[Shotimes] towing and fuel economy

[Bill Murray]

A way to demonstrate this without a trailer is driving up a hill. You'll 
have your foot closer to the floor going up the hill while maintaining 
3000 RPM, then you will when you come back down the hill, again at 3000 
RPM.  You'll probably even be on the brakes going back down, but still 
able to maintain the same RPM.  The only different thing you'll be doing 
is the action of your right foot.

Bill

Paul Nimz wrote:

>Because of the more open throttle plate caused by your foot pushing the gas
>peddle down further which reduces intake vacuum which causes the O2 sensors to
>see the more O2 which causes the PCM to fire the FIs for a longer duration per
>cycle which causes your wallet to empty faster.
>
>TSB 99-26-9 explains it all if you are interested.  Math formula included.
>
>Paul
>
>
>On 5/28/2005 10:33:41 AM, van Oss (vanoss@centurytel.net) wrote:
>  
>
>>You and Porter have explained the physics.  I grasp the physics.  I think
>>my
>>question is more specifically about engine mechanics.  Let me break it
>>down.
>>
>>-- Cruising at 40 MPH in 3rd gear, without trailer, the tach reads 2500
>>RPM.
>>Same speed and gear with trailer, the RPM should be the same, right?
>>Because in the same gear the whole drivetrain is turning at the same rates,
>>
>>right?
>>
>>-- I grasp that with the trailer the engine is "working harder" and using
>>more fuel.  With trailer, it takes more force to push the piston down.
>>The
>>injectors squirt longer, yes.  The computer, aiming for stoich, keeps
>>the AF
>>ratio as constant as possible,
>>doesn't it?  So here is the main thing I
>>don't grasp:  If the RPM is the
>>same, then valves are opening and closing at
>>the same rates.  How does more air pass through if the valvetrain is at
>>the
>>same RPM?
>>
>>Maybe
>>I'm the slowest guy on the list.  Sorry.
>>
>>VO
>>
>>
>>----- Original Message -----
>>It really boils down to simple physics.  It takes X amount of energy to
>>    
>>
>move
>  
>
>>a mass Y distance.  If you double the mass and all else being equal, it wil
>>    
>>
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