Stock battery group size for '87 GTI 16V?

What is the smallest stock battery group size for an '87 GTI 16V? The gti16v.com specs only says this for the battery:
12 Volt, 54 Amp/Hr. (63 Amp. with A/C)
I've currently got a huge group 41 battery, it supposedly weighs 34.5lbs. The alternate batteries that Napa lists are the group 48 and 91 at 36.6lbs. The group 90 battery in my 2001 Focus is substantially smaller...... So I want to see if there is an allowed stock replacement that is smaller and lighter than this huge group 41.

So how do I find out what is the allowed stock size replacement batteries to see if I can shed a few pounds here? (I'm thinking one of you has already done this research, so I'm hoping someone can share. :p)

Go to Wal Mart for a stock battery; they are usually the lightest for a given group.

Note the Group, etc. stuff ifor batteries is no longer as strict a rule as it once was.

YMMV.

Yes, but I'm trying to figure out what group size(s) are allowed. The group 41 looks like the battery I had on my Rabbit diesel! Way big for a gasoline engine. Perhaps I should try the group 90 battery from my Focus on for size. ;)

1) Look at battery tray.
2) Find smallest and lightest battery that fits in tray.
3) Buy battery.

Go racing.

I know for sure that the 16v scirocco came without AC. You need to determine if the GTI 16v came that way - local VW dealer should be able to confirm this. The non AC cars use a smaller group battery. I want to say it is group 42 - but it is about 7-10# less than the big guy.

I am looking for a battery for my car as well. I found a group 42 battery for it at a farm & fleet store. I think it was around $56 plus your old battey. The next time I am in the area I will have the old one with me.

It is smaller then the old one which I thing is a group 41.

Group 42 was the smaller, lighter battery used in most of these cars.
Group 41 was used in diesels, cold weather area cars and lots of A/C cars.

Beware that because of the price of lead, many battery manufacturers are "consolidating" sizes and you may be sold a group 58R battery that is very similar in size to a group 42 but lacks the part of the battery tray case that slides under the backside of the battery to hold it in place.
YMMV
Good luck.
cheers
dave parker

Beware that because of the price of lead, many battery manufacturers are "consolidating" sizes and you may be sold a group 58R battery that is very similar in size to a group 42 but lacks the part of the battery tray case that slides under the backside of the battery to hold it in place.
Good luck.
cheers
dave parker[/quote]

I have to agree with you on this as far as stock mounts on the battery. On a race car I would never depend on the stock mount. I plan on using a bracket across the top and long bolts to hold it to the battery tray.