vetteguy112233

Here in Utah we only have 85, 87 and 91 octane gasoline. I understand that most STOCK Corvettes will run fine on these octane ratings, but GM recommends that I use 92-93 in my ZZ502.

My question is.... What octane booster can I buy to bump my octane to 92-93 or is 91 ok? My engine is not pinging, but will the 92-93 get a few more ponies out of the motor?

SLC, UT is 4500 feet above sea level if this helps with anything.

I've heard from several people that the LUCAS stuff is the only stuff that really works. THOUGHTS?????

Mike Ward

No. If it's not pinging now, raising the octane rating will do nothing except waste money.

auctionman256

i agree

OzzyTom

If you're sure that the motor isn't pinging with 87 octane, I'd stick with the setup you have now as that is readily available to you.

There is a bit of a performance gain with higher octane gas but only if you have tuned for it.
But if you do that, you will have pinging on lower octane gas.

straub18045

go to the paint shop and get a bottle of 'toulene' , its 114 octane out of the can. it is almost a solvent i think. many people use it because its cheap no fuel tax on it. it is harmelss to the car as well.

Mike Ward

Gotta disagree here. Your statement would only apply if the motor had previously been de-tuned to avoid pinging, usually meaning that the timing would be less advanced than optimal.

The OP's motor is already set up for optimum performance, ie. no compromises were needed to run it on 91 octane.

It is false to state that there is an endless loop of increasing octane, which allows more advance, which means more power. Once you've hit optimum advance (usually 36 degrees) then any additional will DECREASE output, not increase.

wiseman79

Detonation begins to be harmful before you can hear it or feel it. Octane additives are junk, they don't really bump octane as much as claimed. I'd mix 91 with race gas if I were you. I can tell a noticable difference in my 10.5 iron headed small block between 93 and 100, even without a retune, even with no detectable pinging with 93.

OzzyTom

Well I stand by my statement.

I would say his tune is NOT optimised for best power with 92~93 octane.
He states the motor runs OK on 87 with no detonation, and that indicates to me he has left some horsepower on the bench.
(A GOOD idea in his situation)

All I was intimating was he should tune his motor so that it runs safely with the readily available gas in Utah, which is 87~91.

He states that GM recommends 92~93 octane for the ZZ502.
I would say that recomendation is so that the motor will meet it's advertised power specs.
The ZZ502 will run OK on 87 if the timing and fuel curve are setup for it, but power will be lower than if the motor IS tuned for optimum performance using a higher octane fuel : eg 92, 93 or 100 octane.

I might just add for our original posters benefit.... Use 91 octane fuel if it is readily available.
The difference between that and an increase to 92 or 93 would be minimal anyway.

Mike Ward

Ah, no he didn't. He's able to obtain 91 octane and by inference we can assume he's using it rather than buying 87 and trying to boost it.

So, assuming that he's using 91 and has no detonation and has not fiddled with the timing to achieve this, he will gain nothing by increasing octane to a higher rating.

And once again-It is false to state that there is an endless loop of increasing octane, which allows more advance, which means more power. Once you've hit optimum advance (usually 36 degrees) then any additional will DECREASE output, not increase.

But you can beleive what you want.

rponfick

The oil companies know you can get by with less octane at altitude than you need at sea level. That is why you won't find 93 at any regular gas station over probably 4000'. Higher altitude means less dense air which means less compression ratio which means less octane requirement. All owner's manuals refer to octane at, or near, sea level.

Ralph

ZL1powr

The high altitude you are at lessens the octain requirement. You should be fine with 91.

OzzyTom

hmmm ? I could have sworn the first time I read that post I saw no mention of 91 octane

aghhh! I must remember to use my proper reading glasses. :o

Z-man

Same situation here in CO.

Use 91 octane and you'll be fine.