Today I bought a couple 50 watt bulbs from Napa just to try them out in
my 87 Syncro. I had already upgraded the tail lights from 5 watt to 10
watt bulbs so the 50 watt bulbs went in to replace the stock 21 watt
turn signal bulbs. These 50 watt models were $$ halogen bulbs so I doubt
that many folks will get them but I wanted brighter bulbs and could not
find a store that stocked anything else.

I installed one 50 watt bulb in the passenger side turn signal and a
stock brand new 21 watt bulb in the driver's side turn signal. I turned
on the 4 way flashers and waited to see what happened. The 50 watt bulb
was noticeably brighter, naturally. I own a digital infrared temp gun so
I used that to monitor the temps of the lenses in the area lit by the
turn signal bulbs.

After 10 minutes I started checking the lenses to see what the temps
were. The 50 watt side was hotter, of course. It kept climbing for a
while and after 15 minutes of flashing these are the temps I saw.

50 watt side, 165 degrees F.
21 watt side, 115 degrees F.

The areas not lit by the bulbs read about 70 degrees and the air temp
was in the 50s.

I may try the experiment again with the brake lights and then I will
prop the brake pedal such that the brake lights stay on constantly.

Mark