H4 Upgrade, Search was helpful, but still have a question... Options

[Lavanaut]

I just purchased a set of H4s with the 55 watt bulbs. I also ordered the powered relay that PP's site recommends. After searching the forum for information on the install, I'm left wondering: do I even need this powered relay if I'm going to stick with the 55 watt bulbs? Several posts make it sound like I don't. We're talking about a stock '74 2.0. Oh, and I did read-up on relays over at the12volt.com but am still unsure.

If I *do* need it, then I've got another question. I think I'd install the relay on the relay board in the spot labeled 'A' in Hayes, p. 128, Fig. 9.22...is that correct? Finally, and here my true newbie colors shine through, how do I get at the relay board? For all of my reading, I can't figure out where the thing is located (best guess is at/behind the fuse panel).

Hmmm...guess that's a 3-part question after all.

Thanks in advance, and happy Friday!! (IMG:style_emoticons/default/beerchug.gif)

[biosurfer1]

not to threadcap, but i'm also initerested in this conversion...does anyone have before/after pics?

[Chris Pincetich]

I've had H4 55W for over a year - no relay and no problems. I'm pretty sure the relay is for the 100W bulbs. A direct circuit from the battery to the new relay, can be mounted in the front trunk near washer bottle or whatever, is recommended for the 100W. The old wires in the 914 were not designed with 100W in mind, so the bulb upgrade has to have its own dedicated circuits. I think the "Aaron Cox Blog" might have photos. I'm very happy with my 55W H4s + 55W Pilot fog/driving combo. (IMG:style_emoticons/default/beerchug.gif)

[Lavanaut]

I've had H4 55W for over a year - no relay and no problems.

That definitely seems to be the consensus Chris, thanks.

Is there anyone out there with the electrical know-how to give a definitive answer though? I can imagine a situation where "one year with no problems" turns into "two years and a fried starter". Maybe that isn't realistic, I'd just like to be sure.

[dimitri]

My 914/6, an import from Germany directly in 1970, came with H4 to start with. This
lamps were illegal in the US at that time, so were the amber rear turn signal lights.
Furthermore, I installed H4 with 100/90 watts bulbs on my sons 914 more than a
year and a halve ago and no problems other than one bulb quit. No relays were
used. Dimitri

[SGB]

I gotta disagree here.
I use 55 w H-4s.
After a few months, I rewired the circuit so the switch only trips the relay that recieves and sends out power through dedicated, fused 10 guage wires.
It is brighter and whiter as a result.
I think the part that is easily overlooked is HEAT. As the original systems age and oxidize, resistance goes up and so does heat output. This is a destructive cycle, b/c the increased heat increase the resistance, etc. Search "electrical problems" or something similar. About 1/2 the fried wires stories involve the HL swicth.

The relay board is on the left side of the engine compartment, under that black shoebox thing next to the firewall. I used square relays from the car stereo section at Auto Zone (1 for regular, 1 for brights) mounted up front under the little plastic HL linkage covers. I also put in a dedicated, fused line for the cd player at the same time.

[davep]

The relay panel that he was looking for is on the other side of the fuse panel above the drivers left knee. I think that relays would be a good idea along with a new supply wire from the battery, fused of course. This would reduce the load on the existing wiring and fuse panel and this would be of benefit all by itself. Yes, the lights would probably be brighter. Get the new SilverStar bulbs.

[dmenche914]

a good relay and wires will assure the full voltage to the lamps. Running too high a current can gradually degrade the components, hence teh voltage,a dn brightness.

See if you do indeed have full battery voltage to the lamps. You might find that you have some voltage drops on the existing lamps such that when repaired, you find that the stock system (in good conditoin) is just fine.
also bulbs degrade with use. sometimes a simple replacement of a lamp with a new one will greatly improve lighting. a lamp gets dimmer with use. yeah you can wait til they fail, but you maybe running with less than optimal light until then.

A relay can only help the sitiutation, besure your grounds are good. Grounds are often overlooked, but they are half the circuit.