omarwashington

iTrader: (2)

I also thought that a filled crank made the entrance of the fuel and air smoother as it travled through the crank, less turbulence.

Roelof

Look back about this and there are many people who has noticed nothing with and without the filling on the same engine. Also my fastest engine at this moment has no balanced crank and has no silicone filling.

merdith6

iTrader: (3)

I really don't know squat about the turbulent ratio of whatever, but from my experience on the track the regular crank Nova engines to the ones that are silicone filled It just seemed more responsive on acceleration, and slowing down too. The engine seems to shut down a bit faster giving me smoother turns off power with less run on...

It seems to make the idle a bit better, and smoother transition throughout the rpm range...

Maximo

iTrader: (11)

Myself I have not seen much power gain from lightening the cranks...or at least not any power while under load...However I have seen power difference by adjusting the amount of filler I put back into the crank after boring it out.... usually too much filler can actually hurt power more then not having enough filler..... There is definitely a sweet spot for the amount of filler an engine likes...

Rcrenew

iTrader: (9)

The engines with a filled crank does have a performance gain. As with anything some engines by design will show higher gains than others but the reduction of mass and the ability to adjust crankcase volume at the same time is a benefit. its not going to be a huge gain, but it is there and all the little things do add up. A couple small increases in power make a good gain in the end.


Lance
RcRenew.com

Rcrenew

iTrader: (9)

NEAL YOU TYPE FASTER THAN ME!!!

Roelof

Crankcase volume is one thing, shortening the road from intake to port does me think there is also some kind of change in timing as well.

Maximo

iTrader: (11)

I don't think adding filler shortens the route any...The mixture going from high pressure to low pressure will always follow the shortest path on its own....Putting filler in a outside radius will not help guide it or push it....if anything it will create more contact area that can cause separation of the mixture.......

kgombe

iTrader: (13)

what you do is decrease crankcase volume (a bit) and lighten the crank.. the engine should be more responsive and a bit smoother.. according to simple theory


DISCLAIMER:::


i have no idea about these engines.. but i did sleep at a HOLIDAY INN when i went to motorama...

maxflo777

Done right...
Helps crank balance, crankcase volume (+low end/+top end), inertia, bearing life, less fluid restriction (+top end), enough?

It will not do a shorter rout for fluid to pass, but it will be a less restrictive one, less restriction means more power, specially top end.

But fluid will not necessarily find the shortest path, it all depends on laminar flows, turbulence, and other flow patterns and properties.

Roelof

True but with these speeds of opening/closing/flow there is a high possibillity that there is a resonance in the crank. If it is right it will help, if not it can affect the performance.

maxflo777

Too short, no resonance. at that temp and rpm power range the resonance tuning length is basically the length of the carburetor track (top of the restrictor stack to crank valve) that is the reason 12s and 21s have somewhat similar runner lengths.

xe

Lille-bror

Old thread, I know.

Need some facts: Will there be any bennifits of putting silicone in a crank you don't lighten which àlso wasn't born with silicone in it?