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http://www.mgnoc.com/rally_calendar.html June 26 to June 28, 2009 38th Annual MGNOC National Rally Rally flyer (PDF, 216k) Salida, Colorado at Chaffee County Fairgrounds, two miles west of Salida. $35 before May 15, $45 after May 15. Grass camping, showers, RV parking and hook ups, Friday and Saturday night dinners, Saturday morning pancake breakfast, coffee and cold drinks at all times. Also available for purchase, pastry from Sons of Italy bake sale. Lots of activities available, see our Colorado and MGNOC webpages (www.motoguzzicolo.com and www.mgnoc.com/rally_calendar.html) for more information or the full page rally ad starting with the January MGNOC newsletter. Also, Bike service will be onsite, rare antique Moto Guzzis, movies, door prizes and approximately 50 vintage cars onsite and a lot more. Moto Guzzi USA will have their demo truck. Send your registrations and/or information, to: Jack Lundberg, 530 Buckeye Dr, Colorado Springs, Colorado 80919. 719-531-6526 Email: mgcoloradorally>at

Darn it! You ruined our secret!!!! But since you started it, we might as well clue you all in: GM Sensor is corporate shill skeptic scientists. Brass is "the man" Silver is the solution to AGW that will cost the economy too much. Heat sink is the ocean Temp Sensor and Al Gore are both too dense. Thermal Inertia is Fubar the philistines living at sea level Air gap is brain matter of those who disagree. Infinitely adjustable resistor is a rhetorical argument for any conceivable Truth.

Thanks, I posted about the weather resistance of brass, but Ratchet ignored it. That could be a good enough reason, to go with brass. For the stud the conductance is more important than the diffusivity, but the diffusivity difference between brass and aluminum should be very large. The density of brass is factored out, or rather not factored in, but the density is a likely indicator that brass will retain more heat. But the weathering issues of aluminum could be a concern. How about titanium?

Thanks! that is interesting. Maybe those lean surging beemers would benefit from what has been discussed here???

Glad to see admit you don't know the difference between mass and weight, or diffusivity and conductance. BTW, consensus is a very important part of science. Consensus validated Copernicus and Galileo. If it did not, think where we would be today. Continue on your merry way experimenting with no temperature or voltage readings, curing not problems, but symptoms that don't exist since you have had a perfect running engine, with plastic that may not be up to the duty cycle, and a brass rod selected over an aluminum rod to show just how excellent your understanding of thermal physics is. Carry on.

So, you are saying air cooled fuel injected engines from HD, Ducati, Buell, and BMW had multiple input feedback systems when Guzzi did not? I thought they all had pretty similar designs. You said BMW uses a true oil temp sensor. That could make a difference, but still it is more comparable than apples and oranges. What about HD, Ducati and Buell?

I ignore very little, and certainly not the heat sink or conductivity effect of the brass adapter/holder. But I must admit, I have paid very little attention to the bypass effect of the brass adapter/holder, since the sensor probe is smack in the middle of both sides of the bypass action. How often do you really think the probe is hotter or colder than both the CH and Sensor body at the same time? If so, when? and how do you know where they placed the thermistor? Wouldn't it be cheaper to put it in the upper part of the probe, considering we have the long probed model? Don't forget, I paid enough attention to bypass to bother trying adding conductive, which was a failure, and have tried reducing the bypass with teflon tape. My experience has shown that keep the sensor from getting too hot has been more important than worrying about bypass. Yes, direct path is better if the sensor and ECU dealt with it well, but they don't. Your latest design seems to be ignoring conductivity(air gap) and mass (brass) I see the reason for the air gap(cooler sensor reading), but not the brass stud. Yes, surprise comes only with an open mind. Confused, I am a little. Perhaps you could edumacate the philistine out of me!?! If you boil three rods for 20 minutes at 100C, 1 cm by 10 cm, one of brass, one of aluminum and the other of copper and take them out of the water and place upright in a 20C atmosphere on top of 1 cm by 20cm by 20cm aluminum plate, how fast would each rod cool relative to one another, measured with low mass sensors imbedded in the rods, at the top of the rods? Which would cool faster measured imbedded at the bottom of the rods? If the plate were made of copper, how would it change the result? If the plate were made of ceramic, how would it change the result? How about if we blew a fan with 100KPH wind speed across? Would the cooling follow the nearly double conductivity of copper over aluminum and the nearly double conductivity of aluminum over brass? Or would it follow the diffusivity numbers? From what I understand the conductivity numbers would be followed more at the bottom of the rod reading, especially when on the copper plate, and the diffusivity numbers would be more closely followed at the upper rod reading, especially on the ceramic plate. I think wind would push it to follow diffusivity. But Heck I could be wrong backassward confused, etc. I previously thought 10 cc tube of air would cool faster than one of these rods, but if diffusivity is what I NOW think it is, than the air would take longer to cool than any of the metal rods, right? Doubt we'll get a consensus on this. Care to explain why the differentiation of weight and mass is important here?

