Where can i buy a small tempreture probe
#1 _jabba_
Posted 15 March 2006 - 05:09 PM
Basically i need a small digital thermometer that i can stick onto the air vent and measure temps to see if what i do has made any difference. Anyone know any shops or online stores that would have what i need?
Thanks
Damien
#2
Posted 15 March 2006 - 05:24 PM
#3
Posted 15 March 2006 - 06:25 PM
Dick Smith, Jaycar or Tandy. Can get single units, or ones that measure both temp at the display unit, and remote temp via a temperature probe with a long cable. Most do around -40 to +50 C q
Yeah....I got mine at Jaycar.
#4 _jabba_
Posted 15 March 2006 - 08:21 PM
What tempretures would i expect from a aircon that was working well at the vent roughly?
Thanks
Damien
Edited by jabba, 15 March 2006 - 08:22 PM.
#5 _CHOPPER_
Posted 15 March 2006 - 08:24 PM
#6 _jabba_
Posted 15 March 2006 - 09:03 PM
#7
Posted 16 March 2006 - 09:16 AM
From my experience, it depends greatly on the fan speed. higher volumes of air blowing through the evaporator will not be as cold at the vents than if the fan is set to a low speed.What tempretures would i expect from a aircon that was working well at the vent roughly?
Thanks
Damien
The LH manual states Torana A/C outlet temps as low as 3C, up to 12C depending on ambient air temperature (15C up to 43C).
My Calais A/C gets down to 9C with fan on low speed, and around 13C with fan on high speed.
#8 _jabba_
Posted 16 March 2006 - 09:09 PM
Edited by jabba, 16 March 2006 - 09:10 PM.
#9
Posted 17 March 2006 - 09:34 AM
Does that matter?
RACV MAN
#10 _devilsadvocate_
Posted 17 March 2006 - 08:24 PM
If you have the full fact setup, the performance data is stated in the aircon workshop manual and gives the following conditions for doing the test for comparative purposes:
Doors and windows of car closed and vehicle out of direct sunlight.
Engine hood up.
Recirculation mode selected.
Blower on HIGH (IV) speed(many ac shops will �try it on� and quote figures at low fan speeds-the difference is huge)
Engine speed at 2000rpm. (these are fairly standard test conditions for aircon)
Here are the ambient/vent temps(acceptable figures) one should see after 10mins of running the compressor:
16ambient/(3-6)vent
21/(4-7)
27/(5-8)
32/(6-9)
38/(7-10)
43/(9-12)
Note these figures are for stationary(better figures will be seen on the move) and require that a fixed six blade fan or seven blade clutch fan is fitted, later models hx,hj had 12 inch auxiliary electric fans fitted in front of the condenser also, however, these were to improve performance at idle and wont make much difference when doing the test at 2000rpm. Effective underhood cooling is a requirement for this system to work properly and the recommended fans are essential for enough heat transfer, especially at speed or if you have any engine mods which typically will always increase exhaust temps. I have done a lot of measurements here and found that, vent temps, condenser, radiator outlet and exhaust temps drop considerably on my system when the fact clutch fan was refitted for both high and low speed work.
This data is of course if using r12 as a refrigerant, other gases typically don�t perform so well in these setups. The system is different in operation to aftermarket systems. Aftermarket systems have a sensor in the evaporator which disengages the compressor once a predetermined temp is reached, typically 3C, the compressor can be felt engaging and disengaging or �cycling�. The poast system doesn�t operate in this way, it basically controls the flow of refrigerant to the evaporator to maintain a set temp of 3C without disengaging the compressor, the load on the compressor varying with cooling demands. The disadvantages of this being that the compressor is running constantly and even when under partial load is still causing appreciable load to the engine. The advantage is that the air coming out the vents remains at a constant temp and humidity, however, at mild ambients this will see the temp of the cabin get colder and colder � making it necessary to blend air from the heater to keep the interior at a constant 20C or so(hardly efficient). In a cycling system, when the compressor is switched out the system tends to blow warm humid air back into the cabin between cycles�.not comfortable either.
The data ^ will be unobtainable if the recirculation flap on the inlet snorkel hasn�t been installed, as warm air will be drawn from outside, often overlooked when retrofitting fact systems.
