What types of uncorrected compression ratios have you guys ran on pump gas with proper head design? I'm trying to decide on whether to run pump fuel or stay with VP110 for my new build. The design of the head is pretty critical so I am looking for people running tight squish(.036"ish), squish bands around 50%, an nice hemispherical domes(no tubs or toroidal stuff). I have heard of up to 15.76:1 with +4 timing @1000 feet of elevation in some drag applications. Albeit that application was not ran for long periods of time whereas mine will be.
Looking at your typical Banshee(64x54) with proper squish and a "20cc" dome our UCCR is 14.36:1 and is well known to run with +4 timing on 93 pump fuel with proper jetting all day long. How much further could that UCCR be stretched before having to reduce timing or start mixing fuel? I figure if I have to cut fuel I'll just say screw it and run straight VP110 with the timing and compression to match.
Also, since I touched on the full race gas builds. Where do you think the tradeoff occurs between high compression and pumping losses causing the engine not wanting to rev out? Where would the cut off of UCCR be in a full drag build with a good amount of exhaust duration(200+), decent timing, and 110 motor octane fuel? I have two different domes designed currently, one for 93 and one for 110 and both of them have great MSV numbers. What say you? Evan