Just got my Borla catback rear exit system installed (01 Screw 5.4 4x4) and im happy to report that the improvement in Lowend torque is very noticeable but the upper range power is down considerably (As if it had any to begin with!!) Anyone else have the same impression?
BTW, got it from the "Clearance Commando" at Truck Performance for $340, regularly ~$450. Fit and finish was excellent!!

Thanks,
Phillip

2001 Screw 4x4 gen1 (i think)
a bunch @ alittle
1995 Cobra Convertible #417 of 1003
12.30 @115

 

I bought the power set, cat back and filter from Truck Performance.
I had the opposite results, low end was down just a bit and high end was up.
I have 99 Off Road w/ a 5.4L
I can't complain one bit, it went on easy and looks awsome. 2 angled chrome tips out the side.

Most people find they lose low end with cat backs.
Did you try resetting your computer?

 

I had a slight drop in low end and got more top end.

 

is your duals out the back? if so did it clear the spare tire? thanks

 

I did not reset the Computer, maybe i need to. I have notice my tailpipes are black from running rich. I dont know if it was like that before or not my pipes were undercoated from the dealer. The pipes cleared the spare easily >1 inch. They muffler shop did have to tie back the brake lines with tie wraps, but no biggie.

 

What what teh Borla Part number you got for the Screw. I know they make one with si/do for the Harley which I do not want becasue the pipe size is larger.

Thanks,