What is the best way to increase brightness in gauges?

[scarceller]

Originally posted by sportline
so after going through this thread, do you have to make a new dimmer or can you use the stock headlight switch?

Thanks

We do not know yet about the dimmer. I just recieved a donor dimmer and will be current testing this dimmer to see if it can handle the load. We just don't have specs on the stock headlight switch, so I plan to bench test the dimmer section of the headlight switch with the yet to be calculated total load (in amps) all this will be done with a 12V bench power supply and load resistors. I will then test the dimmer at it's worse case: when the dimmer is turned down so the lights are dim is the worse case for the dimmer as this is when it will have the highest resistance. Will just see how hot it gets when compared to the stock load.

Bottom line I'm just at this step of seeing what the stock dimmer can hold.

We have concluded that the stock wiring can handle the load just not sure about the dimmer.

[kwm]

So what are the brass tubing added to the back of the bulbs doing for us again?

[scarceller]

Originally posted by kwm
So what are the brass tubing added to the back of the bulbs doing for us again?

The tubing is copper not brass (but could be brass) the 3/8 tube on the back of the bulb is what holds the bulb in place in the gauge. The hole in the gauge that holds the stock bulb holder is 3/8". You can get my draft doc on this modification here: http://members.cox.net/widebody

This gauge lighting modification is still a work in progress so stay tuned.

[kwm]

I am and I like your project. I may do it myself this winter if winter ever starts here in Carolina. Still close to 70s, whoa!

[scarceller]

Last night I started testing the Donor headlight switch I received from Tom (Tanks Tom!). The news is not great but not all bad, here it goes.

First, we should all be very proud of the design and workmanship in our cars! As an electronics engineer I'm very thrilled to work on the electrics in these cars! This switch is very well built and I see why it costs $100.00+, we must keep in mind many of these are 20+ years old and still work, enough about how much I like Porsche.

The reostat/potentiometer for dimming the gauges is actualy visible without taking this switch apart, this was done so the reostat could breath and disipate it's heat to the outside of the switch. You can see the wires that are wound around what appears to be a ceramic center core. Very well built old school electrics here, we don't see this much these days. Upon inspection the wire is about 22-24gauge wire wound around the ceramic, not sure what it's made of, but it's not copper it's some sort of resistive wire.

Using an ohm meter I see that when the dimmer is turned fully clockwise till you hear a click (gauges are brightest in this position) the reostat is actually by-passed 100% and I ran 5Amp load at 14volts with no problem and NO noticable heat from the switch under this condition.

Using ohm meter I see that the reostat resistance is 0-5ohms, 0ohms is gauges bright 5ohms is dim. I then proceeded to apply 2.2amp load at 14volts and if the reostat is in the 5ohm setting (gauges dim) the switch gets warm but not much to worry about. However, in the 1ohm area of the switch (gauges slightly dim) the switch gets HOT! hot enough that you don't want to touch it for to long. The wires around the ceramic center do not glow or anything like that. But I'd say this is about the most current you can put through the switch. I'd say this reostat is rated for about 2 to 2.25amps tops.

What does this meam? can we use it or not with the new bulbs? I'm not giving up here's why:

In the stock configuration the dimmer powers about 10-12 bulbs not exactly sure but here is what I found: 8 bulbs for gauge lighting, 1 bulb for the heat indicator between the seats, 1984 911s and newer have a bulb in the rotary 3 posistion switch between the seats, 1 bulb for the hazard warning lights and a resistor that's in series. So I'm at 11 bulbs already and i may have missed one. These bulbs are 2watt bulbs each draw about 0.15amps at 14volts for a total load of about 1.7amps. Of course this is all theory at this point and I plan to actually measure this load in the car, will do this next. So the numbers seem to add up, 1.7amp load for 12 bulbs and the switch seems to get hot arpound 2.2amps not bad. Of course if you have a pre 84 car you may only have 10 bulbs for a total of 1.5amps. So that's the details on the stock configuration.

