Well, I want to put some time on my race motor before I go to the track, but I'm having a hard time getting race gas during the week without going to the track. I was wondering if I could put in about 5 gallons of 93 pump gas with some octane booster and get by with some part throttle street time. I'm not going far with an 8-gallon fuel cell! Motor is a 462, Alum. Stg 2, cam is basically a 308s, true compresion is 13.3:1. Anybody ever try this idea? Have fun.
Jeff, You should be fine with what you are proposing. It's not so much the cr that gets you its the cylinder pressure and the 308s is a good sized cam. I have an iron head engine with about the same cr and approx. the same specs on the cam. The cranking pressure is around 220 lbs. I would use straight 91 for moving the car around and driving short distances. I've never had a problem or heard any rattling. Make sure your not lean on the carb, timing is reasonable and just listen as you drive. Only thing you may have to do is shut it off in gear. Bruce Kent
You Might use some good 91 or 92 and two gallons of toluene. this would keep it from detonating. My charts show: 6 gallons of 91 with 2 gallons toluene produce 102.8. 6 gallons of 92 with 2 gallons toluene produce 103.5 7 gallons of 91 with 1 gallon toluene produce 96.9 7 gallons of 92 with 1 gallon toluene produce 97.8
Thanks for the replies, guys. I noticed last night that the Mobil station around the corner sells 93 octane. I agree with Bruce, that should be fine for what I need. I might take 3 or 4 degrees of timing out to help. The motor won't be loaded hard at all, the tires don't begin to hook on street pavement :laugh: Have fun.
air temp is a factor also, the cooler it is the less octane you need, the tolulene works good when you cant get to a place to buy high octane
You can also use Xylene, which works like the toulene, I think it is 1 octane point higher (118) as well. A lot of the turbo guys use Xylene and Toulene, just don't spill it on the paint!!!!
Higher Octane The older racers here used 3 or 4 moth balls in the gas tank. It must have worked, but how? I acutally did it a couple of times. Anyone heard of it?
You will be fine on 93 octane. Just dont put your foot in it !!!!!!!! Good Luck with your new combo Wayne
Here's an update. Went for a drive last night. I had about 1.5 gallons of race gas in the fuel cell and I dumped 5 gallons of 93 in it. I fired it up, let it warm up, and took a couple trips around the neighborhood. The car ran pretty good. I kept the RPM's below about 4000, and I only revved it up there occasionally. I did notice something interesting, though. The motor seemed to idle a little smoother. It didn't have that hi-compression "cackle" that it does on race fuel. So there you go, if anyone else was wondering. It seems to work okay. I think I'll venture out to the auto parts store up the road next. I remembered one other thing through this. I HATE the smell of pump gas! :blast: Have fun.
