Battery Replacement

So my battery went recently.  The electronics were doing weird things.  The windows wouldn’t roll up or down for the first 10 seconds after starting the car, my locks would double lock, and the engine, of course, had a harder time turning over.

The MKV stock battery has absolutely no size markings on it.  A part number lookup at a local autoparts store will likely yield nothing.  A 2.0t Jetta, with the same size engine, is listed as a size 48 but that is too big to fit in the GTI’s box.  A size 47 will fit just fine and is probably closest to the stock battery size.

So cliff notes:

The closest battery to the stock size is a Group 47.  I’d like a bigger battery but that would require not using the battery box.  A 48 will not fit.

The stock battery is supposedly rated at 480 CCA (cold cranking amps).  More is better in this department.  The one I just got has 590 CCA.  This is the important number.  Most batteries have another number which is cranking amps or some variation of; that number is usually way larger than the CCA’s but is measured at higher temperatures.  That won’t help you when you need it the most.

When you purchase a battery, make sure that the terminals fit when everything is in place.  The wires on the GTI require some room to fit back in the box.

MK6 Suspension

So the old suspension is out and I’ve replaced it a fresh set of springs and shocks from a MK6 GTI.  I never realized how well the stock GTI handles.  Seems to have more confidence in the corners.  It also feels like it’s more fun to drive.  Lowering springs may have affected the geometry enough to mar the steering feel.

The suspension pieces between both models are completely interchangeable.  The valving and spring rates may be different, but as far as fit, they are identically.


(Available information suggests that the MK6 and MK5 cars share exactly the same springs and shocks, at least for the US market.  The rear sway bar was supposed to be larger than the MK5 as well, but it may very well not be.)