amuscle69

I have a 70 Mach 1 with a fairly built 351C 4V. Running 11:1 compression. I have 93 Octane with a bottle of booster and i still ping at high RPM's. I found some Sunoco 112 that the dirt track racers use. What do you all think about cutting maybe a gallon or two to every 10 of 93 to bring my octane level up? Running race fuel is out cause its over $6gal.

Any info appreciated

Soaring

Have you tried adjusting your timing?

Lumbergh

Sounds like you got problems that increased octane isn't going to help. 11:1 compression isn't really all that high. Agree with Soaring, have you checked your timing? By the way mixing one gallon of 112 octane fuel with 9 gallons of 93 octane (final volume of ten gallons) woudl only raise the octane to 95.

fredjchavez

You might consider running a bigger camshaft to reduce the dynamic compression. What cam are you running?

It sounds like your dynamic compression ratio is too high (around 9.3 or lower is all you can get away with on 93) which is always lower than static which you say is 11:1. Does running the race gas cure it? Or, consider adding a 3-4 gallons of the race gas and also reducing your timing.


Fred

Soaring

Also, check to see that your vacuum advance is working properly.

amuscle69

Well here's the problem. I have a fairly hot Ford Racing cam im not quiete sure of the dynamic compressioin i will have to check. Tried adjusting the timing this past weekend and it appears as though the dampener has "slipped" Im not real good with this stuff but my chevy buddy is and we coulded see how far advanced it is. The guy who i bought the car from said it was tuned for 104 octane turbo blue so i am pretty sure the timing is advanced but i dont know to what. Any ideas? Cylinder one is front on passenger side correct?

amuscle69

I figured the race fuel might be a cheaper fix till i can put some money into the engine. I would like to finish up some body first.

amuscle69

I should also add that Yes the car runs like a rocket with no ping with straight 104 turbo blue

rmodel65

stop wasting money on octane boosters theres not enough stuff in them to even raise the octane 1 point[:'(]

6mustang6

The octane boosters are trash. It says it raises it up to 10 points..... 10 points equals one octane unit.... or something like that. So a bottle of octance booster might raise 93 octane to 94.