stock fuel octane

[94Red5.0]

A couple days ago I purchased a 94 stang gt 5.0. It didn't come with an owners manual so when I filled it I put premium in to be safe but I was wondering what octane it runs on (my only mod is a cai).

 

[95WhiteVenom]

I always run premium.

 

[Black95GTS]

welcome to the boards! You can run 87 on a (mostly) stock engine with factory timing. The vast majority of us run higher octane as it seems (in my case anyway) to make the car run better. I always run middle grade (89) but once and a while she gets the gasoline milk shake with some 94...

 

[swingline]

It will run on 87 fine if the timing is set at stock (10*). I run premium regardless.

 

[SN95Oh]

I don't understand why people run over 87 octane if the car does not detonate... I think it is just a waste of money myself.

 

[AznStanger3v]

I don't understand why people run over 87 octane if the car does not detonate... I think it is just a waste of money myself.

im with you on that one. especially the way prices on gas are. In my area, the prices are considered "cheap". the low test is ONLY $1.73. that to me is not cheap at all.

 

[swingline]

Myself, I run 14* of timing so I have to run 93.

 

[swingline]

im with you on that one. especially the way prices on gas are. In my area, the prices are considered "cheap". the low test is ONLY $1.73. that to me is not cheap at all.

What's the big deal? It is a couple of extra dollars for premium. Buy one less Big Mac a week and you have it paid for.

 

[Mrgreen94gt]

If you aren't detonating, you'll only make less power with higher octane. No reason to not use 87 with stock timing, I've gotten away with as high as 14 on stock heads during the winter. With aluminum heads, you should be easily able to run more timing on 87 due to better detonation resistance. There are often other tuning issues behind detonation other than octane and timing, most of the time.

 

[swingline]

How do I make less power when I run 93 compared to when I run 87 octane?

 

[Mrgreen94gt]

If you aren't detonating, you'll only make less power with higher octane.

How do I make less power when I run 93 compared to when I run 87 octane?

Due to it being more resistant to ignition as compared to lower octane. The 87 burns more completly and easily. The difference in power could only be slight, but enough I can notice it. Just doesn't feel as snappy on higher octane .

 

[swingline]

If you aren't detonating, you'll only make less power with higher octane.

Due to it being more resistant to ignition as compared to lower octane. The 87 burns more completly and easily. The difference in power could only be slight, but enough I can notice it. Just doesn't feel as snappy on higher octane .

So your opinion is based on a car with a completely stock ignition system?

 

[Mrgreen94gt]

So your opinion is based on a car with a completely stock ignition system?

It would apply to any car or ignition setup, so long as there is no detonation. However, in many cases, boost or high compression make detonation nearly unavoidable without higher octane levels.

There have been some pretty lengthy debates in the past over the value of octane, I think most have been over at the Corral. Those threads have more technical info than I can provide.

 

[swingline]

It would apply to any car or ignition setup, so long as there is no detonation. However, in many cases, boost or high compression make detonation nearly unavoidable without higher octane levels.

There have been some pretty lengthy debates in the past over the value of octane, I think most have been over at the Corral. Those threads have more technical info than I can provide.

Cool. I'll check them out.

 

[94Red5.0]

How would I know if its detonating? I've never run into it (I don't think) before on my other car so i'm not sure what to look for. Also, how can I tell what the timing is set at? Thanks for the responses and welcome.

 

[Venom351R]

I don't understand why people run over 87 octane if the car does not detonate... I think it is just a waste of money myself.

full up w/ a full take of 93 after you just used up a tank of 87........you will see why, the cars run SOOOO much better.

 

[Mrgreen94gt]

How would I know if its detonating? I've never run into it (I don't think) before on my other car so i'm not sure what to look for. Also, how can I tell what the timing is set at? Thanks for the responses and welcome.

Most obvious sign is the "rattling" sound coming from the engine. As for the timing, you use a timing light and the timing marks on the balancer. Instuctions can be found in a Haynes manual (those are supremely helpful!).