how to tell if the engine is pinging

[carlp]

I am looking for ideas. I will be taking the car to the track this Thursday and will be spraying a 150 shot of nitrous on my freshly built 347. With my helmet on and all of the noise the car makes, how can I tell if I am getting pre-ignition. I iwll not be able to hear much. I don't want to burn the thing up on its 1st pass. Please share your ideas.

 

[$uperstang]

Spray IT ON THE STREET BEFORE YOU GO AND LISTEN

 

[thehueypilot]

I did not hear mine detonating and I broke four pistons in one pass.(w/o NOS) I recorded the a/f during the run and it had spikes throughout the whole run but averaged 12.5:1 but could not hear any noise at all. After replacing all 8 pistons and rings I did not want it to happen again so I jetted the carb up 5 numbers and increased the fuel line from 3/8 to 1/2 inch. The a/f ratio was 10.5:1 with no spikes. You might also want to reduce the timing back a couple of degrees to be safe.

 

[carlp]

Unfortunately I don't have anywhere to spray the car on the street. I will be retarding the timing 6 degrees. I am also going to data log teh run with the a wideband. I thought 12.5 to 1 was safe. I guess I will be looking for a little bit richer mixture.