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Posted by: 914itis Aug 19 2012, 08:43 PM

I decided to check my gas mileage on the 2.0. (stock Djet)

I filled up, with 89, drove 100.03 miles, averaged 50 miles /HR with slow traffic at times then fill up again. The tank took exatly 2.60 gallons. If i did my math correctly thats about 38.5 miles per gallon.
Is that real?

Posted by: mepstein Aug 19 2012, 08:52 PM

Paul - You probably need a larger sample size (more miles, couple tanks of gas) before you get a good reading for mileage.

Posted by: Cupomeat Aug 19 2012, 08:59 PM

I agree that your consumption size was too small to mitigate factors such as how much you may have filled the tank, etc. BUT I used to get 36mpg with my 75 1.9l l-Jet car.

Posted by: Philip W. Aug 19 2012, 09:11 PM

Could be close on straight highway driving, not stop and idle etc. My 75 d-jet i've done 33-34 on interstate on a 5 hour trip, @75, did one trip since rebuilding my tranny at scotty b' s dr.evil rebuild clinic and @ 200 mile trip was close to 40, but that was to test my gear ratio change of 4 & 5 th. . Seems to jhave made a big difference.

Posted by: kg6dxn Aug 19 2012, 09:15 PM

You also must consider tire size. Smaller diameter (low profile) tire will track a higher speed and more miles than stock tires.

Posted by: luskesq Aug 19 2012, 10:12 PM

With a stock 1.7, including stock tire size (I believe 165's), on the freeway I have had 39 mpg. About half that though around town.

Keith

Posted by: damesandhotrods Aug 19 2012, 11:14 PM

Well in Porsche ads they claimed 29 mpg. In a ’70 Road & Track comparison test a 1.7 Liter recorded 31.5 mpg. So if you were running gasoline your numbers would be ballpark. Now if you have ethanol in your gas like we do then I’d say something is wrong.

Posted by: Dave_Darling Aug 20 2012, 12:12 AM

Could be accurate, but any measurement errors in filling will be pretty large relative to the amount of gas used. And that will have large effects on the MPG calculation with small amounts of gas consumed.

Better is to run down to the reserve light being on, then fill up to where you can see the fuel in the filler neck. Or have it come up to a notch on a pre-measured stick you put down into the tank.

Best is to do that over the course of many tanks. The errors will tend to average themselves out.

--DD

Posted by: ChrisNPDrider Aug 20 2012, 01:57 PM

Likely an over-estimate of MPG
My 1.7 with weight reduction, lowered, and stock D-jet averages 35-37 MPG on the freeway (multiple tank/trips over the years) but much less with stop and go around town and through the twisty roads I typically drive.

Bottom line- 914s can get great mileage and we should drive them more often!

Posted by: The Cabinetmaker Aug 20 2012, 02:25 PM

Put one gallon of gas each in 2 cans. On a relatively flat freeway, drive till you run the car out of gas. Pour in one gallon and drive it at 60 mph till it runs out again. Note start and stop mileage with your gps. Do the math, then pour in the 2nd gallon and go to the next gas staition. I survived the 55 mph national speedlimit. I got 45mpg in my 1.7 at 55mph on a trip to dallas to see bob dylan in the 70's. 39 mpg at 50 in 5th gear in a well tuned 2L is very believable.

Posted by: r_towle Aug 20 2012, 04:11 PM

What is your tire diameter?
Tire rack will tell you if you look up the tire and look at the specs.

38 in a 2.0 liter is really not possible if you have it tuned properly.

I got to 38 in a 1.7 with a ton of work and never got over 40 which was my goal.

Now I run smaller tires and I dont care anymore.
It was a challenge, with quite a bit of fiddling with the fuel injection, the MPS, and tuning.

Rich