It seems that everybody wants a combination of better performance, and more miles per gallon. Well manufacturers can do this by redesigning the entire vehicle. But can you do it, as an add-on? Well, yes and no.

You see, first we’ve started with this Toyota FJ Cruiser. And we wanted to do two of the most common modifications that people do. We put a cold air induction system on it, and a cat-back exhaust system. Now do they improve fuel economy? Well, yea. But there’s more to it than just that. First, what about the modifications themselves? Well, we chose Toyota. And all manufacturers have a line like this. Because, I wanted to make sure that I didn’t go afoul of emissions laws, and wanted things to fit, and didn’t want to damage anything on the vehicle.

Alright, so, we have high quality stuff. We spent roughly fifteen hundred dollars; if you include the normal labor to install the parts and things like that. And, before we did this, we drove it for five thousand miles, to establish a baseline miles per gallon. Now, it was 20.7 miles per gallon. After, another five thousand miles under the same circumstances, and we got 21.1 miles per gallon. Four tenths of one mile per gallon increase. Well, you would say, “Well I’m going to be saving money.”

Well you’re not. First, we have to pay back all of the money we put into the modifications. That’s going to take 46, 47 thousand miles before we ever save the first penny. So you have to look at that part of it. The second thing is, did it improve performance? Well, yea, but we couldn’t measure it on a stop watch. But it does feel more responsive. But here’s the rub on that: You cannot produce more horsepower and use that horsepower, without burning more fuel. So you can drive it normally, and get a little bit better miles per gallon. Use the extra power, and you’re going to get less miles per gallon. There’s no way to produce power without burning fuel. So you have to factor these things in. Is it a feel-good conversion? Yea, it is. That much I can tell you. But do the math before you spend the money. And if you have a question or comment, drop me a line. Right here, at MotorWeek.