Octane requirements

What grade gas do I ened to run?

  • 87 octane

    Votes: 12 40.0%

  • 89 octane

    Votes: 5 16.7%

  • 92 octane

    Votes: 13 43.3%
  • Total voters
    30
  • Poll closed .
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Jarlaxle said:
Not everyone can simply ignore reality and drive a car that gets 7mpg on premium.
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I run 110 in my Roadrunner, at $9 a gallon. Sometimes I mix in a little 90 Rec fuel if I think I can’t make it up to the next town where they have 110. I’m not rich, but I don’t drink or smoke, so if I splurge it’s going to be on the car. And, my Mom loves the smell of 110, so I burn it for her!
 
my 367 has never run anything but 87.
She has run various cams from 249*, to 223*, to the current 230*, all @.050..
She has always run between 10.95 to 11.3 Scr, and from 177 to 195psi
She has always run full Power-Timing .
She has never detonated.
My secret, if you can call it that,
is Alloy heads,
which I run at 207*F.
This engine currently has over 100,000 miles on it.
That 223* cam was pretty good on gas, but the secret included; being geared for 75mph=1850 rpm, mega-timing, and tiny primaries in a custom-tuned 600Holley.
 
AJ/FormS said:
my 367 has never run anything but 87.
She has run various cams from 249*, to 223*, to the current 230*, all @.050..
She has always run between 10.95 to 11.3 Scr, and from 177 to 195psi
She has always run full Power-Timing .
She has never detonated.
My secret, if you can call it that,
is Alloy heads,
which I run at 207*F.
This engine currently has over 100,000 miles on it.
That 223* cam was pretty good on gas, but the secret included; being geared for 75mph=1850 rpm, mega-timing, and tiny primaries in a custom-tuned 600Holley.
Click to expand...

My Roadrunner has never seen ethanol fuel, it was taken off the road in 1978, and put back on the road in my hands in 2018. I would be worried about the ethanol wreaking havoc with my rubber products, and non hardened seats. The 110 or leaded here, and the rec is ethanol free.
 
Yeah your worries seem to be the norm; but I have just not seen it in the fuel system...........yet, lol. Course my Eddies should have ethanol-compatible seats; as should the Magnums.
But I haven't had the heads off since 2004....... so IDK ................
The reason for post 27 was just for the OP to be fully informed. It was NOT to blast you or anyone else, cuz your American fuels seem to be more harsh than ours. Again IDK.
========================================================
Here's the the thing that steered me towards ethanol; Now I read this about 25 years ago, so cannot say whether it is true or not; so here goes;
the octane additives in non-ethanol gas, with each increase in rating, cause the fuel to burn slower. In my naivety, I thought to myself, why on Earth would I want a slow-burning fuel; give me the lightning gas, lol. And so, my engine was designed from the get-go, for ethanol 87E10. If we had say E15 or E20, for a competitive price, you bet I would experiment with it.
But I admit, I reduced the amount of rubber in my system to the bare minimum, and I add stabilizer for storage. The Holley that I now run, leaks it's primary bowl dry in a few days, so that's "covered", Lol. No, the Holley doesn't leak because of the fuel; one of the pump screw holes barely holds torque.
 
AJ/FormS said:
Yeah your worries seem to be the norm; but I have just not seen it in the fuel system...........yet, lol. Course my Eddies should have ethanol-compatible seats; as should the Magnums.
But I haven't had the heads off since 2004....... so IDK ................
The reason for post 27 was just for the OP to be fully informed. It was NOT to blast you or anyone else, cuz your American fuels seem to be more harsh than ours. Again IDK.
========================================================
Here's the the thing that steered me towards ethanol; Now I read this about 25 years ago, so cannot say whether it is true or not; so here goes;
the octane additives in non-ethanol gas, with each increase in rating, cause the fuel to burn slower. In my naivety, I thought to myself, why on Earth would I want a slow-burning fuel; give me the lightning gas, lol. And so, my engine was designed from the get-go, for ethanol 87E10. If we had say E15 or E20, for a competitive price, you bet I would experiment with it.
But I admit, I reduced the amount of rubber in my system to the bare minimum, and I add stabilizer for storage. The Holley that I now run, leaks it's primary bowl dry in a few days, so that's "covered", Lol. No, the Holley doesn't leak because of the fuel; one of the pump screw holes barely holds torque.
Click to expand...


Low RPM engines need a slower burning fuel because you have time to get the cycle completed.

High RPM engines need a faster burning fuel because you have less time to complete the cycle.

AFAIK, pump gas is some of the slowest burning fuel there is. I could be wrong though. It’s almost impossible to get accurate information on pump gas. I do know that pump gas was reformulated once EFI became the OEM standard.

And that low grade pump fuel is full of fillers and junk in it that can’t be legally used in premium pump fuel.
 
cosgig said:
I run 110 in my Roadrunner, at $9 a gallon. Sometimes I mix in a little 90 Rec fuel if I think I can’t make it up to the next town where they have 110. I’m not rich, but I don’t drink or smoke, so if I splurge it’s going to be on the car. And, my Mom loves the smell of 110, so I burn it for her!
Click to expand...
You don't use that as a commuter.
 
I've got a stock 5.9 with ede intake, holley 750dp, accel distributor, MSD 6al, 3.23 gears.
I've got the timing set at 10 initial 30 total. It runs strong on 87 but will ping doing 3rd gear burnouts, after the tires start to grab :usflag:
I ordered a spring kit to bring in the mechanical advance as late as possible.
 
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