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Post by Chuck on Aug 13, 2007 16:41:00 GMT -5
A 100% duty cycle alternative to the Bosch relay is the ST85 (from Napa) or GP Sorensen SF74 (from Advance). They look like starter relays, but they've got better cooling and enough current capacity to handle these fans. Can usually get 'em for $15 or less, if I remember right.
As an aside -- if you're not running at least 30A worth of fan, you're probably way below target. The Taurus fan draws about 35A on high speed. Aftermarket fan manufacturers will try and sell you on low current draw as a "feature", but it's snake oil. They're not running some magically super-efficient new electric motor, and their blade design isn't that much better than the factory (in fact I'm sure the factory has put more money into blade design research). Your current draw is almost a direct measure of the amount of air you're moving.
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Post by Deleted on Aug 13, 2007 17:53:26 GMT -5
Chuck, you're always more knowledgeable about electric currents than I am, but I'm of the understanding those relays won't work for continuous cycles such as an e fan. I know people that have been in trouble because those things aren't designed for continuous current, and it left them stranded rather quickly. That's why I recommended the Bosch 75 amp relay, and you can get one that already has a diode built in to it.
And the Taurus/Volvo fan, ya they draw at least 35 amps, and double that on start up, which is why you'll need the good relay. But enough of that from me, there's a day's worth of reading up on it on corral.net
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Post by CORE 4WD on Aug 13, 2007 20:23:14 GMT -5
Ok guys here's the deal. You know that heat spell we had last week? It was the same stuff (only hotter) last year when we did the cooling system build up. It ran cool standing still, in my garage and down the road. The SPAL fan is specific for this application with 99% fin coverage. A high power (210 amp I'd have to check my records?) alternator powers two 1200 CA Odyssey batteries, providing plenty of juice to the fan. The radiator is an aluminum (Ron Davis?) large capacity unit. The t-stat is 180* although I don't believe it's a Shaw. Need to change that. Auto tranny isn't plumbed into tank either. Water pump that came with Jeg's crate engine was changed to the correct side outlet/inlet. Flogging it on the rocks at Crozet or crawling might get it to 200* but it will drop right back down to 180-190*. The issue came up while driving around town at mid throttle, just cruising around. Possibly a lean condition. There is no pinging at all under accel or light throttle so I think it's not too far advanced. Could possibly try richer primary jets I suppose. Seems to "get it" pretty good when floored. Haven't pulled the plugs yet to check color either. SO having gotten all that out there, any takers? ;D
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Post by Deleted on Aug 13, 2007 20:58:49 GMT -5
Well here I am trying to help out with a problem that isn't a problem. Duh. If you're not getting over 200 at Crozet, then it's not a fan issue. I can help pull plugs, but I'm lost when it comes to tuning carbs, sorry! I still wouldn't think you'd be lean at part throttle, enough to cause it to heat up. I'd start at the t-stat and make sure the waterpump belts are tight, then go from there. Sounds like it could also be a flow problem, which that Shaw might take care of.
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Post by CORE 4WD on Aug 13, 2007 21:33:24 GMT -5
Yea really need to dyno, VaSpeed hiked their prices immensely...
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Post by Chuck on Aug 14, 2007 11:10:11 GMT -5
Chuck, you're always more knowledgeable about electric currents than I am, but I'm of the understanding those relays won't work for continuous cycles such as an e fan. I know people that have been in trouble because those things aren't designed for continuous current, and it left them stranded rather quickly. That's why I recommended the Bosch 75 amp relay, and you can get one that already has a diode built in to it. And the Taurus/Volvo fan, ya they draw at least 35 amps, and double that on start up, which is why you'll need the good relay. But enough of that from me, there's a day's worth of reading up on it on corral.net Regular starter relays definitely won't hold up to continuous useage for an E-fan. I've seen a few friends on the fullsize Bronco board kill 'em. So far my sources say this one is continuous duty rated, though. Looks like a starter relay, but the internals are different. I'm certain the NAPA ST85 is continuous duty, and the GP Sorensen SF74 cross references for the ST85 and lists as continuous duty also (though I don't know anyone personally yet who has run the GP one to verify). The NAPA unit is pretty popular for this, and I've seen it used for other long-use applications like transbrakes and electro-hydraulic power pack units, too. Any of the three will work, though (those two or the Bosch one). Ok guys here's the deal. You know that heat spell we had last week? It was the same stuff (only hotter) last year when we did the cooling system build up. It ran cool standing still, in my garage and down the road. The SPAL fan is specific for this application with 99% fin coverage. A high power (210 amp I'd have to check my records?) alternator powers two 1200 CA Odyssey batteries, providing plenty of juice to the fan. The radiator is an aluminum (Ron Davis?) large capacity unit. The t-stat is 180* although I don't believe it's a Shaw. Need to change that. Auto tranny isn't plumbed into tank either. Water pump that came with Jeg's crate engine was changed to the correct side outlet/inlet. Flogging it on the rocks at Crozet or crawling might get it to 200* but it will drop right back down to 180-190*. The issue came up while driving around town at mid throttle, just cruising around. Possibly a lean condition. There is no pinging at all under accel or light throttle so I think it's not too far advanced. Could possibly try richer primary jets I suppose. Seems to "get it" pretty good when floored. Haven't pulled the plugs yet to check color either. SO having gotten all that out there, any takers? ;D Are you running vacuum advance on it? If not, that may be your problem. Running retarded timing at part throttle will dump a lot of waste heat into the coolant through the walls of the exhaust ports. You might find a little spark tuning will get rid of a lot of the problem ... |
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Post by CORE 4WD on Aug 14, 2007 14:18:23 GMT -5
It runs vacuum advance. Need to check and make sure it's working properly I suppose. The fan gets it's juice from the batteries via a heavy-duty relay that is tripped on via a switch on the dash...
