CCA Requirements? Options

[Literati914]

I'll be picking up a flooded cell lead acid battery soon (budget oriented battery for a rear trunk relocation) and have been leaning towards a group 51R battery. I like this size because they are small - think Mazda Miata, small Honda Civics, Nissan GT-R, IIRC. However, I think the original group 34 had around 700 CCA [is that correct?] and the 51R tends to have a little less (425-/+). The first engine will be a 1.7, but then I'll probably upgrade fairly quickly, possibly before the typical battery dies.

I sort of recall the CCA demand being dependent on the needs of the starter.. or something like that. Anyone know for sure what our starters require, amp wise? And/Or Will the 425 CCA work?

[zoomCat]

Will the 425 CCA work?

The factory battery was a Group 42. The factory specifies 45AH, but don't appear to make any mention of CCA. Group 42 flooded batteries generally make 450 to 500 AH.
One of the most demanding scenarios for a battery is starting after a long cold soak; think a month outside in 10 degree (fahrenheit) weather. Our cars are unlikely to see that situation, any modern automotive battery should be sufficient.
If you're in Texas I'd be more concerned about long term storage in sustained hot weather. AGM batteries appear to abide infrequent use, and I've heard some suggest that they suffer less from electrolyte evaporation. And, all the cool kids run AGM now.
You can find flooded batteries in Group 42, but not AGM. if you're not running in the stock location, size doesn't matter.

The short answer, 425 CCA should be fine. You can overanalyze the problem (as I do (IMG:style_emoticons/default/biggrin.gif)) based on other criteria.