RedFD

I have been reading up on what detonation sounds like and found in many posts that it sounds like popcorn or metal against metal. When I shoot little flames it makes a little pop. How do you tell the difference? Thanks.

TailHappy

What you're describing should be backfiring. I don't think you much need to worry about what detonation sounds like in an FD. From what I've read, inaudible detonation is enough to kill your seals.

But for general information, although I've never heard it in a rotory, in a piston car it sounds a lot like a rattle at first, and when really severe will turn into sporatic little pops that sound like they're coming from the dash. It's usually not that loud, so even your radio would drown it out. Find someone with an old lower horsepower car and have them try to accelerate up a hill in a high gear at lower rpms (not lugging), or have them floor it all the way onto a highway and you'll probably hear it. I used to hear it all the time on an older Jeep Cherokee and an older S-10 when flooring it. HTH.

Jonesboro

The backfire sound comes from the tailpipe and is easily heard. Backfire means unburned fuel is getting through the engine i.e. rich fuel mixture. Okay for rotaries.

The detonation sound comes from the engine bay but is rarely heard by the driver. Detonation is death to a rotary.

KZ1

Detonation sometimes can make a pop, you will knnow when it happens don't worry about it now. However, I have only detonated at very low rpm, so it may sound differnt at high rpm. Also, I only heard it once out of the few times I detonated, other times it was silent.

but all the times detonation sounds like $$$$$ going down the drain.

I am not sure what caused my detonation, maybe egr valve off, airpump, just week seals after 67k and 15lbs of boost. no idea.

Best way to tell detoantion is with a knock sensor.

Toadman

And always stay with good 92 octane gas(91 in Calif.) I prefer name-brand over Joe's thrifty-mart gas.

RedFD

Thanks for the info guys!!! Speaking of 92 octane gas.... what do you guys think about propane injection to lower temps and raise octane. Theres a thread on here somewhere about it but Im about to get off work so I dont feel like posting it. From what Ive read it seems really interesting and makes a lot of sense.

man_of_steel

huh...I'm using 93 octane and I've been backfiring a bit lately...

Jonesboro

The octane recommendation has to do with avoiding detonation, not backfiring.

dzungh

I don't think you should worry what detonation sounds like b/c when it happens, it's probably too late. In end, just make sure you're running enough fuel in a cool engine.