Gas for 11:1 compression

[John H.]

Re: Gas for 11:1 compression

Do you know the reason why?? Government/environmental issues?? Financial?? Legal issues??

Larry

As I understand it, disagreement between the two owners of the business on how to run it.

[Bob B.]

Re: Gas for 11:1 compression

John,

Unless you can tell a real difference between your engine performance with lead additive vs. no lead additive, I wouldn't use anything. 11:1 ought to work fine with 93 octane. I'm running 11:1 with the recommended timing and the engine runs fine, no run-on or anything.

As for hardened valve seats, that was threshed out back in the 70s by the auto manufacturers, who obviously had a big stake in the issue, and they found that only under the most severe racing conditions was there any noticeable difference in the condition of the valve seats.

Bob

[Duke W.]

Re: Gas for 11:1 compression

OE engines actual CR is typically half a point lower than advertised.

Most OE engines will operate detonation free on locally available unleaded premium.

Minor detonation can usually be exorcised with a few degrees reduction in initial timing or slowing the centrifugal curve if it is more aggressive than OE.

If the above doesn't eliminate detonation, owners are better off blending in a little high octane race gas or 100LL avgas than using additives, many of which are snake oil.

Duke

[Carl N.]

Re: Gas for 11:1 compression

John Flitter,

Jack and Kathy were at the Lone Star Classic the last 4 days in the metroplex.

Might give Jack a few days to return home.

Carl

[William F.]

Re: Gas for 11:1 compression

In "Corvette News", vol.4 number 4; 1967 article(I have this in the "Best of Corvette News" book-may be out of print now?) "Wise selection of gasoline" stated that trace knock which is ONLY detectable with special sensors, not by hearing "ping" accelerates ring wear 3X. So, those with higher compression engines who occasionaolly do full throttle "pulls" might want to be more concerned about octane. Mixing racing fuel with 93 octane pump gas would be a better way to go than using some of the snake oil octane boosters.