winter fuel consumption

[Nathan Winters]

How about increased drag related to colder lubricants in the trans / diffs for 
the AWD system?





----- Original Message ----
From: Huw Powell <audi at humanspeakers.com>
To: Brandon Rogers <brogers at terrix.com>
Cc: 200q 20v <a200q20v at gmail.com>; quattro at audifans.com; 200q20v at audifans.com
Sent: Wed, January 26, 2011 4:09:47 PM
Subject: Re: winter fuel consumption

The "more power" only affects it during acceleration, and only if you 
use it.

Under plain old driving down the road, the power needed is all that is 
produced (otherwise you'd accelerate).  It might occur at a slightly 
higher pedal position due to the density of the incoming air, but with 
CIS the plate is going just as high and metering the correct amount of 
fuel, other MAF sensors will react similarly.  If you mat the pedal a 
lot, could end up being significant, of course.

Oh, I just thought of another one - the aerodynamic and other effects of 
snow and ice (and sand and salt) stuck all over the car might matter.

On 1/26/2011 3:53 PM, Brandon Rogers wrote:
> I agree colder/denser air does not affect efficiency, but because the air is
> more dense you have to use more fuel to keep the mixture correct - hence
> these motors making more power (more fuel and more air) at a given rpm
> compared to summer (warmer temps).  That's what makes sense to me anyway.
>
> Brandon
>
>
>
> -----Original Message-----
> From: Huw Powell [mailto:audi at humanspeakers.com]
> Sent: Wednesday, January 26, 2011 1:21 PM
> To: Brandon Rogers
> Cc: '200q 20v'; 200q20v at audifans.com; quattro at audifans.com
> Subject: Re: winter fuel consumption
>
>
>
>
> On 1/26/2011 11:59 AM, Brandon Rogers wrote:
>> I think also, colder, denser air requires more fuel to keep the proper
>> mixture.
>
> But that doesn't affect efficiency, it just makes a higher fuel/air
> charge possible if the engine management can handle it.
>
>> Snow tires affect mileage.  More stop n go during snow storms.
>
> Yup.
>
>> Extra idle time to warm up.  I know I sure like the extra power in
>> cold temps so my right foot gets happy too.
>
> And that too.
>
> Also, no-one mentioned spinning tires, which can happen by accident, or,
> um, on purpose.  Although, theoretically, that would still turn the
> odometer...
>
>>
>> Brandon
>>
>>
>>
>> -----Original Message-----
>> From: 200q20v-bounces at audifans.com
>> [mailto:200q20v-bounces at audifans.com] On Behalf Of 200q 20v
>> Sent: Tuesday, January 25, 2011 7:51 PM
>> To: 200q20v at audifans.com
>> Cc: quattro at audifans.com
>> Subject: winter fuel consumption
>>
>>
>> Every winter my 200 becomes a gas guzzler. With the coldest winter on
>> my ownership on record (global warming?) it has been the worst. It is
>> approaching consumption of a 4.2 V8  in city driving. There is no loss
>> of power, fuel smell, unusual exhaust, etc. VAG-COM data appears to be
>> withing recommended limits.
>>
>> The only observation is that when engine is cold simultaneous clutch
>> disengagement/gas release while driving with no acceleration (2nd or
>> 3rd
>> gear) on a horizontal road results in noticeable RPM increase for a
> fraction
>> of a second. If accelerating it is even more noticeable.
>>
>> Has anyone seen/solved anything like this?
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>

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/
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