Fan Delete Information - BMW Forum

Kevin325i · 05-22-2004, 11:39 PM

Ok, so tomorrow I'm planning on accessing this fan deletion and if all looks good I will get it done tomorrow. I've got a few questions though.

Left hand screws?

How much shorter screws am I going to need?

What exactly is this switch I'll have to be adding?
How much will it cost?
Where should I put the switch?

Anyway I can check if my current fan even works?
When is it even supposed to kick on?

Has anyone actually done this? How hard was it to do?

Well, in any case I'll probably end up doing it anyways tommorrow. I'll post pictures and instructions for a possible DIY.

Kevin

dutchbmw · 05-23-2004, 09:02 AM

Remove the v-belt driven fan, and install an electrical fan? PM autotechnica, he did the same!

Kevin325i · 05-23-2004, 12:39 PM

Ok, I've ordered the kit from www.understeer.com. Should be here later this week. I'll post up some pictures and a how-to when I get the stuff.

If you're planning on doing this don't get your hopes up like I did, and assume the stores in your area will have what you need. I recomend just ordering it online.

Kevin

dutchbmw · 05-23-2004, 02:23 PM

I look forward for your DIY pics. Always interesting to see how people fix things!

Kevin325i · 05-27-2004, 10:11 PM

Ok, so I got the stuff put together/ taken out. Haven't had a chance to test anything really. My little gas guage goes higher than it did before the mod though. So far the needle hasn't moved off of the middle temp indicator. I left it sitting in the driveway with the AC full blast for about 10 mins, didn't even flinch. Works awesome.

If you're interested go to www.understeer.com.

Also, the fan weighed in at 5 lbs

Kevin

dutchbmw · 05-28-2004, 11:07 AM

Nice site 'understeer.com'. What was the outside temperature? Everything looks OK so far!

Kevin325i · 05-28-2004, 10:40 PM

Today the outside temp was about 75, the temp gauge went barely beyond the 12 o'clock position. Also the engine seems to rev a little more freely, but I doubt there was much of a power increase. Every little bit helps though.

Kevin

jllphan · 05-28-2004, 10:59 PM

You've posted threads on this topic before but I missed it. Why did perform this mod? Is it just a weight reduction thing?

Kevin325i · 05-28-2004, 11:05 PM

Basically because I can. But less drag on the engine is the main reason. Anytime you can reduce the rotational mass on the engine you can improve performance. IE lightweight flywheel, underdrive pullies (don't actually reduce the mass you're turning but let the engine spin more freely), AC compressor.

Kevin

jllphan · 05-28-2004, 11:10 PM

Gotcha. Your just reducing the stress normally induced by the extra fan that would rob energy from the engine. Cool.

Speaking of cool, lemme know your temp gauge reacts to a day of 90 degree weather. That is a mild summer day down here, and performing such a mod for a climate that is so f@#king hot and humid in the summer.

Kevin325i · 05-28-2004, 11:19 PM

Yeah it's super humid here normally. Days like that probably won't be around for about a month but I'll let you know when it does.

Anything I've ever read from anyone is that this set up works awesome. They've never seen the needle move off the 12 o'clock position. And the only time the cooling efficiency is actually decreased is below 10 mph (or so understeer.com says)

Another option would be a high CFM aftermarket fan or reinstall like they say. It's pretty easy to do, but I don't think I'd want to swap it in and out.

Anyone know what the CFM rating on the stock electric fan is?

Kevin

dutchbmw · 05-30-2004, 04:24 AM

Quote:

Originally posted by Kevin325i@May 29 2004, 06:59 AM
Anyone know what the CFM rating on the stock electric fan is?

No idea on that.

But when you're driving the OEM fan is also driven by the air that blows through the radiator. This means it doesn't need energy from the engine! Only when the car stands still, the fan decreases the HP........!!?

Kevin325i · 05-30-2004, 09:42 AM

It's really only decreasing power at slower speeds because once the fan clutch has started to turn it spins quite freely.

But it's more mass that the engine has to get turning before you can get going. It's just drag really, and so far there's been nothing close to overheating so I'd say it was well worth it.

Think of it this way. If you're pushing a car into a garage at first it's really hard to get it moving. But once it gets rolling it's quite easy to push. Basically the same thing, less for the engine to get moving.

Kevin