CCA needed to reliably start M103 on track?
 

We're trying to save a bit of weight on our 190 track build. Its already down to 2350lbs but we need more(less)? Whats the lowest CCA battery people have seen reliably start one of these engines? A little 51 group battery out of a civic has around 500CCA and weighs about 26lbs vs almost 50 for the original one.

You might check this thread.

http://www.peachparts.com/shopforum/diesel-discussion/385032-i-replaced-lead-acid-battery-ultracapacitors.html

Probably more than you want to know but it's all here.
http://flashoffroad.com/4runner/articles/battery/bci_2014-battery.pdf

I've been using this tiny "Braille" battery in my 16v track car for 5 years and never had an issue. It is mounted in the car on the floor, right behind the pass seat.
Braille B2015 No-Weight Battery, 425 CCA


..............and here's the car,http://forums.190rev.net/showthread.php?44964-Alain-V-16v-track-day-project&highlight=Alain

The 51 battery will be fine, MB batteries are usually oversized to deal with idling with the AC on or starting well below zero.

Make sure the ground strap between the engine and frame is good and battery ground to frame is good also. ( the battery is or is going to be trunk mounted correct? ) Take the starter apart to make sure the brushes are good as well.

The trigger wire for the starter needs high current otherwise you won't get reliable cranking so either use a 10 G wire / good switch for cranking or use a Ford starter solenoid to trip the starter. ( Look up " hot start kit " )

Thanks for the info guys. Sorry about abandoning this thread. Got really busy prepping the car for a track day and then breaking it :o

We're going to go with the honda battery when we relocate it soon.