Oil Cooler Effectiveness

[posplayr]

[2] Yes, it was simplified analysis since I was interested to get just a ballpark figure to estimate scale of heating power from the stator. So I can easily believe if you say it's 350W with a shunt regulator. However, this is a worst case situation when there is no load from the charging system and the regulator shunts everything to the stator, right? And when the load increases difference between the shunt and series regulators gets smaller.

[3] Correct. But based on my knowledge the total heat dissipation of the engine is approximately the same than the mechanical output power. So at 60mph cruising speed the heat dissipation would be about 10-20kW. Therefore that 10% reduction would be at least 1kW.

Actually I had a series R/R some years ago. I designed one when my original R/R went dead. I can't recall noticing any difference in oil temps with it though I wasn't specifically watching that. But I'm sure there wasn't 10°C drop, few degrees might have got away unnoticed. Later on when my series R/R broke and I changed to FET shunt R/R I also changed the whole engine at the same time so I couldn't compare temps.

But yes, it would be interesting to try again. I know very well that shunt regulators aren't too healthy for the stator so upgrade would make sense just because that. On the other hand my bike has quite a lot of electric load so probably difference wouldn't be that big.

[2a] I tried to be pretty specific; but here goes again 350 watts is what is dissipated in a stator using a shunt regulator when full load of 15 amps (220 watts) is delivered to the electrical system. With LED's it gets worse. With a fuel pump it goes lower.

[3] I am not offering a quantitative technical analysis of the heat flow, just showing that the apparent large disparity between engine power relative to stator power coupled with a drop in temperature is not as inconsistent as it might initially appear. Even your 1K watt estimate is only 4 times what I measured (250 watts). I'm sure if you sharpen your pencil, you will be able to figure out that the actual amount of convective heat flow from the engine (what heats the oil) is not nearly as much as one would suspect and that in fact the strata power can make more that just a perceptible difference, but make 20-30 degF difference.

The phenomena has been documented and confirmed by multiple sources. Off the top of my head, the people that I know who can independently confirm this are:
Katman, WheatDog , Chef1366 and myself.

All of these people have had sufficient experience riding their own big block GS1100 which have OEM fitted temp gauges (or other) to recognize when their temperature gauges drop after an install of the Series R/R. To my knowledge all of these have been with the Compufire and not the SH-775 but I would gather it does the same.

When you say you designed a Series R/R, I'm not sure if you mean an R/R that performs like these I mention or something else. I'm guessing not or else you would have seen a difference for your size motor.

[ArttuH]

The phenomena has been documented and confirmed by multiple sources. Off the top of my head, the people that I know who can independently confirm this are:
Katman, WheatDog , Chef1366 and myself.

All of these people have had sufficient experience riding their own big block GS1100 which have OEM fitted temp gauges (or other) to recognize when their temperature gauges drop after an install of the Series R/R. To my knowledge all of these have been with the Compufire and not the SH-775 but I would gather it does the same.

I'm not doubting your findings. I'm just wondering what is the actual mechanism of the temperature drop.

When you say you designed a Series R/R, I'm not sure if you mean an R/R that performs like these I mention or something else. I'm guessing not or else you would have seen a difference for your size motor.

I think it was equivalent in this sense. It was basically a controlled rectifier bridge and it wasn't doing any current shunting. The engine was stock when I installed it, if that matters anything.

Any ways, I think we have side railed this topic enough already If I can find a SH-775 for reasonable money I will try this during next summer. But if you have any proper reference about heating power of typical motorcycle engine it would be interesting to hear. I have seen just some rough values but usually they suggest that energy loss through cooling is at the same level with outputted mechanical power.

[posplayr]

I'm not doubting your findings. I'm just wondering what is the actual mechanism of the temperature drop.


I think it was equivalent in this sense. It was basically a controlled rectifier bridge and it wasn't doing any current shunting. The engine was stock when I installed it, if that matters anything.

Any ways, I think we have side railed this topic enough already If I can find a SH-775 for reasonable money I will try this during next summer. But if you have any proper reference about heating power of typical motorcycle engine it would be interesting to hear. I have seen just some rough values but usually they suggest that energy loss through cooling is at the same level with outputted mechanical power.

Sorry to be a little snippy but there have been several people questioning the results in fact wanting back to back testing. This is even after multple independent confirmations. Sorry after riding a bike for 10k miles I know how it runs and can clearly see the change and there is no reason to go back.



A firing angle controlled 3phase scr bridge would be what the sh775 and the cycle electric are. The compufire uses mostest to perform synchronous rectification. Transition in the cf seem to be at voltage/current zero crossing to minimize transients.

I did detailed stator currents measurements using current clamp and digital scope. I estimated power based on average current and known coil resistance. With some three phase calculation I derived total stator power.


