Fuel economy on manual m50 and manual m30.

[Rustam]

I am looking to possibly swap to m50 manual from m30 automatic, or perhaps just go with a manual swap into the existing m30, and would like to look into the figures for education.

Please post fuel economy figures of what you encountered in your cars - manual m50, manual m30.

[Dave M]

M50 stick = ~7.5L/100km highway, ~9.0L/100km mixed.

Dave

[Rustam]

M50 stick = ~7.5L/100km highway, ~9.0L/100km mixed.

Dave

Thank you, Dave.

[Rustam]

Dave, what engine rebuild have you done, and did it affect the fuel consumption figure?

[ahlem]

M30 with 5 speed and 3.91 rear gears 22mpg on the highway and ~18 around town.

[Dave M]

Low compression in cyl. #5. Used block, honed, new rings, main and rod bearings. Te head was cleaned up as well. It ran quite well before the work, but burned some oil. Mileage did not improve significantly following the work.

Dave

[Rustam]

Thank you, Dave.

[Rustam]

Interesting Ahlem, and thank you for the post. My understanding per realoem was that 3.45 rear was fitting for m30 with 5 speed... Curious what numbers that setup returns.

[genphreak]

I have both. Definitely the M50 is better on fuel by perhaps 20-30% in real terms. Easiest way would be a whole engine bay content swap- but in real terms, an M52 3.0L would be the best choice- you could handle the OBD1 wiring work without much trouble and it'll run better and return better fuel economy than any e34 ever did. With the 6 spd manual I imagine you'd want a 2.93:1 rear end so something from an e32 would do well, so long as it is LSD equipped :-)

[Rustam]

Thank you, genphreak.