rsmith085

iTrader: (1)

Ok I've got an L03 powered Camaro. It has the stock electric fan that works just fine until I get into stop and go traffic with the A/C on and it'll start to run hot so I've got to shut the A/C off.

I got a 2 speed fan from a Mercury Cougar(thanks Car Craft!) outta the junkyard yesterday and have been thinking about how to get it to work 2 speed and with the A/C.

I think I've got it figured out just wanted some second opinions and to share my schematic with you guys. I'm gonna need two more relays(found a source for an 80a for the high speed) and another temp switch. I'm planing on using the Hypertec 4028 to turn on low speed(at 200) and the GNX switch I currently am running that turns on at 210 for the high speed. The sequence of operation is as follows

1 - car reaches 200 or A/C switched on will ground the low speed relay through the NC contacts of the switching relay

2 - car continues to get hot hits 210 the high temp switch will ground the switching relay removing the ground from the low speed relay and ground the high speed relay through the NO contacts of the switching relay that way both speeds of the fan can not be energized at the same time

Also any suggestions as to where to place the high temp switch? I plan on putting the low temp switch where the stock one is now(pass. cyl head) and have been thinking about getting a t-stat housing that has a spot to put the switch I've seen em before it's either 1/2" or 3/8" pipe thread.

l_dis_travlr

I think the schematic will work, if the high & low temp switches will work
as expected. One question though -- does the high speed really draw
80 amps? That is huge for a 12v system -- you're going to need some
really big wire to conduct that much current. Not to mention what is your
alternator capacity?

That issue aside, can you put the high temp switch in the other cyl. head

As an alternative, Dakota Digital makes a really nice programmable fan
controller unit, that might be worth looking into.

Good luck, and keep us posted.

kk

rsmith085

iTrader: (1)

According to the Car Craft article it pulls 42 amps on high speed. I ended up getting a Hella 70 amp relay from Amazon of all places for 5 bucks. Biggest relay I could find locally was a 40 amp, I figure better safe than sorry. Plus like all electric motors theres Full Load Amps(FLA) and Locked Rotor Amps(LRA). LRA at start up is very, very briefly 4 or 5 times the FLA.

I know for a fact the Wells SW510 switch(the GNX one) I got closes at 210. I put it in a pot of water on the stove(my wife is understanding lol) when I first got it and it closes right at 210 according to my meter. I hope the Hypertech one I'm getting is as accurate as it, I'm gonna do the same thing just to verify.

I've got the stock 100 amp Alternator so I should be fine there. I don't have any subs/amps or anything else that draws major current.

The other cylinder head has the sending unit for the temp gauge in it and the only place that goes into a water jacket on the intake has the sending unit for the ECU. I wish GM would of put two places in it like most aftermarket intakes it would make it simpler.

BTW I had to trim 5/8" off the shroud so the fan isn't as deep to clear the water pump pulley. This fan is a monster, it has a 18" blade and the motor is twice the size of the stock one. It's gonna have no problems keeping the 305 cool and when I start to tear into it and build the motor(hopefully next year) I'll have plenty of fan to keep everything cool.

I'm gonna swap it in and wire everything up over the weekend and I'll post some pictures and update yall as to any problems I run into.

edit - Thought I'd add this link I found where the fan was tested against some Spal fans at some lab and it shows current draw and cfm http://forums.corvetteforum.com/c3-t...pal-duals.html

one92rs

iTrader: (5)

here is an alternative that i have seen used with great results.

http://www.dccontrol.com/fancontrol.htm

rsmith085

iTrader: (1)

Well got it put in. Had to notch the bottom of the core support some so the fan would sit even with the top of the radiator. Also had to cut the two bottom corners of the fan at a 45, I filled them in with some strips of aluminum so all the air will come through the radiator. I ended up putting the high temp switch in the water pump as there was a 1/2" pipe thread there. This thing cools really, really good sitting in traffic yesterday with the A/C going I didn't get over 190 where as before it would start running 230+ so I'd cut the A/C off. I don't think I even need the high speed but it's there if I ever do. I'm gonna get some pics later on today and I'll post them this evening. I was able to do a real clean install, it looks almost stock except for the two top brackets I made to hold the fan.

rsmith085

iTrader: (1)

The high speed relay


The fan


The low speed(stock gray relay) and switching relay(from the jy so I could have the connector)


An overall shot


Like I said earlier this thing cools really good and if anything ever breaks I can head down to the local auto parts store and get parts for everything except the temp switches.