91 octane or not?

Just had the 5,000 mile service for 2004 GT convertible. The tech at the ford shop said that while Ford says 87 octane is fine, he prefers and would recommend 91 for my 'stang. Better all around he says. it's definitely more expensive but I'm willing to do it if it's worthwhile.

Thoughts?

Thanks. Darrin

I dont see why it would even make a difference unless the timing or compression was changed. Now perhaps the modulars are different somehow, but IMO stick with 87. I think your mechanic just doesnt know his octane laws of physics like HiFlow. :icon16:

I dont see why it would even make a difference unless the timing or compression was changed. Now perhaps the modulars are different somehow, but IMO stick with 87. I think your mechanic just doesnt know his octane laws of physics like HiFlow. :icon16:
LOL, yeah foo!

Do a search, there was a goog thread not too long ago with lots of information about octane.

thanks for the help. I went back about ten pages and found the other post on octane fuel. makes sense to me. and my wallet loves 87.

thanks for the help. I went back about ten pages and found the other post on octane fuel. makes sense to me. and my wallet loves 87.
:biggrin:

My wallet hates gas in general!lol

in every newer ford ive driven (focus, stang escort ect) that requires 87 i have noticed tat if you use 89 it seems to smooth it out a lil ie. idle seems softer, acceleration seems smoother(not faster) 91 dosent help anymore over 89


but i dont even have the luxory of being able to use 87, my Escort requires 91+

Just had the 5,000 mile service for 2004 GT convertible. The tech at the ford shop said that while Ford says 87 octane is fine, he prefers and would recommend 91 for my 'stang. Better all around he says. it's definitely more expensive but I'm willing to do it if it's worthwhile.

Thoughts?

Thanks. Darrin

Hey Darin, I'll just tell you my bad experience with the higher octane usage. The newer model Mustangs are meant to best perform on the 87 Octane. I used the high octane on my 2000 and it ran like shit,SHITTY PERFORMANCE and minor pulsing on wanting to accelerate quickly once I switched to the 87 again n burned out the high octane it ran better peformance wise. I asked a ford technician and he advised me not to use it due to the engines compression ratio is meant for the lower octane.

Stick your 87 Octane due to that the mustang requirement is that, as where the 5.0 pre 95 performed best on the highest octane available!

Take care
Jordan

Stick your 87 Octane due to that the mustang requirement is that, as where the 5.0 pre 95 performed best on the highest octane available!

Take care
Jordan

FALSE!