custom ud pulley

[sam c.]

Well alright then... off we go. I'll be sure to post what I discover.

[Topless]

It's a simple math problem really. Calculate the change in wp rpm at different pulley sizes and make your best guess. A flow rate gauge on a coolant line would be useful also. Ideal flow rates for rads is pretty well understood.

I have never seen a smaller one than 4" so I assume someone did the math already.

[sam c.]

Originally Posted by Topless

I have never seen a smaller one than 4" so I assume someone did the math already.

Maybe I'm just cynical about human nature, but my couple of decades in mechanical and nuclear engineering suggest to me quite the opposite. It may not be once a week, but it's prob not too far fetched to say once a month, I hear the general equivalent to this sentiment: "if that was a good idea and/or worked better than what we're doing, someone would have already done it."

The shorter, more common version is: "...this is how it's done and it's always been done this way."

While I have tons of respect for any experimentation/trials/prototyping, even if the results were simply to prove what doesn't work, I honestly have zero respect for any reason for why something isn't done that sounds even remotely like "this is the way we've always done it and there's nothing better."

Just my $0.02

[sam c.]

The other thing I'd be interested in is how much cavitation is occurring in the stock pulley driven WP.

Right now, it's known conclusively that a stock 6" pulley can be swapped with a 4" pulley with no negative effect on cooling despite the WP turning a third or so slower. There's a number of variables in the cooling system including (but not limited to) the radiators heat xfer coefficient, the fluid friction through the system and engine coolant channels, the heat xfer of the block, the thermostat, ambient cooling, oil cooling, etc. All together though, the one thing we know for certain is that the WP is currently being turned a lot faster than necessary.

[sam c.]

I'm with you RK... I'd guess the alt. is really the bigger question here.

[Topless]

Originally Posted by sam c.

The other thing I'd be interested in is how much cavitation is occurring in the stock pulley driven WP.

Right now, it's known conclusively that a stock 6" pulley can be swapped with a 4" pulley with no negative effect on cooling despite the WP turning a third or so slower. There's a number of variables in the cooling system including (but not limited to) the radiators heat xfer coefficient, the fluid friction through the system and engine coolant channels, the heat xfer of the block, the thermostat, ambient cooling, oil cooling, etc. All together though, the one thing we know for certain is that the WP is currently being turned a lot faster than necessary.

Math and experimentation time then! Let us know what you find.

I grew up around scientists and engineers so I understand your burning curiosity very well. One of my friends used to be a model rocket hobbyist and always wanted to build bigger and better. He was building liquid fueled rockets in his garage until a man with money and vision offered him a partnership. The company is now called Space-X Technologies.

[sam c.]

Originally Posted by Topless

Space-X Technologies.

Wow! Maybe I'm a bit of a dreamer, but I believe SpaceX is one of a small handful of companies that are currently in the process of changing the course of human history right before our eyes. Very nice!

[Topless]

Originally Posted by sam c.

Wow! Maybe I'm a bit of a dreamer, but I believe SpaceX is one of a small handful of companies that are currently in the process of changing the course of human history right before our eyes. Very nice!

I absolutely agree. Man on Mars in our lifetime I think. These guys are very focused and determined and currently have a $2Bil satellite launch schedule on the calendar... And Tom owns a Boxster.