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- #41
They didn't give me any pressures "its a little bit low, but in the range" was the wording.
AC effectivness at idle
- Thread starter hammerheadfistpunch
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They didn't give me any pressures "its a little bit low, but in the range" was the wording.
The problem with AC is there are a lot of misconceptions even among technicians. In range at idle can still be under filled. Mine was in range at idle. 28 psi low side 215 high but as soon as the rpm came up it almost dropped to 0 low side. A small recharge has made a world of difference even at idle. Took less than a pound of coolant to fix.
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- #43
Sounds like thats on my list. Since I have no interest in investing in pressure gauges and kits, do you have advice for finding a reputable shop that knows what they are doing?
I find the need for aux fans at idle for both our FZJ80 and LX470 to get freezing cold AC temp when its 115°+
Anyone that tells you an aux fan does help does live where it hot
Anyone that tells you an aux fan does help does live where it hot
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- #46
I don't need ice cubes, but it doesn't do anything at idle. An Aux fan would be nice, but I don't think its not necessary for my locale
Got to agree with LCP. Here we are still two months away from summer and hitting 38c (100+ F ) already, normally 32...ish!
An electric fan will boost AC effectiveness at idle, that is why Mr T fits them as OE in the middle east countries.
We expect 50C (122 F) in Seville in August, not being native, I simply cannot stand those temperatures, car>house>car>bar>car>house, you can forget work!
regards
Dave
An electric fan will boost AC effectiveness at idle, that is why Mr T fits them as OE in the middle east countries.
We expect 50C (122 F) in Seville in August, not being native, I simply cannot stand those temperatures, car>house>car>bar>car>house, you can forget work!
regards
Dave
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IN my experience, the recent install of an aux fan (Spal) has significantly help the efficiency of the A/C while at idle and stop-and-go traffic (ambient temps in the mid to high 90's). The difference is noticeable
However, I have been always careful having lip-sealed the gap between the radiator and the body. I don't think some folks realize the impact (loss) to the air flow of such a gap-particularly at idle and/or low speeds.
Cheers
fj80pb
However, I have been always careful having lip-sealed the gap between the radiator and the body. I don't think some folks realize the impact (loss) to the air flow of such a gap-particularly at idle and/or low speeds.
Cheers
fj80pb
- Thread starter
- #49
I was pretty upset when Big-o not only dented my hood working on my car (which they never did anything about) they also ripped that foam between the rad and the body all to hell. Turns out getting replacement foam isn't easy, so Instead I simply tapped up the gap with high temp gaffers tape (300+ F) which is holding up nicely.
Weather stripping from Lowes / Home Depot works great for radiator saddle gasket
Aux fan (you want one) = low AC output temp
outside temp at test time 109.4°
Left to idle with aux fan on in the sun
intake temp - 132°
Water temp - 184°
Ac vent temp - 47.5°
Without aux fan all reading would be higher
outside temp at test time 109.4°
Left to idle with aux fan on in the sun
intake temp - 132°
Water temp - 184°
Ac vent temp - 47.5°
Without aux fan all reading would be higher
- Thread starter
- #52
Might be worth replacing in the future, but for now the tape is doing a great job, been on there 20,000 miles and its not lost its adhesiveness or split/cracked.
A/C systems are very complex as there are so many variables that can affect cooling capacity. Each component is rated at specific conditions, but when assembled together they function as a system, with constantly changing conditions. Cooling capacity of the compressor is directly related to speed with all other variables constant, so at idle, it will be likely be somewhere between 20% - 40% of rated (likely maximum) capacity. The condenser rejects energy (heat) equivalent to compressor input energy and that of the energy transferred to the evaportor (cooling effect). Condenser cooling capacity will be a function of the temp difference between the refrigerant and air, airflow, refrigerant mass flow and heat exchanger efficiency. You get the picture. Based on my past experience if you can get a delta of 30F between evaporator air in temp and evap air out temp, the system is well designed and working well.
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very interesting since it's an inferior system
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Buddy of mine just bought some big-ass, get-out-of-the-way Chevy 4x4 for hauling his boat around. Didn't come with the tow package, but when he added that on, they switched from an electric fan to a clutch fan. Why?
Who knows? Perhaps there is not enough space to fit a powerful enough electric fan? Or as per Dimples, it was an addition? Or if they needed to fit a bigger electric fan then they would need to alter the wiring, perhaps fit a bigger alternator?
I have said it many times, you CANNOT just bung on the nearest fan from the local junk yard, and expect it to work.
regards
Dave
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I'm not saying you can. I don't remember if it was in addition or replacement. I believe it was the latter, but I will have to double check.
If I had to guess, I would say that is because an engine driven fan is capable of far more CFM than any electric. For putzing around town, electric could work. For my application, it would not. A few rigs out here have tried electric fans, using the ones from factory applications. They are back on clutches now because they ran too hard in the rocks.
I'm not disagreeing that an aux fan will help with AC vent temps, why else would Toyota have made one for our trucks, even if we didn't get it in the US.
I'm merely pointing out that mechanical systems aren't obsolete just yet.
Wrong. Ever looked at the internals of a viscous clutch? They are designed with something of a pump that throws the fluid into a reservoir that stores it outside of the friction plates, and a valve that is temperature-spring activated to let the fluid back into the friction plates. As long as the clutch is setup properly (not too much fluid for the reservoir) it can push all of the fluid out of the clutch plates and spin very free.
When my truck is cold and started, after about 30 seconds (to let the fluid that gravity pulled into the friction plates from sitting still pump back to the reservoir) I can literally grab the fan with my hand, hold it stationary, and rev the engine. For all intents and purposes it completely disengages.
Also, a well-set-up viscous clutch can sit nearly anywhere on the scale between freewheeling and whatever it's max lockup is (determined by fluid viscosity, but MORE than enough lockup at ambient temps to remove any mount of heat being added to the system). Not just two speeds. Yes, there is a delay.. which is one reason I don't like the "throw 25-30k cst fluid in there" mentality.. but our systems don't overheat instantly (that is one of the points of having water as a cooling medium.. absorb an enormous amount of thermal energy and act as a heat-sink). So viscous systems are better at slowly finding balance and removing just enough heat to keep the system stabilized.. while drawing no electrical load whatsoever.
Find me an over the road truck that uses an electric fan. Even our fire apparatus with 600 amps of generating capacity is mechanical. Granted, they usually don't use a viscous clutch, generally running an air-actuated selectable clutch (partly for control over intercooler temps).. but NONE of them are electric.
Likewise, most if not all of the 3/4 and 1-ton diesel pickups come with mechanical fans, usually ECU controlled like the fire apparatus and OTR trucks.
Or maybe they just aren't smart enough to see the light?
All of this isn't to say adding an auxiliary pusher for low/no-speed a/c or engine cooling is a bad idea.. but what you are asserting just isn't true.. an all-electric setup can't compete with a well-designed and maintained mechanical setup, and no, the big manufacturers aren't installing those on heavy duty trucks.
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