jimcabc

I've got an '87 911 cabrio with a weak battery. It has to be at least 4 y/o and suffered through a duff vr until that was dx-ed and was fixed. My question is what is the recommended lead-acid battery for this car. The manual just says 12V 88 Ah, while the battery that is in the car is a Champion UF2 that has 800 cca @32 deg. However the Champion (I just noticed!) is not well secured. The one clamp that I can see is not actually holding the battery down. I had a friend tell me that older 911s required a Porsche battery and using an aftermarket battery requires additional brackets. I may decide on an Optima, but would like to consider the old fashioned kind as well

Jim
'87 911 Cabrio

Bill Gregory

When the battery on both my 911SC and my 964 went, I replaced them with batteries from Autozone. They come with a 6 or 7 year warranty with a 2 year free replacement period. More important, they have the proper plastic foot for the Porsche clamp to lock onto. Around $60, as I recall.

Crimson Nape Racing

the Autozone battery Bill mentions is probably a stronger battery than the Optima, and costs half as much. However, if you do any track or auto-xing, you don't have to worry about the Optima venting acid into your trunk.

jimcabc

Thanks for the info here. Probably not going to DE this car, just spirited driving on occassion. Bill - Do you recall the Group or part number of the battery?

Jim
'87 911 Cabrio

rbcsaver

The opitma's are not a "direct" group fit and require some mods in your brackets. Check and treat existing corrosion. Paint any with Por15, then use one of the yellow battery acid felt mats, obtainable from Performance, Pelican, etc.
regards,
Steve

Bill Gregory

For my 911SC and 964, it's a 48-D, with 700 CCA and 875 CA. And to clarify my original post, the warranty is 7 years. Another thing that was nice on both batteries is that the build date was very recent, like the month before I bought it.

jimcabc

Thanks again for all the info. The Autozone recommendation made me remember that it is another battery made by Johnson Controls. In my youth, I worked at a (then Globe Union) battery factory which made all of Sears, NAPA, Interstate, etc. batteries. My father was manager of the factory, and while I'm sure the job was a ploy to be sure I finished my college degree, I did also learn a few things about batteries which have been useful since. One of which was that different brand batteries can be virtually identical, except for the stickers on the side of the case. They made the first Die Hard batteries for Sears and I once delivered some race prepped Die Hards to Penske Racing in Newtown Square when I was on my to Watkins Glen for the 6-hour and Can Am. As I recall, the only difference from stock batteries were that they were hand assembled and had epoxy at the bottom of the case to keep the plates from rattling around. Die Hards were pretty advanced for the day.

BTW, I checked out the Johnson Controls web site and they have a very cool battery finder. Just enter the battery brand you're interested in from the drop down list, enter your car make, etc. and it gives you the part and group number you need plus the cca. Sorry for rambling - Jim

jimcabc

Got the battery today at Autozone, gp 49. The Autozone showed either a gp 48 or 49 battery would fit. The 49 available was an 850 CCA batt. At first the salesman and I were convinced the gp 49 would not fit, as the distance between the bracket for the existing battery and the inner wheelwell arch was way too small. However. we took the old battery out and removed a rubber mat that the battery was sitting on and lo and behold, another threaded hole that would allow the gp 40 to fit! So, again I learned something new about this car. It has two threaded holes to accept a bolt for the battery hold down bracket. One to accept a pretty big battery such as the gp 49, and another to accept a smaller battery. Anyone know what that would be? I had to really complement the Autozone guy. He worked for a good 1/2 hour installing the battery in what is a very tight space. By the way, I notice the starter spins faster and the power top seems to have no problem closing now.

Jim
'87 Cabrio
blk/blk/blk

ron mcatee

I have an 88 Carrera and put in an Interstate MB66 as it is a smaller battery and the clamp fits quite nicely in that second hole. The larger battery that was in the car hit the front condenser motor housing causing it to crack. MB66 works very well and really turns the starter. I believe it is an option for many Porsches.

jimcabc

Spider 911 - do you know the cca for your Interstate? - Jim

ron mcatee

I think it is around 600. Here in Texas, the temp makes it work very well. we don't get below 25 degrees F very often in the winter. Up in Indy during the winter, you want 700-800 CCA's. Mine has worked very well here. Good luck.