Apparently, diesel trucks and some models (looks like the 190-series) of Mercedes Benz's use an electromagnetic fan clutch, just like the one on an a/c compressor. Looks like a really sweet idea, 100% lockup when on, and 0% drag when off. Anybody tried one of these things? Here are some manufacturers: http://www.hortonww.com/products/products.asp http://www.warnernet.com/smartcat/s...collectionID=CF6336896ABD4CC29E739916943671AA
Why not just run an electric fan? THere would be no drag on the engine (aside from the slightest extra work the alt would do) when the fan is on. They are extremely effective and simple to install.
From what I understand, there are 3 drawbacks with electric fans: 1. They require another set of controls, relays, wiring, etc. 2. They don't move nearly as much air as an engine-driven fan can. 3. The additional alternator load can be quite large (+30 amps continuous), and there's a loss of efficiency going the electric route. Large trucks are using them because of the simplicity and efficiency: 0-100% lockup, and I think there are even some that do 60% lockup, for intermediate cooling needs. It's just something I came across, and was wondering if it had made it to the auto aftermarket yet. I like the idea, but the price is too high, as best I can figure, one runs about $200 or better.
How about robbing the clutch off of an A/C compressor? It probably wouldn't last with doing some type of duty cycle management (i.e. PWM) but you could have on or off control. Just an idea.
I took a quick looked at that, but I don't know how you'd do it without some serious machining, but I may have overlooked something. I wouldn't think the cycling would kill one, at least one off of a newer a/c system, since they cycle all the time. Hmm... uzzled:
I had a 1999 GMC 1 ton turbo diesel van for work and it has a standard fan clutch but it locked up at idle and low RPM's and released when the RPM raised and behaved like a normal fan clutch. You could look into those.
Clint - Wow! Lotsa info there, quite a reading experience...Thanks! Michael - I'll look into one, Thanks for the pointer! :TU: :TU:
From O'Reilly Parts online: 1999 > GMC TRUCK > G3500 VAN > V8-400 6.5L Dsl > HDN Thermal Fan Clutch 1 per car. Part number = 2839 $185.99, Core = N/A Availabile, call store COUNTER CLOCKWISE - SEVERE DUTY w/TURBO DIESEL w/HIGH OUTPUT O.E. TYPE LIMITED LIFETIME WARRANTY I've suddenly gone brain-dead about which way a Buick engine rotates - anybody? Also, my local store doesn't have on on hand to compare mounting flanges, etc :rant: .
If its say counter clock wise it probably a newer serpentine belt system with one big belt that snakes around. You have a vbelt system right?
That's what I was thinking...but now I remember that my v-belts are going around clockwise, ie, the load is on the "top" of the a/c belt, the slack side is the "bottom", for CW rotation. Wonder what makes it direction-of-rotation dependent? Prolly has a one-way centrifugal clutch...darn.
it could be possible if you could get a really long belt and change the fan to v belt. You would have to run the belt backwards around the fan , then down around the crank. I have seen v belt system where the belt did run around backwards with no ill effects.
Not on a car but mower deck for riding mowers use v belts and the run around backwards n snake around. Maybe find a belt shop or check a mower shop for one long enough.
Well, that'd be a lot more trouble than benefit, I'd think...can't see how to get from "here" to "there" with the v-belts. There is the serpentine belt route, though, and that's looking like a going deal! Till then, think I'll just stick to what I've got. Summer's mostly over for now, so heat's not such a concern. Until April. :TU:
