what would the gas mileage on the freeway be on a boosted B18B running say 5-6 psi ?? gas prices flying so high I need to know whether I should buy a B18B and boost when I get a hatch or not...

 

If you don't boost while on the highway, then your gas mileage should be the same as it is without the turbo on there. I slapped my turbo on and I believe I am actually getting a little bit better highway mileage than I was before. Unless of course I feel the need to stretch her legs

 

I just got 27mpg on my Turbo'd B18C1, similar enough.