I made a mistake based on the false assumption that a cc of air would change its temperature, faster than a cc of aluminum or copper. But I stand by the FACT that in your design, Aluminum is better than brass for a mounting stud. For the OE sensor holder I do not contend that aluminum would be better than copper. I contend that aluminum would be better than brass for the brass adapter design, and I suspect aluminum would be better than copper, in that design, but I could be wrong about that. I figure the lower mass trumps the higher conductivity, but as I said I could be wrong about that. But I am not wrong about aluminum being a better stud than brass. You are wrong about brass being better than aluminum. What is your proof or evidence, that brass would be better? I have no proof but based on aluminum's superior conductivity and lower density, it seems pretty obvious that aluminum would be the better choice. Aluminum has nearly twice the conductivity of Brass http://www.engineeringtoolbox.com/thermal-...tals-d_858.html The density of brass 8.4 to 8.73 grams per cubic centimeter. The density of aluminum 2.70 grams per cubic centimeter--wikipedia

Who makes air cooled fuel injected bikes? Harley, BMW, Ducati? Do the others use a similar sensor, adapter, and air gap? I googled a bit and could not find what I wanted, a better OEM setup than Guzzi's. You think Harley would atleast be advertising chrome sensors! Here is all I could find: BMWs R1200 has a shorter probe. (found on ebay)

Hollowed out and filled with diamond powder, then gold plated for corrosion resistance, but leave an air gap just to defeat the whole exercise. But seriously, I am having trouble grasping the air gaps importance for anything other than getting the sensor output to match the engineers intentions, or to keep the plastic from heat damage in Ratchet's setup. Using a copper stud, does having the low diffusivity of air combined with the low mass of air somehow give it BETTER properties that an alumimum stud and less or no air gap would not have(ASSUMING air gaps are set to same maximum temperature at the sensor)? That must be spitting hairs. Forget I asked...

I found a Google Book http://books.google.com/books?id=KmeC6b9hz...num=8#PPA720,M1 From what they say there, your assumption that the higher number is preferred is correct. Silver 149 x 10 to the sixth Gold 127 x 10 to the sixth Copper 113 x 10 to the sixth Aluminum 97.5 x 10 to the sixth Iron 22.8 x 10 to the sixth Mea Culpa! I am surprised that a cc of air has far less diffusivity than a cc of metal! And I am surprised that the much more dense Gold has better diffusivity. So, you are correct, the copper has the better diffusivity, but I still suspect if the brass sensor holder was re-done in Aluminum it would have better thermal inertia qualities than copper, due to the shape and the lower mass of aluminum, but that ain't gonnna get proven on this forum... In either case we can agree the brass is the worst choice of brass, copper and aluminum, with regards to thermal inertia and diffusivity, and we can agree that reducing the mass helps.

LOL! see my post: EUREKA! http://www.v11lemans.com/forums/index.php?...mp;#entry157942

No, now it runs BETTER than perfectly!

explanation 1 explanation 6 You cured no problem, and the bike now runs better than perfectly. And those of us that don't read with perfect comprehension are the ones with reading comprehension symptoms problems.

FWIW $20 on eBay will buy an air temp sensor that looks like a perfect cross ref for the V11 AIR temperature sensor : Ducati Air Temperature Sensor 748 916 996 749 999 848

Dude! is this a reading comprehension test or are you baiting us? I swear you said you had no problem with the OE sensor with air gap, but now you are saying you did have a problem. Do I win the prize for actually reading through your mega-posts? Congratulations! That is great news. Despite my critique and nit-picky analysis, I do appreciate what you have discovered! Thank You! 'But I don't want to go among mad people,' said Alice. 'Oh, you can't help that,' said the cat. 'We're all mad here.' --Lewis Carroll To give it a fair shot, I'd recommend you minimize the gap before filling with thermo-compound, you know conductivity, inertia and all. Looking forward to the result! But still I think you should just switch your Guzzi CHTS with your Guzzi ATS.

More Hair Splitting: EUREKA!!!!! The Guzzi air temperature sensor has IDENTICAL output to the "oil" sensor temperature. So it should be a better solution for the those that aren't content with possibly 10% deviation. But, I don't think it would fit the existing wire harness, or does it? And the GM generic part is cheaper. The GM sensor fits the existing wire harness, right? Remember when Skeeve discovered the factory reversed the seat and "choke" springs? Wouldn't it be funny if reversing the sensors worked better! How many of us would be bothered by delays in measuring air temperature with a heavy brass coolant sensor? Probably not all the people with K&N pods and dangling air temperature sensors. That worth reading through 47 pages for!!!!

