Best Ways To Improve Mpg (all Enter) !!

[ericcamaro]

Just thought it would be a good idea to share ways people have found to increase their gas milage. We should also adress some myths about things that say they increase mpg but dont deliver. So here are the questions, you can address all or just one depending on your knowledge.
#1) what are the best ways to improve your MPG??
#2) what things can kill your milage that you may not be aware of? (obviously a heavy foot)
#3) what are some things that have said to improve milage but have not delivered any sucessful results??

That should do it for now but I may have some more questions down the line. Some things Ive heard of improving milage are K&N filters, Octane Boooster, Performance Chips, Exhaust systems, & synthetic lubricants. let me know what info you have on the subject.

[bullyd]

:p theres a little screw under the right pedal, unscrew it as far as it will go !! :p

[Robin-535im]

My 535 gets 25 mpg when I drive very gently, 19 when I drive like a maniac.

Keep in mind I have a 3.5 bar FPR, so the reported mileage is high... nonetheless it's still a 30% improvement regardless the true mileage.

Driving gently means:
* never giving it more than 1/3 pedal
* accelerate as slow as you can without pissing people off too much
* Never go above 1500 RPM, except in 5th gear
* Shift into neutral when you can
* drive slowly, only getting as high as you need to, and stop accelerating when you see the light change to red in front of you

that being said... I can do this for max 3-4 days before I absolutely have to stomp the gas pedal and clean out the pipes. Just can't hold back too long. And when you do that, all those hours of saving gas are wasted, and it drops your MPG almost instantly! Soooo much easier to make your average MPG go down rather than up.

- Robin

[SRR2]

I just posted a couple of things in the other thread, but I'll reiterate:
1. O2 sensor in good order.
2. Good plugs, gapped a little on the open side.
3. Proper operating temperature. I suppose you could generalize this to simply saying that the engine should be in excellent mechanical condition.
4. Synthetic lubricants everywhere, including trans and diff. I like RedLine. It's served me well and has delivered consistently godo performance both in operation (easy shifting in all temps, no peculiar noises from the diff) and economy.
5. Light, wide-range engine oil. Like 0W-40.
6. Drive intelligently. Look down the road, anticipate conditions. Use engine braking -- it cuts off the fuel over 1500RPM and saves those expensive pads and rotors.
7. Don't idle your engine unnecessarily. Don't start it and let it warm up for x minutes before you drive off.
8. Tires inflated on the hard side. Choice of tires is important too. A few years ago Consumer Reports did a piece on tire construction and rolling losses. The tested tires were all over the place, some (I recall the Michelin Energy MXV led the pack) had almost no rolling resistance, and others could consume almost a half horsepower. Considering that you need only five-eight HP to cruise on good roads, those tire losses can add up real fast.
9. Alignment, particularly toe.
10. Pizza signs. Should be aligned with airflow, not perpendicular to it.


Lastly, avoid all those fradulent add-on gizmos like magnets, "turbo-swirl-intake" doodads, and any gunk to pour into your oil or gas. None of that crap works. If it did, the auto manufacturers would already be all over it.

One thing that people like to recommend, and that's basically an old wives tale, is changing the air filter. Unless the filter is virtually plugged, in which case driveability would be adversely impacted, it will have NO, ZILCH, NONE, NADA, ZIP effect on fuel economy.

[632 Regal]

Drafting behind vehicles on the freeway can significantly improve mileage. I cant do that, I have to be passing constantly so I dont reap the rewards of this one.

[ericcamaro]

SRR2 I agree with all you said exept not letting the engine warm up. I find that if I take off right when its cold I get really bad milage till im up to operating temp and My MPG on my OBC stays higher if I let it warm up as opposed to just starting the car and driving. Anyone want to back up the argument that chipping the engine can give a couple more MPG??? Also has anyone noticed a difference when lowering their car?? I would think that it would improve it a little mostly on highway driving due to improved aerodynamics. BTW another way to help MPG while on the topic of driving styles is,
1 keeping those windows up, improves aerodynamics.
2 Speeding up before a hill and just steadily going up.
3 (the best) Put down that #$%#ing cell phone and pay attention to the road.

[liquidtiger720]

If you see a red light, brake early and try to time it so that when the light turns green, you are still going 10 mph. or so.

[Dan in NZ]

Tire pressure!

When I did Inspection II, my consumption dropped a few L/100km... That was all new filters, spark plugs, valve clearances etc. Valve clearances you can check without spending much, just a few bucks for a new valve cover gasket. Spark plugs aren't that much either if it's been a while since they were replaced.

[SRR2]

Yeah. I just love other drivers 'drafting' on my ass at 70 mph.

[SRR2]

Well, you don't have a lot of company there. Every owners manual that I recall reading that mentions the subject directs drivers to take off immediately at moderate acceleration and speed. Faster warmup under load means less water etc. blown into the crankcase too.

[Kalevera]

Well, you don't have a lot of company there. Every owners manual that I recall reading that mentions the subject directs drivers to take off immediately at moderate acceleration and speed. Faster warmup under load means less water etc. blown into the crankcase too.
I agree.

It's written in the owner's manual, Mr. Camaro.


best, whit

[imnprsd]

From personal experience, with my 1992 525 with GM4L30E Tranny: Do a fluid change and be sure you fill it with the correct level of fluid...drive it a day or two and then recheck the fluid level. This tranny is very sensitve to fluid levels and if you have too much your MPG will be down. In addition, clean your gear selector switch under the shifter cover. That too could contribute to low MPG and less than optimal performance if it's dirty. (One indication of this is that your LCD display may be missing some pixels.)

