Originally Posted by LeftCoast
If they worked the factory would have installed one.
Weird rattle? Have you checked all the exhaust hangers/connections to make sure they are tight? Is there a heat shield under there that may have come loose?
I agree. These computer engines are set by the factory for the very best overall performance. There are several perimeters to consider. different climates, elevations, mileage, power, emissions, etc. The list is long. We drive these vehicles in areas of several changes per hour or day.
The only way to really make any difference is to reprogram the computer to suit your needs. Even with that you gain in one area & loose in others. There is a reason, Engineers are on most race teams. I have been to off road desert races. Talked with engineers running factory vehicles testing different prototype stuff from the factory.
I agree 100% if you can buy a $20 part that makes any difference the factory would have it on. Believe me they test this crap. The manufactures spend millions of dollars on R&D.
Just a note before the Chevy Trailblazer was out in 2002, GM was tested them in Mexico at the Baja 1000. A buddy of mine saw them there in 01. Prototypes, with the I-6 4.2L engine that came out in 02.
I worked for a largest Jeep dealer in the Country Cal Vada Jeep in Reno NV in the 1970s. Jeep use to bring in a car hauler with 6 to 10 prototype Jeeps to run the Rubicon Trail. They kept them in our dealership. Bill Harrah of the famous car collection owned the dealership back them.
I remember seeing a CJ5 with an Audi 5 cylinder being tested one year. From the factory.