re. factory instrumentation accuracy & mpg

Chander Balakrishnan balakrishnan3 at
Sun Jan 26 16:53:17 EST 2003

I have a 87 5ktq with the 1.8 bar SJM modification, and a 1990 200 avant
stock.  The best mileage I have gotten with either car with my daily
driving - a combination of driving around town and highway is 20 -21 mpg (as
measured by fill ups and miles elapsed, not the computer in the car).  It
drops a tad, to about 18-20 mpg in summer on hot days.

Both cars have been on long trips to the East from Chicago, all Interstate
driving, and the best they have done then is about 24-26 mpg.  These mileage
numbers are consistent (as I remember) with the numbers on the sticker on
the 1987 5kcsq (which I still have).  I am surprised at the 28 mpg claimed
here.  I consider myself a normal driver, neither heavy footed or very light
footed.  IS there something wrong with my cars or my driving style ?


-----Original Message-----
From: quattro-admin at [mailto:quattro-admin at]On
Behalf Of Phil Rose
Sent: Sunday, January 26, 2003 3:51 PM
To: Brett Dikeman
Cc: ben swann; flyboysteve at; quattro at;
200q20v at
Subject: Re: re. factory instrumentation accuracy & mpg

At 1:10 PM -0500 1/26/03, Brett Dikeman wrote:
>At 12:24 PM -0500 1/26/03, ben swann wrote:
>>Yes - peeve # 2 on the new aquisition of the '91 200 20v tq avant.  Has
>>SJM chip with 2.5 bar pressure transducer AFAIK.  Gas mileage abysmal
>>on the way home - 20MPG and no I was not easy on the gas and probably
>>averageing over 70.  My '87 5000 tq would get an easy 28 mpg under the
>>same conditions.  I thought Motronic was supposed to be superior at
>>engine management, including economy, over CIS (CIS/motronic).
>>What's up with that?

Ben, were you referring to mileage from the on-board computer--or actual
fill-ups? If the former, don't forget the error in computed MPG may be
pretty large (mine was at least 10% low) unless the fuel-consumption factor
is corrected (this is done by an IC adjustment, and I believe my write-up
about this can be found on Chris Miller's web site.) If you measured by
odometer and pumped amount, then I dunno.

I agree that 20 MPG sounds rather low--unless your foot was really into it
a lot. In my '91 200q, good gas mileage requires an extremely steady
throttle (irrespective of speed it seems). With very steady cruising I'll
routinely get 28 MPG even at 80 MPH; however with a lot of passing, hills,
etc., could easily drop to low 20s.


Phil Rose
'91 200q lago blue				Rochester, NY USA
'91 200q tornado red				mailto:pjrose at

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