What E34 gets best gas mileage?

[James]

just curious
-James
89 525i 285k miles

[Paul in NZ]

and the worst would prolly be the 535ia

[Anton CH.]

I bet the 518 does well.

[dca]

I have 520i manual. It consumes 5.9 liter per 100 km. on 93 octane gasoline.(high way - 90km/h)

in city it is 11 liter per 100 km.

[kentish]

What about the 540ia. Is the worst than the 535ia

[jplacson]

Man, I wish I had the M50 version!!! My 520i (M20) burns a bit more than that on 95 octane. I hit about 9-10 liters/100km on the highway, and about 14liters/100km in the city! This is according to the economy gauge. Does this sound right? Is there anything else I can do to improve fuel efficiency on my 520i?

[dca]

I have no experience on M20, but it is 8 valves. this means it is flexible on lower rpms. but it is less powerfull. 9-10 liter/100 km is too much, but it depends on the current condition of your car,and your reactions to the road conditions.(on of my friend told me that he has similar milage with you, and he is surprised why my car is so, his engine was m50)

I have 205/65/15 pirelli winter tires which has more drifting than all weather tires. I am sure that I can have better milage with 195/65/15 orginal tires.there should be enough air inside your tires as well.

Also air filter is too much important, engine should get clear air without any restrictions. it should use cold air. orginal box is best.

spark plugs has a great effect on performance. use orginals, because it make no difference, use bosch.

use a good motor oil, forexample magnatec is very good. check your brakes, they could be always "on". use your a/c only if you really need it.

never step on gas, use it gently, be patient, do not hurry accelerate it.

do not trust in economy gauge and fuel gauge, they always show wrong, my fuel gauge always show less.

when it is not warm, wait for it to get warmed for 2 or 3 minutes in winter. go on your way but before it passes the blue mark, oxgen sensors are offline so, it is open loop, it consumes really much, do not step on the gas to much. it consumes really much,approx 40 liters per 100 km. (one option, your oxygen sensors could be faulty - this cause same result)

clean your injectors, if it is not cleaned.( It might not be necessary)

lastly there should be air flow meter on your engine, when I disconect it(then I forgot it)it consumed %20 more.

I hope these help.

Cosku from Turkey

[Jeff N.]

just curious
-James
89 525i 285k miles

[James]

I have no experience on M20, but it is 8 valves. this means it is flexible on lower rpms. but it is less powerfull. 9-10 liter/100 km is too much, but it depends on the current condition of your car,and your reactions to the road conditions.(on of my friend told me that he has similar milage with you, and he is surprised why my car is so, his engine was m50)

I have 205/65/15 pirelli winter tires which has more drifting than all weather tires. I am sure that I can have better milage with 195/65/15 orginal tires.there should be enough air inside your tires as well.

Also air filter is too much important, engine should get clear air without any restrictions. it should use cold air. orginal box is best.

spark plugs has a great effect on performance. use orginals, because it make no difference, use bosch.

use a good motor oil, forexample magnatec is very good. check your brakes, they could be always "on". use your a/c only if you really need it.

never step on gas, use it gently, be patient, do not hurry accelerate it.

do not trust in economy gauge and fuel gauge, they always show wrong, my fuel gauge always show less.

when it is not warm, wait for it to get warmed for 2 or 3 minutes in winter. go on your way but before it passes the blue mark, oxgen sensors are offline so, it is open loop, it consumes really much, do not step on the gas to much. it consumes really much,approx 40 liters per 100 km. (one option, your oxygen sensors could be faulty - this cause same result)

clean your injectors, if it is not cleaned.( It might not be necessary)

lastly there should be air flow meter on your engine, when I disconect it(then I forgot it)it consumed %20 more.

I hope these help.

Cosku from Turkey

[tim]

My 540 gets pretty good mileage once you get it up to 80-90mph. I did Austin to Dallas in an 2 hours flat once (safely, btw, for those like myself who are conscientious, but enjoy a spirited jaunt every now and then...) and got 24mpg. Overall it sux though

In a few years gas is going o be $20 bucks a gallon. Live it up while you can.