what kind of gains should I expect over a diablo sport.

I have a 2003 gmc sierra ex cab Z71 5.3 and my mods are

long tubes, true dual with no cats, aerochamber muffler
under drive pulley
electric fans
air intake
diablo sport
vette servo

My truck runs a 15.75 @ 88.6 mph with a crappy 2.4 60'
torque management sucks and my times before and after the diablo sport are the same, no change what so ever. I hope I can see a difference in the hp tuners. I have heard that with the vette servo and a good tune it should chirp the tires at the shift but with the diablo the shift is just like stock. really slow and crappy.
so guys and gals with the hp tuner, tell me what to expect and hopefully I will be happy with it. Thanks Jared

 

When I ran a Diablosport it Banged through the gears so hard I was considering changing the settings to ease them up a little. I'm sure the HP tuners will be alot better and even more fun to play with. But I don't think your diablo tune was very good. certainly should have picked up something, if not on the track at least with mileage...Hmmmmmnnn

 

well once you figure how to use HP tuners you could drop another second off your times, good luck

 

should pick up quite a bit. also, read your stock file and the diablo file and compare the two, you'll get a nice laugh at what they actually change. sometimes i wonder what these handheld tuner people are thinking

 

I read my W4M tune when i first got HPT, man that was funny. I always recommend looking at your previous tuning setup if you have that luxury