Improving fuel economy

[ajajliardo]

I was checking out ecomodder.com, and I was wondering how many of their ideas could be easily applied to e30's. Front airdams and lowering seem to be common, as well as smooth undertrays and blocking off the grill.

I know most here are trying to wring the last bit of horsepower out of their engines and aren't concerned with fuel economy, but I use my 318i to drive 120 mi per day to work.

Has anyone experienced better fuel economy from lowering, or adding a larger front airdam? I've got an is lip to be installed and I want to go to h&r's and bilsteins anyway for the handling benefits.

[ethree]

Weight reduction.

What kind of mileage do you get out of the m42?

I should probably check out the 3 page thread on m42 mpg below huh?

[OrganicMechanic]

supertrapp exhaust with minimal plates. The added back pressure will up your milage quite a bit. Check tire pressure--has big effect on mpg.

[nando]

-skinnier, lighter tires, higher treadwear rating
-lowering and better aero does help
-an OEM rear spoiler will help
-less weight

there's a million ways to do it. I saw you swapped a 3.73 in your 318.. I'm kinda curious how that drives.

[DCColegrove]

-skinnier, lighter tires, higher treadwear rating
-lowering and better aero does help
-an OEM rear spoiler will help
-less weight

there's a million ways to do it. I saw you swapped a 3.73 in your 318.. I'm kinda curious how that drives.

3.73 in a 318is works very well.

[rwh11385]

use your right foot less

[EN318isPDX]

Replace your old worn fuel injectors and o2 = Better MPG

[ajajliardo]

I'm sure most are familiar with conventional ways to improve fuel economy, higher tire pressure, slower driving, blah blah, but the question was:

Have any of you seen any gains from lowering or front airdams?

I would reccomend the 3.73 to anyone with an M42. It feels better matched to the transmission gearing and characteristics of the engine. 1st and 2nd are more useable. I also do not feel any noticeable loss of acceleration. Highway driving is alot smoother.

[kamotors]

on a jeep wrong tire press got 3 mpg worse gas mileage. removing 100lbs got about 3mpg better gas mileage, the more air the better so clean/replace your air filter. fuel system cleaner all the gunk out.

[rThor432]

Interesting topic.. I just picked up an M42 car for my 100 mile a day trip, so I'd like to hear some positive feedback as far as economods go.

[CorvallisBMW]

Everything listed above is good advice, especially the air filter, o2 sensor and injectors. One other thing to try:

Seafom :)

[chrisesteschiro]

I got an extra 3 mpg from lowering and an is lip....another 3 mpg from removing 350 lbs..........2.5 though

[Jon325i]

All the suggestions made are worth considering, they will have a positive effect. However, the easiest & cheapest way to better fuel economy is to change your driving habbits. I use my car daily for work (and keep a log book for miles driven and fuel used) and just by easing the amount of "go-pedal" applied, I'm getting more miles per tank. Less aggressive starts from a stand-still and doing 65mph on the freeway will yield improved numbers - for me about 60 to 65 more miles out of a tankful.

Jon

[rThor432]

I got an extra 3 mpg from lowering and an is lip....another 3 mpg from removing 350 lbs..........2.5 though

It's good to hear of real-world gains like this rather than the internet hear-say. Thanks for posting your experience.

[george graves]

use your right foot less

And your left - carry the speed through the corners!!!!

Try to time traffic lights, so you never get on the breaks.