Performance chips - Do they really give you 20 HP?

Views 389 Likes Comments Comment
Like if this guide is helpful
There are a lot of auctions for performance chips and parts that promise to increase your car's performance by altering the air-fuel ratio, among other things. There is a distinct divide between devices costing less than $20, and some that cost well over $200. What are they, and do they really work?

First off, as a disclaimer: The example I bought was called the "G-Box", and was a small black plastic box with two wires coming out of it. It cost me about $20 after shipping. Most of these install between the air temperature sensor on the intake manifold or air duct. When I installed my G-Box, I noticed two things: The throttle response became "soggy" and I smelled the odor of unburnt fuel out the exhaust. I discovered why when I researched more about the G-Box.

It was simply a resistor inside a fancy package. It works like this: The air temperature sensor changes its resistance based on how warm or cold the air is inside the intake plenum. Warmer air decreases the resistance of the sensor, and the computer reads this signal to adjust the air-fuel ratio. Colder air is denser and therefore requires more fuel to burn properly. The G-Box's resistor made the computer read a false signal -- it tricks the computer into thinking that the air is colder than it actually is, and therefore requires more fuel. Thus, the computer injects more fuel than it normally would.

In some vehicles, this may increase horsepower. In mine, a 1989 Honda CRX Si, it did the opposite. In most cases, it may increase power slightly, but at the expense of failing emissions and degraded fuel economy. At worst, it will cause your throttle body to become dirty, soil valves and spark plugs, and possibly damage exhaust components.

The vast majority of these "Performance Chips" that look suspiciously like a plastic box with a paper label glued onto it are simply resistors that connect to your air temperature sensor. Generally, anything that splices into your air temperature sensor should be a red flag, because most operate in a similar manner.

However, the performance chips and devices that cost significantly more, often over $200, are usually genuine silicon that actually alter the air-fuel curve inside the car's computer. Some of these are easy to use, plugging into an expansion port on the computer or directly connecting through the car's OBDII port, while others are more difficult and require removing the computer and installing a chip. Some even require soldering, but it varies. These actual chips usually do yield positive results, and should not be condemned like the cheaper resistor-type devices.
Have something to share, create your own guide... Write a guide
Explore more guides