Exhaust Upgrades

[fordfan1964]

07 mustang gt manual, airaid CAI, Poweraid throttle body spacer, borla exhaust, u7145 predator.

Is adding a more free flowing exhaust going to make the computer read cooler temperatures in the exhaust system and make the engine dump more fuel into the mix because it thinks its running lean?

can i use my predator to turn off the O2 sensors to compensate for this change.
I've just noticed a small drop in power and also fuel efficiency since i added the exhaust to the mix. I did it all in stages, with the borla being last

Things are much easier to tune on my 64 galaxie!

[Phil]

Fordfan1964, The only parameter you will have to modify for the new exhaust is the rear o2's. If you are running a h or x pipe without cats. You will have to turn the rear o2's off.

[fordfan1964]

how do i modify the rear 02s, the only option i see is to turn them off

[Phil]

Yes the only option is turning them off. Do you have a h or x pipe with no cats ? If you do you will need to turn the rear o2's off. If you have cats on this car you will adjust nothing.

[fordfan1964]

The car is a 2007 Mustang GT, 5 speed manual trans, poweraid throttle body spacer, Airaid Cold air intake with the insert removed, borla exhaust. I have not modified any h pipe or x pipe and im still running stock cats.

I had a drop of nearly 5 miles per gallon after adding the borla this past weekend. the airaid cold air and tune was awesome, i saw such a huge increase in mileage, driveability, and power.

I contacted a dyno shop that someone recommended to me, but they only use SCT tuners. I like your module and i want to keep it. is there any way you could write a custom tune for me that would change some parameters to compensate for the cooler exhaust temperatures? im sure the motor is putting more fuel into the car because it isnt picking up the right temperature from all the O2 sensors. and if i turn the O2 sensors off the computer will just run in safety mode right? i want this car to have great power and still get great mileage.

And if all fails im gonna take off the borla and sell it on ebay, but i like the sound and i dont really want to change it.

any help would be great!

[Phil]

If you have not changed the h-pipe and you still have the cats the o2 sensors are still getting the same readings as before you changed the axleback system. The o2 sensors are reading values as soon as they exit the headers well ahead of the axleback system you installed. The only thing you should have lost is backpressure due to the free flowing exhaust.

[fordfan1964]

is that backpressure going to reduce the power im getting from the motor? and is that reduced back pressure going to affect my mileage?

[Phil]

Pull the battery cables and touch them together.
Re-connect and go, this will reset your learned fuel consumption, and the mileage readout should go up.
Dont pay too much attention to those readouts either, as they are often off by quite a bit.
Log the actual mileage against a full tank of gas to see what you are actually getting.