Ken is running avgas with his 15.5/1 hpd race setup, he says he hasn't had any problems. He's ran it hard for a year and tore it down for a rebuild and is going back with the same piston? I also ran some b32 which is 106 and didn't seem to have any problems. Wouldn't I have excessive heat with detonation. Egt looked the same wether I ran 106-108 or 109 motor octane.

 

Dod you read the article from the link NC had posted? It shows they make 3 ratings of that stuff. Ask Ken if he's using the higher octane or not. HPD also tells people with the full race mod to retard the timing 2 degrees. That might help keep the detonation at bay.

 

I did some checking and they have pretty much narrowed the avgas down to 100 and 100LL. Ken is running the 100LL. It's a dual octane rating, I think I'll get 5 gallons and give it a try. If it's denonating it ought to give me to much exhaust temperatures. I'll let you know just for reference.[img]i/expressions/face-icon-small-cool.gif[/img]