Diablosport Forums

My car was running 14.6-14.9 with 4.10 gears modded H-pipe flowmasters and a TB then i changed the IAC valve and i went to the track this saturday and ran a 14.3-14.6. I was running unconsistant and top end sorda seemed to fade out and i figured i should be in the 13's with all of this so i put on my stock tune with the same modded parameters and went again today and ran consistant 14.0 this is on my stock tune is my perfomance tune for my tuner messed up because i feel no power difference from my stock tune to the performance tune the stock actually feels faster!?

What were the trap speeds?
MPH is the best judge iof additional power, and often ET will suffer due to wheelspin from extra power...

with tuner was around 96 and with stock tune it was 98 it just feels slower with the performance tune too.

anyone? i paid 400 dollers for this so i would like it to work.

btw my car is a 99 mustang gt auto and the tuner is U7146 also have time slips to prove it.

My guess is that you have changed something on the car that is causing it to not run ideally with the performance tune, may be time for some fine tuning on the dyno or even a custom tune...

Thanks

Alright so i put the performance tune on tonight and decided to go into WOT fuel and lean it and move it to 0.50 i did it for both and i seem to notice a difference now is this going to hurt my car? im gonna run it friday to see if i run at faster time like this.

Leaning anything out without knowing hwere you are to start can be scary....look into some dyno time or a wideband.

o i just leaned it one notch from stock seemed alot faster but i took the tune off right when i got done and put the stock tune back on. could it hurt it that much? because there isnt a dyno near here and i dont see why my tuner makes my car slower.

Try lowering your shift pressures back to stock.
I was running 13.6-13.7 at 101-102 mph in my mildly modded 2001 mustang gt.
I knew it had more in it because 2 years ago I ran a [email protected] mph, and was trying everything to find the lost power. finally I lowered the shift pressures back to stock and now most of my runs are 13.4's @103+ mph. New best of 13.415.
I have done the J-mod to the tranny to improve shifts. Check out Tccoa.com for more info on the J-mod.

ive never adjusted the shift pressures but thanks tho! the weird thing is my MPH is only 98

I'd take Mikel's advice, put it on a dyno. You don't know what the diablo tune is doing let alone how customizing is going to affect it. Trial and error might just prove more costly than you'd like.

no dynos around here closest is dyno chips and the 3 hours away