I believe the '10's are running the Bullitt tune (or an equivalent) and ARE capable (and allowed per the OM) to run ANY octane. Can a '10 owner please quote the OM?

 

I guess its possible that they do but isnt it more than just a tune? Do the have the sensors associated with this function?

 

That's news to me. My owners manual says it does.

2010 GT's have variable cam timing and are safe to run on 87 octane according to the manual. If you want to make more power, 91 octane is needed. The car will adjust timing accordingly.

 

Nah, just octane "special"

 

I am wondering, how does the ECU know when to advance or retard my $#!+ for fuel (octane count)?

I am assuming that the knock sensors on the block are what triggers the ECU to adjust the timings (cams and spark) accordingly.

Or is there another means of knowing if your octane count is low and the engine must adjust?

 

I have a brochure Ford sent me on the 2011 Mustang. It lists HP & Torque with Premium fuel as 412@6500 and 390@4250. With regular fuel 402@6500 and 377@4250.

 

Not too bad but if you're spending the $$ for the extra 10 CRANK HP, you'll like how a custom tune should increase that; somewhere in the range of 25 crank or more over 87 octane. I'll have to dig around for the #'s that were posted from a before/after dyno on an '11 5.0 with a tune.

Edit:
This one boasts 28 RWHP gain (see thread for torque): https://mustangforums.com/forum/gt-s...yno-today.html

This one boasts 22 RWHP gain (see thread for torque): https://mustangforums.com/forum/2005...-and-tune.html

 

Thanks for the responses and compliments, love my new ride! My question originated because I don't have access to 91 octane around here, just 87, 89, and a jump to 93. If I had 91, I would have no problem running it all of the time, but 93 octane will break my wallet if used every time, the reason I was wondering about 89.

 

Yeah, it does.

 

It's really not that much difference and gas is cheaper by you than me. I have to use 93 due to FI however I ran a brenspeed tune for 93 NA most of the time I've had the car anyway. I just got gas today so you can compare for yourself:

93 Octane at $2.95 for 12.25 Gallons = $36.25

87 Octane at $2.64 for 12.25 Gallons = $32.45

It's a $3.80 difference per fill out it adds up but I don't think it's unbearable in the overall picture.

(These gas prices are rather high I was lazy didn't want to drive a few more miles to a cheaper station.)