Throttle Body Heater
#21
12-30-2008, 11:11 PM
RE: Throttle Body Heater
ORIGINAL: NiteTrain
if heated intake air is so beneficial then why do people spend hundreds of dollars on intercoolers?
colder air = more dense charge = more power = less throttle
if you believe everything on a LR is perfectly engineered then you should leave your original U-joints in your D2 front drive shaft.
if heated intake air is so beneficial then why do people spend hundreds of dollars on intercoolers?
colder air = more dense charge = more power = less throttle
if you believe everything on a LR is perfectly engineered then you should leave your original U-joints in your D2 front drive shaft.
#23
12-31-2008, 09:49 AM
#24
12-31-2008, 07:50 PM
#25
12-31-2008, 09:51 PM
RE: Throttle Body Heater
[/quote]
Denser charge requires more fuel as well.
[/quote]
Not entirely true. On fuel injection systems it will add more fuel only if the o2 sensora more lean conditionis being exhausted from the cyclinder. But more air means more oxygen which means more power. Fuel is NOT the power adder. But more air will lean it out which creates more power. The exact reason my dragster runs faster when the density altitude drops and slows when it goes up.
I know this was off topic. So as for the heater. I feel it's only needed in REALLY cold climates. I dont really think anywhere in the continental US needs it. These things are built to be sold to any location on earth. So they dont take any chances. So remove the heater and gain yourself an estimated .000001 hp.
and yes, I calculated that. hehe....
Denser charge requires more fuel as well.
[/quote]
Not entirely true. On fuel injection systems it will add more fuel only if the o2 sensora more lean conditionis being exhausted from the cyclinder. But more air means more oxygen which means more power. Fuel is NOT the power adder. But more air will lean it out which creates more power. The exact reason my dragster runs faster when the density altitude drops and slows when it goes up.
I know this was off topic. So as for the heater. I feel it's only needed in REALLY cold climates. I dont really think anywhere in the continental US needs it. These things are built to be sold to any location on earth. So they dont take any chances. So remove the heater and gain yourself an estimated .000001 hp.
and yes, I calculated that. hehe....
#26
01-01-2009, 04:18 PM
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#27
01-01-2009, 09:03 PM
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RE: Throttle Body Heater
Welp, Fellers
After reading all the posts (all helpful) what I have determined is
A. fix it by, by-pass, permanently (I'll probably go this way mainly because the weather sux now and return to factory later)(no garage)
or
B. fix it to original equipment, maybe in another 60k fix again
I have also learned here that my original statement of "over engineered" (although it still kinda applies) was a bit much (me being a new owner) I had never considered the worldwide commitment of Land Rover - This post has improved my knowledge of the system and my apologies to any LR True Bloods I may have offended.
Robert
After reading all the posts (all helpful) what I have determined is
A. fix it by, by-pass, permanently (I'll probably go this way mainly because the weather sux now and return to factory later)(no garage)
or
B. fix it to original equipment, maybe in another 60k fix again
I have also learned here that my original statement of "over engineered" (although it still kinda applies) was a bit much (me being a new owner) I had never considered the worldwide commitment of Land Rover - This post has improved my knowledge of the system and my apologies to any LR True Bloods I may have offended.
Robert
#28
01-01-2009, 09:25 PM
RE: Throttle Body Heater
http://www.odysseyshow.com/
Some Rovers spend their lives in places that we have never even heard of before.
Here is my thoughts on all of the coolant leaks on Land Rover DII's.
They came from the factory with DexCool in the cooling system, LR recommends changing it every 45,000 miles or 36 months, whichever is sooner.
DexCool becomes corrosive if it is not properly maintained.
So I think that if you were to repair the t-body heater and then flush your cooling system and refill with another aluminum approved coolant that it will never leak again.
Some Rovers spend their lives in places that we have never even heard of before.
Here is my thoughts on all of the coolant leaks on Land Rover DII's.
They came from the factory with DexCool in the cooling system, LR recommends changing it every 45,000 miles or 36 months, whichever is sooner.
DexCool becomes corrosive if it is not properly maintained.
So I think that if you were to repair the t-body heater and then flush your cooling system and refill with another aluminum approved coolant that it will never leak again.
#29
12-15-2009, 09:09 PM
#30
12-16-2009, 12:34 AM
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As a pilot I figured I would add my 2 cents.
Light aircraft, in particular aircraft with carburated engines, use carburetor heat to prevent ice from forming around the butterfly valve. When applied it bypasses the air filter and takes hot air from a shroud around the exhaust to heat and melt any ice that is present. The two main factors that lead to carb ice in aircraft (or old cars) are the vaporization of fuel and the decrease in pressure at the butterfly valve at low RPM's. As the fuel vaporizes, it takes heat to change from a liquid to a gas. At idle to partial throttle, the butterfly valve forms a venturi where the pressure of the air drops, also lowering the temperature. If the air has enough moisture in it, this cooling can lead to the air reaching its saturation point and ice forming.
The Discovery uses multiport fuel injection, so the main issue here is the venturi effect at the butterfly valve during periods of extended idling, not at high RPM or full throttle operation when this effect is reduced/eliminated.
"Night Train
I've heard of that (freezing) problem - in theory - but it leads me to these questions
If warm dry air is that important then why
A. isn't the heater at the beginning of the system - the filter element could block because of ice, then the vehicle would just stop
B. isn't this "heater" on all the other cars I've owned "
As described, the heater is intended to negate the cooling caused by the venturi effect at the butterfly valve. Unlike aircraft, where the filter is directly exposed to the elements (ice, rain, snow) the Discovery's filter is protected by the fact that air is drawn in from in front of the drivers side wheel and very little liquid moisture reaches the filter.
