what type of gas should i be using???

[85cleangtvert]

with the price of gas going up...i am wondering if I should be or can be running on 87 or 89. I usually put 91 in my 88 5.0, and have been as long as i have had it. I bought it from my friend and he said he always put 91, so i did the same. It has a stock fuel pump and stock injectors, a 70 mm MAF, stock TB, edelbrock intake, mac cold air, GT 40 heads, e 303 cam, headers. I am not sure what the internals of the engine are or what the effect would be if i put cheaper gas in it, but with the prices of gas I would love to start paying for 87 or 89 instead of 91. what do you guys think??

 

[HISSIN50]

I would run the lowest octane you can without pinging. If you run 87 and it pings, I would just dial the timing advance down.

Good luck.

 

[sgarlic]

Unless you're boosted or something I wouldn't bother running anything above a high quality 87 (Chevron, Shell, etc.)

 

[95COBRA241]

Unless you're boosted or something I wouldn't bother running anything above a high quality 87 (Chevron, Shell, etc.)

Agreed but most of us are running bumped up timing.

 

[85cleangtvert]

cool! ima put 87 in it and if it pings im advancing the timing. its like the prices just went down! haha thanks all

 

[25thmustang]

Agreed but most of us are running bumped up timing.

I used to run 18* of timing on 89 octane, and even ran some 87 octane a few times with ZERO pinging. I have it backed down to 16* and run 87 solely...

The fact is, you will make more power on lower octane fuel so long as the car isnt pinging. Running higher octane allows for a more aggressive tune which is why in some cases it makes more power, but unless your running race gas, run the lowest octane possible!

 

[sunil6784]

cool! ima put 87 in it and if it pings im advancing the timing. its like the prices just went down! haha thanks all

If you put 87 in and it pings, you want to retard the timing, not advance it.

 

[sgarlic]

Agreed but most of us are running bumped up timing.

That's cool. If you would've posted here asking what octane, and said you like running advanced timing, I would've told you higher.

 

[HISSIN50]

Paul, as was already said, even if you are running bumped timing, if you bumped it so much that you need higher octane fuel, you are most likely needlessly spending more on gas than you have to. To reap the benefit of octane and timing boost, you really need to surpass the small octane delta in pump gas.

And with your SN Cobra, you probably are not seeing the ping issues that the GT's do.

Just my two cents...........

Good luck.

 

[darthcual]

I used to run 18* of timing on 89 octane, and even ran some 87 octane a few times with ZERO pinging. I have it backed down to 16* and run 87 solely...

The fact is, you will make more power on lower octane fuel so long as the car isnt pinging. Running higher octane allows for a more aggressive tune which is why in some cases it makes more power, but unless your running race gas, run the lowest octane possible!

Couldnt have been said better. Lower octane burns swifter and gives more power. Unless you have pinging their is no need for high octane.

 

[gooch06]

I use 92 or 93

 

[The Shape]

When I first got my stang I used to run 93 all of the time. But after being on this site for a while and reading about how octane ratings work, I just started running 87 and it has worked fine for the last 3 years .

 

[QDRHRSE]

I run nothing but Super.