Shane

That is exactly how Hacker wired up the fans on my SuperShark.

PorKen

I think I'll get this one.

321959481 | 85-80/93-88c


I can't think of what the greater hysteresis (longer on time) would be good for, except that the second fan would stay on until below the threshold of the first?

251959481K | 85-74/93-82c

David L. Lutz

Glen,

I was thinking of using this relay connecting the sender to the grey wire (ground) which activates the relay.

http://www.spalusa.com/store/main.as...etail&item=FRH

Would I still need the diode? If so could you be a little more specific as to the placement of it. Haven't exactly done that before.

David L. Lutz

Here is the spec. on the relay.

http://www.spalusa.com/pdf/FRH_SPEC.PDF#view=FitH

GlennD

Dave,

Looking at the last page of the PDF specs, you see a device connected across the coil (terminals 85 and 86). This should be the snubber diode. Unfortunately, the manufacturer does not explicitly state what that device is (but if I was to guess ....). May be worthwhile dropping an email to the manufacturer or perhaps your supplier can confirm.

Google 'snubber diode' for an explanation of what the purpose is and how to connect.

whites.sdsmt.edu/classes/ee322/class_notes/322Lecture4.pdf

The diode would be connected opposite of what you think. A diode conducts current in one direction (follow the arrow as shown on the diode). So, positive flows from ------->|---------

Connecting the diode opposite (so the arrow is connected to the ground) prevents the diode from normally conducting. It then only conducts (e.g.: acts as a short) when the coils is de-energized.

This information is for those that wish to wire up their own relay and the relay does not come with a snubber. This saves those pesky induced voltage spikes into the car's electrical system.

Regards
Glenn

GlennD

Let me know if you want more details or a drawing. It would be my pleasure

Glenn

danglerb

Start current is about three times the run current, and with all the nasty back emf issues of inductive motors. Some after market fans advertise using the start current, so maybe some of them might work directly with the switch, or for awhile, but relay that can easily be replaced is the way to go.

If you use a relay rated at least twice the continuous running current, it will usually handle the startup current fine.

One advantage of a dual, or two speed fan, is the ability to start with one fan or on the low speed.

I could have this all wrong, but when I used IR and probe to measure radiator temperatures the return side tank was around 145 F, 85C is 185F, and 80C is 176F, that doesn't sound like it will work to me.

sharknoob

Any reason why you wouldn't want to use a variable speed controller it ramps up the start up to limit in rush and will run fan for 30 secs after car is off

David L. Lutz

Actually I am very much considering this one from Spal.

http://www.spalusa.com/store/main.as...tem=FAN-PWM-V3

But considering the expenses I have just had, I was trying to go a different route using just the relays and sendor.

danglerb

I think a variable controller is the "best" way to go, but the Spal will fry with any of the fans I want to use (max fuse is 30 amp). I have a DC Controls PWM on my 83, and while they seem to work perfectly for most "normal" applications I am still fussing with mine, and the vendor has no interest in sorting out new applications.

Drewster67

http://www.summitracing.com/search/B.../?autoview=SKU

danglerb

I wouldn't trust those fans or their ratings.

BeCool is a fairly respected brand.
http://www.summitracing.com/search/B.../?autoview=SKU

Three things a big factors in what the fan will flow, diameter, blade coverage, and amps. The first two are related to efficiency, and the last is the power.

David L. Lutz

I have very limited space issue on the '87. The 16" fan is mounting in front of the A/C condensor and in total I have less than 4" of clearence.

To date I have tried two Zirgo Fans and on one the shaft striped apart from the blade (this one being their Ultra HP model) and the other was a puller design that was not that high rated to begin with.

I have moved on to Spal hoping for better results, but am always open for new and better options.

The Spal (pt. # 30102047) is a pusher design and seems to move more air than the Ultra Zirgo. (spec. reads 20amps at full draw) I have only had the Spal installed for a couple of weeks now and its doing a fairly good job of keeping temps. down in very hot weather.

H2

I was disappointed w/the Zirgo fan I bought. It certainly doesn't push the air the advertisement claimed.

H2

UncleMaz

FWIW, I used a Flex-a-Lite brand fan on my jeep for years with 100% reliability going everywhere in every condition as a viscous fan replacement.