C12 vs pump gas
 

I have a low compression 340 combo,and when I put c12 or blue in it, it's starts to skip at high rpm in high gear (5800 to 7000 rpm) but with high octane pump gas it runs clean.any help would be great.

Re: C12 vs pump gas
 

Not knowing the rules for stock fuel and your compression this is just a guess, but I'd think you don't need that much octane and at $10.50 a gallon I'd use pump gas.

Re: C12 vs pump gas
 

i do when i can but @ nationals and Lucas Oil Drag Racing Series they have fuel check,and you have to have their fuel.

Re: C12 vs pump gas
 

Use C11 at the track, and fatten it up a bit.

Re: C12 vs pump gas
 

I don't imagine that the brand X race fuel is your problem . Your combination shouldn't require a lot of motor octane . Truthfully , if it runs good on 92 or 93 octane i'd stay with that . Keep a close eye on the plugs at all times , and if you ever see any evidence of detonation , switch to a good 110 . The difference in price between pump gas and race fuel isn't really very significant when you consider the relatively small amount of fuel you use at the track .

Re: C12 vs pump gas
 

You may try C-10

Re: C12 vs pump gas
 

Jet up 6-8 numbers with the good stuff. Possibly more with Sunoco Blue. When guys pick up .15 with the blue it's because they are pig fat. You are lean either due to jetting or insufficient volume.

Re: C12 vs pump gas
 

the best pass my camaro has ever made it had 93 octance from the corner convenience store in it. But it was the middle of January

Re: C12 vs pump gas
 

Be leery of pump gas. Had a friend who worked for a car company as a calibrator. They were having problems with engine detonation, so on a calibration drive from Michigan to Arizona they decided to do spot checks on pump gas from across the country. What they found was, what was being advertised on the pump, did not match what was coming out of the nozzle. Nor saying that all gas stations are like that, but I know of a convenience store that will order fuel and fill the regular tank and top of the premium tank with the same tank truck….

Re: C12 vs pump gas
 

And I thought that only happened in Kingman, AZ!

Re: C12 vs pump gas
 

The readings from one gas station to the next will usually vary , and that's true across the nation . Certain Brand name stations will put only their own gasoline in the tanks , so they're more consistant . Others purchase which ever brand fuel is the least expensive on a given day .
And computerized , fuel injected engines can adjust themselves for changes in gas quality , up to a point . So very precise quality control isn't really needed .
If pump gas quality is a necessity , always go with a Top Tier gasoline . Shell belongs to that program , so does Chevron .

Re: C12 vs pump gas
 

C-11 seems to work well in the low comp. MoPars. Jim

Re: C12 vs pump gas
 

There are several schools of thought on this

What I was told years ago was that the Racing Fuels were a lower density than Pump Gas.
AND It Burns Slower than lower Octanes.

Back in 90's, the racers that ran low compression rides like 455 Firebirds, 6 Cylinder Maverick, Pintos told me to get the racing gas to work they did two things.

Leaned out the Carb and bumped total Timing to 50 degrees.
This seem counter intuitive to me but watched them set records.

Not sure, think they had to use a cooler Plug too.

Not what you want to do for the street or road racing but worked for short duration sprints for drag racing.

Re: C12 vs pump gas
 

Octane slows down the burn rate of fuel. As you add compression you are adding heat by increasing cylinder pressure so you add octance to keep the fuel from spontaneously combusting (detonating). If you don't have enough heat and too slow of burning fuel, it will not light consistently and you can get the miss you are describing. C-12 is 108 motor octane which is probably too much. Try a 110, although ours (Renegade) is 108 octane also, but we have a Blue haze 110 that is only 105 motor octane. You can mix 110 with premium pump gas and you may find a nice happy medium. You'll get enough octane for protection but not too much to light. My son ran this combo in a 350 cu, 10:1 engine and won back to back track championships at Indianapolis Raceway Park.
PS, not saying mixing fuel will win rounds, he is just a helluva driver...but it did keep the engine together.

Good luck!

Ron Finney - 396V S/C
Indiana Distributor for Renegade Racing Fuels

Re: C12 vs pump gas
 

Not sure about other parts of the country but here in Houston that is the way I would say 90% of the fuel is mixed. All gas is "regular" unless you add the percentage of X to make it "Super". They all self mix in the trucks. My dad would tell me that you would see every brand of truck from Shell to Valero to Texaco lined up at the gas racks. Unless it is a corporate station all the gas comes from the same place. You can usually tell the corporate stations because it will be .30 higher. Just because you go to a chevron and think you are getting your "Techron" it is the same gas, from the same truck, that just left the shell station down the street. That is just the way it is.

Re: C12 vs pump gas
 

My car ran well on Torco 112. It doesn't like VP-C12. C-11 is too expensive, but its low motor octane makes it work well for stockers. I now use Sunoco 110. I'm happy with the way it performs.