I finally did get the old ones out and the new ones installed. I ended up jacking up the car in the rear where the lower control arms attach at the bottom. That gave me enough axle drop to force them out. Mine was jacked up way higher than that in the rear and mine did not fall out. Anyway, here are some comparison pictures of the factory GT OTA pipes and the GT500's next to each other. Here are the part numbers on the pipes if anyone is interested. I'm not sure what side is which on the part numbers.
BR3V5A-212AF
A753F
291 11
BR3V5A-213AF
A753F
135 12


Passenger side pipes:






Driver side pipes:




New pipes installed on car:






Car is definitely louder on cold startup and seems a little louder at idle. I'm not sure on acceleration though. They almost seem the same. Time will tell.


Wayne

 

Hey Wayne, I'd be very interested to see what you have to say after a few days of driving with this setup.

Do you notice volume increase in mid and high RPM range, or does it sound about the same? I have GT500's on my car. My main motivation was better tone and slightly more volume so I can hear when I'm approaching the redline (shifting by sound). The stock mufflers were really quiet near top end.

Also I'm curious if you noticed any change in the power band across the RPM range. Based on my (limited) knowledge I know resonators are sometimes used to maintain certain back pressure and for power curve tuning in addition to muffling the sound. I don't know if on the Mustang this is the case as well, but I' curious to see if you've noticed any gains/drops of power, or changes to throttle response at all.

 

This car is not my daily driver so I've only put about 5 miles on it since the swap. The weather has been crappy so I've driven some of my other vehicles. I need to put more miles on the car to really see how much difference there is. There is more volume and the tone does seem to be better but I have not driven the car since Friday.


As far as power goes, to me, there seemed to be a slight loss of low end torque but I'm not sure. The throttle response does seem to be different than before. My car is an automatic and the car now seems to downshift a lot easier when you start getting into it. All of this may change as the computer adjusts for the less restriction.


I will try and give more of my impression after I drive the car more.


Wayne

 

Sounds good. Thank you sir.

 

Did the axle back fit right up to these or did you have to do more modding? Just curious as to how much more work it is for these vs stock OTAs.

 

They fit perfectly. I did the same thing, GT500 axle backs and midpipes from a 2012 Shelby fit my 2014 GT. I do not know if the cats and H-pipe fit though.

 

OTA's have been known to melt the gas tank vent tubes which are near the top of the over axle hoop. Maybe they're for that. If you ever have trouble filling up your tank, and have OTA's, check your vent tubes.

 

What Automatic 5.0 said. They fit just like the factory OTA pipes.


Wayne

 

FWIW I ended up going with Lethal's over-axles due to their revised bends which account for more aggressive setups, I'm lowered on FRP "P" springs and with lethal's pipes I've got plenty of clearance. It's the only lethal product on my car, can't speak for them as a company but their O/A pipes are nice: http://www.lethalperformance.com/sho...xle-pipes.html