What diameter exhaust with 2007 GT? NEW order!
 

Under the heading of better late than never:

Everything in life finally came together and I finally got my American Muscle ordered. 2007 GT Premium/CS Black/Black w/Interior Upgrade, GT Apperance, Comfort Group plus I'm having them order and install C&L CAI and Diablo Tuner. Finally, I'm looking at an X-Pipe with Flowmasters. What I'm wondering is the DIAMETER of the exhaust. I'm worried about back pressure and burnt exhaust valves. Can I go with 3" of should I drop back to 2.5"?

Thanks . . .

Phil Ritzenthaler

RE: What diameter exhaust with 2007 GT? NEW order!
 

Sorry fella, but excessive back pressure has nothing to do with burnt exhaust valves. I suppose that if the mixture were leaned out a BUNCH by exhaust modifications, while making no tune changes to compensate, this could happen, but short of removing the exhaust manifolds altogether, you won't get there.

The factory exhaust system is very free flowing as factory systems go. It would be difficult to open it up enough to cause so much change in mixture that this would be a worry, especially since you will have the diablo and the method to change the tune to compensate.

RE: What diameter exhaust with 2007 GT? NEW order!
 

Your stock pipes are 2.5 inches, you should just get the mufflers. Typically a new x-pipe is only worth a few hp.

RE: What diameter exhaust with 2007 GT? NEW order!
 

i have heard nothing but bad things about fllowmasters. I talked with another mustang owner that had to have a pair of flowmasters replaced due to the baffles inside loosening up and ratteling three times. Thats why i choose another muffler.

RE: What diameter exhaust with 2007 GT? NEW order!
 

Brent at brenspeed.com says the off road X is worth about 10 hp with tune, vs tune alone.

RE: What diameter exhaust with 2007 GT? NEW order!
 

Black is very hard to keep clean and avoid swirl marks.

I think Midas carries Flowmasters with black tips though.