downundarv8builder
Member
After the Superior XP-400/382 buyback I'm now looking at getting an IO375 engine for my RV8 with the fastback conversion. Among my many options, I have the choice of whether to get a counterweighted or non counterweighted crankshaft. I'm also looking at putting on a 74HRT composite propellor and also 9.7:1 high compression pistons. I do understand that the issue of vibration has a huge number of variables and is quite dynamic and decidedly not simple however is anyone out there able to shed some light on some information that may be able to help me make a decision? I am not an engineer so if replies are kept relatively simple, I would appreciate it. My building supervisor down (who is an engineer) here has the same engine (375, high compression with a 200RV prop) in his RV8 and it's generally as smooth as silk. The sales guy at Aerosport seems to think that as long as you stay under 9.0:1 compression, the non counterweighted crankshaft would be OK. Any thoughts on this issue would be appreciated.