My TBI E-Fan Adventure

[mistaake]

I'm in the process of replacing my traditional clutch fan with an electric fan setup in my 92 305TBI. I've heard that I can gain about 5-10HP and 1-2MPG, faster warm up times, better throttle response. and better AC at idle which is why I'm doing it.

My setup is using two 14" Hayden 3690 fans (I believe they are rated at 1200cfm in free space and 1000cfm when attached to radiator). These fit perfectly side-by-size since the radiator core is 28" across.

While I'm also using the Hayden fan controller, I'm not wiring it quite the same as they recommend. I've read a lot online about these controllers failing, the relays melting, etc. So rather than running the fans off the controller I got two separate relays that are actually powering the fan, while the controller is just turning those two relays on/off. This way I don't have to worry as much about the controller leaving me stranded, and if one of those two relays running the fans goes out, they are standard and cheap and hopefully still won't leave me stranded because I'll still have one working fan.

So far my install is going well - I have the rough wiring done, and one fan wired up to testing. I'm awaiting a few things, so I can't do the final install yet so no pics and schematics at this time, but I do have a problem I've run into so far. If I start the truck now that I have removed the old clutch/fan it seems that the pulley is not properly balanced over the water pump? I did reinstall the bolt/stud things. Do I need some washers to make up for the fact that I'm not bolting the clutch/fan back on? Currently it kind of vibrates and makes a noise.

 

[magimerlin]

Yes. You either need a couple washers or take the studs out and just use some short bolts. Alot of times the factory, and aftermarket, studs have a pretty long void in the middle(no threads) and the nut will tighten before it gets tight on the pulley.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[mistaake]

Yes. You either need a couple washers or take the studs out and just use some short bolts. Alot of times the factory, and aftermarket, studs have a pretty long void in the middle(no threads) and the nut will tighten before it gets tight on the pulley.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Hey, that's exactly what it is! There is a large unthreaded section. I'll put some bolts instead. Thanks!

 

[TylerZ281500]

why dont you just let the computer run the fans?

 

[mistaake]

Yes. You either need a couple washers or take the studs out and just use some short bolts. Alot of times the factory, and aftermarket, studs have a pretty long void in the middle(no threads) and the nut will tighten before it gets tight on the pulley.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Thanks, four bolts worked perfectly. No more noise!

why dont you just let the computer run the fans?

Uh, I don't think TBI ECMs have that capability. If my computer you mean Hayden fan controller, I've heard so many complaints of these controllers failing and the only reason I can come up with is all the amperage being pushed through it, and by running the fans on seperate relays I'm removing a lot of that load from the controller itself, and moving it to a standard, cheap relay that I can get for a couple bucks literally anywhere.

 

[TylerZ281500]

they indeed do, they have economy mode too. hayden sucks, i ran a jegs before i learned tbi computers can control them based off the cts sensor inputs.

 

[mistaake]

they indeed do, they have economy mode too. hayden sucks, i ran a jegs before i learned tbi computers can control them based off the cts sensor inputs.

So... how do I do it? I'd love to do it that way instead of the Hayden thing.

 

[TylerZ281500]

hop yourself on gearheadefi.com for tbi is your best bet, theres walk throughs. i couldnt tell you offhand cause its been a minute. vortec has a spot in the relay that you can turn on and off with hp tuners.

 

[mistaake]

Eh, I went ahead and pretty much finished my e-fan conversion using the Hayden controller, since I did some reading and I'm pretty sure the TBI ECM can't do it from the factory, and may require additional wiring and programming, which I'm not going to deal with. The final thing I need to do is wire the AC override - this controller has a wire for when the AC is on, to enable the fans, regardless of engine temperature. I'm not sure where the best point is for that - any ideas? In the mean time I did a quick-splice into a headlight wire, just so that if I needed to force the fans on I could, and it wasn't hot enough today to warrant AC anyway.

The only thing I need to do now besides the AC thing, tidying up a few more wires, finding a way to secure the temp probe to the radiator, and doing a better job holding in the radiator (the fan shroud used to hold it), is upgrade my alternator. With the AC on, the headlights on, and at idle, I'm almost at battery voltage. At idle in gear, I'm literally at battery voltage and I can see the display of the radio and climate control flickering. On the other hand, once I properly wire the AC wire to something besides the headlights, it's unlikely that I would ever need the AC and headlights at the same time - let's face it, you only use the headlights at night when it's cold. But I want reliability, and so an alternator upgrade is in the future, especially because I want to put in a modest sound system and maybe a light bar on the truck.

For the alternator, I should determine whether I have the "standard" 85A, "optional" 100/105A version or the "heavy duty" 120/124A unit. What's teh best way to determine which one I have, would the 124A unit be a good enough upgrade to run my e-fans, or is there something else I should consider?

 

[Blackwater]

Flexalite has one that fits GM GMT400. Flex-a-light 280.