<VV> Fuel mileage

Sun Apr 17 10:12:56 EDT 2011

Forget the Prius etc.  My son bought a used 2003 Jetta TDI wagon with 
350,000 miles on it for $5000.  I recently received this email from him 
about his "record" tank.  " Filled up tonight, managed to (barely) get the 
magical 1000 miles on a tank,  worked out to 59.8 mpg.  It took 16.743 
gallons to fill, so I probably had a quart left."

   Pretty good for an older used car.  He drives 60 highway miles to work 
each day.

Dennis D.

----- Original Message ----- 
From: "Ken Pepke" <kenpepke at juno.com>
To: "Vair Views" <virtualvairs at corvair.org>
Sent: Sunday, April 17, 2011 9:31 AM
Subject: <VV> Fuel mileage

>
> Anyone wishing to get the best fuel milage possible should first, know 
> what they have.  The first step would be a trip to a chassis dynamometer 
> ... Find out the engine RPM at the point the torque curve crosses the HP 
> curve.  It is in this area that the engine is operating at its maximum 
> volumetric efficiency.  Do this at the level of 'tune' at which the 
> vehicle is driven regularly but do adjust the timing between tests.  Gear 
> the vehicle to run in that RPM range for most of the type driving done in 
> the vehicle.  [City, highway, flat land, hills, mountains, etc.]  High 
> gears / slow engine speed is not necessarily the best mileage builder.  A 
> Corvair with the 3.27:1 axle gear and driven in the city might never 
> shifted to a gear higher than second.
>
> Even the best of the 'stock' Corvairs do not have a particularly good 
> performance level ... The torque curve, instead of being high and flat, 
> builds slowly with engine RPM and never gets all that high.  Sadly, long 
> ago the Corvair was saddled with an 'affordable' reputation.  I say sadly 
> because the Corvair engine has a whole world of potential that has not, 
> and will never be, explored.  Had the aftermarket seen a potential for a 
> performance market, we would be miles ahead in available equipment.  A 
> respectable, by today's standards, torque curve is just not available. 
> While there is some possibility of increasing fuel milage in a daily 
> driven Corvair, a respectable by today's standards, torque curve is just 
> not available.  The car will probably not produce a feel / sound level to 
> which we have become used to in vehicles of much more recent manufacture.
>
> A few years ago several of my co-workers decided to buy Suburbans.  While 
> they were ordering, one of them came to me and asked about rear axle 
> ratios.  I got the engine torque specs and vehicle weight information, 
> plugged them into my 'handy dandy' calculator wheel and recommended he 
> select the lowest available 3.90:1 axle ratio.  That vehicle got the best 
> milage of the group and was the most pleasant to drive ... even on his 
> trips to Florida although he did notice the engine speed on the 
> expressways.
> Ken P
> Wyandotte, MI
> Worry looks around; Sorry looks back, Faith looks up.
>
> **********************
>
>> From: FrankCB at aol.com
>> Date: April 16, 2011 12:32:01 PM EDT
>> To: chartzel at comcast.net, virtualvairs at corvair.org
>> Subject: Re: <VV> Fuel mileage
>>
>> Right On, Clark!
>> Further on the "overdrive transmission", the important thing is the 
>> OVERALL
>> ratio from engine to rear wheels which takes into account BOTH the
>> transmission  ratio in top gear and the axle ratio.  Most of the Corvairs 
>> have the
>> 3.55  to 1 axle ratio and 1 to 1 top gear transmission ratio giving
>> something like  3000 engine rpm at 60 mph.  In contrast, my 1995 
>> "Dustbuster" Trans
>> Sport  Minivan has a 3.06 axle ratio and an overdrive ratio (less than 1 
>> to
>> 1) in the  4th speed of the 4T60-E auto trans.  The result is only 1800
>> engine rpm at  60 mph.  This gives me 26 to 28 mpg on long highway trips 
>> with an
>> engine  (3.8 liter) that is 40% LARGER than the Corvair's 2.7 liter 
>> engine.
>> GM did have a 3.08 axle ratio that they put out briefly to achieve better
>> mileage for the Economy Runs in the 1960s.  That would certainly help
>> improve highway mileage.
>> In addition, a modern EFI engine has computer-controlled feedback from 
>> the
>> exhaust gas oxygen sensor that continually adjusts the EFI to maintain 
>> the
>> correct fuel to air ratio giving great mileage.
>> But perhaps the GREATEST influence on highway mileage is due to the "nut
>> behind the wheel".  I'm continually amazed at the number of people who 
>> come
>> up behind me in traffic, pull out and pass me and then race to the next
>> traffic  light where they have to JAM on their brakes to stop at the 
>> light.
>> Many  times, by the time I coast up the to the light, it has turned green 
>> and I
>> can  get through it WITHOUT stopping.  Guess who's getting the better gas
>> mileage!!
>>
>> Frank "tightwad" Burkhard
>>
>>
>> In a message dated 4/16/2011 7:54:02 A.M. Eastern Daylight Time,
>> chartzel at comcast.net writes:
>>
>> Harry  Smith wrote about using a Corvair as a daily driver.  I doubt  a
>> Corvair is going to get 20 MPG in the city.  I have never gotten  more 
>> than
>> 22 MPG in any Corvair I ever owned.  Corvairs have two major  drawbacks 
>> for
>> good fuel economy:  carburetors and no overdrive.
>> If  you are looking for good economy get a small fuel injected car with 
>> an
>> overdrive transmission.
>> Clark  Hartzel
>
>
>
>
>
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