Hi was looking for some ideas 92 evo 10.5 to 1 comp screaming eagle heads ev57 cam screaming eagle ingnition.When i let out the clutch in first gear i can hear a engine ping till i get the rpms up.Just did the timing 35 full advance.Mikuni 42 carb seems fine no backfiring through carb or pipes.Maybe voes giving me problem?using 91 octane fuel.Anyone have any ideas ?Thanks in advance

 

You can't run 91 Octane with that comp ratio mate.

Grab a can of octane booster and dose your gas, ride it hard and see if it goes away.

I ran 10.5:1 in a 96 Dyna with an EV-46 on 98 octane and nobody here would believe it wasn't pinging...I guess we just have better gas in NZ....

 

Spanners,
We use a different rating method for gas here. We use an average of two methods. 91 (sometimes 93) octane is the best we can get and that is about the same as your 98 octane, give or take.
I have a JDM 4AGE 20 valve motor in my Corolla, about 10.5:1. It calls for 100 octane, but that's 100 octane in Japan or Kiwiland, not by the US reporting methods. It runs fine on 91 or 93 here.
I agree that more octane may help him, but that's not terribly practical. We can get some real high octane gas but at about double the price and with very limited distribution (race gas, aviation gas, etc.) I suggest backing the timing off, especially if you have some type of control over it besides moving the entire curve. A more modern ignition system that allows you to pick what curve you want may do it. Otherwise, back the timing plate off until it doesn't ping. That's your only real choice here. Going richer on the lower end of the carb may also help some. And, of course, confirm that the VOES is working properly.

 

35 degree's? Sounds like WAY to much timing. Thats MAX timing on any setup. Way to much for high compression and pump gas. No, I'm no expert but my Shovel had the same compression and we had to set it down to 32 to be even a little livable on the street and race gas was needed for any higher than that.


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Thx i am going to retard the timing a few degrees and see how that is.

 

I run the head quarters ignition for high compression. It only advances 25 degrees at full advance so you can set the timing normal and still not over advance at wide open.

 

Try some colder plugs.

 

Yeah I forgot to metion that. Mine was so bad it was salting the plugs until I went two heat ranges colder from a NGK BPR5ES to a BPR7ES. I keep a 2 ounce bottle of AMSOIL octane boost in my bag too. I dump it in from time to time and just refill when I get back home.

 

Im running 10:5 wiseco's in mine, and i rarely get pinging. Only time it may ping is if i lug the motor at slow speed in to high of a gear. U should be fine with engine knock up to 11:1 with colder plugs and premium fuel only with timing at or around 30-32 degrees, get rid of the voes if u can.

 

Cam plays a part in the equation also. I run a Woods W6 with 10.5 to 1 and head work.