These air cooled bikes have little reserve capacity for cooling, the relatively small stator power causes a surprising large temp differential to get the extra heat out.

[Nessism]

Count me as another with questions about how much effect the R/R has on oil temp. There is no direct oil flow onto the stator for one thing, so even if it's running hot, how much contact does it have with the sump oil? There is splash lubrication to the stator, but how much oil volume contacts it, and how much could that affect the sump oil temp? Also, lets not forget that in order to heat the oil the stator temp must be higher than the oil itself. So with a typical air cooled engine that's running at say 225F, the stator temp would have to be above this temp in order for heat to be added to the oil. Are you guys suggesting the stator is running upwards of 300F due to shunting current? On my 1000S the oil temp gets up into this range on a hot day. Having a hard time getting my mind around the stator contributing to this.

[posplayr]

Count me as another with questions about how much effect the R/R has on oil temp. There is no direct oil flow onto the stator for one thing, so even if it's running hot, how much contact does it have with the sump oil? There is splash lubrication to the stator, but how much oil volume contacts it, and how much could that affect the sump oil temp? Also, lets not forget that in order to heat the oil the stator temp must be higher than the oil itself. So with a typical air cooled engine that's running at say 225F, the stator temp would have to be above this temp in order for heat to be added to the oil. Are you guys suggesting the stator is running upwards of 300F due to shunting current? On my 1000S the oil temp gets up into this range on a hot day. Having a hard time getting my mind around the stator contributing to this.

Ed,
I'm baffled by this question.

How do you think stators turn into crispy critters?

Jim

[Nessism]

Ed,
I'm baffled by this question.

How do you think stators turn into crispy critters?

Jim

Jim,
Obviously, the stator gets hot under some conditions. I'm not clear when that occurs though. When the charging circuit wiring corrodes maybe, and increases in resistance? Even if the stator is getting hot, is the small amount of splash lubrication that comes in contact with the stator sufficient to increase the entire sump oil temperature 30F? Maybe on your bike with an oil jet spraying oil on the stator, but what about a normal bike?

[JEEPRUSTY]

The stator is attached to a rather significant heat sink I.E. the engine cases.
The heat from the stator would most certainly be carried off to the engines cases and then to the oil.

Anyone have a fancy camera that shows heat via infra red?

[posplayr]

Jim,
Obviously, the stator gets hot under some conditions. I'm not clear when that occurs though. When the charging circuit wiring corrodes maybe, and increases in resistance? Even if the stator is getting hot, is the small amount of splash lubrication that comes in contact with the stator sufficient to increase the entire sump oil temperature 30F? Maybe on your bike with an oil jet spraying oil on the stator, but what about a normal bike?

So you think that a stator getting hot and getting crispy is a malfunction and not a normal "design feature"?

Please pray tell, what malfunction would cause a stator to get hotter than it would under normal conditions?

[posplayr]

The stator is attached to a rather significant heat sink I.E. the engine cases.
The heat from the stator would most certainly be carried off to the engines cases and then to the oil.

Anyone have a fancy camera that shows heat via infra red?

It has been documented and posted in several places. Do a google search for Compufire. I think there is even a link under my Compufire install thread.

[JEEPRUSTY]

It has been documented and posted in several places. Do a google search for Compufire. I think there is even a link under my Compufire install thread.

I bet an infrared scan would show the stator cover as being hotter than everything but the cylinders and exhaust.

[posplayr]

I bet an infrared scan would show the stator cover as being hotter than everything but the cylinders and exhaust.

The data if available for your review.

Edited 2/5/2014
An interesting thread discussing Compufire and SH-775 Series R/R's. It appears that in comparable tests the SH-775 gets hotter for high current applications and it was also noticed at high RPM for (16K RPM) there was one instance over voltage break down in regulation reported on the SH-775. Not likely an issue with any GS's around here.

http://www.vstrom.info/Smf/index.php/topic,20426.0.html

Vstrom Discussion of SH-775 and Compufire Series R/Rs

HIGHLY RECOMMENDED FOR A Warm Running 16V GS1100/1150. For you naysayers out there. There is a significant temperature drop if you are running stock in the 250-270 degF range (My 1166 went down to 210-220 degF max).

Aprilla but shows back to back temperature drops

UPDATE; Wheat dog has confirmed a nominal 30 degF drop in operating temp for an 83 GS1100ED with 1166 kit after making this change over to the Compufire-Fire R/R
Installed Compufire RR - Way Cool!!

[sharpy]

OMG all this talk, Just bolt a huge sucker of a cooler on and forget about oil temps.

[tkent02]

There's a leak waiting to happen.

[sharpy]

There's a leak waiting to happen.

50K and not one leak. Earls quality all the way.

[posplayr]

50K and not one leak. Earls quality all the way.

Bike looks very clean