Bosch Sealed Beam Replacement (pictures)

[jplucas]

A coworker had some Bosch H4s which are drop in replacements for sealed beams that he bought for his Miata from Flying Miata; he's decided not to install (turning into a track only car) so I thought I'd give them a try since they also fit my 84. These are Bosch DOT parts intended for motorcycles, p/n 0301600118, and they come with boots to seal the bulbs on the backside.


First of all I was curious about the lens curvature difference. The Bosch lenses are not flat but they are noticeably less than the stock sealed beams.

Before:


After:


Straight on:


The Miata guys post some beam pattern comparisons here of multiple brands starting at post #136.

I still need to aim them before I use them at night but that will have to wait till tomorrow.

[Reifle]

These are not sealed beams - these are replacement Bosch headlights with H4 bulbs. These are pretty good lights and it is normal to have the cut off (seen on the Miata site). If you want to go even one better get a relay for the headlights and you can install a brighter light - say 55W low beam and 100W high beam. The relay will also assist intake some of the electrical stress off your headlight switch - like cleaning up the current to and fro the switch to the lights etc...

[jplucas]

Perhaps conversion is a better word than replacement.
Headlight relays are already on my order list.

[jplucas]

Got a chance to do a little night driving yesterday. These are a huge improvement over the stock sealed beams both in the total amount of light and the beam pattern/focus. Highly recommended even with the stock wattage bulbs. 4 screws per side and your done, so very easy.

Gave me plenty of warning to avoid a bambi crossing!