Originally Posted by
ifuonlyknew
So what is your point of posting here? Are you going to make something? Do you even race r/c cars?
You are kinda gruff.
I don't mind sharing, but who am I sharing with?
Originally Posted by
ChrisAttebery
Actually, it's not the tight squish that causes the detonation it's the raised C/R. If you could lower the squish and open up the chamber the motor would actually run cooler. This is what the high end tuners of the late 90s were doing to boat and ducted fan motors.
We were running really tight squish bands (.003"-.008") on up to 65% nitro. You just have to open the bowl of the head to compensate.
This all applies to hemi head motors. I haven't looked at a RC car motor in a long time.
Yes I also agree with you.
But what I don't understand is why a good 2.5cc airplane engine will run .005" - .006" and run up to 35% nitro
on the same set-up, why doesn't the car engine manufactures do the same? Is this something they save for there
own team engines, or is it goon clearance, or something else?
It seems counter productive for the manufactures to sell 30% nitro, and promote such large squish clearances.
But the same myths were relevant in the 70's. I found an article a while back written by Henry Nelson complaining
about engines that were sent back to him, and this very issue.
Bill Mazz
Roelof: If you don't already know how to calculate the speed of sound for a given engine set-up, and tuned length
for mufflers or pipes, I will share. BM