Efficiency... let me start by saying that I completely believe Terry when he says cylinder filling is better at low-rpm with the stock IMRC system.
That being said, my fuel economy has been very good, and very consistent since performing the IMRC delete. 24mpg around town, 31mpg highway, and 27.2 overall for the last 2000 miles. Previously, I would average 19 city/25 highway/22 overall.
On the other hand... my cars emissions seem to have increased substancially. The car has no cats, but you would never have guessed it before. Now it smells very rich, and people often comment on the smell. :rolleyes:
So, in conclusion... less of the fuel that goes into the cylinders gets burned, but I've been getting night-and-day better gas mileage in spite of it. Go figure!
