Oldskooler Ramblings

the unlikely child born of the home computer wars

Hacking MPG

Posted by Trixter on July 23, 2007


In 2001 at the height of the internet bubble, I sold stock options to pay for a minivan for Melissa. I knew she liked to have the air conditioning on all the time, and we needed to merge onto the highway a few times a week via a terribly-designed onramp (where you have about 1.3 seconds to merge or you will die) they could really use some help from www.melbournelinemarking.com.au to make a better design, so I made sure the minivan had a V8 in it so she could have no problems merging onto the highway with the air conditioning on.  My prior experience with doing so was in a tiny Ford Escort, which has an engine so weak that turning on the air conditioning effectively acts as a secondary braking system.  I thought that getting a V8 was a good idea in this context.

Big mistake. A V6 would have been sufficient; a V8, on the other hand, guzzles gas like it’s going out of style. This wasn’t a problem when gas prices were $1.60 a gallon., but now that they’re $3.50/g, we’re spending nearly $200 a month on gas, sometimes more. For some people, this is nightly dinner money. For us, it’s the utility bill, so it hurts.

I read in a recent Slashdot post (URL escapes me at the moment, sorry) that modern cars can get nearly hybrid-like gas performance if computers were installed to learn how to coast to stoplights. Due to broken air conditioning in the van, Melissa and I have traded cars for the summer (I don’t mind the heat) and I decided to put that theory to the test in the V8 gas guzzler. Bottom line: It works, but you have to exercise discipline.

When Melissa drives the van, she drives it hard, and the average MPG is about 14mpg. I, however, have been setting cruise control to exactly the speed limit every chance I get, and coasting 100 feet or more to stoplights. My average MPG? 21mpg. Just by adjusting driving habits, I got an average of 126 more miles out of each tank; filling up the tank twice each month, that’s a savings of $42. It’s essentially one free fillup a month.

The tradeoff is that you need to be very aware of the car and the road when you do this. For example, don’t accelerate quickly to get to the speed limit, which burns all your savings in a few seconds; instead, try to keep your engine’s RPMs under 2000 no matter what. (Warning: This may piss off the people behind you.)  Also, constantly scan far ahead to anticipate how early to cancel cruise control — too late, and you miss out on gas savings; too early, and you’ll be coasting up to the stoplight for nearly a full minute.  (Warning: this will piss off the people behind you.)

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4 Responses to “Hacking MPG”

  1. I don’t mean to nag, but 21 MPG isn’t very impressive for even high-performance vehicles. I expect you got an American-made minivan? If so, I seriously suggest you replace it with a Japanese or even European model (the Peugeot 307SW with 2 litre engine, for instance, is reasonably quick and can easily do 25 MPG with no “user mode hacking” necessary).

    My parents’ Chevrolet Vivant (actually a modernized Daewoo model, but never mind that) does 15 MPG, which I consider bloody awful. I wouldn’t consider any engine doing under 25 MPG purchase-worthy, particularly with the gas prices nowadays. For reference, the Israeli gas price is roughly $5.75 per gallon, and it’s even worse in Europe.

  2. phoenix said

    21 MPG is pretty impressive for a minivan with a V8. :) Actually I didn’t even know there *were* minivans with V8’s.. Dodge Caravan SRT-8 Hemi?! Wouldn’t shock me at this point.

    Re: Tomer’s reply.. I know that “MPV”s are very popular in Europe and, being smaller than the average US minivan (making the term a bit ironic), get better mileage. But they haven’t made it big in the US yet. For the average American family, you’ll have to pry their full-size minivan or SUV from their cold, dead hands. We all want better mileage with high gas prices, of course. Most people just don’t want to change their vehicle or driving habits. Also, Jim and Melissa are, and I mean this in the least offensive way, large people. It’s just a matter of fact that they’ll have trouble squeezing into a Kia Rondo or Mazda 5 MPV. Oh, and Peugeots haven’t been available in the states since the 80’s. :) Ford and GM have actually abandoned the minivan market here, leaving Chrysler and several Japanese/Korean makes, but with new legislation to increase MPG finally passing, we’ll see more MPVs imported here, plus some new “mini-SUVs”, if you will, in the next few years. I just wish the $/Euro rate didn’t suck so bad so we could get some more cool European imports.

    Engine technology is improving now more than ever. Unfortunately, most automakers, in some kind of mine’s-bigger-than-yours-war, have used it to raise horsepower as high as possible while keeping fuel economy the same, not improving it. I honestly don’t believe a family vehicle needs 250HP to merge onto the highway, but maybe that’s just me.

    So, drivers here want to have their cake, and eat it too, and not gain any weight from it. There are all kinds of aftermarket products that promise better fuel economy, but don’t really work. Careful driving habits, like Jim tried, do work. Cruise control on the highway works wonders. I would however suggest not to overuse cruise control in city/urban driving because it can be dangerous. And of course keep your car in good shape, as a bad transmission will kill your MPGs.

    And while the Prius is great, it’s made most Americans think that any car with a “hybrid” label on it is a magical solution to fuel economy. So giant, “hybrid” SUVs are coming out that get 2-3 MPG more. BFD. Sites like http://www.fueleconomy.gov are great for comparing mileage and getting real numbers from actual people. You’ll be surprised how some vehicles stack up against others.

  3. Trixter said

    Tomer: I think you’re missing the fact that it’s a V8. 16MPG city is average for a V8. And yes, it sucks ass, but I didn’t realize that when we bought it. My next car won’t be quite that disgusting.

    Phoenix: Yes, it can be dangerous; hopefully the post illustrates that it’s not for everyone in the city. As for “real” fuel economy, my next car (scheduled for purchase in 2 years when Melissa starts working) will not be a hybrid, but will be under a Prius by only about 8-12 MPG. As for being large, I would have preferred “tall” (I’m 6’2″) :-D but your point is well taken, I don’t fit into tiny cars.

  4. nissantruckster said

    the best thing to do buts its technically illegal is take a broom handle and run it through the catalyic converter i have a friend with a v-8 engine that gives the back wheels 514 hp and hes getting between 19-23 mpg in the city no matter how he drives now thats good. so if you give it some thought the govt. is f@#$ing us but making us have a cat converter. by taking out the cat you increase airflow but 50-60% and an average of 30 hp increase making you engine work less to move you thats the trick your making it stronger and having it breathe better it will give you better mpg try it you notice the dif.

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