EOT meter for OEM oil cooler

[dsinned_imp]

Here are some photos of a completed installation . . .


Note, the bolt used at the top of the fan mount directly to the frame of the bike. This is one of three bolts (1-top, 2-bottom on each side) used to hold the EOC to the front of the bike. I had to get a M6 x 60mm long hex head bolt from my local hardware store to replace the existing (much shorter) bolt provided by the factory at this mounting point. Also note, this cheaper Chinese made fan has no finger guard, but is much less powerful, so I'm not too concerned.

The wad of dark gray "sponge" material shown close up in this last photo is there for added insulation of the Trail Tech temp sensor. This helps keep it from being directly in the air stream, thereby improving its accuracy.

Liberal use of wiring protection flex tubing and cable ties are essential for this project!

The Trail Tech meter had to be cable tied to the handlebar, because it's intended to be panel, not surface mounted. This is the "TTV" model that comes in their Universal Fan Kit. It can be purchased separately if you call TT to order. It also displays the bike's battery voltage and has an automatic back lighting feature. It is programmable, with the little blue button in the lower right hand corner, to turn the fan on/off anywhere between 150 to 200F, and comes with a "fin type" temp sensor. It costs a lot at $89, but can be quite valuable for monitoring purposes while actually riding a bike.

 

[the Ferret]

Interesting.

 

[dsinned_imp]

Today, I repeated "test #1" but this time with a fan mounted. This is the fan pictured in my last post, which is the least costly and probably the least effective due to its relatively small air flow capacity. Nevertheless, I opted against a larger, much more powerful fan (Spal 5.2" pusher) primarily due to the much heavier load it puts on the battery. That fan would do the best job of cooling, but has this other downfall.

I believe the ideal fan would be a 4" Spal pusher, but that's the one fan I don't yet have in my "collection". It would probably do the best overall job of cooling the EOC without overloading the battery. Also, I can't find a supplier with the same fan with a finger guard. Spal makes it, but nobody seems to stock it. A finger guard is worthwhile the added safety it would provide for this application. I might have to call Spal's NA sales office in Iowa to order this particular version.

Anyway, the results of the repeated test was still favorable. The peak EOC temp was 210F over exactly the same route and nearly identical environmental conditions as Test #1; maybe a tad cooler OAT and a bit more wind. The fan was running continuously since I set it to turn On at 150F. The Trail Tech meter worked perfectly and the voltage out of my battery (with fan running) was nominal at 14.2V.

The stationary heat load on the EOC is too much for this little fan to overcome. I'm sure it helps, but it does not flow enough air into the cooler to be of much value in worse case stop and go traffic. It works fine at a sustainable road speed of 45 mph or greater. That's not saying much because the cooler itself can do nearly as well without no fan.

Bottom line, the feasibility of mounting a pusher fan has been demonstrated. It's just a matter of selecting an appropriate fan such as a 4" Spal.

 

[kvdv_imp]

With all due respect, and I hope not to be blacklisted, but I am not getting this at all. It's almost as if the OP is afraid the engineers at Honda (we're talking about HONDA, mind you!) know little about how to properly design an air/oil cooled engine, and that our bikes are just one sunny day away from disaster. If there's something I think all of us can agree on (except perhaps the OP?), it's that the engine in our CB1100's is a masterpiece on nearly every level. Has even one of us yet encountered engine damage related to the oil getting too hot, assuming normal usage and oil level? If the fine folks at Honda had seen the need for an oil cooler fan, would they not have included it in the design?
I will say, the OP is tenacious, extremely focused and imaginative in his approach to this problem. Too bad it's not actually a problem :huh: Truly, no insult intended here; I'm truly just baffled, astonished... imagine the fine engineers at Honda if they were to read of this, and what they would think...
Ok, I'll quit now and get ready to head out for a ride!

