High Output H5 Bulbs
 

Are relays needed when I upgrade bulbs for my '88 911 Cab on the H5 and H3? Is the stock wiring good enough? I would like the 100W H3, and a brighter H5 than stock? Any tips?

I have the same question: Can I use brighter bulbs in my H-5s? Do I need relays and/or an upgrade in wire harness?

Thanks,

Lew

Adding a relay is probably the way to go. It should also increase (restore) output a bit. However, I've seen a few "high wattage" H5 bulbs (over 100W) that have melted the mounting and wiring harnesses in no time. You just have to make sure that you use a high quality, properly insulated bulb.

I'd say both, relay and upgraded wiring if you plan to run high wattage H5s. When I got my `87 Carrera it had 80/100 H5s in it. One day I noticed the RH headlight out. I opened it up to have a look and the connector was toasted and wires discolored. I installed a relay kit I bought from a Rennlist member Marcus Sucro and went back to the original (I think) 45/55 watt bulbs. I think the best upgrade is to Euro H4's, which is the direction I'm going. But you need to get the rims painted to match.

That's my .02
John

Regardless of the system, high output bulbs need the relays and sufficient wiring. Even with stock bulbs, the relays are needed in order to keep the headlight current from going through your stalk dimmer/turn signal switch.

As a separate issue, I believe the H5 systems have had trouble with plastic parts in the fixture that hold the bulb. I am not familiar with these systems and am speaking from memory, but you should check it out. I think the H4 system is the overall best.

Parallel question: has anyone ever installed Philips "Vision Plus" bulbs? I've read on a French website that these would be said to produce upto 50% more light than a regular (European) H4, for (said to be) 10-20 meters further forward vision.