In my quest to learn everything I can about my new Mustang, I stumbled upon an article at MM&FF (http://www.musclemustangfastfords.co...ine/index.html) that states:
"Ford also worked outside the engine to make the package a better fit for the Mustang. The powertrain ECU has been upgraded with a very aggressive deceleration cylinder shutoff for fuel economy, coupled with very rapid tip-in for street performance. On the flip side, the ECU has been reprogrammed with adaptive-knock spark control. If the two knock sensors embedded in the cylinder block don't hear knocking, the ECU will keep advancing the spark until it does.

What this means in performance terms is that, if the owner uses premium or race gas on weekends, the engine should make considerably more power and torque than the numbers quoted here, which are the product of standard SAE dynamometer laboratory testing procedures and not real-world driving."

I have been pretty interested in getting a tune, but this makes me wonder if it's even necessary since I have a 6mt. I understand a tune might still be beneficial for a 6AT since it can adjust shift points. Unfortunately the article doesn't state how much more power could be made, and I can't find any other information to corroborate that using higher octane will increase power in our cars. It all really depends on if the ECU can adjust on the fly or not I guess. Any insights?

 

The RWHP gains from your stock tune on 93 octane is minor compared to the gains from a custom tune. The custom tune does much more than simply adjust timing based on octane ratings. On the 5.0, you might see about 4-6 RWHP gain with the stock tune going from 87 to 93 octane, a custom tune would make that more on the order of 20-30 RWHP gain if I recall what I saw in some dynos. Even on the '05-'09' GT's, a good custom 87 octane tune (with a CAI) would gain 15 RWHP or more over the stock 87 tune.

 

The article inferred that you would get substantially more power just from switching octane.

 

On the GT 87octane 402 HP 93octane 412 HP, that 's a .02427 % gain. If the 3.7 has same gain, we get 312 HP.
"The article inferred that you would get substantially more power just from switching octane." Seven more HP going from 87 to 93 octane, may be called substantially, by dollar cost per HP.

 

I'd buy that. So for me it wouldn't be worth it to get a tune if for $400 more I'd only get maybe another 10HP on top of the 12 from upping the octane. I still think a custom tune might come in handy if you change out intake, exhaust or other components like flywheel, headers etc, but if you simply desire to stay stock, going with 93 octane might be a little more fun.

I have experimented with 93 octane in my mustang but really haven't noticed any difference in speed or MPGs. I think it runs a little more smoothly, but that may just be psychological. It's nice knowing I can run 87 octane in my car for once though, since most of my previous cars required 91+ (VW Eos, 350z, S40 T5).

 

nice and interesting stuff, now on the '10 4.6 it actually said use nothing lower than 87, as it says in the v6 manual, but it said to give the '10 GT better performance try 93.

now in the v6 manual it does not say use anything higher, wondering if that means wasting money putting 93 in, but right after that it does say this about the 5.0,

" Octane recommendations (5.0L V8 engine)
Your vehicle will run normally on 87 octane regular fuel without
damaging the engine, but premium fuel with an octane rating of 91
(R+M)/2 or higher is recommended for best overall performance.

" hi nuke, changed my sig. this is GTJT2010,


Also hoggass, something you posted here I'm going post under vibration cause so many have talked about that strange shake that we aren;t used too

"The powertrain ECU has been upgraded with a very aggressive deceleration cylinder shutoff for fuel economy, coupled with very rapid tip-in for street performance."

 

It would be interesting to see a stock dyno of all the different octanes verses a custom tune, to see the gains.

 

I almost forgot, I use gas that is ethanol free. Suppose to be 100% gasoline.