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 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.