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240 High-Amp Alternator Belt Idler Pulley Project

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NEW CHANGE: I modified the bracket to move the idler up a bit and increased the belt-wrap to over 180 degrees. Still putting miles on it to see if anything breaks. Car is down for a few days now cause I had a condenser fan fail and I'm waiting for a new one.

I thought I would try a belt slip test using socket wrenches on the crank pulley bolt and alternator pulley nut. Doing that before with a stock setup showed tons of alternator pulley slip. Now I find that the alternator pulley is actually gripping slightly better than the crank pulley. Appears to be a pretty significant improvement.
Dave
 

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dbarton said:
So, discussion killer, I'd like to hear what YOU think a proper sized fan is. 15 inch 940? And why you think my fan is not proper. Remember that my fan is PWM controllered, so it runs as low as 20%.

The amp rating on that Derale controller makes me laugh (below). My current PWM controller is 125 amps.

So for example, my 240 mile drive yesterday from Austin to North TX in 100 deg mid-day heat included a nightmare 2 hour freeway closure. So during that 2 hour crawl my external temp reading went from 102 deg to 138 deg. My oil temp went from 200 to 250. Glad I had AC and I'm glad I DIDN'T have a 940 fan, or I guarantee AC would have to go OFF and I seriously doubt I could have kept the car from overheating without turning the heat on or simply getting off the road and shutting things off.
Dave
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I too have lived in extreme climates with a hot B2xx and AC. I never needed anything more than a reasonably sized fan (spal 12", volvo 940) in a proper shroud. Oil cooler, trans cooler on the auto car, big intercooler and anything from an aluminum aftermarket radiator, to a brass recore, to a new aluminum with plastic endtanks radiator. I never got hot. The AC never stopped working.


http://forums.turbobricks.com/showthread.php?t=325313

You consider this rube goldberg device to be PWM?
 
Lord_Athlon said:
I too have lived in extreme climates with a hot B2xx and AC. I never needed anything more than a reasonably sized fan (spal 12", volvo 940) in a proper shroud. Oil cooler, trans cooler on the auto car, big intercooler and anything from an aluminum aftermarket radiator, to a brass recore, to a new aluminum with plastic endtanks radiator. I never got hot. The AC never stopped ?
Click to expand...

Was this a 240 with a B21FT?
 
dbarton said:
Dual V-Belt
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Those are known in the HVAC industry as 'PowerBand' belts. That was the Gates name for them when they came out ~20 years ago. They are intended for use on a matched sheave in belt driven applications. My experience with them is in HVAC pumps and fans up to 250 motor HP. They come in widths of up to ~12 ribs or so. Great for running cooling tower fans and last a lot longer than individual belts.

They wouldn't be appropriate in this application as our belts sit down deep in the sheaves. To run a PowerBand belt you have to have the correct A or B series sheave. For us the belt would just ride on the peak of the pully between the two grooves and be quickly cut in half resulting in two belts.

Dave, have you though about adding a spring tensioner to the idler? In that case you would be able to run a fixed alternator mount and do away with the adjuster entirely.
 
Lord_Athlon said:
Thats a nice controller. I thought you were still using that cascading monstrosity.
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Yes, the Autocoolguy is the best thing I've found so far.

I made the cascading monstrosity before I discovered Autocoolguy. I made it more out of frustration because every available PWM unit I tried eventually failed after 1 or 2 years, usually far from home, in traffic or something.

The Autocoolguy I bought is 125 amps and it's what they recommended for a Mark VIII fan. They offer bigger ones than that for RVs or multiple fans. One cool feature I really like is the trimpot to adjust the AC fan speed, currently set at 50%.

If I start the car cold and let it idle, it eventually comes on in about 10 minutes at a very slow speed. You don't hear it come on usually, since it's slow and quiet until the sensor says it needs more.

The cascading monstrosity did the same tricks mostly, except it wasn't as smooth or as quiet. And since it regulated between only 3 different speeds, it wasn't as efficient.
Dave
 
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quillc said:
Dave, have you though about adding a spring tensioner to the idler? In that case you would be able to run a fixed alternator mount and do away with the adjuster entirely.
Click to expand...

No, haven't considered it. I'm not well versed in serpentines or tensioners, so for me it would probably be like finding a jelly bean in a pile of pea gravel in the dark.
Dave
 
I had a few of these made and powder coated and they're now available on a limited basis. So let's see if the interest was geniune. Final design pic below.

See more in my Alternator Page HERE:
https://www.240turbo.com/alternators.html#idler

Thanks, Dave B

idlerbracket12alo.jpg
 
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