I often see ads related to chips or modules that are supposed to enhance performance and/or improve fuel economy. Some of these are as cheap as $50 while others go up to the many hundreds of dollars. I have always figured that these are a bad idea but have never studied them. I know they void most warranties on new cars and wouldn’t the manufacturer have spent tons of money making sure their engines were running optimal from the factory?
Anyway, I have some friends who swear by these types of devices, especially on Diesel pickup trucks. Some use them to blow black smoke which I hate. I am sure this is just a waste of fuel. They indicate these have like 5-6 different modes you can use with one being optimized for power/towing, another for fuel economy, and so on.
I know some of these alter shift points of an automatic transmission but how would this apply if you installed one in a car with a manual transmission? If I were to ever do one, I would definitely use a “mild” version where no other modifications are required on the vehicle such as the fuel, ignition, and exhaust systems. Some of these just plug into your diagnostic port and have no settings you can change.
I want to hear some opinions on these. What do people who have worked with them think? I can understand them for racing but how about daily driving?