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Why old cars in thailand have less engine power when aircon is open?


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The aircon is driven by the engine, not the battery.....it's essentially like the pump on your fridge.

It takes quite a lot of power to keep a car cool - depending on the size of the cabin.

So if you couple an inefficient air-con to an inefficient engine, you are going to get problems in the long run.

With the air full on, you should notice things like loss of performance and increased fuel consumption. however as most people seem to have their air just about full on all te time it is more likely to show a difference the other way - if you run for a month with it off.

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older cars use piston pumps in the Airco which takes a lot of Horsepower to turn

new cars use rotary compressors which use about half as much HP

When not in use the pump freewheels and takes very little power , ( electric clutch in the pulley)

one trick is to set up a switch under the pedal so when you push hard the pump shuts off (freewheels) and you can use the power to pass.....

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Because your engine has no torque.

next question? smile.png

Rather than just make a facetious comment perhaps you'd like to back that up with some reasoning and even a solution?

Eeeeeeeeeeeeeeer, IMHO is right................smile.png

A/C is driven by engine power, robs stuff from the drive train. On small engines with low torque numbers you will feel it. Unlike a diesel truck where max torque is available at very low RPM.......

..and what car do you think it is?

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Because your engine has no torque.

next question? smile.png

Rather than just make a facetious comment perhaps you'd like to back that up with some reasoning and even a solution?

Eeeeeeeeeeeeeeer, IMHO is right................smile.png

A/C is driven by engine power, robs stuff from the drive train. On small engines with low torque numbers you will feel it. Unlike a diesel truck where max torque is available at very low RPM.......

..and what car do you think it is?

Sounds like a knackered one..laugh.png

Same scenario, worn bores, power loss. Plus depends if you have a piston type compressor. These rob oodles of engine power. My old V6 Volvo had one, switch the A/C on and it was like someone pulled the handbrake on....facepalm.gif

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Because your engine has no torque.

next question? smile.png

Rather than just make a facetious comment perhaps you'd like to back that up with some reasoning and even a solution?

Eeeeeeeeeeeeeeer, IMHO is right................smile.png

A/C is driven by engine power, robs stuff from the drive train. On small engines with low torque numbers you will feel it. Unlike a diesel truck where max torque is available at very low RPM.......

..and what car do you think it is?

One with poor levels of torque :)

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The engine must be in a bad way. Even my swift with a paltry 91 bhp is barely affected by turning on the air. It sounds like the engine needs an overhaul and/or perhaps in older cars the air cond systems were not as efficient as modern ones. Changing the battery won't do anything.

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Because aircon uses power.

You can put a circuit at the end of your throttle peddle which connects up when you push the throttle to a certain level which has a relay in the circuit with the off position connected to your aircon button/power circuit.

This will temporarily disable your aircon when you push the accelerator beyond a certain adjustable point giving you that extra boost.

You won't notice any increase in temperature unless you drive with your foot to the floor for a few minutes.

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I've never been in any car that wasn't effected by turning on the air. It always sucks power. True it wasn't a big deal back in the States driving big V-8s, but on these tiny motors sold in Thailand, of course its going to markedly reduce engine power, even in a new car. I usually turn off the air by pushing the 'compressor button' or turning the cool dial to zero if I have to do some momentary accelerating.

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I usually turn off the air by pushing the 'compressor button' or turning the cool dial to zero if I have to do some momentary accelerating.

You turn off the AC to accelerate? :P

I don't even want to ask what you drive :D

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older cars use piston pumps in the Airco which takes a lot of Horsepower to turn

new cars use rotary compressors which use about half as much HP

When not in use the pump freewheels and takes very little power , ( electric clutch in the pulley)

one trick is to set up a switch under the pedal so when you push hard the pump shuts off (freewheels) and you can use the power to pass.....

Most AC compressors are Piston, very few use rotary vanes, they fail too easy when gas is low and the oil isnt there to lubricate, it is the efficiency of the newer compressors that has improved, they still are around 1-2hp drain though.

Some older cars use whats called a suction throttling valve and run the compressor 100% of the time and bypass the evaporator when cooling isnt needed, thse suxk hp all the time but provide much better cooling, they were used on GM's a lot with Delco 12 cuin compressors.

Most small cars use a 5-8 cuin compressor now requiring a lot less hp

A swash plate compressor, fairly efficient usually 5-9 cuin capacity

post-4090-0-36308200-1428215659_thumb.jp

An old York on the right, inefficient but last forever next to a newer style

post-4090-0-00675800-1428215672_thumb.jp

An A\old AC Delco A6 used by GM and Jaguar 12 cuin of cooling power big bulky and heavy, like putting the breaks on when they kick in

post-4090-0-17675400-1428215640_thumb.jp

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Nice post Baz, Delain Air supplied Jags with their systems , just to add info for you.thumbsup.gif

I should have qualified it better, The only ones I worked on were XJ6 S1-3, S1 were aftermarket mainly in Australia and ran York (pictured previously) style coms, while S2-S3 6 and 12 ran AC Delco's (Harrison GM A6), which always eneed up leaking at the front or rear case oring.

post-4090-0-32173800-1428599896_thumb.jp

A6 fitted to a V12 Injected

post-4090-0-04718600-1428601095_thumb.jp

These Sanden Scoll compressors were the worst thing ever, the carbon facings broke down so easy, easpecially on low gas, and the proceeded to block the TX and Receiver dryer, need a full overhaul afterwards

post-4090-0-32261500-1428599906_thumb.jp

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