Going from a 4cyl car to a V8 has been a shock in many ways. For instance My current mileage for past 2300km street driving is around 19.5L/100km or roughly 12mpg. This is at average speed of 28km/h or 20mph....about 70/30 city/highway.
My mileage is now actually worst than it used to be after I started experimenting with quicker acceleration to speed and then just cruising rather than babying it. I figured I will accelerate at better brake specific fuel consumption if the throttle is more open?! According to my scangauge, TPS is only at 18-20 TPS when accelerating casually (idle TPS is 14)...so i'm assuming the throttle is only open 5-10%? the pumping losses must be massive. However larger throttle opening for acceleration did not work. I think this car has been tuned to run rich. I have not been able to find a BSFC dyno or graph for C63, but from looking at EFI converted domestic V8s, they all produce best BSFC at peak torque. which is what I target for acceleration (3500 RPM). In street driving, I turn off engine at lights, try to drive without brakes and perform mini pulse & glides. Also the car engine-brakes heavily at low speeds closed throttles and dropping to neutral makes unhealthy sounds.
currently not sure if the mileage is normal or due to poor driving habits. Highway driving, best I could do by cruising at 65mph speed limit is 13 lhk or 18 mpg. Should I give up or are there certain tips/tricks for V8s ?