914und993

I reviewed the past threads on putting a higher wattage bulb in the 993 in hopes of better output, and was surprised that no one found an improvement.

Even worse than the 993 headlight design is the 964 design, and putting higher wattage bulbs in that car resulted in a considerable improvement in the low beams - though the pattern was still pretty sorry.

So now I have a 993. An HID low beam conversion may be in my car's future, but for now I thought that 100w H1 bulbs in the high beams might be nice. I located some Philips 100w 12v H1 bulbs, and ordered a pair. After installing one into the right high beam, I turned them on to compare to the left which still had the original 55w bulb. No improvement! In fact, the 100w right looked a little bit yellower than the 55w in the left. So I pulled out my photographic incident light meter and took some measurements that confirmed my eyes: the 100w was not putting out any more light than the original Osram 55w.

The only way I could understand this was if I had been sold 'mislabeled' bulbs, so I decided to bench test them to find their current draw and actual wattage at a regulated 14 volts: the 55w Osram drew 4 amps, for an output of 56 watts, while the 100w Philips drew 6.2 amps for 87 watts.

So why is the higher wattage bulb no brighter? I'm not certain, but since its output is slightly yellower, the visibly larger filament must be operating at a lower temperature, converting less of its power into visible light.

The bottom line is that this attempt to get more high beam light with a 100w bulb has failed!

Chip Stratton

Terry Adams

<a href="http://members.aol.com/ajaynejr/lumen.htm" target="_blank">lumens and watts explained, sort of</a>

Knute

Hmmm...

I have heard it postulated that unless the wiring is upgraded (stock wiring is not designed for the current flow associated with the higher wattage) that the resistive losses of the sub-optimal wiring gauge prevent the high wattage bulb from seeing the voltage it ought to, and if it doesn't see enough voltage, it won't heat up as hot as it is supposed to, hence less light.

However, this doesn't account for the less than expected light output in your "bench test" with regulated voltage. Did you test the light output with the regulated 14 volts to the bulb, or was the light output tested only when installed in the car?

Curious!

And, I have a set of 55W H1 Philips Vision Plus that arrived this week from England (www.autolamps-online.com) that I'm about to test, having read good reviews of this bulb and anxious to improve my headlight brightness...

Which type of Philips bulb did you test?

-Knute

914und993

Well I didn't measure the light output on the bench before my first post, but I just went back and did so, while measuring everything else more accurately.

At 12.61 volts, measured at the lamp base itself:

55w Osram 4.61 amperes = 58 watts; EV 11.4
100w Philips 7.27 amperes = 92 watts; EV 12.1

The 100w Philips, at this constant voltage, gave 62% more light than the Osram (converting from EV to relative lumens), which is pretty close to what you would calculate from the measured wattage differences.

I suspect Knute is right, that the voltage drop in the 993 wiring does somehow reduce the efficiency of the 100w lamp relative to the 55w. The ideal would be to measure the voltage and current of each in the car itself to see what is really happening, but I think I'll pass on trying to do that.

Chip

WillyC4S

Good solid data on the testbench!

I've been using H1 100w bulbs from Hella for the high beams and it's not really a significant improvement. It's been in there a while so I've gotten used to the slight change, but I remember myself being under-whelmed when the bulbs were changed.

I'm probably going to change back to the stock bulbs and reduce the chances of any wires over heating to cause electrical damage.

*****

maurice97C2S

And while you're at it check that your bulbs sit in the correct position in that (delightfully plastic) hi beam mount - the clip doesn't usually hold the bulbs in the centre of the reflector - non-optimal for the crappy design of reflector, even. No attempt is made to capture 70% of the light output of the bulb.

Is this the nadir of Bosch headlight design / Porsche quality control ? Perhaps the same guy that specified the '95 wiring looms?

Cheers, Maurice (dimly lit) (don't need shades !)

FlyYellow

Good data with the bench test. On the car I would suggest some possible explanations:

1. the 993 hi-beam reflector is of poor design. Therefore adding more wattage does little to no good if much of the bulb output is wasted in the design effeciency.

