The 135i will come with an AGM battery!

[mikeo]

Good question. Let's look at the known basic effects first before guessing at the the changes in handling dynamics. For purpose of this exercise let's say the bumper ballest is 50 lbs (NOTE: THIS IS NOT A FACT).

1. Less weight behind the rear axle line would mean slightly less polar momentum in the rear.

2. Center of gravity moves slightly forward and up.

3. Removing ~50 lbs from the car is a 1.5% weight reduction.

OK, anyone want to jump in with ideas how these three things would change handling dynamics?

[larryn]

Originally Posted by mikeo

OK, anyone want to jump in with ideas how these three things would change handling dynamics?

I'll stick with:

Removing weight from the rear would likely cause it to not throttle-oversteer as easily, and could make it plow (understeer) more... in theory. In practice, who knows.

[crzy4135i]

Originally Posted by mikeo

Good question. Let's look at the known basic effects first before guessing at the the changes in handling dynamics. For purpose of this exercise let's say the bumper ballest is 50 lbs (NOTE: THIS IS NOT A FACT).

1. Less weight behind the rear axle line would mean slightly less polar momentum in the rear.

2. Center of gravity moves slightly forward and up.

3. Removing ~50 lbs from the car is a 1.5% weight reduction.

OK, anyone want to jump in with ideas how these three things would change handling dynamics?

The more I hear about this car the less I like it. Any chances the "ballast" is actually some sort of bumper structure for added safety? I hate to think they added dead weight to this car.. in addition to a 75lb battery. Maybe they're setting themselves up for easy weight savings gains on the Tii?

[ChrisK]

Originally Posted by crzy4135i

The more I hear about this car the less I like it. Any chances the "ballast" is actually some sort of bumper structure for added safety? I hate to think they added dead weight to this car.. in addition to a 75lb battery. Maybe they're setting themselves up for easy weight savings gains on the Tii?

I have owned a few BMW's that have had a "ballast". What's the problem?

[ChrisK]

I do remember reading this somewhere:

I believe the extra capacity battery is for the electric water pump that will cool the turbos down after the car has been shut off.

[crzy4135i]

Originally Posted by chriskurn

I do remember reading this somewhere:

I believe the extra capacity battery is for the electric water pump that will cool the turbos down after the car has been shut off.

That makes sense. If the electric pump runs you'll also need one of the electric radiator fans running. Although I doubt they would need to run more than a minute or so after shut down. With this car, I guess it'll come down to how the test drive goes. I wish the dealers would go ahead and get their demos already!

[Brandon26pdx]

Also the fact that its mounted in the trunk might have something to do with them using a drycell battery. They are 100% sealed, no leaking or acid buildup on the terminals like a standard water filled battery. I've got an Optima Redtop in my current car...clearly a superior product.

[john970]

Originally Posted by crzy4135i

That makes sense. If the electric pump runs you'll also need one of the electric radiator fans running. Although I doubt they would need to run more than a minute or so after shut down. With this car, I guess it'll come down to how the test drive goes. I wish the dealers would go ahead and get their demos already!

I think somewhere we determined this doesn't happen - search for "turbo timer".

I know my A4 doesn't do this and my turbo glows bright red at night if i pop the hood. Also, I think the single turbo in my a4 is larger and hotter than the turbos in the 135.

[ersatzS2]

Originally Posted by Brandon26pdx

Also the fact that its mounted in the trunk might have something to do with them using a drycell battery.

Originally Posted by chriskurn

I believe the extra capacity battery is for the electric water pump that will cool the turbos down after the car has been shut off.

no no no, go read the E82 Training & Information manual posted by Rook. The whole "Intelligent Alternator Control" ("IGR") is based on a system that allows the battery to become far more discharged than normal because it favors re-charging only while the car is braking. The very design of the system requires different characteristics than the avg battery. It's actually a pretty significant paradigm shift. Also for this reason I doubt it will be possible (without creating a lot of problems) to replace this battery for a lighter one. (besides the obvious weight distribution issue)

On the ballast issue: lightening the rear will excacerbate understeer. So if you remove the ballast, remove a comparable amount of weight from the front of the car.

I know I'm the only one on the planet to say this, but I like the weight of the one since this is my spouse's car, (and I like my wife!)

You want a light car there are lots of other options...

[MZWIE]

Has anyone thought of a spare saver tire? I don't know if there is one made to fit these cars. Heck you only need the spare for a few miles anyway. Soooooo....

I'd just as soon have one of those in the trunk and change out to non-run flats.

[larryn]

Originally Posted by e34m5

Has anyone thought of a spare saver tire? I don't know if there is one made to fit these cars. Heck you only need the spare for a few miles anyway. Soooooo....

I'd just as soon have one of those in the trunk and change out to non-run flats.

This is a good idea, but it won't fit under the carpet, and you'd need a tire iron and jack too, which don't come with the car.

I'll be using an M Mobility Kit, like the M cars have. It's a portable compressor and a can of fix a flat (plus rubber gloves and wipes) in a nice zippered case.

[Sherifftruman]

So, the One does not even have a jack? My MINI had run flats, but they gave me a jack at least.

[MZWIE]

Is there any room on the sides of the trunk like my E46 has. There are some nice small hydraulic jacks that fit nicely in cubby holes.

[atr_hugo]

Yes there is room on the outboard edges of the trunk aft of the wheel wells.

[MZWIE]

Aha...I don't have an issue with carriyng a spacesaver in an soft enclosure even if it won't fit under the carpet. I don't ever carry anything bigger than a gym bag in the trunk.

So for me I will look into a small jack, wheel wrench and a space saver.

Look at this: http://www.felcojacks.com/pages/3/index.htm

or this http://new.minimania.com/web/Item/NM.../InvDetail.cfm

[mikeo]

Are there space-saver spares that will fit over the 135's front brakes? If someone finds a source do post it.

[stylinexpat]

Anyone here actually remove the stock battery and weigh it ? I'd like to know an exact weight. I am sure there are higher capacity after market batteries that weigh less then the standard stock battery. Would be nice to save 20-25 Lbs. on a better battery with more power but less weight.