fuel octane
Race Director
Joined: Sep 2005
Posts: 18,640
Likes: 121
From: Farragut,TN
You probably wouldn't have any issues with 93 less the so called octaine boosters. My 69 has 10.25/1 and dosen't ping with the 93.
Race Director
Joined: Sep 2005
Posts: 18,640
Likes: 121
From: Farragut,TN
Octane Boost - Maybe it's a mental thing, but when I don't use it she diesels slightly on shutdown. With it, she stops with no fuss at all. It may be a lot like your car always seeming to run better right after you've washed and waxed her. I guess that's why they call it a treatment. We all like being catered to, so why shouldn't a Vette?
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
Pete
Race Director
Joined: Feb 2001
Posts: 11,283
Likes: 2,092
From: Grapevine Tx
2018 C3 of Year Finalist
2016 C3 of the Year Finalist
Racer
Joined: Jun 2005
Posts: 409
Likes: 13
From: Lavonia Georgia
Search Kemco Octane Supreme 130. It's one of the last remaining ways to boost octane using Tetraethyl lead...the old fashioned way. It's listed as being for offroad and racing use only because it's the same stuff used to manufacture leaded fuels. Do not use it on anything with a catalytic converter.
I run it in my '68 with a built 383. It's not cheap, but a little goes a long way. Just .6 oz per gallon nets a 2 point increase in R+M/2 octane rating. I live near a lake and have several stations that sell no-alcohol gas (marine fuel systems really don't like the ethanol). I fill up there and add 8 oz to 12 gallons of 91 to net 93. I use it as much for the valve and combustion chamber protection as the octane. I can get non-ethanol 92 locally and with my 11.5 DCR would probably be fine but it's still unleaded. I buy from a different station that has the 91 cheaper and bump to 93 using the lead.
The documentation says you can add in ratio to gain up to 16 octane points but if you need that high a rating, you likely aren't reading this post!
I run it in my '68 with a built 383. It's not cheap, but a little goes a long way. Just .6 oz per gallon nets a 2 point increase in R+M/2 octane rating. I live near a lake and have several stations that sell no-alcohol gas (marine fuel systems really don't like the ethanol). I fill up there and add 8 oz to 12 gallons of 91 to net 93. I use it as much for the valve and combustion chamber protection as the octane. I can get non-ethanol 92 locally and with my 11.5 DCR would probably be fine but it's still unleaded. I buy from a different station that has the 91 cheaper and bump to 93 using the lead.
The documentation says you can add in ratio to gain up to 16 octane points but if you need that high a rating, you likely aren't reading this post!
Intermediate
Joined: Dec 2012
Posts: 42
Likes: 4
You may be on to something 694Spd350. No soot, I do have it idling high around 950 due to no choke and a rough idle street cam. I did a total rebuild on the Holley Double Pump and wasn't privy till later that soaking Holley Body Parts in a true Carb Cleaner can compromise some seals. As a check for this, I hear spraying the exterior shafts with an ignitable spray can detect vacuum leaks by elevating the RPM's. Any thoughts on the soaking or spray is appreciated.
P.S. She runs strong with no hesitation at all, and the RPM's climb smooth with no smoke or soot out the exhaust. Plugs and Mallory ignition/coil are new and match previous. You've gotta Love these C3's!
P.S. She runs strong with no hesitation at all, and the RPM's climb smooth with no smoke or soot out the exhaust. Plugs and Mallory ignition/coil are new and match previous. You've gotta Love these C3's!