If we use 5watt xenon bulbs for only the gauge lighting this means we replace 8 2watt bulbs with 8 5watt bulbs and these 5 watt bulbs draw about .4amps each so 8 5watt bulbs will draw about 3.2amps and this is just to much current to power via the dimmer. But, what if we only power 5 bulbs via the dimmer? hear me out: what if we live with only dimming the center 3 gauges? (speedo, tack and oil temp/pres) then we'll be right around 2amps. Not sure how many bulbs are in the oil gauge yet but it may have 2 if this is the case then I'm at 2.4amps. Once again all theory here and I'll test current load for all 5 gauges while wired in the car.

Also, the headlight switch has 2 terminals for gauge/interior accesory lighting. Terminal 58a is the dimmer output terminal that has variable output based on the dimmer position. Terminal 57 is also for interior accessories but is constant battery voltage output (fixed 12volt). So you could move all the wires from 58a to 57 and live with all interior accessory lights not dimmable. Or you could elect to put what you wish on terminal 58a (dimmable terminal) so long as you don't exceed 2amps.

I will play around with the idea of only making the 3 center gauges dimmable with the stock dimmer. But in the end I actually don't mind gauges and accessories that are NOT dimmable. So I may just place all wires from terminal 58a onto terminal 57.

So there you have it, bottom line I see NO way to power all the gauge lighting with the stock dimmer safely. But we may be able to power the center 3 gauges with the dimmer and place everything else on terminal 57 (fixed 12volt).

Of course I will follow up theory with real numbers once I place the new 5W bulbs in all the gauges with the new wire harness.

Any thoughts or creative ideas from others? Ron?

[911 in SC]

IMO, that's great news Sal. It's good to know where 'we' stand if we upgrade our bulbs to 5 watt xenon bulbs. Again, IMO, I don't need to 'dim' my lights, as I have always wondered why anyone would want to 'dim' the gauges in a car - I mean, they are certainly there for a purpose, and are very useful 'tools'.

It looks like I need to order some bulbs and take a trip to HD for the 'toilet' tubing kit... Sounds like a great project to work on during the two weeks of Christmas! Thanks again Sal and everyone else that has worked on this.

Later,
Mike

[scarceller]

Originally posted by 911 in SC
IMO, that's great news Sal. It's good to know where 'we' stand if we upgrade our bulbs to 5 watt xenon bulbs. Again, IMO, I don't need to 'dim' my lights, as I have always wondered why anyone would want to 'dim' the gauges in a car - I mean, they are certainly there for a purpose, and are very useful 'tools'.

It looks like I need to order some bulbs and take a trip to HD for the 'toilet' tubing kit... Sounds like a great project to work on during the two weeks of Christmas! Thanks again Sal and everyone else that has worked on this.

Later,
Mike

Mike, you could also try 3watt Xenon from www.bulbs.com part# B715533. These bulbs will draw about .21amps so 8 will draw 1.7amps or so, this will allow you to run the gauges from the dimmer.

I'm just running out of steam trying bulbs, been at this for 2 months now. The 5W Xenon is part number B715205 from www.bulbs.com.

I like the way the 5Watt bulbs look so I will go this route first, then maybe will order some 3watt in the future and try that route as well. Unless someone else wishes to try it, most likely will be someone who really wants the dimmer to work.

The hard part of this project is preping the bulbs with the copper tube, be sure to order 15 or so as you may make mistakes plus you will want spares for the future.

What we really need is someone in the lighting industry to manufacture these for us. Any ideas?

Good luck.

[Walt Fricke]

Sal

I agree with you about the high quality of the headlamp switch. But Porsche seems at times to ignore the simple stuff, like what can handle what current. My switch quit providing power to the headlamps because they drew too much current (well, perhaps I had been experimenting with higher wattage bulbs, to be fair). I took it apart and was awed. However, one of the silvered (or so it appeared) runs on a ceramic core had blackened and pitted where it ran past its contact. And cleaning and a coat of solder was no long term fix. The fix was a "good" used switch and the use of relays for both highs and lows.

