100 Octane

[WhalePirot]

I found a local Union76 station with 100 octane at the pump. Knowing that my ECM is setup for 'premium', but also can do limited learning, I thought I'd try some and see if the car is faster. Besides, it gave me a reason to drive with the top off and to shed that last bit of water, after a wash.

Wow, the stuff is higher than the gas I buy in Japan for my bike, at $5.49/gallon! The tank was about half full, so the $50 automatic shutoff, filled it.

I did not expect nor feel much change, but it did seem to pull harder in second gear. I hope to play some more today.

 

[Ken]

Yeah, there are a few 76 stations around that still sell the good stuff, Mike. :cool

There used to be a link to a list of Union 76 stations selling race gas in SoCal (Schube.com), but it's out of date - I just try to go there and it's dead.

 

[Edmond]

Wow, the stuff is higher than the gas I buy in Japan for my bike, at $5.49/gallon! The tank was about half full, so the $50 automatic shutoff, filled it.

Oh man! $50? My neighbor puts 100 in his lawnmower and snowthrower.:L

 

[rrubel]

We're lucky - a local Sunoco sells 102 race gas for ~4.50 a gallon. Haven't tried it yet, but plan to.
[RICHR]

 

[Vettefan87]

Both of my friends fill up with 100 octance that a Citgo station sells around my house, they both say it helps, the one has a 91 VR4 and the other one a 89 Turbo TA.

 

[G Winter]

take your trusty gas cans and make a trip to your local airport.

 

[WhalePirot]

take your trusty gas cans and make a trip to your local airport.

That's low lead, not no lead though, right?

Wait, my airport uses kerosene! Jet A, it's called.

 

[wishuwerehere82]

I have tried the 100 octane mixed with 94 octane several times in my '82(back when I could afford to waste money). Just enough to get it up to about 96 octane average. The detonation rate is significantly reduced to the point that I could hardly hear the engine running. The only bad thing is I have tried to start the engine a few times when it was already running.:L Runs really fast when you mash the throttle down.

 

[PLRX]

Is this "healthy" for a LT1 engine?

 

[wishuwerehere82]

My biker friends say not to use it straight, because it will fry the pistons on their Harleys. I would suspect a Vette might do the same.

 

[8388]

take your trusty gas cans and make a trip to your local airport.

That fuel is formulated for low rpm engines. Not a good idea if your engine is high reving. Also, even though it's labeled low lead, it has enough to clog the O2 sensor in a short time.

Also, adding higher than needed octane to your engine will actually produce less power. If your engine detonates on 93 pump, then 100+ may be required, but if there's no detonation, then your just throwing away your money, and possibly slowing down your car.

 

[WhalePirot]

Thanks. Great feedback for a seemingly frivolous post!

No, I believe in getting bang for the buck and will not soon purchase more 100. This 406 runs just fine on the 91 found locally.

 

[Ken]

Is this "healthy" for a LT1 engine?

Higher octane gasoline will never "hurt" your engine.

Look at it this way: good food versus junk food.

 

[Mad-Mic]

100 octane is not needed on a stock tune stock motored vette. it shouldn't ping on 87 octane.

100 octane burns slower than a lower octane fuel. this negates detonation just that much longer. this is why boosted cars run "race fuel" 100 octane+ i've tried it at the track a few times because i run alot of timing as it is. more timing then you will get knock or what some call detonation. when this is happening the ignition is on the piston up stroke and tries to push the piston anti clockwise or back down resulting in broken rods, pistons, or wrist pins. this is why people run higher octane "race fuel" to delay detonation and make more HP and in boosted situations means you can run more boost. to make maximum horsepower is not to just port match and calculate lift, cfm, injector size, fuel pressure, ect, fuel it's self is another tool of the trade. it's not just what makes power but by adjusting heat ranges and fuel octane is just another tool of tuning. think of it as fine tuning. the idea is for the the fuel to burn and "make" power just as the piston is about to reach TDC. basically when the force of the piston on the up stroke is at it's slowest point TDC before rotating to BDC

so rule of thumb is if your car runs good on 91 or 93 octane run that. your not going to go any faster unless you add timing. if your plug setup is too hot on a stock car it will melt a hole in your piston.

it's hard to explain but i used to pick my uncle's brain alot and helping him work on his Top Alcohol Dragster that ran 5.4's at 265 mph was alot of help. unfortunatly when i went to Lincoln Tech for Automotive Technologies they didn't teach Engine Theory like i wanted to learn. i think only a few specialty schools do.
sorry for the complicated explanation....lol i know how it works just hard to explain.

 

[Mad-Mic]

also if you have cats DO NOT run leaded race fuel. it will clog your cats. they do make unleaded race fuel into the 118 range i think. anything over that is leaded.

also when you got a tank fuel of 100+ octane and pull in your local car hangout on a saturday night and people smell the Cam 2 and hear a nice lopety lope they look at you very weird :L

so many people think i put that cam in along time ago cause i run long tube headers with no cats and no mufflers. i gotta clean the IAC and fix that code 36 :L should of seen the looks i was getting when the car was running rich with a 1/2 tank of 110 octane unleaded last fall when i rolled thru miccy d's

 

[WhalePirot]

Thanks, Mic. Anti-clockwise? U a Brit?

This engine is far from stock but the chip was extensively worked for THIS motor, as it is. Base timing is set at 10BTC and the chip expects it. If it were easier to get to the securing nut, I might play with the timing a bit, to see how the car responds on this pricey fuel.

I know the response you mention when others hear this Corvette's lumpy idle. Even 'amateurs' recognize the power it represents. Thankfully, due to great (custom) chip work, little mixture richness exists.

The 100 octane was a lark; not soon repeated. No lead means NO LEAD. I don't need to clog a CAT.

Now, if I can just find some 4-bolt flange exhaust gaskets!

 

[Mad-Mic]

Thanks, Mic. Anti-clockwise? U a Brit?

i ment before the piston reaches TDC and starts is BDC stroke if the spark fires it could lead to failure due to the pressure of the combustion trying to push the piston back down before it reaches TDC. another words if the spark fires before the piston reaches it's compression stroke while the piston is coming up before it hits TDC.

hope that makes more sense :L

sorry my brain hasn't been working right lately :L

 

[Hib Halverson]

take your trusty gas cans and make a trip to your local airport.

DO NOT use any AVGAS in any Corvette with cats. All gasoline sold for aircraft be it LL100, 80/87 or 100/130 use contains lead. The lead will destroy cats in short order. There are other reasons for not using AVGAS but they are not damaging just compromises in power and driveability.

 

[Ken]

I worked at the Chevron refinery and we blended Avgas. After the lead ban went into effect, there is no longer any lead in (California) gasoline; not in any aviation nor in any motor gasolines. Zero, zip, zilch, nada... No lead whatsoever.

 

[8388]

Ken, how did they manage to remove lead in general from aviation ? Some of the planes flying still today require the lead for lubrication. I know for a fact that in my area Avgas still has a lead content for that basic reason.