Difference between H4 and H5 lights

[Fishcop]

Can anyone explain the difference between H4 and H5 lights, and which one is the better?

Thanks

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John Forcier
69 911T

[Yargk]

I would like to know the real answer to this myself. I just assumed that H4 was the older style with a lip around the head light so things like bugs could get stuck in there. H5 would be the new ones, like on turbos 1986 and on, without the lip. Someone please tell me if I'm right.

Keith
79 930

[Early_S_Man]

Well, the feeling which is better is probably a subjective one ...

If you like something you can maintain and fix if a rock cracks the lens, and parts made of metal and glass ... choose the H4.

If you like the latest plastic technology with parts glued together and throwaway assemblies ... choose the H5. An answer to a question nobody asked!

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Warren Hall
1973 911S Targa

[Don Plumley]

Here is the data from the Pelican Parts (yes, right here) site (and borrowed also from a post on Rennlist by Carnut169):

The Bosch H4:
The Bosch H4 Euro Upgrade is one of the most popular for these 911s. This upgrade kit replaces the entire headlamp assembly inside the headlamp bucket. A new special lens focuses the light more completely and directly so that you can see farther, and avoid hitting things when travelling at high speeds at night. The entire installation is a snap, and can be completed in about a half an hour with only a phillips screwdriver. For more information, take a look at our Pelican Technical Article on the Bosch H4 European Assembly Installation for the exact procedure on how to perform the rebuild yourself. We also recommend replacing the headlamp to fender seal when you are installing a set of new H4s. Want to protect your new investment from rocks and stone chips? Consider a pair of our H1/H4 Airplex Headlamp covers. These custom-fit clear acrylic plastic covers mount over the lenses, and are nearly invisible!

The headlamps come in either chrome or a black anodized finish. There is a factory cover plate that fits around the outer headlamp rim (covering up the chrome or black), that is primered, and can be painted the color of your car. However, to install this cover rim, you also need to replace the single lower attachment screw for the entire assembly with the inner and outer screws listed below. The inner screw actually fits inside the outer screw and holds the primer ring to the assembly.

Most replacement parts for H4s are unavailable in the United States due to import restrictions on the parts. Porsche will not import replacement parts that were only used on European cars for DOT concerns. As a result, only a few replacement H4 parts are available. If you would like to replace the retaining ring, reflector, or even the outer black or chrome ring, you will need to purchase an entire H4 assembly. The H4s have an additional small bulb inside the assembly that is used for daytime running lights on European cars. The US-spec cars do not have the wiring installed to utilize this feature of the H4s.

The Hella H4:
These lamps are one of the most popular upgrades to the 911 (1965-86). Replace your dim standard headlamps with high powered halogen Hella lamp assemblies. Guaranteed to melt holes in the plastic bumpers of the Honda in front of you! Combined with a uniquely formed lens, the newer lamps give you more than triple the light than the stock tungsten sealed lamps. Unlike the 'European' headlamp kit detailed above, this kit allows you to keep the original headlamp look and style of the 911. The upgrade kit ships with 1 headlamp with 55/60W H-4 bulbs; 100 watt bulbs available as well for faster, more efficient bumper melting. The bulb and lens in this kit directly replaces the sealed-beam lens that was originally used on the 911.

The H5:
The H5 Headlamps were used starting in 1987, and despite the higher H-number, they are not as bright or as focused as the European H4s. It is still considered an upgrade to move from the 1987-89 Carrera H5s to the European H4s. For those wanting to adapt the H5s to the earlier cars (1974-86)

Also H1s:
The Bosch H1 kit is similar to the H4, except that it has dual reflectors that allow for individual adjustment of both the high beams and low beams. The H1 assemblies use the same sized housing and a similar, but different lens. Internally, the H1 has an additional reflector for focusing the high beam. Original H1 kits are no longer available, however, replacement bulbs and lenses are indeed still available for replacement.

Here is an older thread on the topic: http://www.pelicanparts.com/ultimate/Forum3/HTML/009931.html

Don


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don@plumley.org
Das Zoom - '87 Carrera

[This message has been edited by Don Plumley (edited 07-14-2001).]