I can't wait till we get to the air temperature and pressure sensors!!!

I think my laughter in that quote was for the next line down...my bad.

I agree with regard to his setup! Except that Brass piece he is using could surely be improved upon by either PURE Aluminum or PURE Copper. (splitting hairs I would choose aluminum, if I could find it easily because it has less mass to heat up and more than adequate conductivity) After that, he just has to find the ideal air gap and make sure the plastic assembly holds up to his infamous Mojave runs.

Yah, if we are talking a copper or aluminum replacement for the brass housing, choosing copper over aluminum to increase the conductivity that minimal distance and then using an air gap as a buffer does baffle the mind. Other scenarios it is trickier to determine if copper or aluminum is ideal. If you are talking the threaded rod from cylinder head to the possibly heat damaged piece of plastic, housing the GM sensor, I don't think a pure aluminum rod with less or no air gap will behave very different than pure copper rod with more air gap. It would depend on the air gap. I don't think you could easily calculate what gap with copper would have the same conductivity as aluminum with no gap, since in either scenario you have to heat the air around the GM sensor's thermistor, not just the thermistor or the air in the gap. If you ignored the air and housing that would be heated, the air gap would be less than a hundredth of a millimeter, but that is strictly theoretical with very crude math. In the case of the OEM plastic housing, the thermal inertia of copper or aluminum would be pretty similar, by itself, but with a heavy sensor like the OEM, I agree the conductivity of copper trumps the lower mass aluminum, and copper is the better material.

Sorry, my vote is still for Aluminum to replace the brass adapter, or the body of the sensor, assuming the same volume. But sure, drill a hole and tap in a copper or silver bolt to approach the air gap This horse can be led to Kool-Aid® but he ain't drinkin'. The Sheople can fall for that. Anybody weigh the brass adapter? How does it compare to the mass of the sensor? I will agree that in the plastic adapter copper is the better choice since there is not much mass to effect thermal inertia. But surely the brass adapter would be much better off made of aluminum than copper. The conductivity is only needed for the short path from cylinder head to probe, assuming you add conductive, as if we even need that much conductivity with stock mapping!!!! But yes, for those running rich enough to benefit on a warmed up engine from adding thermal goo, you might actually benefit from replacing your brass adapter with a copper one and your plastic and copper alloy OEM adaper with a core of PURE COPPER!!! Checkout the lousy conductivity numbers for "copper brass" which is probably what he OEM plastic adapter utilizes. http://www.engineeringtoolbox.com/thermal-...tals-d_858.html Of course someone could probably take the brass adapter to a lathe and shave off half it's weight, but it still won't conduct like aluminum. Weather resistance is about all the brass has going for it.

Using Wiki's number for a common brick: Common brick 5.2 × 10-7 is equal to 520 x 10-5 which is greater than either the copper or aluminum And for air: Air (1 atm, 300 K) 2.2160 × 10-5 It is actually the lower number that we want. So, I guess air has a better number than copper or aluminum. So, it looks like the highest OR lowest thermal diffusivity is NOT exactly what we want. Not Wiki's fault but mine. Diffusivity being the ratio of thermal conductivity to volumetric heat capacity is not exactly what we would want. Air would be ideal if it was dense enough to raise the conductivity number, which won't happen on this planet. Aluminum still is a better metal than copper or brass, but that is assuming the same volume. Certainly one could make a smaller part out of copper that would work better, due to copper's superior strength. High conductivity and low mass is the bottom line, which air has the best ratio, but that alone does not make it the best material. What would work better than aluminum or copper is aluminum with a copper or silver core to do increase conductivity, but that may be overly complex. Again, why not put the sensor directly in the head? I still have not heard a convincing answer. Anyway, through your experimentation I think you realize that the ultimate conductivity is not necessarily what we want, otherwise you would not be running that GM sensor with an air gap, right? Keeping the mass down is what makes the GM sensor work well. Aluminum is lighter than Copper and that is what gives it an edge, IMHO. (and wiki's numbers back it up)

Short distance commuters will probably pick up even more MPG. I think if ratchet shortens the airgap in his GM setup we'll see claims of 5MPG improvement over the "problem" free OEM sensor setup. FWIW, since I took the solder out, I think I lost about 1 or 2MPG, but the bike runs far better. I took the beautiful warm day off and averaged about 35MPG where I suspect I would have gotten 37MPG with conductive, but the bike is running much better. Sure I could go back to conductive if I remap, but I see the inertia/difusivity issue as the better starting point towards a more perfect system. I stopped by Sonny Angel's today. He is still looking great at 85 years of wising up, but still no sensor adapter to be found. Probably got filed under Norton, since the part wreaks of Lucas engineering. Maybe I'll search my garage for the slightly mangled OEM adapter and see if I can remold it out of JB weld, maybe even epoxying in the GM sensor