 

[Cormanus]

kvdv, perhaps this will help—

I DO plan to continue working on this project. I'm a retired electronics component engineer, and in the Navy I was an Electrician, so these kind of DIY projects interest me and within my skills set. Again, this is my second air cooled bike to be modified with an EOC fan. The first was a complete success. However, I ran into a lot of "resistance" to the idea (on another forum). A lot of guys expressed sentiments of basically, "if it ain't broken, don't fix it", or words to the effect that I have too much idle time on my hands. Guilty as charged! )

As to aschem comment, that is one of the secondary benefits of a fan, i.e. keep the fan running for a while after turning off the ignition to aid in engine cool down and helping to prevent heat soak.

 

[the Ferret]

OP is a retired guy and cooling things was obviously his field of expertise. He is apparently just playing with it to see what he can accomplish. No different than guys who put on power commanders or ecu reflashes imo.

 

[dsinned_imp]

This has been a learning experience for me, and kind of a FUN project. I learned there are some things you just can't do, but always another way. The main issue has been finding the "ideal" size "pusher" fan. A 4 inches fan is too small. 5.2 inches is too big. The sweet spot is somewhere in the middle, around 4.5 inches, but locating a powerful enough fan with the correct dimensions for a pusher application has been very difficult. The first fan I tried has the right dimensions, but isn't nearly powerful enough. I am currently trying another more powerful fan of 5.2 inches, but its actually a little too big to fit the EOC on the CB1100.

Another snag, this weekend I learned the hard way that I cannot use a Trail Tech to control a more powerful fan. TT must be using a low power MOSFET to supply current to the fan, but when I connected a Spal 5.2", Trail Tech's temp meter and with an integrated power switching control circuit immediately failed. This circuitry is sealed inside an encapsulate meter module, so I could only troubleshoot it externally to come to this conclusion. Fortunately, as a temperature/voltage display "meter" it is still functional, so I'm continuing to use it solely as a monitoring device.

Despite this limitation, I decided to use the more powerful fan made by Spal; a 5.2" pusher fan, but will now have to control it with a manual On/Off rocker switch mounted on my handlebar. This switch is located next to the TT meter on the center section of the handlebar for easy access and viewing. Luckily, Honda's handlebar has a diameter of 7/8", which is the most common size for this type of rocker switch.

I came to the conclusion that a more powerful fan is necessary to move sufficient air to be of any real benefit. I already had this fan, so might as well use it for this project. The added advantage of this fan is that it has a finger guard (most others do not). The disadvantage is that it draws a lot of current, approximate 4.5 amps, which may be too much extra load on the battery. To prevent overloading the battery, having a manual power switch for the fan and the means to monitor EOC temperature, I can just leave the fan off until it's actually needed.

Because of the high current, I wired it directly to my bike's 12V battery, and fused the fan at 7.5 amps with a single conductor power lead to the positive polarity of the battery. I connected the negative polarity of the fan motor via a short pigtail to frame ground. I'm using the upper attachment mounting bolt to the frame for the oil cooler to make this ground connection. This is a very convenient location since it is only a few inches from where the fan mounts to the front of the EOC. It also simplifies the fan and rocker switch overall wiring scheme.

Another advantage of this fan is that it can be heard running over the CB1100 engine idle, so no need for a fan running indicating light. No place to easily put a status light anyway.

I finished the installation late this afternoon and did a stationary op check in my garage. The fan, On/Off switch and TT monitor all work great! I didn't have time for an actual test ride to verify the fan's effectiveness on the road, so that will have to wait till next week. My expectation is with THIS fan, I will not have to worry about being stuck in stop and go traffic anymore.

Stay tuned for a follow up test report on this project . . .

 

[dsinned_imp]

Some more photos of installation #2 . . .

In these photos, the Spal 5.2" fan appears massively over sized for this application, but still only overlays ~1/2 of the total available front surface area of the EOC. It fits quite nicely nevertheless, without mounting ear obstructions, but perhaps the aesthetics could be better.


All wiring comes together on the side of the steering column in the lower left front of the tank. "Hiding", protecting and allowing for slack in the harness throughout the wiring was probably the most challenging aspect of the project. I freely admit, there probably is a better way to do such unsightly wiring. Thankfully, there is enough room UNDER the tank to hide the longest run to the battery under the seat.


