From: Andrew W on
Does using the air conditioner consume much more fuel, especially when
accelerating?
And wouldn't one save fuel by installing a vacuum switch that disengages the
aircon while accelerating?
Perhaps some newer cars already have this?


From: dsi1 on
On 4/18/2010 2:11 PM, Andrew W wrote:
> Does using the air conditioner consume much more fuel, especially when
> accelerating?
> And wouldn't one save fuel by installing a vacuum switch that disengages the
> aircon while accelerating?
> Perhaps some newer cars already have this?
>
>

Using the air conditioner will consume more fuel. I don't know what you
consider "much more." My guess is that it uses a little more fuel. We
used to have a Ford with an AC that shut off under low vac conditions -
boy was that annoying!
From: Sharx35 on


"dsi1" <dsi1(a)spamnet.com> wrote in message
news:t%Uyn.76924$iL1.31771(a)newsfe24.iad...
> On 4/18/2010 2:11 PM, Andrew W wrote:
>> Does using the air conditioner consume much more fuel, especially when
>> accelerating?
>> And wouldn't one save fuel by installing a vacuum switch that disengages
>> the
>> aircon while accelerating?
>> Perhaps some newer cars already have this?
>>
>>
>
> Using the air conditioner will consume more fuel. I don't know what you
> consider "much more." My guess is that it uses a little more fuel. We used
> to have a Ford with an AC that shut off under low vac conditions - boy was
> that annoying!

Remember the days when vacuum operated windshield wipers would shut down
while climbing hills?


From: dsi1 on
On 4/18/2010 11:57 PM, Sharx35 wrote:
>
>
> "dsi1" <dsi1(a)spamnet.com> wrote in message
> news:t%Uyn.76924$iL1.31771(a)newsfe24.iad...
>> On 4/18/2010 2:11 PM, Andrew W wrote:
>>> Does using the air conditioner consume much more fuel, especially when
>>> accelerating?
>>> And wouldn't one save fuel by installing a vacuum switch that
>>> disengages the
>>> aircon while accelerating?
>>> Perhaps some newer cars already have this?
>>>
>>>
>>
>> Using the air conditioner will consume more fuel. I don't know what
>> you consider "much more." My guess is that it uses a little more fuel.
>> We used to have a Ford with an AC that shut off under low vac
>> conditions - boy was that annoying!
>
> Remember the days when vacuum operated windshield wipers would shut down
> while climbing hills?

I have heard of vac operated wipers but that was before my time. The
oldest car I've ever had was a 65 Nova. Just lucky, I guess. :-)
From: C. E. White on

"Andrew W" <removethis_ajwerner(a)optushome.com.au> wrote in message
news:4bcb9fb0$0$22779$afc38c87(a)news.optusnet.com.au...
> Does using the air conditioner consume much more fuel, especially
> when accelerating?

In theory using the A/C should consume more fuel. In practice, I've
never been able to detect the difference. I keep fuel log books for
all my vehicles. I've looked at fuel consumption by month numerous
times and find that often my lowest average fuel consumption is in the
summer, when A/C usage is the highest. My assumption is that changes
in fuel composition, driving patterns, warm up time, etc., etc.,
totally mask any additional fuel consumption related to A/C usage.

> And wouldn't one save fuel by installing a vacuum switch that
> disengages the aircon while accelerating?
> Perhaps some newer cars already have this?

I think all new cars have the ability to disable the A/C during period
of maximum power requirements. There is no longer a need to use a
vacuum switch for this function. The engine computer can decide to
disengage the A/C compressor only at wide open throttle or some as the
result of other combinations of conditions based on the various sensor
inputs. This is a lot more sophisticated than using a simple vacuum
switch.


Ed