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Re: Cubes, cubes, I want more cubes!!!
Posted: Tue Dec 05, 2017 6:49 am
by RManson
Darrell,
What are the rod specs (length, weight)? And piston weight?
I never weighed my 125mm rod or 76 mm piston. Just wondering so that I might have a baseline comparison if it ever becomes an issue.
Thanks!
Re: Cubes, cubes, I want more cubes!!!
Posted: Tue Dec 05, 2017 9:49 am
by drunkmunkey6969
GeorgeS wrote:Is there an estimate of when to convert from air to LC on a lambretta engine based on cc? I mean, when is air cooling no longer sufficient on larger engines?
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We printed a very comprehensive guide to this in Scootering. Darrell Taylor researched and wrote the article, and when you boil it down...it’s the BMEP of the engine you should be looking at.
Re: Cubes, cubes, I want more cubes!!!
Posted: Tue Dec 05, 2017 11:52 pm
by Chris in Margate
Excuse me if I've read this wrong, but how do you get 70mph at 4500rpm on an SX200 box with standard sprockets?
Is that a typo?
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 1:36 am
by RManson
Chris in Margate wrote: ↑Tue Dec 05, 2017 11:52 pm
Excuse me if I've read this wrong, but how do you get 70mph at 4500rpm on an SX200 box with standard sprockets?
Is that a typo?
Coasting!
lol
I meant 6500.
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 7:17 am
by Chris in Margate
I knew.
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 4:32 pm
by wrecklessrobbie
What does BMEP...mean..
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 7:37 pm
by drunkmunkey6969
wrecklessrobbie wrote:What does BMEP...mean..
Its a standardised reference when you examine an engines power, revs and CC together.
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 10:59 pm
by wrecklessrobbie
Errrr right that clears that up then
Back to my book on quantum physics....
Think I should master that easier
Re: Cubes, cubes, I want more cubes!!!
Posted: Wed Dec 06, 2017 11:02 pm
by drunkmunkey6969
I’ll post something more helpful soon....lol
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Re: Cubes, cubes, I want more cubes!!!
Posted: Thu Dec 07, 2017 5:30 pm
by warts
Brake Mean Effective Pressure. The average of the pressure that produces downward force on the piston by the process of combustion. Less the negative pressures, ie pumping losses.
The graph of BMEP will be an identical curve to the engine's torgue curve.
With different units as the crankshaft will have translated the piston's linear motion due to gas pressure into rotary motion. With more attendant losses.