AirborneCZ

i was wondering...

is there any significant improvement while using 95/98 or even 100 octane fuel???

I understand that Stang is designed to run on 91, which is lowest octane fuel you can get here (and still not everywhere!!) where I live....

Also, can I hurt engine by using different types of octane fuel (95+) ??? or should I stick to lets say 95 or 98 or use Diablo to adjust ECU?

Thank you for input

KdF

Where do you live?

The New Mustang GT was designed to run on REGULAR gas only.

Thats 87 octaine in the States.

You go to 91 octaine with a S/C.

Higher Ocatine will hurt more than Help!

RTFM!!!!!

MikeVistaBlue06

In Europe gasoline is rated by Research Octane Number (RON). In the US, gasoline is rated by the average of RON and Motor Octane Number (MON)--> (R+M)/2. This average is also called the anti knock index (AKI).

Usually there is a 4 octane number spread between RON and (R+M)/2. Therefore, the 91 you see in Europe is the same as 87 in the states.

http://en.wikipedia.org/wiki/Octane_rating

http://www.repairfaq.org/filipg/AUTO/F_Gasoline.html

You will only need higher octane if you modify your car such as:

Cold air kit with a new tune, or just a custom dyno tune by itself to increase performance.

Add a supercharger like a Saleen, Kenne Bell, etc.

Re-do the engine with more compression and cam.


Hope this helps.

Mike

wmtheflash

It's pretty easy...the car is designed from the factory to run on 87 octane. Higher octanes are used for their anti-knock properties, they actually don't burn as readily as regular gas. Burning a higher octane than recommended will produce less horsepower, make the car run worse, cost more money, and will lower your gas mileage.

A reflash to a 91 or 93 octane tune will, amongst other things, advance the timing. Advancing the timing will give you more power, but requires you to use higher octane fuels. The explanation is easy: higher octane gas does not ignite as readily and therefore guards against predetonation (knock) that can cause engine damage.

Using an octane higher than what's required will not damage your engine, but it has no positive benefits in an unmodified car, as explained above. Many vehicles designed to run on premium can safely run on lower octane from the factory (the owners manual will let you know what's safe and what isn't), however, reflashing the computer with a higher octane tune and then running a lower octane gas than required by the tune is entirely UNSAFE. You risk engine damage, then.

To sum it up:

Stock Mustang GT: REGULAR GAS ONLY!
Mustang with SCT or Diablo tune: ONLY USE THE OCTANE THAT IS REQUIRED BY THE TUNE!

AirborneCZ

thank you for valuable input!

QuickShortBus

+1 with what Mike said, people need to find out all of the facts before they offer their input. RON is different than what we use in the states to specify octane ratings.

P Zero

The higher the compression the higher octane you NEED. Running too high of an octane with too low compression, the fuel does not completly burn, this will acutally cause the unburned carbon to deposit on the top of the piston. It will also foul out spark plugs. Not to mention your car will run like crap.
-P.

teksp0rt

great explanations... this should probably be a sticky or part of a FAQ thread....

good job guys.

JT_Moore05

Just please make sure you tune before you use a different octane.

rebelyell06

Unless you have a tuner of course. I run 89 with my Performance tune, seems to hit just as hard, but cheaper on the wallet then 93.