M50 w/ 4.10 16.5mpg highway-normal?

[lolcantturn]

I remember my old swap with a 3.73 getting 26mpg with an M50 @ 70mph indicated
With a 4.10 my current M50 is getting 16.5mpg @ 65mph indicated.
Is this normal ? I have a new O2 in there (but I do get the O2 heater relay code sometimes).

[Matt-B]

I got about 22 or 23 mpg with my 4.10LSD and m50

[318isbmw]

I was around 22-25 with 4.10 gears on my old car.

[lolcantturn]

jesus christ my car sucks

[e30trooper]

what trans are you running?

[lolcantturn]

what trans are you running?

Getrag 240.

There's nothing I can even conclude as to why my mpg sucks either. EVERY maintaince item is up to date..like <1000 miles. fuel filter, plugs, O2, FPR, everything.

[scottinAZ]

yep, its all about RPMs. if you slow down the motor, you will get better mileage.


I was getting about 22-23 with 4.10, G260 and M50TU before I swapped it around.
I am now averaging 24-25 with 2.93, ZF320 and M50TU. rpm at an indicated 80mph is a shade over 3k

[Matt-B]

dont base it on your gauge.


I just do my ODO, and divide by tank size

[scottinAZ]

dont base it on your gauge.


I just do my ODO, and divide by tank size

I use ODO miles and divide by gallons added to fill. sometimes I refill before the light comes on, but not very often......

[Matt-B]

yea, Im am averaging 26-27 mp with m50 :)

2.79 diff

[psyber_0ptix]

21mpg avg mixed driving

s50 getrag240 4.10 LSD

[M-technik-3]

Depends on how you drive, traffic conditions, altitude, Tires-width and height and compound as well as condition of engine.

TU or non TU? Too many unknowns. Your life always seems like a soap opera.

[trackjunkie21]

I remember my old swap with a 3.73 getting 26mpg with an M50 @ 70mph indicated
With a 4.10 my current M50 is getting 16.5mpg @ 65mph indicated.
Is this normal ? I have a new O2 in there (but I do get the O2 heater relay code sometimes).

I have the same problem as him, 4.10lsd with an m50nv full refreshed and a g240 and I average 15mpg, and that's not using the gauge, ODO/gallons method.

[lolcantturn]

Depends on how you drive, traffic conditions, altitude, Tires-width and height and compound as well as condition of engine.

TU or non TU? Too many unknowns. Your life always seems like a soap opera.

I drive like an old man. Seriously. In the city my RPMs never go past 3k. On the highway I only see past 70mph on a downhill. My tire width and height were the same as the M50 car i was getting 26mpg with. Non vanos
And yes my E30 life is plagued with trouble.

[sofa KING euro]

well gears ratios per gear in the g240 could also be affecting your mpg. A high fifth gear ratio can yield low mpg