Dual electric cooling fans

[ForceFed70]

Hi guys,

I'm in the process of setting up my Megasquirt EFI controller to run some cooling fans for me.

I think I want to go with a dual fan, 2-stage setup. Meaning the 1st fan will come on at about 190* engine temp, the second fan will come on at 200* engine temp.

I'm going to use pusher fans as part of the reason I want to do this is to make room for a supercharger/turbo install sometime in the future.

So my question is what do you guys think is a better combo? Dual 12" fans (approx 2500cfm total) or a single 14" fan and a 12" fan (about 2800cfm). Due to space limitations, this is the largest I can go (radiator is 25"x15")

Obviously the extra cfm is a good thing. If I do go with a 14" and 10" fan...which fan do you think should be primary and which one do you think should be secondary?

 

[WORTH]

Personally I don't like electric fans, but if you have to use them, do not have them come on at 190 degrees or they will be running all the time, the primary should come on at 210 at the lowest, and the secondary at 230.

 

[ForceFed70]

Personally I don't like electric fans, but if you have to use them, do not have them come on at 190 degrees or they will be running all the time, the primary should come on at 210 at the lowest, and the secondary at 230.

Hmmm... that may be a problem. Over 215* the megasquirt ECU goes into falt tollerant" mode (it thinks the sensor is busted) and pretends the temp is 170*.

I should be able to bump that up to 200 and 210 tho.

 

[iskwezm]

i dont think the extra CFM is that important, the more surface area your fans cover the more air you can push through the core to cool it. I have 2 16", push/pull and run both constantly, but sometimes turn the pusher off on the freeway

 

[ForceFed70]

i dont think the extra CFM is that important, the more surface area your fans cover the more air you can push through the core to cool it. I have 2 16", push/pull and run both constantly, but sometimes turn the pusher off on the freeway

How did you get a 16" fan in the front? Do the earlier models have a larger radiator or something? I've only got 15 (maybe 15.5") of vertical room on the front side.

I'll have to do some math and see which combination results in the most surface area.

 

[WORTH]

Hmmm... that may be a problem. Over 215* the megasquirt ECU goes into falt tollerant" mode (it thinks the sensor is busted) and pretends the temp is 170*.

I should be able to bump that up to 200 and 210 tho.

Damn, what do they want you to use for a t-stat with that setup? I've never heard of an EFI that liked to be cool. Most of the OEMs are turning the fans on at 220.

 

[WORTH]

i dont think the extra CFM is that important, the more surface area your fans cover the more air you can push through the core to cool it. I have 2 16", push/pull and run both constantly, but sometimes turn the pusher off on the freeway

cfm is everything, that is the amount of air it will circulate threw the radiator, the more cfm the more heat transfer.

 

[iskwezm]

cfm is everything, that is the amount of air it will circulate threw the radiator, the more cfm the more heat transfer.

I understand that, but what good is a fan in the center of the core, some of the core wont get any air pushed through....so what is better a little less CFM but covers more of the core or more CFM but less surface area covered.A couple hundred CFM is not gong to make that much of a difference.

 

[ForceFed70]

Damn, what do they want you to use for a t-stat with that setup? I've never heard of an EFI that liked to be cool. Most of the OEMs are turning the fans on at 220.

Yeah, I've got to look into this. I read it on the megasquirt discussion forums, but it doesn't make much sence. I'm sure there's a way to change this (you can change just about everything in the megasquirt) I just have to look into it.

I'm running a 180* T-stat, but it's the same thermostat as when I had it carbed.