Here's a closeup of the Trail Tech temperature sensor attached to the upper right corner of the EOC. This is presumably the hottest temperature point in the engine's lubrication system after oil is pumped thru the heads, drains back into the sump and then flow out to the external EOC to be cooled. Also, it can be seen that at least half of the entire frontal surface area of the cooler is still open to natural air flow. This is important in case of fan failure.


Here's a closeup of the main attachment point for both the fan and the EOC, which also serves as an electrical ground return to the battery for one side of the fan's DC power circuit. This photo also shows the "overlap" where the fan sticks up over the top of the EOC. It may look odd, but it actually helps reduce back pressure on (and load current drawn by) the fan, as well as directing cooling air directly to the oil supply and return lines and the top of the engine.


All said and done, this is still one absolutely beautiful bike, with or without an EOC fan!

 

[dsinned_imp]

Okay, so today I rode my bike with the 5.2" Spal fan and repeated the same test route and under very similar atmospheric conditions as before. Almost a continuous up hill road in 2nd gear, averaging about 25 mph, with OAT in the mid 70s under fairly breezy wind conditions. There is about a 2000 ft change in elevation over ~5 miles on this road. It is a good way to test and evaluate the effectiveness of an EOC fan.

At the end of the up hill road, the peak EOC temp reached was 197F.

This is a net reduction of -28F compared to no fan, and -13F compared to the previous (smaller and less powerful) fan.

Just before this latest "on the road" fan test, I had to ride in stop and go traffic for about 10 miles to an appointment. This is when the fan really came in handy. Turning On the fan occasionally during this time kept my EOC temp within the range of 165 to 185F. If I didn't have the fan, I believe the temp would have gone up much higher, because there is little air flow thru the EOC under stop and go riding conditions. For just such occasions, it is clearly beneficial to have an auxiliary EOC fan at the flick of a switch!

 

[the Ferret]

Sounds as if you have found a set up that suits you. Congrats.

 

[dsinned_imp]

Thanks Ferret. Yes, I am quite pleased with how this project finally turned out.

I forgot to mention one other thing . . . I lowered the fan slightly to be flush with the bottom of the EOC by offsetting it downward about half an inch from the EOC's center mounting point. I did this to prevent any fingers from accidentally touching the blades while the fan is operating. The rotational speed is over 6000 rpm!

The fan has a finger guard already, on the front side only. However, without this mounting offset, there was too much of an accessible opening at the back side above the top of the cooler. This potential safety hazard has now been avoided because access to the blades is no longer possible. The gap is greatly reduced, plus the oil return pipe along the top of the cooler blocks what little opening remains.

 

[Ulvetanna_imp]

With all due respect, and I hope not to be blacklisted, but I am not getting this at all. It's almost as if the OP is afraid the engineers at Honda (we're talking about HONDA, mind you!) know little about how to properly design an air/oil cooled engine, and that our bikes are just one sunny day away from disaster. If there's something I think all of us can agree on (except perhaps the OP?), it's that the engine in our CB1100's is a masterpiece on nearly every level. Has even one of us yet encountered engine damage related to the oil getting too hot, assuming normal usage and oil level? If the fine folks at Honda had seen the need for an oil cooler fan, would they not have included it in the design?
I will say, the OP is tenacious, extremely focused and imaginative in his approach to this problem. Too bad it's not actually a problem :huh: Truly, no insult intended here; I'm truly just baffled, astonished... imagine the fine engineers at Honda if they were to read of this, and what they would think...
Ok, I'll quit now and get ready to head out for a ride!

I strongly, emphatically recommend you make SURE the front fender has adequate clearance under maximum fork compression. The front forks have quite a bit of travel, around five inches, and if they were to make contact with this apparatus it could be problematic.

I've checked fork travel on my bike, and I am very light, 143 lbs. I can and have used every millimeter, right to the stop, under either heavy braking or when thumping into a nice road divot or pothole.

This measurement is done by using a ziptie on the forkleg as some folks know and I've seen mine move the full travel many times.

If you were to strike a pothole and bottom the fork, it could conceivably crush the fan into the oil cooler and make a mess, or compromise the steering.

Just saying that your bike can be a laboratory kit, chemistry set, or whatever you like but it's also a motor vehicle and was designed to work properly and safely as it came from Honda. There may not be adequate room there.