Comparison with other vehicles isn�t really relevant, it is important to compare apples with apples here. In newer vehicles, the ac systems have been designed to keep vent temps typically >7C, but one can find they can maintain their low speed temps at higher blower speeds and ambients as well. This is so that occupants near the vents don�t get frozen knee caps etc and so that the possibility of the ac ejecting out any soiled condensation onto someone�s nice white evening gown is brought down to zero. The performance figures quoted ^ are easily obtainable if all the system is in working condition, I have verified them on my system when using r12��..don�t settle for less or be persuaded that 9C is good at 25C ambients just because that is what comes out of a new car.
In relation to insulating the underbonnet box. I have done that to mine, but at the time(~12years ago) didn�t measure a b4 and after temp, can only comment that it didn�t do any harm but certainly wasn�t the answer to getting the vent temps to drop to acceptable levels. I used some insulation for homes, ~1cm of foam + reflective aluminium coating, I�m assuming its got fire retardant built into it, but sure it was never designed to sit close to exhaust manifolds.
If you do decide to insulate yours, then testing it with the aircon on is going to be problematic in getting consistent conditions in which to make a meaningful comparison. It is best to test it with the aircon off�. All the air that enters the cabin using the fan has to go through the evaporator. With the engine at operating temp compare the temp coming out of the evaporator/centre vents/fan assisted with the air coming out of the side vents, (I think I�m correct in saying these aren�t connected to the evaporator on the HQ) the difference between them will tell you how much temp the evaporator is picking up by being in close proximity to the engine. You can then see how much difference any insulation will make. On my vehicle I see about a 2deg difference atm when cruising at 60kmh at 25C ambient. The difference will be higher at higher ambient. You will notice considerable heat soak into the evaporator from the engine after a hot shut down.
For this test ^ to work effectively(and your ac) you must be sure that no water is flowing through the heater core and that the vacuum operated heater valve has been installed in this line, should be no heat on the heater hoses at the heater inlet. Also, check that the bonnet is sealed effectively at the rear and doesn�t let any air pass directly into the plenum chamber. You can test this while you drive along by sticking a thermometer in the plenum chamber, if it goes higher than ambient � you have a leaky bonnet seal, or just rev the motor while stationary and feel for any air blown through by the engine fan.
Hope that gives you more background for your setup.
#11 _jabba_
Posted 19 March 2006 - 12:26 PM
Im using the full factory heater/evaporater box inside and out, but they will be making ducting to feed the two side dash vents. Ill be blocking off the 'fresh air' vents in the plenum all together. I didnt think of testing the setup without the aircon going, thats a great idea and should give more accurate results for heatsoak.
The setup atm is 1 elec fan on the radiator and 1 elec fan on the condenser. What i think im going to do is after its going is install a second fan on the condenser which fits perfectly and covers it completely. I think ill have to replace the radiator fan with something like a falcon thermo fan setup to keep everything cool.
Damien
Edited by jabba, 19 March 2006 - 12:35 PM.
#12 _devilsadvocate_
Posted 19 March 2006 - 03:03 PM
Id give careful consideration to blocking of the side vents from fresh air.
The advantage obviously is to be able to get fan forced refrig air and heater air onto ones face and if you block the inlets at the plenum youll get no outside air leakage into the cabin at speed(we all know how they leak)
Disadvantage is that these vents alone will keep you comfortable when moving (up to a certain temp anyway)and if you have air routed through the evaporator it will come out these vents hotter(due to placement of evaporator as mentioned ^), which basically means youll end up needing to use the aircon more often than if they were kept unblocked(hope that makes some sense)
Probably all up its a plus, sounds like there is enough room in the HQ to do all that, too tight in a torry.
#13 _jabba_
Posted 19 March 2006 - 05:29 PM
Basically just trying to set it all up as per the HQ statesman as best i can, ill probably leave the fresh air ports until i can go look at my dads stato again at Easter. On his statesman there are no fresh air ports, theres metal plates blocking atleast the drivers side (the passenger side fresh air may be ducted straight into the evap box) and im not sure if there is a freshair/recycle option for them?? His car is completely stock and un restored in perfect nic.
I think your right, i would have to use the aircon more often than not if i remove the fresh air all together but then again im not sure if id even them once i have aircon. I know when doing long trips i can point the side vents to blow across the car door and it keeps the air fresh inside but when the aircon goes in ill loose that function anyway and i dont use the huge floor vent as you just get blown away haha.
Edited by jabba, 19 March 2006 - 05:41 PM.
#14 _jabba_
Posted 20 March 2006 - 04:10 PM
I also found that clark rubber make an adheasive stickon heatshilding for about $36 p/m so ill be getting some of that once this is all setup.
Edited by jabba, 20 March 2006 - 04:14 PM.
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