does anyone know where to find a fairly cheap lightweight battery with good cold cramk amps? i would prefer to shave off 22 pounds by adding a lighter battery than relocating the battery to the front trunk and adding 5 pounds of cable.
The Deka batteries are marketed for motorcycles. They won't be as strong as the Optimas but they are reported to be decent. I did a fair amount of research into batteries a while back but never ended up buying a lightweight battery.
The Deka ETX14 (the 11lbs one) is rated at 200 CCA but I've read a lot of reports that put them up around 400 CCA. I know they can start AE86s and since the OP talked about relocating the battery to the frunk, he must have a mk1 which is pretty comparable to an AE86. They will probably discharge after a week or a few days of sitting and you wouldn't be able to sit and listen to music with the car off for very long.
I'm curious to find out if the ETX14 can start a mk2 turbo reliably. That's why I had both model numbers handy -- they were the ones I had narrowed my choices down to.
You might also hear about Braille "race" batteries. From what I can tell, these are just rebranded Dekas.
It's been awesome. I have a big sound system as well as still running AC, power windows, etc etc and I've had it for nearly 2 years now. It has sat once for 5 months fine and this last time nearly a year. Wasn't totally dead but didn't turn the car over this time haha