Landracing Forum
Tech Information => Technical Discussion => Topic started by: manta22 on August 26, 2016, 04:41:35 PM
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Has anyone measured the temperature rise of his manual transmission oil during a run? I'm trying to decide whether to mount an oil cooler for my transaxle.
Regards, Neil Tucson, AZ
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Neal if You do I have a used Dry Sump style unit meant for a rear end mount (9" Ford) and yolk with a v-drive pulley and cooler. If you could figure out how to mount it You could run it off of a electric pump or whatever. I believe it was made by Stock Car Products so You could take a look at their online catalog and get a Idea. If You are interested I will dig I out and open up the cases but from looking through the line fittings the rotors look good.
Another place to look would be Racingjunk.com.
Bob Drury
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You won't run long enough to build much heat at the salt. We ran a AA/BF KB on a Weismann without a cooler & never had an oil temp issue even on turn around runs.
Sid.
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geez Sid, I was going to sell it to him for only $3,000. Do you kow how much Nitro costs nowdays? :roll: :roll: :mrgreen:
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Thanks, Bob. I have an oil cooler and an electric pump, I just wondered if it was worth the trouble of mounting them. I guess 5 miles is not the 24 hours of Le Mans.
Regards, Neil Tucson, AZ
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Neil, what Sid said is what Beaver at Winters said about a cooler on a quick change too. And I was going to give You the "insider deal"... Nuts.
O.R.B., out..................
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Cold transmission oil can cost you a lot of power, in road racing circuits it typically takes a couple laps to get the transmission and differential up to temperature.
I have seen an item talking about dyno tuning that mentions cold transmission oil can cost a Porsche 40 hp at the wheels.
One of the tricks of the dyno trade is to put the car on the dyno relatively cold, get a "baseline" fiddle with it a bit making several passes then rerunning a final horsepower plot which shows a gain. Most of that gain is due to warming up the oil in the engine, transmission, u-joints and differential.
Not saying all dyno guys do that intentionally, but there is a reason lots of professional race teams preheat engine oil and transmission prior to qualifying.
Unless you are seeing excessive oil temps I would think heating pads for your oil tanks, oil pan and transmission (especially on return runs) would be a better expenditure of money.
I have a friend who builds gear sets for high end Porsche racing teams and this discussion came up some time ago and I asked him the same question.
I can't find the exact message he sent me on it, but as I recall full transmission temp should be something in the order of 180F before you get minimum power loss from the gear lube being cold. On most road racing circuits that takes a couple laps so depending on course length you are talking 3-5 miles to come up to full temp.
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0-20 syn. eng oil intentionally run low--- barely warm on my little 7.5 GM after 5
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Cold transmission oil can cost you a lot of power, in road racing circuits it typically takes a couple laps to get the transmission and differential up to temperature.
I have seen an item talking about dyno tuning that mentions cold transmission oil can cost a Porsche 40 hp at the wheels.
One of the tricks of the dyno trade is to put the car on the dyno relatively cold, get a "baseline" fiddle with it a bit making several passes then rerunning a final horsepower plot which shows a gain. Most of that gain is due to warming up the oil in the engine, transmission, u-joints and differential.
Not saying all dyno guys do that intentionally, but there is a reason lots of professional race teams preheat engine oil and transmission prior to qualifying.
Unless you are seeing excessive oil temps I would think heating pads for your oil tanks, oil pan and transmission (especially on return runs) would be a better expenditure of money.
I have a friend who builds gear sets for high end Porsche racing teams and this discussion came up some time ago and I asked him the same question.
I can't find the exact message he sent me on it, but as I recall full transmission temp should be something in the order of 180F before you get minimum power loss from the gear lube being cold. On most road racing circuits that takes a couple laps so depending on course length you are talking 3-5 miles to come up to full temp.
x2 to all items . . . . and this works on cars of ALL power levels, not just the big hp deals. The trick is to get as much of the engine power as possible, out of the engine, and to the contact patch of the tire.
Easy to say, tougher to do.
:cheers:
Fordboy
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Thanks to everyone for their response. It sounds as if putting an oil cooler & pump on my transaxle won't be necessary. I'll use that time to finish lots of other little things on my car.
Regards, Neil Tucson, AZ
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Perhaps you could use it to preheat the oil?
Just a thought.
Dave
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I have just gone to some lengths to fit ex Nascar tank heaters into my dry sump tank, transmission and differential to pre heat the oil. These are 500 watt, 110 v heaters. We currently don't have an alternator on my engine so sit in line often with a small generator going on a battery charger. Will plug the heaters in during that time. Haven't figured how much to do/how long and don't want to cook the oil. Just sticking one of these into a can with about a pint of oil took the temp up nearly 100* in a couple of minutes. :-o FWIW I checked with one of those cheapie IR guns the temp of the differential of my tow truck (not towing) after a 300 mile trip. It was about 135*. I surely wouldn't worry about needing a cooler as Hotrod and others have mentioned. Want it HOT.
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I agree with Sparky, if you do not want to use a heater then just start with a much thinner oil. Look at a viscosity chart for oils and 140-180 wt gear oil at what is considered its optimum operating temp (180-200 deg F) has approximately the same viscosity as Sparky's 0-20 wt synthetic, and as Sparky has proven in the running of his cars the oil temp is only slightly higher at the end of a run. Old habits die hard, I know that we all believe that we need to use the 140-180 viscosity oil in trannys and diffs but for Bonneville this is just throwing hp away. Just another observation is that the BW T-5 tranny that I have in my lakes style roadster requires that you use ATF which has very low vis and I have hammered over 20,000 miles on it without problems. I would personally use one of Mobile Oil's DTE hydraulic oils as they are very high in wear inhibitors and low friction additives and I have used them in hydraulic pump systems at over 8000 psi with out any failures.
Rex
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... temperature rise of his manual transmission oil during a run? I'm trying to decide whether to mount an oil cooler for my transaxle...
I see you've pretty much decided against a cooler. But if a person wanted to follow through on the analysis, please note that, in general, a transaxle (especially if using hypoid ring/pinion) generates much more heat than most transmissions (either straight-cut or helical spur gears). And in direct-drive a transmission generates practically zero heat.
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GV now recommends that we run syn. ATF for B'Ville
not the syn. 70-90 they recommend for units that pull much higher GVWs on the Hwy.
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Pre-heat the oil on a stove, add it just before starting the engine.
When & what: 1914 fighter plane engines.