The Heat is OFF (almost)

peter f · 02-13-2009, 08:43 AM

Well friends,

Whilst I'm working on that latest invention of mine (n345 - pics soon) with that HIGH R12S oil cooler temp readings (dense urban traffic), here's 2 questions for you:

Note: Fan (peak start-up ~ 7.1Ah) is controlled via a handlebar mounted Touratech switch + fuse + relay. Mode is strictly manual (I hate complexity). Fan is connected directly to the Odyssey PC535GS (adios OEM crap battery).

1. I want to trigger the relay via CAN-BUS in order to allow current only if the bike is switched on. Any ideas what to do?

2. Denso alternator...erm...hmmm...can we find information about the amount of current available at idle/very low rpm? (where the fan is required the most = dense traffic etc).

BMathison · 02-13-2009, 09:27 AM

I am sure it is not a manual system, but I'm pretty sure the RTP versions use a fan (or two). I would bet that they use a higher output alternator, but I would think that they would at least pick up a signal of when the bike is running vs not from the canbus, along with temperature.

This may be of no help whatsoever, but it's all I got.

RBMann · 02-13-2009, 09:28 AM

How about a couple of muffin fans? I don't know if they would move enough air but they might fit the space and look better too. This is the first link that came up when I Googled 'electric fans'. I don't know anything about the company, this is just an idea.

http://www.sofasco.com/dcaxial.html?kc=fyfGr&tsid=googleppc&gclid=CO-8y52L2pgCFQwxawodkBfvbA

Peter Parts · 10:01 AM

A manual switch is smarter than a thermostat because you can anticipate the need for cooling before a thermostat can, duh.

But given the longish time constants of a cooling system, I'd just get a surface mounted thermostat but with a manual switch over-ride parallel to the thermostat (that's a popular suggestion I made to the Maserati magazine a few years ago). The switch then can be used to turn on the fan in anticipation of needing cooling, like when you see stalled traffic ahead. Much to be said for wiring always-hot, see more below.

You can also use a switch with an indicator lamp for some valuable if trick information - but you have to think imaginatively about wiring to get it right. A flashing LED will also serve as a decoy burglar alarm. Gawd, some know-nothing will blast me for being "academic" if I go into any details about that here; of course, I could use some disguise like drunken spelling or down-home bad grammar.

The fan makes a lot of noise and so I wouldn't worry about forgetting the manual switch when you dismount, even if the thermostat has a big temperature hysteresis. Not bad for the fan to run after you get off and start walking away. If something fails some night, it will only fail once before you know better next time.

I gather you have in mind a 12 V, 7 A, 1/10 HP fan motor. With just a bit of onset rush and inductance in series, fan motors are reasonably kind to switch contacts and so you needn't unreasonably sweat about the switch ratings.

Likewise, in a warm country, not major issue running a 7 A device for 2-3 minutes to cool the little rad, even with the engine off. To get some perspective, you could see how happy your battery is powering a headlamp, roughly the same power ballpark.

BMathison · 02-13-2009, 09:44 AM

Back in my racing years, we found that the most failsafe mode was to run the manual and thermo controlled fan units in parallel like you have already said. There were many times sitting on the grid that you knew the fan was going to be needed so you manually switched it on, but while driving in anger it was not something you ever thought about. It was those times that the thermo controlled switching came in handy.

I could see this happening on a street bike also.

SergioK · 02-13-2009, 10:16 AM

Is that the type/design of fan you are going with? I think you'd be better off with two smaller box fans. Check out the 2nd page of this thread: http://www.bmwmoa.org/forum/showthread.php?t=31296 There are photos of two side by side 4" puller fans. Absolute Radiator part #30103018

As for question #1, the easiest way to trigger a relay for the manual switch is via switched power only and the closest thing up front to tap would be the headlight. I doubt the canbus would notice the extra draw from the relay - light bulbs end up pulling more amperage as they age anyway.

PFFOG · 02-13-2009, 10:45 AM

Here is a great place to get box fans, they have several 12v styles, also sell the small button type thermal-switches.

