Even when i run 89 it sting pings just a little bit on acceleration.

[jbritt1234]

With a chip you are going to have to run 93 because that is what it is calibrated for...

[jonastang4.6GT]

I think that i am going to stick with 93 all the way. It may be moe expensive but in the long run it will be worth it. Hey Vortex, where do you get Redline or Lucas FI cleaners at? And how do you know that they really work?

[Vortex]

Lucas you can get at Autozone, Pup boyz, etc.. any auto parts chain. The redline you can get from SummitRacing.com but some stores may carry it.
With the redline I acutally felt performance increase due to how bad it was inside there... with the lucas, I was still working in parts and I had to change a head gasket on my jeep, so when I pulled it of i saw how bad it was... My store "sponsored" me and gave me a free bottle and two free head gaskets.. I asked the Mgr. why he gave me two. He told me to put the new gasket on, run the treatment and then pull the head again.. sure enough I could see how much carbon was taken off.. didn't look brank new do to excessive miles and scratches, but it was a lot cleaner.

[kchronister]

For me it's simple: 93 - no ping, 87 - ping.

[GTRaptor]

Things that would affect your choice:

1. Timing advance
2. Altitude !!! actually the higher you are located the less need to use high octane.
3. Engine condition, carbon buildup can cause detonation or pre-ignition, use TB cleaner once in a while to reduce the deposits in the intake and combustion chambers.
4. AIR heat, Exposed filters inside the engine are No-No, they would ingest hot air= detonation.
5. Bad plug heat range or gap.
6. Bad cooling system !!! flush it !!!

If you run ok with 87 stick to it, else try the next higher rating until ping stops.

[MUSTANGRIDA]

doesn't high octane burns slower?

[Protree750]

High Octane Gas is for High Compression Motors, if you are wanting to run a higher grade of gas you may need to bump up timing a bit to burn correctly. I have to run 104 octane (C12 or C16) minimum, not cheap at 67.15 for 5 gallons but Im also 13:1 Compression. You should be good with a 89 to 92 grade at stock compression. Depending on your mods to come will determine if your going to need to do a higher grade..ie. dome pistons and low cc heads. Not recommended for daily driving, trust me 20 gallon fuel cell and don't pay attention to miles per gallon, thats 268.60 to fill up and play, not enough to drive to work and back home.

[k9kevin]

Originally Posted by sehrmude

With some research on OCTANE levels, I have found that a lower octane rating actually ignites FASTER. My 97 GT's computer is calibrated from FORD for running 87 Octane. A higher octane will ignite too late in the combustion chamber. (I read about this because I ran premium thinking it would be better in a sports car and my check engine light came on before that tank of gas was gone)

If you advance the timing, increase compression ratios, or add boost you will have to run higher octane gas. Adding a computer chip normally requires the use of higher octane gas because they change the timing or the fuel mapping parameters.

Put in 87 Octane and save the 5-7 cents per gallon! Take that money and buy the supercharger.....then run 93 Octane.

He is right Octane is the stability of the fuel to resist dieseling. The higher the octang rating the more compression the fuel can take before ignition. In a low compression engine a low octang rating is fine but as you add compression in the form of a super charger or new pistons you need the higher octane rating. I hope this helps

[Old man]

Originally Posted by MUSTANGRIDA

doesn't high octane burns slower?

No. That is a myth.

Burn rate is unrelated to octane.

Octane is tied to the amount of pressure that can be tolerated before a mixture self-ignites. Burn rate has nothing to do with octane.

For an example look at alcohol. It has very high octane and burns very fast. Other fuels or additives in fuels do the opposite.

The correct octane is the octane that does not spark knock or ping upon acceleration....assuming the timing and other things already mentioned are proper. More octane won't help power or how a vehicle runs, once it is high enough to not ping.

Tom