4500rpm propeller to negate the PSRU

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Pops

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Pops:
Something tells me VW redrives don't weigh 89 pounds!

You can't hand prop a redrive. So start adding the extra weigh of starter , mag and starter mount, starter flywheel , Starter solenoid , large enough battery to do the job of starting, alternator and belt, wiring. Remember it is the firewall forward weight, so that also includes the weight of the engine mount, bolts and prop and bolts.
My 1835 cc, non-electric firewall forward weight of 141 lbs and I tried to same every ounce. The 2232 cc with redrive, firewall forward of 230+ lbs. The 2232 cc engine lasted 87 hrs and the case cracked on the way to OSH. Always had heating problems and he was the person that tried welding larger cooling fins on the heads. Fat fin heads. He then installed a R-912.
There is real life and then --------.
 

proppastie

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Want to save money. ....buy a completed hombuilt.......on an engine a core......want to do lots of work, stay busy, have lots of challenges and satisfaction solving problems do something different......
 

lr27

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Pops:
Something tells me a redrive, lithium starter battery, and a starter don't weigh 89 lbs. Adding an electrical system would be apples and oranges. Also, I'm guessing that if the other guy would have ended up with more firewall forward weight even if he was installing the same sized motor without any starting system or redrive.

If someone wants to abuse an engine, they don't need a redrive to do it.
 

Pops

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I believe him when he said the firewall forward weight was 230 lbs. I know him very well. Believe what you want.
 

lr27

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I believe you. I just don't believe he was trying as hard as you to save weight. Plus he doesn't really NEED a generator and an electrical system. Just a battery with enough charge to start a few times.
 

Pops

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I believe you. I just don't believe he was trying as hard as you to save weight. Plus he doesn't really NEED a generator and an electrical system. Just a battery with enough charge to start a few times.

I agree with you.
 

BBerson

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Need a flywheel on a crankshaft with a PSRU. A direct drive hand flipped prop doesn't need an additional flywheel.
 

B100

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Yeah!
Nobody runs direct drive at 4500 rpm for general use.
Chris Beachner ran his Buick engine direct drive at 3600 rpm max, cruise at 3300 with a 58" prop.
Ok.... from what I read guys ....I conclude that this sort of prop and rotation combination would be ideal for "direct drive" diesel ? Any thoughts on that ?
 

dog

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Ok.... from what I read guys ....I conclude that this sort of prop and rotation combination would be ideal for "direct drive" diesel ? Any thoughts on that ?
Spining a diesel at 4000 rpm,you might be able to
make your power and reduce the torsional vibration normaly assosiated with diesels running
at lower rpms.With a mechanicaly pumped turbo diesel you can keep adding boost and air until you
push the crank down out of the block.
A non turbo will run out of air and you will start to make smoke.
There are not a lot of choises.The interesting one to me is the tiny 3cylinder super charged and turboed, diesel in the smart cars.
Suposed to be good for 75kms between rebuilds in a car.
 
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