What is the correct Battery group size for a 1987 3.2 911?

spsfiend · 01-25-2009, 01:06 PM

I recently bought my 1987 911 3.2 and the battery it came with was a group 48 size. I was having problems starting my car about a week ago and figured my battery died somehow so I charged it yet the problem remained. I tested the battery and it tested ok. Was reading 12.4. This morning I smelled sulfur after start up in the battery area so I decided to buy a new battery. Went to buy a battery and to my surprise the recommended group size was 49 instead of of 48. The 49 is a few inches longer and the main difference is the Cold Crank Amps. the 48 is 700CCA and the 49 is 850 CCA.

Could this explain why my battery was having trouble starting up the car and why the battery is probably fried?

Also, can someone confirm the correct battery group size?

Thanks so much!

pozee · 01-25-2009, 04:15 PM

Everything I have simply spec's it as an 88ah.

Interstate has the following spec'd for 87 3.2's

MTP-93-Mega-Tron Plus - 85 Months - 850 CCA

COL 911 · COL 911's Garage

I know the books say Group 48 was OE, but my 87, purchased in SEP '05 from third owner, cam with a 2005 Duralast (Autozone brand) Group 49, 850 CCA, which bit the dust during recent cold snap, and luckily, accepted a recharge. I too was shopping for a 48 based on all the books until I realized I could try a quick charge.

The larger Group 49 fits tightly, but I buggered the first few threads of the front battery retainer clip hole trying to replace the self-tapping allen head bolt home during replacement. The battery is secure side to side, front to back, but still has some play if I lift it vertically. Trying to find longer allen head to get enough leverage to retap through the first threads I damaged to the remaining original threads.