[ericcamaro]

Ive never heard it was a good Idea to start your car and immediatly start driving it, but if thats what the owners manual says then they should know better thank I do. What ive heard is that 75% of engine wear occurs within the first couple minutes of driving so If you let it warm up those extra minutes then you will prolong the life of your engine. but bimmers are wierd.

[SRR2]

If the subject is mentioned, I've never seen an owner's manual for any car that doesn't give the same advice. Porsche says "Prolonged "warm up" idling wastes gas. Start the vehicle just before you are ready to drive. Accelerate slowly and smoothly." I don't have the Toyota any more, but it said something similar. Chrysler doesn't bring it up. It makes sense though. The idea is to bring the engine up to operating temperature ASAP to minimize fuel usage and condensation in the crankcase.

[Jason]

valuable info in that owners manual. It was especially the case with the E30 ///M3. but man, that car HATED the cold.

[stx133]

put your car on a diet. more weight more fuel used. dirve with nothing in the boot, 1/2 a tank of fuel or less and (sic) no spare.. take a can of tyre inflate. i wouldnt do this myself, but for some who stay clost to home it may be worht it.
i get 21-23 mile / gal on my 540 on average over the last 20,000k

[genphreak]

Turning the A/C off helps of course... opening the windows/sunroof down in slow moving traffic so you cop all the fumes...

Of course what som might have to do is downgrade our bigger motored e34s to 518/520/525 versions.... I'd personally like a late 525i with a small turbocharger set for ultra-economical operation- it'd have some oomph when u need it, but she'd hardly be a 540...

:) GP

[SRR2]

I've had my E39 540i/6 a little over a month. It's turning in fuel mileage slightly higher than my '89 E34 535. Admittedly, it's a small sample size. Conclusion is that even with the big engine, that tall sixth gear combined with the V-8's diesel-like torque can wring a lot of travel out of a gallon of gas, and the concept of small engine => good economy, and large engine => gas hog isn't always true.

[Bill R.]

attention to this issue in the past? There are a number of misconceptions out there...
First off, driving it like there's an egg under the gas pedal doesn't always increase the mileage... An engine operates most efficiently near its torque peak , so instead of creeping off from a start you'll actually get better economy by accerating at a reasonable pace up to speed, not flooring it ,but not a snails pace up to speed either, the reason for this is based on your engines maximum efficiency rpm and load, thats why cars with cvt transmissions are more efficient. So accerate briskly but not wide open throttle, and once you get up to speed ,say 40 to 45 backing off on the gas until you're just maintaining speed,no more no less, try to be smooth and consistent. Anticipate lights and traffic,,, be the guy that pisses everybody off because you back off on the gas 300 yards before a light coasting ,waiting for it to turn green, every time you slow down requires more energy to get back up to speed, so slowing before lights and traffic so you don't have to come to a complete stop pays off.

I try to do the same thing when making turns , if at all possible .
There are a number of low rolling resistance tires out there nowdays that will make as much as 5% difference in gas mileage. Heres a link to a pdf file that was done in 2003 listing a number of low rolling resistance tires (http://www.greenseal.org/recommendations/CGR_tire_rollingresistance.pdf)

Obviously remove as much uneeded weight. Also on the subject of tires the narrower the tire you that you can get away and still enjoy the better off your are. Synthetic oils in the lightest weight that your engine specifies. 20w50 has more frictional losses than 5w30 does. This wastes fuel. Synthetic oils in the differential and gearboxes also, checking brakes for any drag when spinning freely. Airdams typically help mileage by reducing turbulence under the car... Some truck owners are picking up a couple of miles per gallon on the highway with airdams and making sheet metal belly pans for the complete underside of the trucks, the smoother the underside is the less drag. The iridium plugs i just put in a lexus owners car made by nippondenso claim a mileage improvement of just under 2.5%... not much but ever little bit helps.
Obviously careful attention on tuneups will help, some of the new refrigerant substitutes for r12 claim to operate at much lower head pressures which would require less horsepower meaning greater economy, something to think about instead of just changing to r134a which has higher head pressures.
Strangely enough HID headlights will reduce alternator output needs helping to save consumptions. On weight savings some of the modern univeral batteries you can get as a replacement for the stock battery are much much lighter with the same output and reserve capacity.
Led brake lights and other lights for the car use much less energy also , the only problem is you would have to fool the ccm since the current draw is different.
If your o2 sensor has a 100k miles on it and hasn't been replaced a new one will usually help some.

[Martin in Bellevue]

... An engine operates most efficiently near its torque peak , so instead of creeping off from a start you'll actually get better economy by accerating at a reasonable pace up to speed...
I've been spouting this to somebody for a while now. I think it is why my 535 likes 80+ mph on the highway, achieveing 28-30 mpg on roadtrips.

[E34-520iSE]

QUOTE=[the concept of small engine => good economy, and large engine => gas hog isn't always true.]

Absolutely! I have a 2 ltr M20 in a very good state of tune, but to get my car moving I have to be a bit heavy on the throttle to compensate for the lack of power, whereas a car with a larger bhp output doesn't need the throttle wide open on hills, therefore returning better mpg.

Maybe I could fit a 12 ltr engine and just keep it ticking over, like railway locos?! Might get 60 mpg.........

Cheers,

Shaun

[genphreak]

Indeed, the key is really car size, and engine efficiency. I would trade my 535 for a 530 or 525 any day to improve the latter. A 540 is fundamentally more efficient than an M30. However I'm doing much better these days with replacement parts bringing mine back to (and perhaps beyond original spec). a la Bill R's comments about O2 sensors...

I agree also- the best way I've ever found to practically improve economy (other than fixing the obvious) is to maximise speed round corners (ie lay off the brakes) and accelarate less. Plus work to keep the engine within its most efficient operating speeds. Smooth driving is key. Oh yea, and get a manual. Having an auto is like having a slow leak, you can never work out where that fuel went....