What octane to run on 4.6 GT Anyway?

where you guys getting ONLY 91, in FL its 93?. I have to use 93, its 100+ here most of the yr, and i autoX the crap out of it. my wifes 01 honda oddyessy even runs better on the 93(honda claims +10hp with 93).

I run 94 because of the chip.

david97gt46 said:

where you guys getting ONLY 91, in FL its 93?. I have to use 93, its 100+ here most of the yr, and i autoX the crap out of it. my wifes 01 honda oddyessy even runs better on the 93(honda claims +10hp with 93).

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Out here in Vegas they don't have anything higher than 91 octane. 76 does offer 100 octane unleaded for 3.49 per gallon.

I use good ole' 87 and I have no detonation problems and I just had my best tank of gas 275miles when the low fuel light came on!!

Dr. Black said:

A while back motor trend did a study on octane, used several cars, honda, saab, MUSTANG GT... with each car used the recomended fuel (mustang 87). Did dyno test for hp and tq, and a gas milage test. The mustang made less power and got less miles per gallon with 89 and 92 than with 87 (not by much but stll worse). I would not use higher octane gas unless SC or Turbo or other major type of performance mod.
Hope this helps. (remember your cars computer was designed to run with 87)

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That's correct, but yet you continue to see people waste money on higher octane. Gas companies love those people.

Higher octane is not necessary until you change your timing curve.

I am sure someone will debate this.

2000GT said:

That's correct, but yet you continue to see people waste money on higher octane. Gas companies love those people.

Higher octane is not necessary until you change your timing curve.

I am sure someone will debate this.

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My Honda del Sol Si seemed to make a little more power with 93,(Maybe just in my head, or maybe because the computer bumped up the timing a little) but my Stang doesn't seem any stronger, and loses about 2mpg with premium. On a stock Stang, save your money and run 87. At higher elevations, you can probably get away with 85.

I think Honda and Toyota both have something in the computer that will advance timing until it detects knock for the highest power. That's what the salesman said he thought it was when my dad bought his '03 4Runner.

I use 91 in mine, if I use anything less I ping, but I also have several mods, I wont use 89 cause it is blended, ethenol, which is part grain water, I work for a auto dealership, we recommend people to not use in there cars, exspecially during the summer, you want to see vapor lock, also eats fuel regulators.

i would get mild det on 87 on my 00gt..89 worked great!...93 for my new girl

Any way to find out which gas is mixed with ethanol? I really can't see it being too common here in Bum-**** Texas

Mustang_1 said:

I use 91 in mine, if I use anything less I ping, but I also have several mods, I wont use 89 cause it is blended, ethenol, which is part grain water, I work for a auto dealership, we recommend people to not use in there cars, exspecially during the summer, you want to see vapor lock, also eats fuel regulators.

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I want to hear more on this. I use 89 also, because 87 makes me ping at times.

NiteMareGT said:

HERE'S THE DEAL !!!!

UNLESS your timing has been bumped UP FROM THE FACTORY SETTING, or you have an AFTERMARKET CHIP that has reprogrammed your vehicles fuel octave rating, you are WASTING YOUR MOOLA on higher octane gas, and you are HURTING YOUR CARS PERFORMANCE and HORSEPOWER !!!! This is not an opinion, this is a FACT !!!!

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I quote myself................LIVE IT, LEARN IT, KNOW IT !!!!!

i'll stick to 87 till i go blown and save every penny i can

Your Honda may have had an automatic boost retard/advance system. In a car with such a system, higher octane WILL help, because it will allow more timing.

If not, it was all in your head.

98stallion said:

you'll get less power more than likely. the most power you'll get is by running the lowest octane possible without detonation

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Let me preface this by saying I'm a total newbie and a bit of a mechanical dumb*ss, but I'm learning. Good example... I've been running mid-grade on my virtually stock 98 GT thinking I was doing some good.

Anyhow, my Steeda T/A is sitting right beside me here and I'm armed with new knowledge courtesy of StangNet. So, could I do the following: with my T/A installed can I buy the highest possible octane gas and up the timing until it pings, then bump back the timing a notch? It's kind of the reverse of what 98stallion said... match the timing to the octane you're running instead of vice versa.

Ethanal is mainly run through the midwest states, they say it helps the farmers, and it is usually a penny cheaper than 87, but I still wont use it.

Check some site for gas companies you will find more on ethanal, but this is from experiance why I dont run it and we the shop I work at dont recommend using it.