I am not an expert either, but I believe it retards the timing by 5 degrees. If you run the 87 tune with a CAI and don't adjust the timing then your air/fuel ratio will be off. Your check engine light may came on and in the long run will damage the engine.

 

just spend the $50 and then you dont have to worry about any of this stuff...I would trust dougs tunes way before messing with timing and **** myself.

 

I had no idea i had to mess with timing...i thought it was just select 87 tune, then select K&N as the canned tune, then i'm good to go...i thought the diablo would do all this itself..

 

you dont have to mess with anything. You can just load the KN tune and run 91 oct and be fine

 

Yeah but 91 is so expensive, reg gas is 1.40 per liter. 91 would have to be about 1.50 per liter.

 

I am sure Doug can make a tune for your CAI using 87 or 89 octane.

 

is your GT your daily driver? if not, do your stang a favor and get the 91 race from doug. it did wonders for my sixer and i'm sure it will do bigger wonders for your GT. i went from diablo's 87 perf to diablo 91 perf to bama 91 race. the difference between each step was a proportional increase. you can't go wrong with bama. great tunes, lots of fun.

also, think logically. if fuel economy is of concern, you can always revert back to your diablo 87 perf.

 

I think for all around purposes, the 89 tq tune would be the ideal tune. One poster on another thread said there is very little difference between the 89 tq tune and 93 race tune during daily driving.

 

7hp sounds very disappointing from a 400$ product. Did you use the same dyno each time?

 

FYI, this thread is over 5 years old and I haven't seen most of the posters for more than a year or 2.