100 Octane with 12:5:1 340??

-
Going off your cam and what you say the static compression is your dynamic compression is up around 9:1 which is a bit over the safe limit for pump gas. But that depends a lot on your head/piston setup, if you have good squish area and efficient chambers. You may not hear the pinging but I'm guessing your engine is loud as F*%@ (lol) so you would not be able to sense it if it was mild, which is still bad for your engine. What are your rear gears?
 
391s in the rear and low gears in the 4 speed. Yep, shes pretty miserable on the highway, but damn shes fun to drive.
 
1968FormulaS340 said:
Probably because E85 allows you the convenience of driving up to a fuel pump like any other car on the road.
Click to expand...

Anywhere you get fuel you can fill up your meth injection for $2.00 a gallon. Never seen it ran on a n/a car but i sure love it on my turbo car no more exspensive racegass fill up the tank with 91 buy a bottle of windsheild washer fluid to fill up my devils own meth injection tank and hit the road. :)
 
Go to S&W race cars. Look up P/N 6079. I mix 93 nolead with with this product all race all day long with 11.8:1. No Ping runs consistant. Figure your own mix ratio. The 5 gallon pail is the best deal
 
emnestor said:
K Black pistons and going with Edelbrock aluminum heads.
Click to expand...

I think you will be OK running pump 93 if you go with aluminum heads. If you didn't notice any detonation running 93 on iron heads then it will be even less likely with aluminum heads due to the higher rate of heat transfer away from the chambers. I would still run 100-octane when racing though just to be safe.
 
emnestor said:
391s in the rear and low gears in the 4 speed. Yep, shes pretty miserable on the highway, but damn shes fun to drive.
Click to expand...

Try a GV Overdrive. I love mine.

ALso, with your octane question. Simple solution is to run premium and set your total timing and curve to whatever works with your combo. I run 24 initial, 32 total.
 
roccodart440 said:
Try a GV Overdrive. I love mine.

ALso, with your octane question. Simple solution is to run premium and set your total timing and curve to whatever works with your combo. I run 24 initial, 32 total.
Click to expand...

I agree, try to find find the optimal timing for power on race gas, record it, then dial it back just enough so it runs safely on 93. The difference shouldn't be much maybe 4 degrees?
 
1968FormulaS340 said:
Probably because E85 allows you the convenience of driving up to a fuel pump like any other car on the road.
Click to expand...
and water methanol injection gives you the liberty of filling up with 93 octane gas at ANY gas station and then you put a gallon of windsheild wiper fluid in your water/meth kit and BOOM you have the equivilant of 112 octane gas.

Meanwhile, I have a hard time finding E85 stations around here, not like I need it anyways with a N/A motor with 7.6:1 compression if I'm lucky.

And for those who say, "I'm not running my car on windsheild wiper fluid" I say go ahead and piss your hard earned cash to the wind while many people are paying $2 for a gallon of wiper fluid to essentially turn "regular gas into racing fuel."
 
Run it. If you don't hear marbles rattling in a tin can, and plugs show no aluminon flakes from the pistons, you are good.
 
93 will support right around 195 / 200psi cranking pressure max, my demon has about 200/205 I run very cold plugs, no heat crossover, carb spacer, 4,400 stall, ram air, and 30
Total timing, if at the track I would run 100+ and bump the timing up.
 
You must log in or register to reply here.
-

Back
Top