2. i believe there might be some logic in the wiring explanation. so to test that theory i would run the light measurement test with 100W on the left and 55w on the right - both on. Then remeasure the 100w with only the left light on (unplug the right one). If it increases you've decresed the load on the system and it was able to deliver sufficient voltage to your 100w bulb.

3. Take apart both headlight assemblies and clean them inside. I did that and what a difference! They have an explanation for this at Robin's site.

Let us know what you come up with.

Cheers,
boris

PK

It's good to know all that data on the H1 hi-beam current draw and wattage output.
And I don't mean to spoil the party, but....why all the fuss?

Prior to my HID Conversion, I had replaced both Hi and Low-beam factory bulbs with 100W aftermarket bulbs resulting in non-significant improvments.
After the HID conversion on the low-beam, I have NOT touch that Hi-beam since. Basically, I'm keeping hi-beam operational only as in case of emergency the low-beam goes out on me.

So, if anybody still contemplating on the HID or Litronics conversion, just go for it. You'll only wonder why you waited so long to jump on it.

Peace. <img src="graemlins/wave.gif" border="0" alt="[byebye]" />

maurice97C2S

[quote]Originally posted by PK:
<strong>
After the HID conversion on the low-beam, I have NOT touch that Hi-beam since. Basically, I'm keeping hi-beam operational only as in case of emergency the low-beam goes out on me. <img src="graemlins/wave.gif" border="0" alt="[byebye]" /> </strong><hr></blockquote>

Not to disagree too much, but HIDs or not , you need more in the hi beam area - I hope you aren't driving on the same road as me if you rely on HID lo beams and nothing on hi!

Cheers, Maurice

WillyC4S

I'll second Maurice's comment on the need for high beams. Even with the poorly designed high beam reflectors, they still shoot farther than the Litronics and where I live you really need that stopping distance in case of deer and other animals at night.

I just wish they made a Litronics for the high beam as well as the low beam. That would be a totally killer headlight system (like the new 996TTs, except 2 bulbs instead of a movable reflector). Probably light up the road for construction work with that setup.

*****

Jeff 993TT

You could always install something like these:

<a href="http://www.piaa.com/displayLamp.php3?inc=930.html" target="_blank">http://www.piaa.com/displayLamp.php3?inc=930.html</a>

in the fog light area. It might take some custom fitting to make it look nice. I've been thinking of doing this if I get my bumper repainted. But at $1800, it's a bit pricey.

Jeff

Knute

Most of the comments I see on this thread (and others in the archives) seem to focus primarily on two alternatives: higher wattage bulbs, or conversion to HID lighting. I do understand the argument of those who have gone HID, but since project budgets aren't unlimited (and personally I'd like to put those pennies in the piggy bank towards an ROW M030 suspension), I'd be very interested in people's experiences with the THIRD option:

How much of a difference does it make to drop in H1 bulbs with the stock wattage (55W) that actually have higher rated light output? Specifically, which bulbs are the best choice?

One of the references I've uncovered was a review in Auto Express magazine (UK):

<a href="http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=503287&page=6" target="_blank">http://bimmer.roadfly.org/bmw/forums/e39/forum.php?postid=503287&page=6</a>

This review actually measured output in lumens (and beam pattern) and really liked the Philips VisionPlus (which is why I procured a pair) but PIAA and some other options are not well represented in this testing, nor is the testing specific to H1 bulbs, which may make somewhat of a difference.

Anyone?

-Knute

maurice97C2S

I tried PIAA hi output 55W in Mine shortly after buying it - made very little difference due to the plastic mount / poor locating clip / minimal reflector / bloody awful design generally!

HIDS absolutely worthwhile @ £400 or so - just think how much hitting something at night would cost you!

If I ever find a good solution for hi beam, I'll let you know! I'm experimenting on some spare headlamps at present.

Cheers, Maurice