My observations on the fuel economy of a 97 Jetta.

"Decay buys too many beaters" (decay) 08/12/2013 at 19:12 • Filed to: VW, Fuel Economy

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My DD is the 1997 VW Jetta pictured below.

Over the past few months I have been experimenting with how different driving behaviors affect my fuel economy. The best I've been able to do is just below 33MPG. Mind you this includes less than 5% highway driving, 85% country roads (45-55mph), and about 10% city driving. I recently moved to a new apartment, which required me to load up my car several times and ferry things to my new residence. With all this extra weight, I figured my fuel economy was going to suffer, so I decided to see just how bad I could make it.

Over the next few weeks I drove quite a few trips that saw my car filled to capacity, which in a mk3 Jetta, is quite a lot. I also carried out (whenever it was safe to do so) jackrabbit starts, full throttle acceleration, heavy braking, heel-toe downshifting, and I actively kept the engine spinning about 2-3000 RPM faster than normal. Every time I drove, all of my windows were down, and I managed to keep the same highway/country/city split as my normal driving.

...And what was the result of all this? 29.5MPG . That’s it, only a 10% reduction despite doing everything I possibly could to drive that number down. I’m not sure what kind of witchcraft the folks at VW used when they designed the ABA, but I’m rather impressed.

Has anyone else experienced a car that returns roughly the same fuel economy regardless of how it is driven?

trynthink > Decay buys too many beaters 08/12/2013 at 19:16

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My Civic returns 26 MPG in the city, exactly what the window sticker claimed. Despite the fact that my driving is usually 100% city, and I tend to be a little aggressive at the lights, I've never gotten less than 25 or more than 26.5 MPG. I thought that driving gently for a tank would help, but it didn't really make a difference.

BugEyedBimmer - back in the Saddle Dakota Leather > Decay buys too many beaters 08/12/2013 at 19:28

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My 94 Integra GS-R always got 27mpg. I couldn't NOT get 27mpg, regardless of driving style or environment.

Decay buys too many beaters > BugEyedBimmer - back in the Saddle Dakota Leather 08/12/2013 at 19:32

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That was pretty much my experience with the Jetta as well, 32-33MPG always, no matter what I did.

29.5 is far and away the worst I've ever seen from it and I was actively trying to drive down fuel economy.

Decay buys too many beaters > trynthink 08/12/2013 at 19:42

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Strange thing is, I'm still getting better than EPA fuel economy (21 City 29 HWY).

J. Walter Weatherman > Decay buys too many beaters 08/12/2013 at 19:55

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I can see pretty wide swings in fuel economy in my TDI, but they generally all fall somewhere between "really good" and "exceptional". I have never once, over the course of an entire tank of gas, gotten my car to return anything less than the EPA numbers (and that is not for the lack of trying). I usually beat the EPA numbers by about 10-15% without making any effort whatsoever.

DocWalt > Decay buys too many beaters 08/12/2013 at 20:06

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My GTI with a 9A is lucky to get over 20mpg... But I have cams, a chip, and a heavy right foot, plus mostly "city" driving.

Decay buys too many beaters > DocWalt 08/12/2013 at 20:21

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How did the chip and cams help with engine response? The stock ABA is really unresponsive and I very nearly have to floor the accelerator on downshifts to rev match. I was thinking of moving to a performance chip/cam combo a while back, but decided that the ABA was not really worth the effort. I've heard a lot of good things about the 16V engines though.

Spasoje > Decay buys too many beaters 08/12/2013 at 21:33

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Ironically, the answer is another Jetta.

My '03 1.8T actually uses slightly MORE fuel if I drive it like a granny - i.e. not enough gas applied to make the turbo kick in... Its efficiency sweet spot seems to be spirited but not too aggressive driving.

Regardless, changes in driving style don't change its fuel consumption in any significant way.

Decay buys too many beaters > Spasoje 08/12/2013 at 22:10

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Not sure if it applies to the ABA, but I'll have to try driving kind of 'medium spirited'. Most of my tests thus far have either consisted of granny driving or forza driving (within reason of course).

DocWalt > Decay buys too many beaters 08/12/2013 at 22:47

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I'd say the chip made the bigger difference in response, but the cams make revving past 6k RPM worthwhile. I'm actually building a second engine with a P&P head to try and let the cams really breathe.

Assuming you've kept up on maintenance, a mild cam and chip should really wake up an otherwise stock ABA. A 2.0 Beetle exhaust manifold swap will really help too.