1987 911 turbo battery size? what is best?

[transadapt]

looking for some direction.. i have a 1987 911 turbo, there is 2 battery sizes you can use.. what do you Porsche people recommend? there is a H8 (49) and weighs just over 55lbs and it is a super tight fit, but fits... and there is a H6 (48) that is just over 45lbs and is a lot easier fit.. one last question, would you use a dry battery or a wet battery? thanks for all you help in advance... K

[EauRouge]

I have been using the smaller 51R, available at Costco, for several years with no problems.

[Alan L]

I have been using the smaller battery size. It is plenty - as long as you don't have starting issues.
Alan

[Garen]

I got about 7 years of use out of my PC680. The car started very easily, and I shut the battery off with a kill switch after every drive, so that may have contributed to the long life. I also never put it on a trickle charger.

[transadapt]

thank you, for all your input... k

[mark houghton]

I have yet to understand why the God's at Porsche felt we would need a mondo huge tractor battery, unless maybe it was for those nights in the mother country where it was colder than a witches tit and needed the CCA to crank through frozen oil sludge. Mine died over a year ago and I happened to have a standard 12v battery on hand for almost any application. Works fine other than having to fabricate hold down straps.

[slow&rusty]

In the past I used the PC680 Odyssey, but their prices have sky-rocketed, so now use the ETX20L battery which is dimensionally identical incl. weight but available at a much cheaper price from nearly all auto stores.

I modified the Odyssey aluminum battery holder to fit the ETX20 and always keep it on a tender.

As it is an AGM battery it hates voltage swings and if they drop too low, it will drastically reduce their life. A $25 tender from Amazon goes a long way.

[crb07]

I'm old so I will have to go and look in my car, but, 90% sure the new Odyssey R37 has the posts on the correct end and on towards the center of the car. I have a plate it bolts down on so that the factory battery securing points work. I got almost 8 years out of my last one. Battery tender is a must.

[David]

I've had good luck with Optima so I just replaced my 6 year old ~40 lb 34/78 with a 34 lb 75/25 battery. They don't have hold down tabs on the bottom so I bolted an aluminum tray on the bottom the same dimension as the stock battery.

[crb07]

Originally Posted by David

I've had good luck with Optima so I just replaced my 6 year old ~40 lb 34/78 with a 34 lb 75/25 battery. They don't have hold down tabs on the bottom so I bolted an aluminum tray on the bottom the same dimension as the stock battery.

^^^ that's what I just replaced, Optima, not Odyssey.

[turbobrat930]

I run a Oddesey PC925 in my smugglers box. I usually have to replace it around the 4 year mark. It's lightweight, and has plenty of power to start our 930's. and it gets that weight away from that outer corner, and more centrally located in the car.

[David]

Originally Posted by turbobrat930

I run a Oddesey PC925 in my smugglers box. I usually have to replace it around the 4 year mark. It's lightweight, and has plenty of power to start our 930's. and it gets that weight away from that outer corner, and more centrally located in the car.

I have no real world experience to base this thought on but one reason I keep a near full size battery at the stock location is to somewhat offset the turbo weight at the other extreme end of the car. So when I'm pirouetting off the road, it's more of a constant speed rotation

[Black_Hat]

1991 C2 Turbo
all electric everything

I have been using for years with zero issues:

a small AGM - 189 $

https://www.batteriesplus.com/battery/car-and-truck/mazda/miata/1999/base/l4-1.8l

Porsche 930 and 964 Turbo's are low compression

Stefan

[Tippy]

I have 7.5:1 CR and a gear reduction starter. I’m pretty sure a lawnmower battery would be enough CCAs to start mine