Marine engines usually run similar, if not the same timing numbers as the Car (on road) engines. Buggy engines generally have lower timings in the sleeve and in the crank. Some as low as 180 degrees duration open in the crank window. (They don't use as much fuel if they can't breathe) Nothing that can't be fixed by a competent engine builder B) Most engine builders would aim for at least 213+ open on the crank in a marine application, where fuel consumption and nitro% aren't an issue like in buggies. 215 duration / close at 65 ATDC is pretty common.
Marine engines tend to see a lot higher nitro %. Liquid torque.
Please don't take this as a shot Mike, but very few people on the planet have heard a 45,000rpm 2 stroke engine! (especially from a 21 engine with a car pipe) It's very, very easy to overestimate rpm. Even manufacturers do it - to sell engines.
32,000 would well and truly stand out over engines only pulling 28,000 under load, and is a more likely and realistic number. No mean feat either - still a tremendous accomplishment. Few people in the R/C hobby outside of pylon racing have ever heard 35,000rpm!
Tim
I have run the Mac buggy engine in the street and let it fully rev out (about 250'). With the Novarossi 086 pipe the buggy topped out at 51 mph. With the gearing and tire diameter the MAC had to turn 45,000 rpm to reach 51 mph.
Mildly timed buggy engines will hit 40-44 mph in 100 ft. This equates to about 37,000 rpm.
However, there is not much power at this rpm. Those engines make peak power at about 25,000 rpm.
If you put a buggy engine in a boat it must be propped to stay on the 25,000 rpm peak.
On-road engines always peak at well over 40,000 rpm somewhere on the track.
peak power will be at 35,000+ RPM
Very poweful .21 boat engines will make peak power at 36,000 rpm.
