[kyleb]

I was talking with a guy the other day who is ex EPA and he tells me that there is a number of things that can affect your test. E.g. positioning of cats so they light off, the type of cat used, back pressure in the exhaust, mixture being too rich, he also says a lean mixture is just as detrimental as being too rich due to lean misfire, which a lot of the time is not detectable. Also how the test is conducted with regards to getting the engine hot before the actual test runs, (note the factory running temps for your engine, you will find most run quite hot these days which is for emission control purposes ) and limiting idle time between runs....I am running XF cats behind an LS1 and am just about ready to do the IM240 test ( if I ever get my diff centre back). The guy I was talking to is coming along to ensure they tick all the boxes on their end to give us the best possible chance of passing.. Will keep you posted..