Fan Delete, 1997-1998 2.8L Z3

[DuWop]

(" the AFRs under almost every condition is a steady 14.4:1, Randy F ") Randy --that's way too lean for WOT

I was thinking that sounds a bit strange.

A rich mix burns slower than a lean mix, effectively decreasing the probability to knock.

I had an engine that at 14.7:1 (best it could maintain it, sloppy system) built up a little carbon on the plugs. I adjusted the AFR to 14:1 and the plugs stayed clean. I'm guessing the engine was misfiring when the AFR drifted leaner than 14.7:1.

My mpg increased by 10% at 14:1. I guess misfiring at round about 14.7:1 caused the lower mpg. Just a guess. I had no need to worry about the cat on that engine (off road).

[green racer]

Yes. I run a supercharged S52 with a fan delete. Everything else is stock, save the aluminum radiator. Literally removed the fan and closed the hood.

Is this all it takes?

Sent from my iPhone using BF.com

[DuWop]

Is this all it takes? Sent from my iPhone using BF.com

Works for /.randy, but my situation is a little more involved. You may want to read the entire thread closely.
Due to low oil pressure (40 psi max with 5W 30 oil), and using 87 octane E0 fuel, I'm going with the 180F thermostat, the lower temperature fan start temperature switch (177 F), and 10W-40 (Recommended by Mobile 1) for the 2.8L engine) Mobile 1, advanced full synthetic, for high mileage engines, official motor oil of NASCAR.

It will be interesting to see if my OEM water temperature gauge moves from the 12:00 O'clock position.

I currently have 4 gallons of slightly used synthetic oil of the wrong viscosity for the 2.8L engine. When I discovered the low oil pressure problem I changed the oil from 5W-30 to 15W-50 (knee jerk reaction to the low oil pressure).

When My Z3 was due for an oil change I did my homework. Everywhere I looked 5W-30 was recommended and the previous owner used 5W-30. Bad advice. 10W-40 should be perfect, I hope. I won't know for sure until next summer after running the engine hard.

[steve f]

Is this all it takes?

Sent from my iPhone using BF.com

Most people change to a low temp fan switch and thermostat at the same time. Water wetter has also been recommended, but I see some good argument against its use.

I did the fan switch only on the 98 M when I deleted the mechanical fan. It worked out fine and the engine temps run normal, but will consider the lower temp thermostat when I work on the cooling system this winter.

[rf900rkw]

Some seem to thing the fan switch measures engine temp. It does not. On all three of my 6 cyl cars, fan removed and close hood. No thread covers, no lower thermostats or fan switches, no pink jello. 30% antifreeze (rarely gets below 20F here). And drive.

[kojohns]

Some seem to thing the fan switch measures engine temp. It does not. On all three of my 6 cyl cars, fan removed and close hood. No thread covers, no lower thermostats or fan switches, no pink jello. 30% antifreeze (rarely gets below 20F here). And drive.

I'm actually thinking of going back to this setup... I went with the trio of lower 80C/176F thermostat, lower 80/88C fan switch, and water wetter mixture... I feel my engine runs too cold now. Oil temps never-ever break 200F... sits happily around 180-190 on my middle gauge in this pic, but thinking my engine would be happier slightly warmer? or is that just my own issue of the needle not being in the middle between the 200F and 260F tick marks?

[green racer]

Thanks for the replies.
I've decided I'll go with rf900rkw's recommendation.
So this weekend the fan is coming off, I am closing the hood and going on a road trip to the hills.
I'll see how it goes from there.

[coolguy147]

Previous owner of my 2.3L basically just changed the coolant out, pulled the fan and clutch, and put in some water wetter. I've never seen it overheat in FL.

[DuWop]

Learn from my mistakes.

Today I put a new sub folder in my Z3 folder titled "Aw Sh*t". My money and effort is returning this car to the stone ages. I installed an inferior water pump with a roughly cast aluminum impeller and removed the BMW water-pump with a stainless impeller that apparently a previous owner installed. I assumed the original OEM pump with a composite impeller was was still in the car. I don't know how many miles is on the BMW pump I removed but I'm putting it back in the car.

The inferior pump along with the inferior 180 F thermostat I'm installing would cost considerable engine efficiency/HP/petrol. High drag, low efficiency impeller, and excessive needles coolant engine re-circulation flow.

This link is to a picture my new radiator vent line, installed around a month back that I discovered had cracked. I dug the 15 year old OEM vent line out of my junk pile. It didn't have any cracks. I was told by the sales dude at BMP Design that their parts were OEM/Manufactured by the companies that made the original parts. BS!!!! I became suspicious when I un-boxed the hoses and found they were manufactured by various companies. Unfortunately I threw the bags/labels away. Link to a photo of the cracked vent line. https://www.facebook.com/photo.php?f...type=1&theater

Link to (cracked vent line) hose kit:
https://www.bmpdesign.com/product-exec/product_id/4666

Link to the new 198F (OEM temperature, Standard Thermostat 92 Degree Celsius. Recommended for cooler climates. ) thermostat I installed (Vendor BMP Design). It's stainless and it appears to be designed similar to the OEM thermostat, so maybe it meters engine re-circulation flow. I was told it fails open. Maybe it does: https://www.bmpdesign.com/product-exec/product_id/2345

Link to thermostat with an opening temperature of 75 degree Celsius / 167 degree Fahrenheit. (Vendor BMP Design). It's stainless and it appears to be designed similar to the OEM thermostat, so maybe it meters engine re-circulation flow. In my opinion 167 F is to cool but it may be OK with some: https://www.bmpdesign.com/product-ex...ch_model/flash

This is the (BECK/ARNLEY Part # 1430700 Alternate Temperature 180 F) thermostat I bought. It appears that it does not meter engine re-circulation flow which will cause a loss of efficiency. Unless I can find an OEM equivalent 180 F thermostat I'll install this one. http://www.rockauto.com/catalog/more...766&cc=1313663

This is a link to the water pump I installed. I'm happy to be rid of the composite water pump pulley but I don't like the cast aluminum impeller. I thought the pump would be OK but after giving it more thought I regret my decision.
https://www.bmpdesign.com/product-exec/product_id/8462


EMP = EXTREME METAL PRODUCTS
I wish I had bought an EMP Stewart Performance Water Pump (Manufacturer Part number not stated in the ad) $179.95 (I think the will ship this free)
Proceed with caution. I do not trust BMP Design:
http://www.bmpdesign.com/product-exe...earch_model/64



Amazon.com EMP Stewart Performance Water Pump (

Manufacturer Part Number

30330)

$195.00 + $5.99 shippinghttp://www.amazon.com/EMP-Stewart-Hi...productDetails

A good water pump/plastic pulley discussion. http://www.bimmerfest.com/forums/sho....php?p=5305654

Hind sight is 20 X 20. How come a person doesn't know what they should have done until after they did it?

[steve f]

Some seem to thing the fan switch measures engine temp. It does not. On all three of my 6 cyl cars, fan removed and close hood. No thread covers, no lower thermostats or fan switches, no pink jello. 30% antifreeze (rarely gets below 20F here). And drive.

The only car I have that still has the clutch fan is the M54. I have not removed it because there is no lower temp option for the thermostat. Based on the experience you shared, someday, I'll go ahead and remove the clutch fan on that car and not be concerned about changing to the lower temperature thermostat on it or the S52. I like the idea of continuing with the engine operating temp the car was originally designed to use.

I'll stick with low temp fan switch on the S52 and may install one on the M54, just for the increased low speed heat rejection through the radiator. I don't see much harm in that other than a little increased load on the electric fan.

[DuWop]

They are watching us http://boardreader.com/fp/Bimmerforu..._8_537204.html

[Randy Forbes]

... Randy -- that's way too lean for WOT, and too rich for normal cruise. 14.7 cruise or you will destroy the cats; WOT into the 12s.

I haven't checked the fuel trims lately (I doubt I've put 200 miles on it since the swap) from all types of driving conditions, to see if it's trying to compensate. I'd like to get it fine tuned on a dyno, but mine, like everyone else's time, is scarce.

I'll make a greater effort to get it done. In the meantime, I have to figure out how to get RPMs to log on my LM1, then I might at least be able to get a temporary fix via E-mail...

Thanks for the warning though, I have the highest respect for your opinion, just wish we lived closer together!

[rf900rkw]

Pin 1 pin the diagnostic 20 pin port. It's a nice 12v square wave, three pulses per revolution.

[Coppock]

That's the right part and should fit the radiator. I have that in my 2.8. You will have to trim off a small tab inside the plug for your plug to fit the new switch, though.

What you mean trim off a small tab inside the plug?

[Migou]

I removed the clutch fan and installed an electric fan. I put the lower temp switch in the lower radiator hose. Left the regular switch in the radiator. I did that because 2 switches failing is slim. Overkill maybe. It makes me feel better.

[43bullet]

reviving the thread....

thoughts on aux fan and clutch fan delete with installation of spal electric fan wired to aux fan wiring?

[deni2s]

reviving the thread....

thoughts on aux fan and clutch fan delete with installation of spal electric fan wired to aux fan wiring?

Don't think it's a good idea. Aux fan with spal puller as comment above yours IMHO is the best option. Actually I am waiting for all parts to arrive to do the same ASAP.

[Tim95M3]

Oh man. This topic again!

[K&B.21]

Yes. I run a supercharged S52 with a fan delete. Everything else is stock, save the aluminum radiator. Literally removed the fan and closed the hood.

I like your style. May I ask a question. I don't get to much into all the tech stuff, I like your simple answers.

My USA 97 z3 "2.8", If I remove the clutch fan, is there a flex fan available that you might know of. (Sorry I come from V8's) so I know it as a flex fan.

Flex fans are usually alloy bladed fans without a clutch that bolts directly to the engine's water pump/belt driven in place of a clutch fan.

They are designed in two different ways for flexing "Low rpm and high rpm for differing driving conditions.

One, as the engine rpm goes up the blades flex to change the pitch and suck more air through the radiator. lots of drag at crusing rpm but Good for 1/4 mile racing.

Two and the one I would like to find, a reverse flex fan, at low rpm the blades are at max pitch for full air flow through the radiator at low rpm "Stop and go traffic), then as engine rpm raises, the pitch flattens out, less air flow at high rpm (Highway speed where a fan is not really needed), less drag at high rpm. Great for highway and stop and go. Less drag on the highway and mega cooling in stop and go traffic.

I would like the latter for highway use. Just wondering if flex fans are an option, or known of. I contacted Flex A Lite Fans, just waiting for a reply.

Figured you guys on here would know. I somewhat want to keep the engine fan "Well a flex fan" that is.

Soon I will be removing my A/C, and such, most likely will remove the electric fan as well. Just wondering if that is even an option.

Thanks in advance and I know it's an old thread.

DSCN4326.jpg

[BimmerBreaker]

Never heard of that type of fan for a BMW. Never heard of that type of fan at all, though im a diehard BMW guy

I would posit that the fan's clutch serves the purpose of what you describe, except better. A fan clutch will lock up and engage the fan whenever it gets hot enough to need it, so it isnt RPM dependent it is temperature dependent. It will disengage at highway speeds or when temps are low enough, it will lock up and engage when idling to help pull additional air through radiator to cool.

The electric fan in front of radiator is not just for A/C. That is your main cooling fan too. I would advise AGAINST removing it. You can delete your A/C and leave the aux fan in place.

[K&B.21]

Thanks I understand clutch fans, electric on the other hand not so much.
I figured when I removed the A/C I figured the wiring would be all messed up for the electric fan. I'm glad I posted about removing the electric fan, I assume removing my A/C won't hinder the electric fan. Great.

The reason for the Flex Fan is because I live out in the middle of nowhere, so I am able to really drive upwards 130 plus for miles on end, so I figured might as well have a solid mounted fan for the "slow downs". Like I said I come from V8's Chevy's, everything is a learning curve with this BMW being new to me. Love it just the same. I'll be doing the fan delete tomorrow after the test pipe job. Turner shortys, and mild cams and a stage 1, to come soon. I just want to get at least 225ish HP. Highway driver, just to be able to make passes of trucks easier is all.

The welds in the trunk and underside are in great shape. You all had me worried about the diff mount, "Keeping me up at night" Just playing. But I am keeping my eye on the under side.

I noticed the pulley has 4 bolts so if I do decide to put a flex fan, I know I can, that's what I was worried about. I probably won't put a flex fan on now, after really reading this thread and some others. And your info on the A/C I figured the wiring and A/C worked together. I figured unplugging the compressor would break the circuit. For lack of better words.

Thanks 100% It's a learning curve coming from v8 hot rods "1/4 mile cars to roadsters.
Below is a flex fan. certainly won't shred apart. I probably won't use one, Thanks!!
81VzjoAc5NL._AC_SL1500_.jpg

[BimmerBreaker]

BMWs were built to cruise the Autobahn. At high speeds you will have plenty of airflow cooling things up front and the fan clutch will disengage. This minimizes how much horsepower it is sucking from the system whereas a fan mounted directly to water pump as you describe will rob power regardless of airflow and speed. How much is a fan helping airflow at 130mph anyways? It would seem to me the fan clutch is a better system, especially for higher speed driving. A lot of people also simply delete the clutch fan and clutch, some supplement that with a lower temp fan switch mounted in the radiator to trigger the electric aux fan to come on earlier

Removing the compressor from the circuit has no effect on the functionality of the aux fan as a cooling fan