MVVS 2.5 Glow
10-23-2011, 06:04 PM
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MVVS 2.5 Glow
I'm assisting a young guy get his MVVS 2.5 glow (#3029) to run in a control line speed model. Can you please provide the following information:
1. What is the exhaust and transfer port timing?
2. What is the intake (shaft) timing?
3. Is the peak power figure of 26,000 rpm realistic?
4. Any bench test results with standard (eg APC) props?
Thanks for your help.
Ron
1. What is the exhaust and transfer port timing?
2. What is the intake (shaft) timing?
3. Is the peak power figure of 26,000 rpm realistic?
4. Any bench test results with standard (eg APC) props?
Thanks for your help.
Ron
10-24-2011, 11:21 AM
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RE: MVVS 2.5 Glow
Timing depends on year of production
exhaust was 155°, shorter timing worked better and was introduced in later models
intake closes at 40° ATDC
with 150° exhaust timing, we got 19000 rpm static using MA 8x3 props and 3241 muffler. 26000 is on special tuned pipe with the 155° engine. Only the best selected engines would get these numbers though. For racing, you need to be a good mechanic who knows how to prep engines. That includes relief lapping of cylinders etc. From your questions it seems you have some miles to walk yet. There realy are no simple oneliner answers.
I suggest you get a fistful of props to experiment. Use only castor in the fuel, and run in the engine first. That may take a while; my best engine needed a whole season.
exhaust was 155°, shorter timing worked better and was introduced in later models
intake closes at 40° ATDC
with 150° exhaust timing, we got 19000 rpm static using MA 8x3 props and 3241 muffler. 26000 is on special tuned pipe with the 155° engine. Only the best selected engines would get these numbers though. For racing, you need to be a good mechanic who knows how to prep engines. That includes relief lapping of cylinders etc. From your questions it seems you have some miles to walk yet. There realy are no simple oneliner answers.
I suggest you get a fistful of props to experiment. Use only castor in the fuel, and run in the engine first. That may take a while; my best engine needed a whole season.
