Quote:
Originally Posted by caverman
From my understanding adding headers allows more air flow which in turn should cause your car to run more lean. However the computer can make small adjustments so it might be putting in more fuel.
The CEL comes from the Cats. The basics behind it this is that there are two sensors reading your cats. One is before the cat to get the initial reading and then one after the cat to get the post cat reading. If the rear sensor doesn't see enough of a change (based on whatever parameters set in the computer) then it will assume your cat is not working properly and thus throw a CEL.
I've heard that because the cat is farther away from the engine it can't heat up enough to burn whatever it needs inside the cat to make the exhaust cleaner. It's also my understanding that the OEM cats have 600 (can't remember the name) cells meaning exhaust holes vs high flow cats have a 200 cell cat. Based on that I would think the 600 cell cat would heat up more as well.
If it wasn't for the cats you wouldn't get a CEL....your car just wouldn't run as good. From my research GM made the OEM tune pretty rich in order to accomodate all the different environments. After all a car in higher altitude is going to act differntly than say a car somewhere that is closer to sea level. You'll pick up close to 10 rwhp just by adjusting the Fuel Trims the correct settings.
I'm no expert but that was my understanding of it.
Of course know that by tuning the car you'll run the risk of losing your power train warranty. Still worth it in my book. Headers and tune made a huge difference.
|
I second this.
Mine was running lean after the header install...the headers and new exhaust flow so much more the ECU tries to add more fuel but its usually not enough and not able to compensate fully. I voted yes, but again I think most of the time you're going to run on the lean side.