ORIGINAL: airraptor
Guys we gave advice and he doesnt want to take our advice.
i think that if you can measure your rpm in the buggy then you have a good set up already. see what rpm you get at the end of the straight of just before a jump amd then try another engine to see if it reaches that same rpm or better.
also if your engine already is hitting 39,000 i think you need to regear some to better use the power of the engine. i would think most of these car engines ,ake thier best power in the 20,000-28,000 rpm range.
Good luck!
Most car engines are ported for that rpm. Most of the car engines I own currently have at least 175° of exhaust duration and average 17-19° blowdown timing. The highest timed engine I have runs 186° Exhaust and 19° blowdown. The crank timing varies significantly, but thats no different than airplane engines. I haven't seen any patterns with crank timing as I have with exhaust and blowdown. I have a tach sensor for my Spektrum DX3S radio, but most of the car guys that have this radio have said the Tach isnt accurate anyway so I havent bothered trying it on any of my cars.
As far as the prop choice on a car engine, I would think a Ducted fan prop is going to be the right prop to handle 30k+. Even carbon fibre props which was brought up before may not be robust enough. I would think a 6x4 or 5x6 would be small enough to let the engine turn up but load them enough to keep the conrod from going AWOL.
I like the break-in stand idea better - looks safer and easier at the cost of roughly $140..