battery

Group 91 for a 1987 TR, not sure if yours is the same............I kind of think it would be.

 

The biggest one that fits in the box without touching anything!!! Gotta have lots of power to turn those 12 cylinders over and get those horse's kicking !!!!! More amps the better!!!

 

I'm using a Group 34 Diehard Gold (which seems to be a mid-level quality Group 34) without trouble (but don't know if it's the "stock" TR size) -- just another option maybe (not to say that a Group 91 wouldn't work fine, but, if the price is higher for the Group 91, I can confirm that the slightly taller height of the Group 34 seems no trouble).

 

Don't forget to order the battery with reverse poles.

 

+ ! !!!!

 

Using a Group 34 (not Group 34R) in my TR:

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Do you have a photo or reference showing a TR with a Group 34R battery?

 

No changes made that I know of, and the cabling/orientation matches the TR SPC figure so please supply your evidence and/or example for "34R IS the correct fit". I do agree that a person would have trouble using a battery (might be Group 47) shaped like Jeff shows here (but with the posts in their proper stock TR locations) in your prior thread:

http://www.ferrarichat.com/forum/boxers-tr-m/273316-tr-battery.html

so the "R" version from that manufacturer (as shown in Jeff's photo) would work better on a TR -- but it puts the posts forward (when they are rearward stock).

I've tried searching for some 308 battery photos, and find more examples and evidence that Group 34 is the proper size there too (and plenty of examples of odd sizes with the posts wrongly placed forward ). Couldn't find a photo of a Group 34R in a 308 (although I did find a posted picture with text that said it was a Group 34R, but the post locations look Group 34 to me -- if someone has a shot of a Group 34R in a 308, please post).

 

What I have in my 308 is a group 47. Bottom is tight but it fits.

 

And are your battery posts towards the front/leading edge of the battery?

This photo shows what I (presently) believe to be correct for a Group 34 in a 308/328 -- posts to rear (gives best clearance to cover), "+" post on LH side, "-" post on RH side:
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Steve my post are towards front but clear the cover.

 

Understood (since the Group 47 is about 3/4" lower than the Group 34), but you are giving away some oomph since the Group 47 is in the 600 CCA ballpark; whereas, the larger Group 34 is ~700 CCA.

 

600 cca is more than enough for a summer car with a 3.0 liter engine.

 

the battery question has been for a TR, 5 ltr. not for a 3 ltr.
or is there outside anywhere a TR with 3 ltr??? I mean not the old TR 250

 

The only TR battery "specs" that I can recall finding are on page I8 in the TR WSM ("Euro-standard dimensions L3"), and, from that (and the TR SPC illustration), I went with the Group 34. Can you post a photo of your present TR battery and cabling? Are you saying that a Group 34 would not work in your TR?

Obviously, other battery sizes can work, but, for example, the Group 91 that Ken mentioned is designed with a special cell venting system for application that require it (that is not really needed on a TR) -- so they tend to be more expensive.

 

I don't know what group my battery is but it's an Interstate Mega-Tron II (MT-34R) delivering 800 amps (700CCA). It's 10.25"L X 6.88W X 7.75H and fits nicely in the compartment, using the existing hold-down and cables.
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I need to correct myself. I'd swear that I knew this, but the TR SPC actually shows what I (now) think is a battery shape closer to a Group 47 battery (which has pole locations more similar to the 34R, but with the poles down in a step). Isn't going to change my opinion that the Group 34 is a better TR choice! Sorry for adding confusion...

 

I believe this was the OEM (AC Delco) battery for (at least) US model Testarossa's. The model # is 20-66. I found a old reference table that lists the specs as:

L: 277mm
W: 175mm
H: To top of case height 1: 190mm
H: To top of case height 2: 190mm
Approx. weight: 17.15 KGS.
Ampere Hour AH: 66
BCI CCA @ 0 degrees F: 500
DIN CCA @ 0 degrees F: 300
Reserve Capacity (minutes): 110
Amps for load test: 250
Term. Conf: SAE
Term. L/O: RH
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It never really occurred to me that all these different batteries would work. I put a group size 91 in my car because that's what was in there when I changed it out. I found below, it looks like there saying a group size 27/
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Nothing wrong with that Group 91 in your TR IMO (except maybe the price ). It's a big, powerful battery with a very low height (although with a slightly larger length to help keep the inside volume up) and the cell venting feature -- all driven by modern coachwork pacakaging and increased "electrification" trends. When they need a new size or feature, they just make one up and add it to the list .

IIRC, there is some vertical headroom above my Group 34 battery, and the TR photos seems to indicate that there's some room available in the length direction, so would love to try/see a Group 27 mounted in a TR (wonder if the negative terminal access gets more difficult). Group 27 is an older design with good power, but needs a largish size (it's very tall and long compared to more modern Groups) to achieve that power and keep cost low. I'd bet that F went with that smaller AC Delco in Tim's photo just in order to keep the weight down even though they had more room available.

PS I still want to see a picture of a Group 34R in a 308 and/or 328 (and would prefer it here rather than starting a separate thread in the 308/328 forum) so please (anyone) post if you've got it.

 

Also keep in mind that there are tabs on the bottom of the battery that need to fit into the retaining bracketry. The correct battery is the 34R and check out the small Mercedes battery that fits PERFECTLY. Maybe Costco has a 34R. There are a few drawings in the manuals that show the battery posts forward and the negative terminal outboard, positive closest to the car center. It is not a good idea to run the cablesover the top of the battery. FWIW


Jeff Pintler
89 348tb, 86tr, 99 360 3-pedal