What would happen if I used a group 34 battery in my 06 rx8 mt? The battery im look

ing at is in the pic.

 

Electrically it would work, physically its a tight fit that you don't want. The battery needs to be cooled with air flow, wrong size battery will not be cooled as intended. It's a small difference but surely you can find a group 35 that fits your needs? There's nothing special about the one you're looking at there.

 

Thank you so much.

 

Here is a PDF from M-Tips (Mazda's version of a TSB) that specifically mentions a Group 35 which will leave some room around the battery inside the battery box for cooling. Remember, the under hood temperatures in a rotary engine compartment tend to be considerably higher than an IC engine! Good luck.

 

While theoretically you shouldn't put a bigger battery on the battery compartment for cooling reasons, I 've been using a bigger battery for around 4.5 years now and it still has some juice. Not ideal but ok, it works. Just my 2 cents.