Driveability of high compression cars

[Johnny Horsepower]

In a pinch and only in a pinch I use store bought (black bottle 104) with a real lead additive. I have been told that Marvels mystery oil is good for keeping your valves happy but have not tried yet (anybody have?). But for more GPM (grins per mile) I run a blend of 93 and 110 race fuel. My GTO club has a fuel finder on its site. I personally go to the track and buy cans of it. There is no need to run strait 110, its a whaste. you want to run enough to stop pre-ignition.
I usually run 4 to 1 (93 to 110) and it runs and smells like a champ. Unless you are driving this car all the time, there is no need for a big 55 gal drum. Ten gallons on hand, will give you 50 gallons of useable fuel.

[Xplantdad]

[ QUOTE ]
I don't know about every track but most tracks here in Arizona won't let you fuel directly into a street car. have to purchase fuel in a gas can then you can do what you want with it.. sounds like the feds to me but can't vouch for any other tracks..

[/ QUOTE ]

Hey Bill...go to the corner of Cave Creek and Union Hills...near where I live. They sell racing fuel at a seperate pump there (Chevron Station?)!

Another choice is to buy racing fuel from your local ATV dealer in either a 5 or ten gallon mini-drum. In your case Bill, you can get the fuel from Town and Country Motorsports at 3333 Arizona Ave. (between Guadalupe and Elliot).

I mix 60/40...normal/racing fuel.

[musclecarjohn]

I have three 11.1:1 cars and have always blended 110 leaded race fuel with pump gas,about 60/40 (race/pump) or 50/50.
Have never had a problem with detonation but I don't drive these cars a whole bunch either...
Having a true 11.1:1 forged steel 550hp/383 stroker built right now for the X-77,it will be a monster by the time I'm done.

[Jacsey 70Z]

We have a pump at the local Sunoco station that sell the Turbo Blue 110 leaded, and as long as I can get it I'll use it. The car run great and cool and the performance is well worth the cost, as long as it's a weekend car and not a driver. At 11:1 compression I hate to cut the octane very much at all, Oh Yeah the smell is almost worth the price alone.

[@wot]

Raising the octane from 93 to 102 is very difficult to do with boosters or other additives. The problem is simply volume. 16 or 32 ounces of additive can't chemical change 18 gallons of fuel. Advertising claims are designed to make you buy, but the reality is you'll need 5-10 gallons of race fuel to start raising 93 octane fuel. A couple gallons of toulene is also very effective if you want to expirement.

[budnate]

[ QUOTE ]
Raising the octane from 93 to 102 is very difficult to do with boosters or other additives. The problem is simply volume. 16 or 32 ounces of additive can't chemical change 18 gallons of fuel. Advertising claims are designed to make you buy, but the reality is you'll need 5-10 gallons of race fuel to start raising 93 octane fuel. A couple gallons of toulene is also very effective if you want to expirement.

[/ QUOTE ]

I have heard/read that as well if you really have a 11:1 motor the little bottles dont work enough to get by on..I did the 50/50 deal with prem unleaded and 110 that the Union 76 guy had in a pump off to the side, when he quit I ran the same mix but with Av gas...both seemed to work fine and never heard a ping once...and with drag boats there either off or the pedal is on the floor and running hard across the lake.

[Belair62]

Toluene is nasty stuff !!

[@wot]

Most AV gas sold is 100ll (low lead) and will work in a high compression engine. I have not bought any in a while, but it is probably around $3.00 - $3.50 a gal. A relative bargain, considering racing fuel is over $6.00 per gallon. It is formulated to run at 10,000 feet of elevation, not sea level. So if you're going to keep usinf it, especially without mixing, you may want to re-jet the carb.

[Paul D]

Also, I've found that AV gas seems to have a much longer shelf life. It must have some "Stabil" like additives to keep those Piper Cubs from falling out of the sky after sitting for six months.
Paul

[Lynn]

[ QUOTE ]
Toluene is nasty stuff !!

[/ QUOTE ]

Anyone actually use Toluene? If so, what kind of ratio? I can still buy a 5 gallon can at the local paint store. Don't remember the price, but last time I checked seemed very reasonable. I was even thinking of putting it in my old BMW turbo as I have modified the boost levels and thought I might squeeze a few more grins out of it.

When I build my engine for my 69 Z, I plan on having the pistons cut down slightly to lower the compression and cc the heads just a bit bigger, shooting for 10.25:1 compression. Still figure I will need some help on the octane and was planning on about 10% toluene.

Just for the sake of discussion, here is a guy that really likes the stuff.

http://www.elektro.com/~audi/audi/toluene.html

As for using thicker head gaskets, that is a huge losing propostion in my opinion. Anything that kills your quench will only make detonation worse, especially below 3,000 RPM, even though compression will be slightly down. Yeah, I would like to say I was a genius and figured this out by just looking at the physics of the situation. Truth is, about 25 years ago I had a 302 with original 11:1 compression that was pinging ever so slightly. I put on double headgaskets, and it was 10 times worse. Did some research and discovered how critical the quench is to combat pinging. So when building from scratch, go for the lowest piston to head clearance the piston manufacturer recommends.

Just my opinion.

Lynn