Originally Posted by vmaxbaby
Will the computer learn the air ratio? With my 03 focus I did airbox and cat back the same time. When I started it for the first time the car idled at 3K rpm..I was thinking shit I screwed somwthing up. Then after about a minute the idle started dropping down and down until it was at normal idle. Waiting a minute turned off the car started it backup and went right to the correct idle. Did not retune and drove it 7 years that way until I sold it to buy the 2012. Was hoping it would work the same?
To a point yes the Focus ECU will learn, the problem is the ECU will only make changes to the fuel in closed loop , closed loop is the fueling done at idle cruise and part throttle , closed loop on the 03 Focus can adjust fueling by 25% +/- either direction. The problem is in open loop fuel nothing gets adjusted so lets say your running 8-10 % lean and the ECU adjust this in closed loop fueling when you go to open loop fueling (wide open throttle) there is nothing to adjust the fuel and you will run 8-10% lean
You have to ask your self if you had a tune how much better would those mods of been and how much safer would the engine have been
When you add mods 95% do it for better performance if you add mods and have no idea if your rich or lean you could be hurting the mods and loosing power from them
Yes I know some one is thinking I did mods and it felt great with no tune , the butt dyno lies because it comes from the same place that just added the mods so it thinks better gains , How much better would it be knowing its right and actually making that power