 

[dsinned_imp]

Ulvetanna, your point is well taken and you're absolutely correct. I completely forgot about a front fork compression issue with a fan now attached to the front of the EOC. The CB1100's front suspension travel is spec'd at 4.2" max, but with a fan, there is only ~3.5" of travel allowed before the rear fender touches the fan. Obviously, this presents a potentially serious safety hazard in a panic stopping situation or when riding over a large pothole/rut/bump on the road.

Thanks to Ulvetanna's warning, I no longer can recommend the installation of a fan to the front of the EOC as I have just done in this DIY modification. To do so, would be too risky due to insufficient front suspension travel clearance between the rear of the front fender and the front of the fan.

Unfortunately, the oil supply and return tubes that go to and from the front of the engine are located behind the center region of the EOC. There are also massive down tubes as part of the frame just behind the cooler on either side. These OEM obstructions are in the same area where ideally an auxiliary cooling fan could have been located.

As pointed out by other members here, Honda's designers apparently did not see any need for such a cooling fan, so they did not allow any space to install one.

In all frankness, after all the time invested in this project, I'll probably keep the fan, at least during the Summer riding season, but I will be doing so at my own risk! Fortunately, all the roadways around my area are well maintained, and I never ride off road. Nevertheless, any unforeseen panic stops could potentially damage my fan and EOC.

A big THANK YOU to Ulvetanna for the warning!

 

[flynrider]

One more thing to keep in mind is the amount of weight the bike is carrying. You'll use quite a bit more fork travel when braking hard with a passenger or lots of gear on board.

I learned this the hard way years ago when I attached some clamps to the upper fork tubes as part of a fairing installation. I thought I'd tested it thoroughly and that the clamps were plenty high on the fork tubes. It worked fine for 2 yrs., until I loaded up the bike with camping gear for a 2 week road trip. The extra weight compressed the forks much further under heavy braking and the clamps ended up destroying my fork seals in short order.

I also destroyed a perfectly good pair of jeans

 

[dsinned_imp]

I never have a passenger or carry any gear with me, but I weigh plenty at nearly 260 lbs. I always avoid bad roads and am continuously scanning ahead for dips, bumps, ruts and potholes (as well as all cars). My last panic stop (thankfully, without incident) was about 15 years ago, but no guarantee that my next won't be tomorrow.

I still wonder why Honda did not see fit to provide an engine oil temperature gauge, or at least a warning light that comes on way before 340F (can this really be true?) For this reason, I still "recommend" the use of a Trail Tech oil cooler temperature sensor and handlebar mounted monitoring unit ($43), fan mod or not. I find it important to KNOW how high my oil temp is getting under adverse riding conditions such as in stop and go and/or when OAT is already almost unbearable for a leisurely ride. I feel this add on EOC temp monitoring capability is still a very worthwhile mod.

http://www.trailtech.net/digital-ga...mperature/tto-temp-meter-black-8mm-fin-sensor

 

[Ulvetanna_imp]

Ulvetanna, your point is well taken and you're absolutely correct. I completely forgot about a front fork compression issue with a fan now attached to the front of the EOC. The CB1100's front suspension travel is spec'd at 4.2" max, but with a fan, there is only ~3.5" of travel allowed before the rear fender touches the fan. Obviously, this presents a potentially serious safety hazard in a panic stopping situation or when riding over a large pothole/rut/bump on the road.

Thanks to Ulvetanna's warning, I no longer can recommend the installation of a fan to the front of the EOC as I have just done in this DIY modification. To do so, would be too risky due to insufficient front suspension travel clearance between the rear of the front fender and the front of the fan.

Unfortunately, the oil supply and return tubes that go to and from the front of the engine are located behind the center region of the EOC. There are also massive down tubes as part of the frame just behind the cooler on either side. These OEM obstructions are in the same area where ideally an auxiliary cooling fan could have been located.

As pointed out by other members here, Honda's designers apparently did not see any need for such a cooling fan, so they did not allow any space to install one.

In all frankness, after all the time invested in this project, I'll probably keep the fan, at least during the Summer riding season, but I will be doing so at my own risk! Fortunately, all the roadways around my area are well maintained, and I never ride off road. Nevertheless, any unforeseen panic stops could potentially damage my fan and EOC.

