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A More Perfect Honda Fit: Toward More Perfect MPG, Part 1

PHOTO (select to view enlarged photo)
Jackman's Almost Perfect Honda Fit

by Michael Jackman
The Auto Channel
Louisville Bureau


Welcome back to A More Perfect Fit, my Auto Channel column covering how to make a nearly perfect car, The Honda Fit, even more perfect.

This column begins a series on a topic that gets high mileage on discussion boards: how to max out the Fit’s miles per gallon. I’ll be covering standard mpg tips and some Fit-specific tricks I’ve developed.

PHOTO (select to view enlarged photo)

But there’s more: I’ll also write up some interesting gadgets, such as the ScanGauge II by Linear Logic (pictured here), and Airtabs by Aeroserve Technologies Ltd.

Wanting a more fuel efficient car is what drove me and my wife Dana to purchase the Honda Fit. We needed a replacement for my aging, incontinent bachelormobile, and after what seemed like endless family discussion came up with a new car mission statement: our ideal car needed to look good, help the environment, not break our budget, and help us save gas money. Our vivid blue 2007 Fit Sport AT (automatic transmission) fit all our ideals.

I have to confess, though, that because I love to drive our Fit (I’ll drive it two blocks to get bagels, rather than walk, because of how much I love to drive the car) saving money on gas has been a problem. So I’m as interested as you are in learning how to squeeze the most mileage out of it.

These first five steps to increasing gas mileage are common-sense principles. You may have heard them before, but they’re important, so here they are again. To get at the reasons behind these steps I interviewed Richard Kahn, owner of the most originally named repair shop in America, Earth In Upheaval Auto Repair of Sebastopol, Calif.

Step 1: Step Lightly. The Fit’s 1.5 litre engine is a marvel of tuning, able to accelerate from 0-60 in under 10 seconds. But forget how exciting it is to rev, and reserve quick starts and stops for emergencies. Cultivate what Kahn calls, “Boring, moderate driving habits.” After all, “where you’re making a difference is transition acceleration When you’re cruising at 55 there’s nothing else you can do.” Just this one technique alone will add up to gas savings. So whether you’re in the middle of your teenage years or your midlife crisis, accept that in order to save gas, you’ll have to be a boring driver.

Step 2: Inflate Your Tires. We’re in the middle of an election campaign, so we expect inflated rhetoric. But while we wish our candidates might underinflate their air, the same isn’t true for your tires. Despite McCain’s criticism of his rival, Obama actually got it right, says Kahn, who adds that when it comes to air pressure, “better a little high than a little low.” The Fit’s tires should be inflated to 32 psi when cold, but let’s say you’ve let them run down 8 psi, to 24. According to Kahn, that extra 25 percent down “creates tremendous heating and friction as the tire compound heats up.” This results in more rolling resistance because the tires are folding more, and scrubbing more against the pavement. The result: significantly lower mileage and higher tire wear.

By the way, don’t rely on built-in gauges when you pressure up. I recently tested a filling station’s air hose gauge against a precision gauge I purchased at an auto parts store. The station’s gauge registered 5-6 psi over mine, which meant that when I thought I had properly inflated my tires, I was actually running 20 percent under. So take my advice: buy a good pressure gauge and use it.

What about the hypermiler’s advice to seriously overinflate tires. Kahn strongly disagrees. “A lot over will help your gas mileage, but ruin your handling, and is very dangerous in anything but ideal conditions,” he says, adding that he has read accident reports where the cause was listed as tires inflated 20 percent over. Simple put: “For brakes to work tires have to remain in contact with the road.” So overinflate a tad (I add 3 pounds from the recommended 32 psi cold pressure), but not enough to risk your life to save a few bucks.

Step 3: Roll up Your Windows (on the highway). Kahn repeats what has become mpg dogma: keeping the windows up lets an aerodynamic car such as the Fit do the job it was designed to do: cut a more efficient swath through the atmosphere, thus reducing power and gas needed. But the tradeoff to flying more friendly skies is having to blast the AC on hot summer days. Using AC increases the engine rpms, reducing mileage. One answer might be window deflectors, but I have yet to find a manufacturer who will send me a set for testing. Therefore, since at the age of 51 I’m no longer willing to subject motorists to the sight of me driving shirtless, nor am I willing to sit in a portable oven with the AC and fan off, dripping all over the upholstery the way dedicated hypermilers do to save a few ounces of gas, I’ve developed a compromise: intermittent AC. More about this technique in the next column.

Step 4: Don’t Skimp on Oil. Kahn warns that sometimes the fast lube franchises will use big drums of cheap oil rather than the oil that’s recommended for your car. So this tip has two parts. Part 1: change your oil according to the maintenance schedule. When the oil gets old, “lubrication qualities go down, friction goes up, and you waste gas pushing your motor around.” Part 2: Use the oil and filter recommended for your car. The Fit uses 5W-20 and contains a built-in oil life indicator in the odometer display. Additionally, a service reminder light should come on when the oil life reaches 15 percent, but I’ve never seen the light since I’ve never let the oil life get that low.

Step 5: Replace Your Dirty Air Filter. “There’s lots of talk out there that air filters don’t make a difference with modern fuel injection,” Kahn says. Modern fuel injector systems compensate to make up for reduced air flow (such as from a dirty filter or a dead critter in the air hose). But air filters are still an important part of an efficiently-running car. Kahn explains that while it’s true “the injection adjusts for the amount of air going in, the farther you have to put down the pedal to have the same effect, the more fuel you are going to use. It just wastes gas. You want the most free flow of air possible.”

There’s a lot of talk on the Honda Fit forums about whether or not to replace the air filter with specially designed turbo air filters that are said to increase air flow and thus engine power. The short answer is, if you’re tuning your Fit to race, or just like tuning your car as a hobby, maybe. But if you’re driving to save gas: no. According to the specs for one popular model, you can perhaps achieve a four percent power gain at the 5,800 rpm level and above. Since the goal of conserving gas is to drive the Fit as close to the boringly efficient 1500-3000 rpm range as possible, a turbo air filter isn’t going to help. Kahn urges his customers to remove them and reinstall the original air filter system. He warns, “Whatever performance you gain, you lose by wearing out the engine.”

So these are the five mpg basics. Follow them, and you’ll get the most fuel efficiency that common-sense techniques can give you. In my next few columns, I’ll go beyond the basics to explore how to squeeze some extra mileage out of a Fit. In the meantime, be a boringly safe driver, and spend some money on maintenance to accelerate toward a more perfect mpg.

Michael’s Honda Fit accessories and mods to date: Zeta Products dead pedal, armrest, satin dash kit, and hood deflector; Honda all-season floor mats, cargo tray, rear bumper appliqué, and tonneau cover; ScanGauge II by Linear Logics ScanGauge II, a great way to get to know your car.

Michael Jackman is a Louisville, Ky. based writer and professor of writing at Indiana University Southeast. More info at