I always thought that o2 sensors were put in the car to keep the A/F at the ratio it Should be. I know that you have to tune a car after doing air and fuel and Turbo upgrades. I know you have to tune it, But my question is Why. I thought That's Why o2 sensors are there.
For any small upgrade like a different intake or exhaust the ECU works just fine asis. It's when you start installing bigger turbos and need to add more fuel. Since the ECU is setup to run 360cc injectors even with the o2's un-plugged it will run somewhat "safe" if you change the injector size the ECU still thinks it is running 360cc injectors so it will +\- fuel based on the stock injector size. If the injectors are bigger the ECU needs to be "tricked" because it can only compensate so much before it runs out of adjustment.
At WOT the ECU runs off a internal map thats based off 360cc injectors "open loop" so it does not even look at the o2's
Hope this helps? I am even a little confused after re-reading :-)
Last edited by rymer21280; 11-19-2012 at 03:52 PM.
and unfortunately you can't just make adjustment for the injector size and the map still be right. So you have to add and take away fuel at different rpms in order to achieve and maintain the 10.X to 12.x target you are looking for when running WOT. The O2's will try and hold the car at 14.7 which is great when at idle or cruise, but way to lean when your getting on it.
Need to fined a good tuning book or start reading about tuning/fuel injection/basic engine knowledge on the internet. Did you get the AEM fail safe gauge? It's better than a regular AEM wideband since it's easier to data log.
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