Odyssey battery @ Daytona

Craig 930 RS · 02-10-2005, 07:12 AM

About 1/2 the teams ran the Odyssey PC680 battery at Daytona;
placed not in front of the windshield as stock, but moved forward as in our earlier 911s for 'better weight distribution' acc'd to the winning team.

Must be a good battery
Makes one curious why one would move the battery BACKWARDS to the smuggler's box

Some thoughts.

Zeke · 02-10-2005, 07:46 AM

Good point. I put it in the SB simply because there are some neat ways and made up kits to do so. I had a full size spare and will be taking track tires in the car (one in the spare position), so I didn't have to choose between left and right weight.

On my 914, I put the battery right behind the pass seat. That would seem like a good idea on a 911 since it eliminates about 5 feet of cable to the starter and somewhat offsets the weight of the driver. (15lbs. to 180! LOL)

Chuck Moreland · 02-10-2005, 08:39 AM

If the battery is light enough, I guess it doesn't matter where you put it!

Eric_Shea · Eric_Shea's Garage

Who makes batteries for the original twin boxes in my 71?

I just went through a battery strap project that ended up with a gas tank removal "while I'm in here" project.

I think I'll need a few new batteries

911teo · 02-10-2005, 08:59 AM

Those batteries are really neat. Huge saving in weight vs stock and do not cost that much more. Plus the fact that you can put them flat... makes them very versatile.

widebody911 · widebody911's Garage

One thing to keep in mind is that the optimal weight distribution for an all-out race car is going to be different than for a warmed over street car, in addition to the fact that other bits may have first dibs on the smuggler's box area, if that even exists in the later cars. A lot of the hard core pre-90 race cars I've seen put the oil tank in the smuggler's box area.

Craig 930 RS · 02-10-2005, 09:12 AM

If the battery is light enough, I guess it doesn't matter where you put it!
I thought the same thing. 13 lbs won't make much of a difference. But if you have a choice, move it forward acc'd to the Farnbacher boys -

Diminishing returns?

------------------
Unrelated, but a battery story:

Team Seattle had a short in the electrical system a day or so before race day - the (large factory) battery EXPLODED. What a mess. Acid all over.

klaucke · 02-10-2005, 09:34 AM

Moving the battery forward increases the polar moment of the car, that is, its ability/resistance to turn. Although the change may be very slight, it is none the less optimal to put as much mass in the center of the car as possible, so that the car can easily change direction.

Think of it this way, is it easier to spin a 20lb bowling ball, or a 20lb, 10 foot ladder? The bowling ball is of course much easier to spin because its mass in centralized.

Now, the real question is if the mass centralization of moving the battery into the battery box is going to help the cars turning capabilities more than having a higher front weight bias by moving the battery as far forward as possible? I think the battery way up front would help reduce understeer more, for sure. But if you've got an all out race machine with super light weight everything, and it handles well, the place for the battery is in the center of mass.

Craig 930 RS · 02-10-2005, 09:38 AM

But if you've got an all out race machine with super light weight everything, and it handles well, the place for the battery is in the center of mass.

Yet the all-out race teams at Daytona specifically went out of their way to mount the battery *up front*

Ah well.

klaucke · 02-10-2005, 09:43 AM

Craig, what I meant was that in the "all out race machines" that ran at Daytona, the handling still left something to be desired (apparently), hence mounting the battery up front.

Craig 930 RS · 02-10-2005, 09:58 AM

I have my suspicions that their battery idea is based upon a theory that the factory placement in front of the windshield is from a crash standard (aka smashed battery/electricals in an accident) mandate rather than something proven. Some so-so pics of factory location -

Blue box at top of pic

911teo · 02-10-2005, 10:02 AM

Anyway no matter where u put it it's a cool battery

http://www.batterymart.com/battery.mv?p=ODY-PC680MJ

911pcars · 02-10-2005, 01:44 PM

If you live and operate in freezing climates, then you should be aware that the Odyssey only produces 220CCA. The battery capacity will shrink in cold weather. Should be fine for warmer climates, and it's relatively light @ 16 lbs. Not sure about its longevity.

Sherwood

Eric_Shea · Eric_Shea's Garage

Do they fit in the early cars??

911pcars · 02-10-2005, 02:47 PM

Yes. You should find many examples in the archives.

Sherwood