Dave
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Post by Chuck on Aug 15, 2007 8:54:50 GMT -5
How much vacuum advance, when does it come in, and what's your cruise vacuum?
What ignition system are you guys runnin' on that thing, anyway? I know the stock Duraspark systems are very tunable and adjustable (have at least some flexibility in tuning both the mechanical and vacuum advance curves stock, without even having to by a tune kit).
How was the timing tuned? Sticking with the example of the Duraspark system, the stock distributors come with an advance plate with two stops (usually something like 20* and 30*), but they're almost always on the bigger advance stop with a really stiff advance spring. If your timing was set based on ping at a higher RPM (like 3500 or so), you're probably low on base timing. If you flip the advance plate to the other stop and bump up your base timing, you can up the timing across the entire low end (and improve both mileage and cooling) ...
Of course that's just an example, since I don't know yet what you have or where it's set... Actually that's exactly what I need to do with the 250 when I have some time. Right now I've got the base timing and vacuum advance set about right (right enough to get 11mpg out of a non-OD four barrel 351W brick of a pickup on 31's!), but I ping at over 3500rpm on full throttle. I already know my advance plate is set at about 35*, and 3500 is about where the mechanical advance passes 20*.
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Post by CORE 4WD on Aug 15, 2007 20:00:27 GMT -5
Haven't checked that yet.
I think the t-stat needs to be a Shaw, just cuz they're supposed to be the best for flow and reliability. I'm wondering if the one that's in it may be partially stuck.
I'm also wondering if, at speed, the engine bay isn't getting enough hot air out for some aerodynamically-induced reason?
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Post by broncobilly on Aug 15, 2007 20:04:19 GMT -5
How much vacuum advance, when does it come in, and what's your cruise vacuum? What ignition system are you guys runnin' on that thing, anyway? I know the stock Duraspark systems are very tunable and adjustable (have at least some flexibility in tuning both the mechanical and vacuum advance curves stock, without even having to by a tune kit). How was the timing tuned? Sticking with the example of the Duraspark system, the stock distributors come with an advance plate with two stops (usually something like 20* and 30*), but they're almost always on the bigger advance stop with a really stiff advance spring. If your timing was set based on ping at a higher RPM (like 3500 or so), you're probably low on base timing. If you flip the advance plate to the other stop and bump up your base timing, you can up the timing across the entire low end (and improve both mileage and cooling) ... Of course that's just an example, since I don't know yet what you have or where it's set... Actually that's exactly what I need to do with the 250 when I have some time. Right now I've got the base timing and vacuum advance set about right (right enough to get 11mpg out of a non-OD four barrel 351W brick of a pickup on 31's!), but I ping at over 3500rpm on full throttle. I already know my advance plate is set at about 35*, and 3500 is about where the mechanical advance passes 20*. Do you have any free time to help sort this mees out? |
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Post by Chuck on Aug 16, 2007 8:53:15 GMT -5
I can find some in bits and pieces. I'm going to be out of town this weekend, but I should be able to help ya out next week, as long as you don't mind doing a little wrenching after dinner time (I'm working 11 hour days for the next month, so my weeknights I don't get off until 7:30 right now). I think I'm still fairly free next weekend too, so whatever works best.
Besides, I haven't gotten much of a chance to check the beast out in person yet. So yeah, not going to take much arm twisting to get me to help out. ;D
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Post by broncobilly on Aug 19, 2007 16:30:17 GMT -5
I can find some in bits and pieces. I'm going to be out of town this weekend, but I should be able to help ya out next week, as long as you don't mind doing a little wrenching after dinner time (I'm working 11 hour days for the next month, so my weeknights I don't get off until 7:30 right now). I think I'm still fairly free next weekend too, so whatever works best. Besides, I haven't gotten much of a chance to check the beast out in person yet. So yeah, not going to take much arm twisting to get me to help out. ;D Thanks. I am going to take a look at some issues starting Wed 22nd and the following weekand if that is good for you. Just let me know what you can do and I'll try to work that into my schedule. |
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Post by Chuck on Aug 20, 2007 9:58:29 GMT -5
This weekend's looking best. I'm starting the week tired already (just got back from a run out of town), so I'm thinking sleep is my best plan on weeknights this week. But my other plans for this coming weekend (helping my roommate's girlfriend lay some hardwood flooring) are getting delayed by the material delivery date, so it looks like a good weekend for wrenchin'. ;D
Where's this beast located right now, anyway?
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Post by broncobilly on Aug 22, 2007 19:56:25 GMT -5
Located at my house which is 100 yds away from dave p.
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Post by Chuck on Aug 23, 2007 18:08:24 GMT -5
::scratches head:: Haven't actually been out that way yet. Can you PM me an address so I can snag some directions? I'm still trying to figure out when will work best this weekend, only time I'm tied up for sure is Saturday after noon. What's best for you (and do you have any no-go times)?
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