1) my prop is a 3 blade 70inch Warpdrive (large paddle) set at 14.5 degrees. Angle is taken at 70% of the blade lenght - not at the tip. The tip is too small to make a good angle calculation...
2) my redrive is 2.32 to 1 ratio and my engine is turning 5200rpm at WOT which is 2250rpm at the prop. I used to run the engine at 5600rpm (lower blade angle) but wasn't getting all the speed I could at level flight.
3) What is your reduciton (beltdrive) ? 2to1, 2.5to1, 2.3to1 ? If your prop turns too fast it is not helping your engine to cool off.
4) Did you do a PULL TEST ??? Mine showed between 420-450 pounds of thrust static which place the engine at the same HP level as a 912ULS. I'm asking this because if you overrev the engine you may not load it enough.
1) check fuel delivery (mixture needle) at high speed may not deliver enough fuel to the engine causing overheating. Fuel quality (90octane+)
2) Glycol radiator installation : large enough rad, large enough EXIT area, glycol quality, NO THERMOSTAT and NO AIR in the system. Air should be PULLED out of the cowling from the rear so that cold air can get IN from the front.
Thanks for the infos, obviously it helps to diagnose a problem if we get all the parameters... From what you told us :
1) I would seriously consider changing the oil to 20W50 full synthetic oil to keep internal temp as low as possible.
2) make sure your rad is large enough; see my blog post How to calculate glycol radiator for your engine on this website. I used that calculation and it turned out OK
3) how is your fuel system built from the fuel tanls to your engine ???
4) you mention the Aerovee carb, are you using the right needle ?
Mine came with 3-4 different needles - maybe the one installed is not sending enougn fuel to your engine...
5) air goes thru your rad to cool off the glycol, what about EXIT for the hot air ? Exit area should be 1.5 larger than the entry. Also, air should be forced out - pulled ´
6) what type of gearbox - reduction, propellor, engine speeds are you looking at ?
7) what blade angle ?
I got no clue about your setup so I wont comment on it.
I can however tell you what I did :
1) NO thermostat : they tend to open too late and respond too slowly to quick temp changes
2) No glycol mixture, ALWAYS PURE.
3) add an oil cooler so both the glycol AND the oil will keep the engine
4) use only FULL SYNTHETIC OIL 20W50 grade.
5) use best OIL FILTER (race car) type you can find
6) use only SUPER UNLEADED (90+) grade
7) make sure your glycol radiator is large enough and is double row stacked. Should be race car grade. Mine was made to my specifications - not more expensive than a 912ULS radiator and very effective
8) make sure your EFI is getting the FUEL PRESSURE recommended - fule restriction will cause overheating problems...
That's all I can think for now.
Let me know gow this turns out.
Also, would be a GREAT IDEA to give out details of your installation that way we could help you better.
Finally, my installation is running at WOT (Wide Open Throttle) for extended periods and never. experienced overheating. Also ran the Soob on 90F+ days for extended periods without any problems...So, It can be done.
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