Go BottomJD 4310 at 6000 ft Above Sea Level
 | steube59
Join Date: Feb 2004 Posts: 1 UP-Michigan 
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2004-02-16 77074
I'm both a Newbie to this Forum and CUTs in general, and I'm looking at buying a JD 4310 for my projects. But within a few years though I’ll be moving from the flatlands of the Midwest to the high regions of Montana; that’ll be between 4500 – 6000 ft above sea level. I’d assume some minor engine performance loss in that thinner air, but I don’t really know. Are there any high altitude veterans out there who could share their experiences and advice..?
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 | blizzard
Join Date: Jul 2003 Posts: 282 Central Maine
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2004-02-16 77075
Been a long time since I was in country that high, but here's a line from the web I found.
“Power loss on a normally aspirated engine can go as high as
three percent per thousand feet of elevation,” says Abbott.
“With a turbo, the loss is less than a half a percent per
thousand feet.”
bliz ....
Link: EngineLosses
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 | Peters
Join Date: Feb 2002 Posts: 3034 Northern AL 
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2004-02-16 77078
There are a couple of members that have their tractors at high altitude. One member bought a larger HP tractor initially to minimize his losses.
Most of the CUT are not turbo charged. I believe one MF model is and some of the McCormick etc., but most are on the higher end of the CUT HP range. ....
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 | Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee
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2004-02-16 77080
Here is a formula for rough approximation of horsepower loss with altitude. ....
Link: click here
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| Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee
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2004-02-16 77085
steube59, you came to the right place to get answers for your 4310 on Tractor Point. Your post asking the same thing you asked here in this thread which you posted on the "TLTB" aka the "Other Tractor Board" is still setting there unreplied to. ....
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 | DRankin
Join Date: Jan 2000 Posts: 5116 Northern Nevada
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2004-02-16 77092
This brings up a topic I have had on the back burner for a while. Maybe our Engineering Friends can help with my question.
As a private pilot I am well aware of HP losses at altitude and have had a couple of instances where it caused problems.
But diesel engines operate differently from gasoline engines. In simplified terms, the air in a carburetor controlled engine drags the fuel with it as it enters the engine in a predictable air/fuel ratio governed by the venturi effect.
If the air is thin, it drags less fuel (generally speaking)and therefore less (fewer?) horsepower is generated.
The key element to my question is based of this assumption....... and on the fact that both air and fuel together are used to moderate or control the power generated in a carburetor-gas engine.
In diesel technology, the is no air restriction to the engine..... no buttery-fly valve..... no choke to restrict incoming air flow the the engine.
Instead, there is a wide open manifold offering ambient air pressure to the cylinders at all times and we control engine speed and power by the amount of fuel injected directly into each cylinder.
So at low speeds we run very lean.... so lean that our engines may not warm up in colder weather, and at higher speeds we are running much a much richer fuel/air ratio because we are injecting a greater volume of fuel into the same amount of air.
Does this make diesels less prone to loosing power at altitude? even a little less?
It would seem that since the power generated is based on the amount of fuel injected rather than the amount of air aspirated, that the power loss curve would lag behind that of a gasoline engine.
What say youse guys?
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 | kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-02-16 77093
My guess is that high altitudes affect normally aspirated engines, diesel or gas, equally. I don't think the butterfly makes much difference. It's a simple matter of how much air gets packed into cylinders at any given rpm. As you know, thinner air at high altitudes means less oxygen gets into the cylinders when the intake valves are open. This is also due to lower manifold vacuum as altitude increases. Of course I've been known to be wrong :) ....
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| HuckMeat
Join Date: Jan 2004 Posts: 121 Colorado
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2004-02-16 77097
Living at altitude, I can say, it affects both gas and diesel pretty much the same. I think it works something like this, but I'll claim some ignorance - Tuning hotrods was always "play with the jets" until the emissions guy said you passed.
I don't think the air really "drags" the fuel in, but when you are at higher altitude, the partial pressure of oxygen is lower. When your engine takes a gulp of air and gas at sea level, it gets the right mix and you get lots of power.
At higher altitude, when the same engine takes a gulp of air and fuel, it gets less oxygen, but pretty much the same amount of fuel, so you don't get a complete burn (too much fuel, too rich) so you get less power and a bad mix. You can't do much about there being less oxygen and less overall power, but you can re-jet, or adjust the mixture (for example, with fuel injection) to get the amount of fuel back into proportion so that you don't waste fuel sending unburned fuel out the exhaust.
I believe the only real way around this is the "pack the charge" by compressing the intake air so that there is more oxygen than is normally available in the atmospheric air. This is done with either a turbo or super charger, and probably the reason that the only diesel pickups sold around here are turbo'ed. (Even VW bugs have turbo diesels). Also the reason the cop cars in the mountain towns have turbo's... :)
So for a CUT, you either buy bigger, or spend some time in the shop retrofitting... Might be fun when a warranty expires and you have some free time. :P
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| blizzard
Join Date: Jul 2003 Posts: 282 Central Maine
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2004-02-17 77099
DRankin,
I think 'at low LOADS we run very lean' would be more accurate. Then with less oxygen available, it would seem there would be less heat produced and less maximum power at any rpm.
Just my 2cents,
bliz
PS- Thanks for the hitch help. ....
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