Improving fuel economy

[E30Kaiser]

Anyone know what are some of the best tires for Bottlecaps to increase fuel mileage?


Also as some people have said, your odo may be wore out and thus say you haven't gone as far as you really have. Mine is for sure, as after driving from Winston to Boone, a distance of 82 miles, it said I had only gone 70.3 miles.

[moatilliatta]

Yah, Good Year actually makes a tire called fuel max.. Im not sure if it lives up to its name or not. I know they seem to be a little lighter than other tires. Also Michelin I think talks about better fuel economy. It would seem like the higher tread ware rated tires would have less rolling resistance. Kinda like rolling wooden wheel vs a softer material wheel...

[E30Kaiser]

Yeah but I don't think a lot of those are made in sizes that fit on the bottlecap, which is why I asked specifically, though I haven't looked too too hard, just a quick browse of Tirerack.com

[nando]

Anyone know what are some of the best tires for Bottlecaps to increase fuel mileage?


Also as some people have said, your odo may be wore out and thus say you haven't gone as far as you really have. Mine is for sure, as after driving from Winston to Boone, a distance of 82 miles, it said I had only gone 70.3 miles.

ODO's don't "wore out". They do occasionally break, though, but then they stop working entirely.

[E30Kaiser]

ODO's don't "wore out". They do occasionally break, though, but then they stop working entirely.

I had this symptom. Cured it by replacing odometer gears that had half the teeth missing. Doubled my gas mileage immediately.

When I said wear out this is what I was referring to where the odo starts to be less and less accurate due to missing teeth. I assume funcrews explanation is what is happening to mine as I doubt my speedo is that far off.

[Edev]

Yes! Right on! This could be one thing most commonly overlooked.
I'd like to focus on non-engine related issues that cause poor gas mileage. These non-engine issues should be checked first. I've had problems with my brakes causing resistance and therefore resulting in loss of good gas mileage.
Mine is 1986 325e Automatic 210,000+ miles. I've always gotten 22mpg.
I agree, there is hundreds of things to look for when trying for better mpg.

This is the easiest no cost way to check for brake resistance:
Make sure car is cold and has been sitting for atleast overnight just to let brakes cool completely.
Jack one end of the car up and make sure its in neutral (if checking rear wheels) and turn your wheels by hand and check that they rotate easily and compare the resistance by feel. I found that you should be able to turn your rear wheels with one finger. If you have to use any more fingers then you definitely have to adjust your brake hardware or bleed the fluid lines.
Yes sir! Air in your calipers is causing a tiny amount of resistance and prematurely wearing your pads out.

I found that my emergency brakes were causing resistance. Not adjusting the emergency brakes correctly or precisely is one of the easiest things to screw up when changing your emergency breaks. And the hardware wasn't gliding easily because of rusty surfaces (sand where necessary)
I highly suggest always getting a new hardware kit when changing rear emergency brakes shoes. Of course all new brake discs and pads will definitely give you peace of mind.
Only heard great things about Seafoam. Gotta try it in my fuel.

To me these are the QUICKEST most important to get best mpg:
- most important of all is engine AIR FILTER
- DRIVING HABITS
- O2 sensor(s)
- type of TIRES (air pressure is most important then tire size-smaller diameter tires than original will yield more revolutions per mile and result in many less miles per gallon of fuel as is the same when driving on very worn tires.)
- SPARK PLUGS change twice a year- Its the cheapest insurance for your engine!
- GASOLINE octane rating- use higher octane 91 or 93
- OVERALL CLEANLINESS of emission and fuel components-definitely give Seafoam a try! Why the heck not? Anybody object?

You know what? I like this guy. First post is very well thought out and organized. Good stuff here.

[red325i]

Im getting around 250miles per tank, '93 Vert (after market air filter, 19lb injectors, lowered, 16" rims, etc,etc)...i drive about 70% highway now...ive always thought i should get better mileage.. but i think though im a little heavy on the gas... ;)

Also-- anyone know the affects of 19lb injectors in MPG versus 17lb injectors??

[ciscoboy]

Eric, Haven't been in this forum for a while but a late thanks is better than no thanks.
Thanks for the comment Eric!
I'm a mechanical engineer and I understand many more things by virtue of an experienced engineer's mentality and the constant pursuit of order, correctness and preciseness to try to make things work optimally and efficiently.
Anyway, I had a little time on the BimmerForums and then came here to check it out and thought I'd drop a cool note.