Fuel saving mods???

[little740girl]

So gas prices aren't dropping yet, but unfortunately: my mileage is. The gas is crap right now, and in the past month my mileage has gone down from 14 to 12.5, and now, with this tank of gas, it's dropping even more. I was wonder if there are any gas saving modifications out there. Does air intake take the edge off of mileage? I'm operating on a low budget right now (partially why I'm looking to save money on gas) so if anyone can think of any low cost mods that can save my mileage before it's as bad as a raised F350, I'd be very grateful.

[SI///M3]

1x1x1" wooden block, put under accelerator.

[Rob ITR1035]

exactly, thoughtful throttle application is the key to better mileage.

[Agaru_Vala]

Originally posted by SI///M3
1x1x1" wooden block, put under accelerator.

How much $50 shipped ? (joking)

[e36rieger]

ecu chip/intake raised my gas mileage a bit. But i guess the no brainers are to check your tire pressure and take it easy on the throttle....good luck

[porkyzilla]

check on your o2 sensors that low of a gas mileage is unaccecptable, unless under constant wot..... when o2 sensers start going wacky so does your gas mileage

[Agaru_Vala]

What does everyone get MPG wise, I get 21.1 and then some city drives I get 19.7 Around

[Tom]

I usualy average 22-26mpg depending on how hard and how often I push my car.

[MadWheel]

34mpg in my 02 vtec civic. good for the gas issue but that car's gone soon, im admitting myself to the dtm realm.

[Kyle M]

around 22

[little740girl]

Originally posted by e36rieger
ecu chip/intake raised my gas mileage a bit. But i guess the no brainers are to check your tire pressure and take it easy on the throttle....good luck

A performance chip, or are you talking about another ecu upgrade? I have a performance chip, and that brought my mileage down a bit, not up.

But I don't wanna be easy on the throttle, I like my gas petal. I tried that, the whole grandma driving... it lasted for about oh, 15 minutes before I got bored. It's no fun driving that way.

[little740girl]

Originally posted by porkyzilla
check on your o2 sensors that low of a gas mileage is unaccecptable, unless under constant wot..... when o2 sensers start going wacky so does your gas mileage

I changed them @ 100K, so about 10K ago, so they’re good. I just remembered though... my air filter may need a cleaning. I have a K&N, which I hear needs to be cleaned every couple thousand miles. I'm going wipe the dust off an old "how to" thread on how to clean the K&N. That should help bring the mileage up again...that's for mentioning the 02's, reminded me of the air filter.

[e36rieger]

Originally posted by little740girl


A performance chip, or are you talking about another ecu upgrade? I have a performance chip, and that brought my mileage down a bit, not up.

But I don't wanna be easy on the throttle, I like my gas petal. I tried that, the whole grandma driving... it lasted for about oh, 15 minutes before I got bored. It's no fun driving that way.

what performance chip do you have? i was referring to the dinan ecu chip:
http://www.dinanbmw.com/html/740-1996/740-1996-soft.htm


Performance Engine Software
Scroll down for 1996-9/98 740 Specifications)

Could there be a device that improves both acceleration and fuel economy? Dinan Performance Engine Software says, "Why not?" Taking full advantage of 91+ octane fuel, Dinan Software unleashes more power by re-programming the fuel mixture and ignition timing parameters of the engine management system. Furthermore, the software safely raises the factory rev-limit from 6100 to 6400 rpm. A higher rev-limit gives your BMW a broader power band and greater road speed in each gear. But just because you can now out-accelerate other cars, that doesn't mean that you have to pay the penalty of more frequent gas stops. During part throttle or "cruise" conditions, the Dinan software actually improves fuel economy. You will also notice that significant power gains were achieved at part throttle, as well as full throttle. That means extra power is available where you spend most of your time driving. The Dinan software also removes the factory top speed governor. Granted, you probably wouldn't take your BMW over 128 mph; but now you can.

9/1998-2001 740 Performance Engine Software


Peak Horsepower Gain: 16hp @ 5700 rpm 9hp @ 4500
Peak Torque Gain: 25 lb/ft @2500 rpm 11 lb/ft @2500 rpm
Rev-Limit Increase: +300 rpm

[TabulaRasa]

A clean airfilter (I'd reccomend a K&N panel filter, not a cone).

Tuneup. (Plugs, maybe plug wires)

Use the brakes to slow down as little as possible. Instead of braking, let off the throttle earlier and coast to slow down. I find that opening the sunroof and all the windows helps slow down as well. I open the windows/roof to slow down all the time to save brake wear when coming down from high speeds.

Lighten up. Lose any excess weight you don't really need. Rear headrests, spare tires, jacks (the factory jack is junk anyway), tool kit, etc.

This won't work for you as I assume your 740 has an auto but...

When accelerating with a manual, the most economical way to accelerate is to upshift early and put your foot all the way to the floor. This way there is less restriction at the throttle body. Don't rev too high though. At lower RPM's, the greatest restriction is the throttle body butterfly valve. At higher RPMs (around 4.5k+ in my opinion) you run into greater frictional losses. Of course the throttle body thing doesn't apply if you have a E46 M3.

Make sure your tires are properly inflated. I would suggest to OZ Supraleggra or various BBS wheels to lower unsprung weight. Don't buy a wheel any bigger than what is needed to clear your brake rotors/calipers.

Oxygen sensors--make sure they're working.

Timing and valve adjustment--make sure they are in spec. (Audi's have hydraulic lifters and don't need valve adjustments. )

That's all I can think of for now.

[Nathan]

take out ur passenger seat and rear bench.. so u got an excuse not to drive ur friends =)


-nathan