I've recently changed my exhuast to true 2.5 duals no cats and magnaflow mufflers. The exhaust sounds great idle, 2/3 throttle but when i'm WOT it makes a really weird/crackley/raspy sound between shifts(4l60e). Anybody else have this or just me. Allen is sending me out a retune, will this help at all, is it a timing/torque managemnt issue? Thanks in advance!

 

That snaping is normal, it comes hand in hand with glasspacks and no cats. How is your low-end torque? I plan on removing my cats this summer after getting a tune from allen.

Yesterday I raced a kid with a 2wd chevy short-box with a pre-vortec 350, i whipped him good in front of his girlfriend, so it goes to show that our 4.8s are snappy engines!

 

Lowend torque didn't change much, my heavy 18's and no gear don't help either.

 

[QUOTE=screamingjimmy]That snaping is normal, it comes hand in hand with glasspacks and no cats. How is your low-end torque? I plan on removing my cats this summer after getting a tune from allen.

It also did it with the one chamber mufflers.