I have an HX35 on my 89 W250 automatic.I am wondering if swapping out the stock 12 CM (wastegate wired shut) exhaust housing with a 16 cm non wastegated housing would net a MPG gain?Ever sense I installed the turbo the truck gets 15 MPG no matter how I drive.With the old h1c it got about 17-20 mpg..
thanks in advance...