A big THANK YOU to Ulvetanna for the warning!

Dang, I actually did something useful!

What about a thinner fan? Seems like I've seen some designed for CPU cooling much thinner, maybe those would work for you.

 

[Magnus_imp]

Interesting project. I'm not particularly experienced in motorcycles but I do have a lot of experience with auto racing, even oil cooled Porsche race cars. One thing to note is that oil temps can generally get a lot higher than water temps without terrible consequences. For example if you saw water temps of 300F you'd be done for but an oil temp of 300F, while above optimal, is not going to destroy the motor if you have a good quality oil. But... as I said in the beginning... I have little experience directly related to motorcycle engines so don't take my word for it..

 

[dsinned_imp]

It's not so much the oil itself, but EXPOSURE to high temps by all other components in and around the engine may eventually take its toll. This is particularly true of less conspicuous "components" like rubber and plastic hoses, seals, gaskets, electrical wiring and insulation, etc. They may not withstand such high temperatures - including heat soak - as well as internal engine components made of metal.

ALL engines, over time, tend to literally "wear out" due to continuous high heat exposure. Reliability of engines as a whole can be extended by better thermal management, thus preventing high temperature excursions. With air (oil) cooled motorcycle engines, such excursions are all but guaranteed in very slow paced, stop and go, riding conditions.

This is why ALL other cars and motorcycles with water cooled engines have radiator fans. I don't know why OEMs bother to equip air cooled bikes with oil coolers, but leave out auxiliary cooling fans for just such worse case thermal conditions.

Btw, I already tried a thinner fan, which fit in front of the oil cooler much better. It's cooling capacity was just about the same as a fan in a desktop computer, but not nearly powerful enough to be of much added value in this application.

 

[the Ferret]

Nobody can say that you are not really into this stuff lol

 

[Ulvetanna_imp]

It's not so much the oil itself, but EXPOSURE to high temps by all other components in and around the engine may eventually take its toll. This is particularly true of less conspicuous "components" like rubber and plastic hoses, seals, gaskets, electrical wiring and insulation, etc. They may not withstand such high temperatures - including heat soak - as well as internal engine components made of metal.

ALL engines, over time, tend to literally "wear out" due to continuous high heat exposure. Reliability of engines as a whole can be extended by better thermal management, thus preventing high temperature excursions. With air (oil) cooled motorcycle engines, such excursions are all but guaranteed in very slow paced, stop and go, riding conditions.

This is why ALL other cars and motorcycles with water cooled engines have radiator fans. I don't know why OEMs bother to equip air cooled bikes with oil coolers, but leave out auxiliary cooling fans for just such worse case thermal conditions.

Btw, I already tried a thinner fan, which fit in front of the oil cooler much better. It's cooling capacity was just about the same as a fan in a desktop computer, but not nearly powerful enough to be of much added value in this application.

To me, I see these questions as a result of your being involved in a highly specialized field.

Air-cooled engines have been around a long time, aircraft engines, motorcycles, power equipment. Pretty much all aircraft piston engines are air-cooled, for example, except maybe some experimental stuff. These manufacturers have been doing this so long they've learned to make their engines so they will last a very reasonable lifetime.

In the case of the oil coolers, a large example such as that on the CB1100 or the earlier GSX-Rs qualifies the bike to be called "oil-cooled" or "air-oil cooled". These bikes have a much larger volume of oil than comparable liquid-cooled examples.

It may seem self-evident, but Honda, et. al. have been making these kinds of engines for many decades and if cared for reasonably (not necessarily even to the recommendations) they last a very, very long time. It is not unusual to see examples with over 100,000 miles.

Simply put, your concerns about durability and reliability are unfounded. You should enjoy riding the bike as it was designed and have no concerns as to its longevity.

The idea that the metal front fender could in fact come into contact with this modification would be of grave concern to me. It could very easily cause a serious accident. And the mod that could cause it will really do nothing to extend the service life or value of your machine.

Engines wear out but they can be overhauled. People cannot so easily be repaired or replaced.