Square headlamps

[Fozziebear]

Are rhd square headlamps a direct fit for left hand ones?
And would the only benefit fitting them on a lhd vehicle be that you don't have to put on the beam deflectors?

[R0B]

Yes and yes.

[California Dreamin]

Fozzie, and your L/H/D lamps are perfectly legal (will pass the MOT) as long as beam deflectors are correctly fitted and don't effect the light intensity significantly.
The most common complaint from owners is that the lights just aren't bright enough and this is usually fixed by fitting relays with Osram Nightbreaker bulbs.

Martin

[Fozziebear]

Fozzie, and your L/H/D lamps are perfectly legal (will pass the MOT) as long as beam deflectors are correctly fitted and don't effect the light intensity significantly.
The most common complaint from owners is that the lights just aren't bright enough and this is usually fixed by fitting relays with Osram Nightbreaker bulbs.

Martin

Hi Martin,
Ok thanks for the info when you say relays why would you need to fit these?
Can't you just fit the nightbreaker bulbs for on their own?

[California Dreamin]

Fozzie, and your L/H/D lamps are perfectly legal (will pass the MOT) as long as beam deflectors are correctly fitted and don't effect the light intensity significantly.
The most common complaint from owners is that the lights just aren't bright enough and this is usually fixed by fitting relays with Osram Nightbreaker bulbs.

Martin

Hi Martin,
Ok thanks for the info when you say relays why would you need to fit these?
Can't you just fit the nightbreaker bulbs for on their own?

Of course...Nightbreakers will give you a modest improvement in overall brightness but the real problem is the age of the wiring, connections, earths and the lack of switching relays which means lots of voltage drop at the bulb. There is a graph somewhere (posted previously) that shows something like a 40% loss in light intensity for around a 1.5 volt drop (this is measured on supply being somewhere around 12.5 volts) these might not be the exact figures but you get my point? Typically (headlamps on, engine running) owners are seeing less than 11.5 volts reaching the H4 bulbs which represents a massive loss in 'POTENTIAL' light intensity.
In short, You could be be loosing 35 - 50% of your lamps designed intensity through tired wiring/earths and switch connections. Relays eliminate much of this, re-establishing something near full voltage to your bulbs.

Martin

[California Dreamin]

There is tons of stuff written about 'relaying' and several different ways to achieve the same thing...one thing is for sure, everyone without exception agrees that it is worthwhile.
Discussions include:
Improving the main feed: battery to fuse box (this lowers voltage drop to each of the consumers particularly under high demand i.e. when everything is turned on)
Earth crown cleaning (above the fusebox) this is as important as the feed itself in order to complete the lighting circuit with minimal resistance and consequent voltage drop.
Relaying at the fuse box but still keeping the existing wiring to the lamps. (eliminates the main causes of voltage drop, i.e. through the switch contacts but still relies on old relatively thin wiring that was adequate at best, to the lamps)
Full relay mod which gives new feeds and earths all the way to the bulbs. (as good as it gets and done properly will give you the highest voltage at the lamp contacts) more complicated so many avoid this for options above.
Don't be tempted to fit 'illegal' high powered bulbs, the extra ampage draw could burn out your switches and many report only slight improvements in performance.
Big lamp debate: around fitting aftermarket 'Halo' and other modern alternatives...really only concerns round headlamps though.

All have positive effects in improving the intensity of the lights...some might even say 'miraculous' improvements.

Martin