Each vehicle is different in how the engine is mounted, how air flows around it, and how and where the different components are mounted. If the throttle body is mounted in a way that allows it to draw a large amount of heat from the engine, then this system might not be needed. I'm not an engineer and I had nothing to do with designing this engine, but the people who did apparently saw a need to add additional heating. I'm sure they studied how heat is dispersed in and around the engine and deemed this necessary.
"NiteTrain
I think its only beneficial to keep the throttle body heater in really cold climates."
In really cold climates, you probably don't need this. Antarctica is actually a polar desert, with very low relative humidity. Relative humidity in Antarctica can be as low as 1%. With such a small amount of moisture in the air, the chance of any ice forming is almost non existent. However, on a cool but humid day in Texas, you have a much much higher chance of ice forming as the moist air is cooled to at or below freezing. Prime conditions for carb ice to form in an aircraft is a descent at idle on a humid, 70 degree day.
"LambChop
Ever notice that engines tend to get better gas mileage in warmer climates? I would venture a guess that the throttle body heater is not only there to prevent freezing, but also to improve mileage. Warmer air = less dense air which means less fuel for the intake charge... better mileage typically."
The amount that the actual air is warmed will be minimal at most. You are really just heating the metal bits. Besides, the inlet air temperature sensor is co-located with the MAF, well upstream of the throttle body.
Sorry for the long post, but hopefully this helped clear up some of the mystery around the throttle body heater.
Last but not least this is taken from FAA.gov (http://www.faa.gov/ats/afss/newyork/ENROUTE.htm)
“Throttle ice is formed at or near a partly closed throttle valve.**The water vapor in the induction air condenses and freezes due to the venturi effect cooling as the air passes the throttle valve.**Since the temperature drop is usually around 5°F, the best temperatures for forming throttle ice would be 32-37°F although a combination of fuel and throttle ice could occur at higher ambient temperatures.**
In general, carburetor ice will form in temperatures between 32-50°F when the relative humidity is 50% or more.**If visible moisture is present, it will form at temperatures between 15-32°F.”
Light aircraft, in particular aircraft with carburated engines, use carburetor heat to prevent ice from forming around the butterfly valve. When applied it bypasses the air filter and takes hot air from a shroud around the exhaust to heat and melt any ice that is present. The two main factors that lead to carb ice in aircraft (or old cars) are the vaporization of fuel and the decrease in pressure at the butterfly valve at low RPM's. As the fuel vaporizes, it takes heat to change from a liquid to a gas. At idle to partial throttle, the butterfly valve forms a venturi where the pressure of the air drops, also lowering the temperature. If the air has enough moisture in it, this cooling can lead to the air reaching its saturation point and ice forming.
The Discovery uses multiport fuel injection, so the main issue here is the venturi effect at the butterfly valve during periods of extended idling, not at high RPM or full throttle operation when this effect is reduced/eliminated.
"Night Train
I've heard of that (freezing) problem - in theory - but it leads me to these questions
If warm dry air is that important then why
A. isn't the heater at the beginning of the system - the filter element could block because of ice, then the vehicle would just stop
B. isn't this "heater" on all the other cars I've owned "
As described, the heater is intended to negate the cooling caused by the venturi effect at the butterfly valve. Unlike aircraft, where the filter is directly exposed to the elements (ice, rain, snow) the Discovery's filter is protected by the fact that air is drawn in from in front of the drivers side wheel and very little liquid moisture reaches the filter.
Each vehicle is different in how the engine is mounted, how air flows around it, and how and where the different components are mounted. If the throttle body is mounted in a way that allows it to draw a large amount of heat from the engine, then this system might not be needed. I'm not an engineer and I had nothing to do with designing this engine, but the people who did apparently saw a need to add additional heating. I'm sure they studied how heat is dispersed in and around the engine and deemed this necessary.
"NiteTrain
I think its only beneficial to keep the throttle body heater in really cold climates."
In really cold climates, you probably don't need this. Antarctica is actually a polar desert, with very low relative humidity. Relative humidity in Antarctica can be as low as 1%. With such a small amount of moisture in the air, the chance of any ice forming is almost non existent. However, on a cool but humid day in Texas, you have a much much higher chance of ice forming as the moist air is cooled to at or below freezing. Prime conditions for carb ice to form in an aircraft is a descent at idle on a humid, 70 degree day.
"LambChop
Ever notice that engines tend to get better gas mileage in warmer climates? I would venture a guess that the throttle body heater is not only there to prevent freezing, but also to improve mileage. Warmer air = less dense air which means less fuel for the intake charge... better mileage typically."
The amount that the actual air is warmed will be minimal at most. You are really just heating the metal bits. Besides, the inlet air temperature sensor is co-located with the MAF, well upstream of the throttle body.
Sorry for the long post, but hopefully this helped clear up some of the mystery around the throttle body heater.
Last but not least this is taken from FAA.gov (http://www.faa.gov/ats/afss/newyork/ENROUTE.htm)
“Throttle ice is formed at or near a partly closed throttle valve.**The water vapor in the induction air condenses and freezes due to the venturi effect cooling as the air passes the throttle valve.**Since the temperature drop is usually around 5°F, the best temperatures for forming throttle ice would be 32-37°F although a combination of fuel and throttle ice could occur at higher ambient temperatures.**
In general, carburetor ice will form in temperatures between 32-50°F when the relative humidity is 50% or more.**If visible moisture is present, it will form at temperatures between 15-32°F.”