To get a rough base line, I looked at what these motors get in the considerably heavier Integra chassis.

I'm curious how the MPG is improved in the EG / EK chassis? ( minus 200-800lbs depending )

Anyone with these swaps running well chime in here? Or someone just with knowledge in this area.

 

I have zero knowledge of B series; however, i did just swap in a single v-tec in my civic vx. Before the swap i was getting around 30 mpg with the d15z1 and a y8 tranny. I am now currently running a d15b with the same(failing) y8 tranny. I had my ECU tuned on a wideband o2 sensor, and im getting the same milage 30-35 depending on how i drive it.

So my advice to you is do the swap you want then get it tuned (wideband o2, not a regular o2). I had my ECU tuned for WOT( advanced the **** out of the timing and fuel) and partial throttle(leaned out the timing and fuel). I have the best of both worlds Its a bad *** single v-tec when i step on the gas, and a wussy econo car when im not stepping on the gas.

edit* also an engine will get better gas millage when its in a lighter car.