I have an SL with a moonroof deflector. I read in Car & Driver or another one of those car mags that with the moonroof open you lose mpg. I was curious if this also related to cars with deflectors? Would having the deflector on introduce more drag and thus decrease mpg? If I have the moonroof open would I get pretty much double the drag or would the deflector pretty much take care of that?

Unless you have access to wind tunnel, it's anybody's guess.

philipa_240sx wrote:Unless you have access to wind tunnel, it's anybody's guess.

I lost my access last year.