In a shocking turn of events, the 328i with 8 speed automatic had its highly touted EPA fuel economy numbers squashed. BMW had been using 36 mpg as their official EPA number, better than the now defunct 335d. But when the EPA recently tested a 328i with the ZF 8 speed they were awarded with a measly 33 mpg, the same number BMW is placing on Monronies for the much more powerful six-cylinder 335i.
The jury is still out on what the real world MPG of the four-cylinder 3 series is, we’ve had limited time during normal commuting with the 328i so we can’t provide you with our own figures but they were certainly better than the 335i. Will the EPA take the ax and shave off some mpg from the 335i? We are predicting that with this significant drop in mpg they will test every BMW model this year and what they will determine is anyone’s guess. BMW’s official comment states that they have no recourse for this model year with the EPA so the numbers will stick- lucky for them the 3 Series will get an early model year change sometime in June.All manufacturers are responsible for testing and submitting fuel economy figures each year to the EPA (based on physical tests following the EPA test cycle on a dynamometer). Occasionally, the EPA will validate the figures that we provide. When this happens, there are sometimes small changes in the published EPA fuel economy figures (usually 1 mpg up or down).The EPA recently tested the 2012 328i Automatic and obtained a highway mileage result that was 3mpg lower (33mpg versus 36mpg) than the BMW test result. We are very surprised by this result and are currently working to determine how this is possible. The new rating seems abnormally low in relation to the other models in the BMW range and by the real-world fuel economy that we are seeing from this model.Unfortunately, there is no provision in the EPA rules for a re-test this year. Therefore regardless of the results of our investigation, the new rating will stand for this model year.
Source: http://www.bimmerfile.com/2012/03/21/ep ... estimates/