running avgas (100 octane leaded gasoline)

[slash crashley]

[spudz]

if you mix it half an half its ok. smells good too!

[slash crashley]

awesome. that's what i was thinking, but really wanted a second opinion.

thanks.

[BaddBusa2005]

It does smell good. I have ran 110 leaded in my 5.3, with no problems.

[Morgsie]

If you have a cat or an o2 the lead will foul them. Aside form that I don't see a problem. Avgas is also excellent to put in things that sit over a long period of time. It last a lot longer than that "fuel saver" stuff. It's ashame they don't have 130 any more :/

[1970pelle]

Slightly off topic.When we ran cars in the demo derby we used avgas.Because it will still fire when the engine is so hot that its boiling the regular gas.So we were able to run a bit longer.Always got killed anyway.Have ran it on the street mixed like others said.Love the smell.

[James McClure]

Boy, I'm showing my age now. When I used to drag race we ran Sunoco 260 and that was over 100 octane and the good av gas was 140. You can run any of these without any problem at all and you can push the timing up a few degrees. The higher the octane rating the smoother the burn will be, the cleaner it will be and it's resistance to spark knock is greater because the flame front is more concentric. Regular fuels, for lack of a better term "explode" in the cylinder and are used up in the first 60 to 70 degrees of crankshaft rotation. High octane fuels "burn" in the cylinder more slowly and the duration of the burn is longer giving a greater "push" on the piston. Burn duration increases to 100 to 115 degrees of crankshaft rotation. Hope this helps, jim

[streetstar]

100 Low Lead (the blue stuff) - can be ran straight in a vintage vehicle. Its not optimum and will not necessarily increase hp's if the vehicle is already running tip top, but you can advance the timing and other things without worrying about pinging

[Tom]

Originally Posted by slash crashley

i'm sure i could get a couple extra horse out of the blend too.

Im sure you'll loose a few. Higher octane just means it takes more heat to start burning and it burns slower. So if your engine is made to burn correctly at 87 octane then putting in 100LL is going to mean the flame front does not have enough time to burn all the fuel = wasted power, high carbon build up, and less milage. Hell chevy even had a technical bulletin in the 90's because everyone was putting 91 octane in their trucks and it was screwing them up big time causing lots of warrenty complaints.

[BaddBusa2005]

Originally Posted by Tom

Im sure you'll loose a few. Higher octane just means it takes more heat to start burning and it burns slower. So if your engine is made to burn correctly at 87 octane then putting in 100LL is going to mean the flame front does not have enough time to burn all the fuel = wasted power, high carbon build up, and less milage. Hell chevy even had a technical bulletin in the 90's because everyone was putting 91 octane in their trucks and it was screwing them up big time causing lots of warrenty complaints.

93 octane seems to work just fine in my truck, so does 110 leaded with good o2 sensors

[MylilBowTie]

Originally Posted by James McClure

Boy, I'm showing my age now. When I used to drag race we ran Sunoco 260 and that was over 100 octane and the good av gas was 140. You can run any of these without any problem at all and you can push the timing up a few degrees. The higher the octane rating the smoother the burn will be, the cleaner it will be and it's resistance to spark knock is greater because the flame front is more concentric. Regular fuels, for lack of a better term "explode" in the cylinder and are used up in the first 60 to 70 degrees of crankshaft rotation. High octane fuels "burn" in the cylinder more slowly and the duration of the burn is longer giving a greater "push" on the piston. Burn duration increases to 100 to 115 degrees of crankshaft rotation. Hope this helps, jim

Do you also remember how common and often valve jobs where then also?

[James McClure]

Badd is right. I was working for Chev back then and I remember all the trouble. When fuel injection came out the engines were redesigned to run on watered down donky piss and didn't benifit from higher octane rated fuels. While this holds true for fuel injected stock configuration engines, it doesen't hold true for carburated engines that have, even to a small degree, been modified. So, use the highesst octane you can get in a carburated engine, especially if you can get it cheap!!
To Bowtie, I remember valve jobs all to well, but in the vehicle\drag car I was driving I ran the av gas all the time, I had little choice. From an avation mechanic I got a source for the lead\nickle additive that fuel dealers put in gas at thier distributon centers and started mixing my own. Spark knock issues disappeared even when initial timing was pushed to 16 degrees and total timing advance was at about 40. Thats in a LS 7 454 with 12.5 to 1 pistons, open chambered heads and 2 Holley 850 double pumpers on a high rise Edelbrock intake!! I ran this car (69 Chevelle) on the street!! It was rated at almost 700 horsepower at the rear wheels. My best time ever was 9.9 seconds at 148 MPH in the quarter at National Speedway, Center Moriches Long Island NY. Back in 1974 it cost me almost $9000 to build the engine and I got the block and pink crank for free. God only knows what it would cost today. jim