http://www.allelectronics.com/make-a-store/category/220/Fans/1.html

Kieran R1100S · 01:50 PM

Apparently BMW make a fan set up for the RT, used on Police bikes I suppose for slow stuck in traffic situations.
Here in Adelaide SA we have a toy run every year. It's where motorcyclists take a toy and trap it on your bike and take it to the designated spot for needy children, I've always avoided it because of being stuck in traffic. Anyway 3 years ago we went on it and sure enough we're pilled up at lights. My thoughts turned to over heating on my R1100S. It got that hot I could smell the motor so I pulled out about 50 min into it. The question is would have it boiled!!! and done damage to the motor!!
The reason for oil air cooling is because oil has a higher boiling point then water.
Also the engine has greater tolerances to allow for expansion over water cooled.
Water boils at 100 degrees c and oil at around 300c +.
It will start to smoke first before boiling. These bikes use oil all the time depending on what sort of riding you do and need a constant visual on oil levels.
I suppose the Question is for the Mechanics out there is at what temp and duration do we pull over and turn the motor off before we do damage. And if a fan set is fitted will it cool the oil enough so it does not burn off and use all the oil in the motor. Depending on the ambient temp and stuck in traffic will the fan/s cool enough??? Or are you just wasting your time and money? I'm sure someone has cooked a air or air/cooled motor before but is it from lack of checking oil levels before taking off or is it just from being stuck in traffic that it got so hot that it burned all the oil causing the motor to seize.
BMW bikes export all over the world, so different oil viscosity is veried and recommended in each country. Peter is concerned because he is from Greece and temp there can get very hot as it does where I live. We just had 2 weeks of it being over 40c, it got to 46c. I would not ride in those temp because it would be too uncomfortable, but is there also a temp where BMW recommend you don't ride the bike?

Kieran R1100S · 01:56 PM

I've just given this a bit more thought. Given the boil/burn temp of oil which is huge 250c + for it to smoke. How much would the temp drop if a fan is fitted ? If you said 20c to 40c I don't think it's going to make any difference anyway. I've owned bikes for 33 years and have never heard of someone cooking the motor from being stuck in traffic or have not had anyone come up to me and say that be carefull not to cook your motor. Meaning what's the point of fitting a fan. My brother has a 850 Bravo Moto Guzzi air cooled and it only holds 1.8 Lt of oil, air cooled and our BM's hold 4.5 lt air/oil cooled. Is there a BMW bike Mechanic out there that would like to comment.

Cheers.

markjenn · 05:17 PM

Quote:

Originally Posted by Kieran R1100S

I've just given this a bit more thought. Given the boil/burn temp of oil which is huge 250c + for it to smoke. How much would the temp drop if a fan is fitted ? If you said 20c to 40c I don't think it's going to make any difference anyway. I've owned bikes for 33 years and have never heard of someone cooking the motor from being stuck in traffic or have not had anyone come up to me and say that be carefull not to cook your motor. Meaning what's the point of fitting a fan. My brother has a 850 Bravo Moto Guzzi air cooled and it only holds 1.8 Lt of oil, air cooled and our BM's hold 4.5 lt air/oil cooled. Is there a BMW bike Mechanic out there that would like to comment.

I'm not a BMW mechanic but oil temperature definitely is important and after a certain point, any increase is bad. Plenty of folks have "cooked" their oil in traffic enough to dramatically shorten engine life and in some cases, lunched the motor all-together. XR600 motors are notorious for overheating their oil in desert riding. Someone chime in if I get this wrong, but I believe the accepted rule of thumb is that for every 20-deg F over 220 or so, your oil life is halved. So running your oil hotter than optimal is something that is to be avoided. What you generally want is around 220-deg F which is hot enough to to boil away moisture but not too hot. Another 40-deg or so beyond this and the oil usually holds up Okay, but things start running away very quickly after this.

The reason many bikes have oil coolers is to keep oil temps in check and certainly anything you can do to move more air through it will help. That's why BMW fits aux oil cooler fans to their police bikes which see a lot of idling and traffic.

Whether this exercise is necessary on a stock R1100S/R1200S is something that would depend on how high oil temps typically run which I have no info on. But I don't doubt there are situations in traffic or very hot weather where a reduction in oil temperature would be desirable. You definitely would want it under thermostatic (or user control) as you don't want to run your oil below the boiling point regularly or prolong engine warmup.

Bottom line is that this is a progressive thing. A few excursions are Okay, but over time, high temps take their toll. An engine that has had moderate oil temps throughout its life may last 2x one that hasn't been so lucky, or make rated power at 50K miles where the other one is down 20-hp and smokes like a chimney.

- Mark

lightfighter · 02-13-2009, 07:12 PM

the fan on my ktm 525 is 5in wide, 2.5 thick, and sits on a carrier a little longer than that... i can measure and photo it this weekend if i take the tank off if you would like. i think it might fit behind a boxer oil cooler maybe.

OwenM · 02-13-2009, 08:46 PM

It’s important to pull air through the largest possible area of the oil cooler for maximum cooling efficiency, so work on a twin fan solution.
You could us a single fan but a shroud would need to be fabricated so that the single fan pulls air through the entire cooler, not just part of it.

At high speed the fan or fans could become a restriction and flow less air then standard, but airflow over the engine should more then compensate.

peter f · 02-13-2009, 10:42 PM

Well friends

1. I have checked the dual computer fan combo but the idea had rejected due to non waterproof fan assembly. I know that PC-RT case but maybe the huge RT fairing protects the fans in heavy rain. Dual fans could severely compromise the air flow when fans are NOT required.

2. designing a proper housing for the max possible oil cooler area is the next step...but after installing the gizmo and doing some real-life tests. It's easy to design anything and doing it via a Z Printer - Z corp (the thing that makes one-off 3D models).

http://www.zcorp.com/

PS: I'm thinking to design some proper belly pan that way (there's a variety of resins available for rapid prototyping these days)

3. in fact this Piaggio scooter fan has an "air-flow-redirection" plastic housing but space is tight in that R12S and Televeler has "some" conflicts with the housing - not to mention the brake circuit. Thus the fan that you see is the original with the plastic stuff removed.

more in a while...

peter f · 02-13-2009, 10:51 PM

Quote:

Originally Posted by lightfighter

the fan on my ktm 525 is 5in wide, 2.5 thick, and sits on a carrier a little longer than that... i can measure and photo it this weekend if i take the tank off if you would like. i think it might fit behind a boxer oil cooler maybe.

Mille Grazie. Please post some info about the part/fan ordering code as well.

PS: it's a funny thing > I've e-mailed KTM that makes the BMW oil coolers asking for a ready solution > they said that BMW doesn't allow them to sell such stuff to individuals. That's pretty much the same with the R12S Ohlins that are NOT available in any Ohlins e-commerce site. Yikes!

SergioK · 02-13-2009, 11:27 PM

The fans that I linked to above are purportedly waterproof/resistant.

chewie · chewie's Garage

could you have another oil cooler?

like a secondary one that gives it another cool down before it goes about it's business?

maybe another r12 cooler sitting under neath the telever somewhere, with a nice screen in front of it - or does doing this sort of thing affect pressure and stuff?

I wouldn't have a clue, as this post probably illustrates but hey, might plant a seed for some other idea or solution - perhaps.

peter f · 02-14-2009, 12:00 AM

Quote:

Originally Posted by SergioK

The fans that I linked to above are purportedly waterproof/resistant.

Yes Sergio, but I forgot to mention the fan diameter restriction > 100mm max (due to extremely tight space available there).

peter f · 02-14-2009, 12:08 AM

Quote:

Originally Posted by chewie

could you have another oil cooler?

like a secondary one that gives it another cool down before it goes about it's business?

maybe another r12 cooler sitting under neath the telever somewhere, with a nice screen in front of it - or does doing this sort of thing affect pressure and stuff?

I wouldn't have a clue, as this post probably illustrates but hey, might plant a seed for some other idea or solution - perhaps.

Yes by using the Megamoto oil cooler (in a "serial" way) and a "flat" fan the likes that Sergio and others posted. That could rise the whole cost...well...you can imagine.

The plus side could be a Blade Runner aesthetics stuff...pipes going all over the place etc etc .

The minus thing > plan C not possible that way > the new HPE headers (not ready yet) + the new Ilmberger belly pan (HP2S look a like, not released yet).

peter f · 02-14-2009, 02:03 AM

Quote:

Originally Posted by Kieran R1100S

BMW bikes export all over the world, so different oil viscosity is veried and recommended in each country. Peter is concerned because he is from Greece and temp there can get very hot as it does where I live. We just had 2 weeks of it being over 40c, it got to 46c. I would not ride in those temp because it would be too uncomfortable, but is there also a temp where BMW recommend you don't ride the bike?

A last note:

With "winter" (for Greece , he he) ambient tmp (12o C), yesterday I was blocked in the typical Athens dense traffic (plan was to go for some canyon riding, in theory anyway). After 35 minutes or so (+ filtering where possible) > max oil temp (all bars) > broken nerves > stop > have a nice espresso/cigar/wait/etc.

Castrol 15W/50 semi synthetic in use. But with a stationary bike even NASA couldn't solve the problem I guess... (without a fan).

lightfighter · 02-14-2009, 03:31 AM

this fan:

http://cgi.ebay.com/ebaymotors/01-07-KTM-EXC-250-450-525-RFS-RADIATOR-COOLING-FAN-KIT-_W0QQitemZ260350990232QQcmdZViewItem

is at its base plate 121 mm by 160 mm. the fan would unscrew from the base plate for custom mounting.

the fan is 105 mm in diameter, approx 55 mm from the back of the motor to the front of the blades, 70 mm from back of motor to the radiator, as mounted on the ktm.

the 105 mm measurement, depenting on how it was rotated in a custom mount could be tapered to about 70 mm to clear the tubes at full lock. im not sure how to explain what i mean here, but as it is mounted, the narrowest axis of the not really circular housing is not straight up and down.

though i dont pretend to know if it would actually fit, i just figured i'd offer it up as something to look at. it moves a ton of air. on my dirt bike it is on a thermostat, and when my kids bike pukes coolant steam, my fan turns on for a couple minutes, and i can quite literally feel the hot wind if i put my hand under the tank behind it.

sorry, no pics right now, my lunch break is almost over...