I don't run straight synthetic in anything except my bike. All you have to do is use Omega of the same nitro content as you are presently using CP and voila there's the castor you need. Omega is 17% total oil, 70/30 synthetic/castor. I run it straight on sport engines like my .46 FX etc., but for any higher performance stuff I add castor to bring it up to the target total oil content. Ducted fan engines on props for example, I bring total oil up to about 23%, same as for 1/2A stuff. I'd prefer 18-20% total oil for everything but Omega is the dominating brand around here, so for regular ol' sport engines I don't bother, it does well. The only SIG Champion I see up here is quarts, nobody stocks it as their standard fuel in gallons. Wish someone did, I think SIG makes every fuel I might ever need.
Last edited by MJD; 02-26-2014 at 02:58 PM.