3 simple tweeks give a solid extra 3-5 mpg.

tgray

Veteran Member
Joined
Sep 12, 2004
Location
Marengo, IL
TDI
'02 Beetle, '05 Golf, 2000 Jetta, 2001 Jetta, 2002 Jetta
I adjusted the timing up in adaptation when I first got the car about 7 years ago. That bumped my mpg up a mpg or 2 and for the past 7 years I enjoyed 49-50 mpg on my daily commute. At my last timing belt change at the 200,000 mile mark I had time to try some more adjustments mentioned on this forum. I set my egr higher a few numbers rather than lower as many on the forum do and don't realize that this actually makes the mpg go down as the computer compensates by retarding the timing. I am not too concerned about intake clogging as I did mine at 200,000 and it was not too bad with a fully funtioning egr valve all those miles. As well, I set my timing to the top end of the graph from the adjustment bolts on the injection gear. With all of these adjustments it runs better than it ever did, starts very easy and has a lot of smooth power. (Still running on the same stock injectors). I now have been getting a solid 52-53 mpg without much effort at all. I pretty much drive with the flow of traffic and my hit 70 mpg once in a while so I am not hyper-mile driving to get these numbers. My car is a new beetle so the wind hits me a little harder than the others. All I can say after 7 years of driving I am still impressed. My one nagging question is what could a tune chip do with bigger nozzles over and above the mpg's I am getting now? I see many claim better mileage after the tune and nozzles but I wonder if they have just ended up with the same end results of advanced timing over the stock settings. Bigger nozzles by themselves end up advancing the timing by getting the fuel delivered quicker into the combustion chamber for a longer burn.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
My hat is off to any and all that do things to increase MPGs.

I do have one question, do you keep records on the gallons of fuel consumed (at least two decimal places), miles, vent until filled completely, etc., tank-after-tank?

I have 253,987 miles (386 fill-ups) being 5,042.82 gallons of fuel (life time average of 50.366 MPGs). According to my records (in Excel spreadsheet), when I did the EGR mod the MPGs did increase (very slight, maybe 1 mpg). The timing has always stayed very near the upper limit within the graph, TB change after TB change. I have never had to set/re-set the timing.

Since I retired (3/2008) my driving habits have changed unfavorably for good MPGs. I do far more driving that's similar to city driving now than previously. So, the MPG average is slowly moving down. Of course, at almost 300k miles with original injectors it's probably going to continue to drop in MPGs. Also, for about the last five tanks of fuel I've been running a GASSER 5th gear due to tranny issues. That has dropped my MPG to around 46-48. A new 5th gear upgrade is just around the corner.
 
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