, and do a before/after with the mufflers, as well as probably get an SCT XCalibrator and get a tune on it.