Inspired by this discussion I hunted around in my bulb box. Found some bulbs that fit and were brighter. Installed one. Then found I had no light from that bulb - must have been a 6 volter from a VW, and it promptly burned out. I have a bunch of bulb holders from VWs that fit nicely in the holes. Maybe I can convert one of those to hold the better bulbs. Lots of work, but speedo and tach are all I need to brighten. Speedo especially, as you have to interpolate with it and it is smaller and harder to see (I have mine rotated about 90 degrees to the left due to a small steering wheel).

Walt Fricke

[911 in SC]

5 watt Xenon bulbs ordered! Going to HD tomorrow to get the tubing. Man, I can't wait to have better lighting in my 911! That's one of the many small things that have bugged me since I first drove it. I understand it's a fairly involved process, but it just takes time. I feel I'm pretty good at soldering. I've been soldering at some rate for the past 20 years.

Thanks again to everyone that has researched and worked on this. I think it's a worthwhile modification.

Mike

[FinallyGotOne]

PLEASE CONFIRM: I just did this and updated to white faces. but bought new bulbs instead of going to LED. I was told the HEAT of the LED woulld cause problems. so anyone agree with that?

[Early_S_Man]

The most powerful of the current SuperBrite LEDS still only dissipate 1 - 3 Watts ... comparable to 0.5 - 1.5 times the power of OEM BA7 bulbs! There must be soething else going on ...

http://www.cree.com/products/pdf/XLampThermalManagement.pdf

http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

http://www.cree.com/products/pdf/XLamp7090XR.pdf

http://ledlightingsupply.com/ledlightingsupply/Reference%20Materials/XLamp%20Soldering%20&%20Handling.pdf

http://cree-microwave.com/products/pdf/XLamp4550.pdf

[Mysterytrain]

Sal, I think you did a great job with this research paper I have to be honest and admit that I don't think I have ever dimmed the dash lights on any car I have ever owned. So I don't think bypassing the dimmer is all that much of an issue.
I've been looking for a self contained dimmer module online. I was hoping to find something that was the size of a square relay that could easily be mounted out of the way and wouldn't require any special wiring and insulating skills. The trick for me is to be able to use the variable voltage from the OEM dimmer to control the aux hi-current dimmer.
This is what I've found so far.

http://www.midwestmotion.com/servoamp/25a12v.html

http://www.imtra.com/product/marine_lighting/dimmers/dimmers/iml_rotary_dc_dimmers/ildim_rot10.htm

http://www.theledlight.com/pdf/controls/mini_dimmer.pdf

http://store.qkits.com/moreinfo.cfm/MX033

http://www.electronickits.com/kit/complete/motor/ck1400.htm

http://www.sailorsams.com/mall/dimmers-ilvpc.asp#Specifications

It appears that most will allow you to take the voltage from the non dimming terminal on the light switch and have the provided dimmer tucked away someplace.

I'll see if I can make some calls to these guys and find it if any of the dimmers will work with the factory dimmer.
Sal..what is the resistance of the dimmer?

[scarceller]

Originally posted by FinallyGotOne
PLEASE CONFIRM: I just did this and updated to white faces. but bought new bulbs instead of going to LED. I was told the HEAT of the LED woulld cause problems. so anyone agree with that?

This makes little sence to me since LEDs produce much less heat than the stock 2W bulbs. Also Hollywood Spedo does an LED install that puts the LEDs inside the gauges for around $400.00 they can be reached at http://www.nhspeedometer.com I spoke to them a few months back and they place LEDs inside the gauges at unique points. I have heard the gauges look nice and they do a good job. Of course it's $400.00. My research was to project was to figure out howto improve the gauge lighting with out opening the gauges and come up with a solution that's in the $50-$100 range and could be dne at home. Also keep the gauges looking stock.

As for the heat, I'm not 100% certain but it is my educated guess that these gauges can handle the 5W bulbs, I already have them in my Clock and Speedo for a month and I am checking them for signs of heat or other issues and have not seen any problems.

By the way I tried 5 or so diffrent tpes of LED buls and had little to no luck. It has been my experience that the approach of trying to just place LEDs into the existing sockets in the gauges is a waist of time. I even tried BA9 larger based LEDs (very bright) but they don't work because they seem to shoot the light straight ahead while standard bulbs have lots of side light, I'd say 80% of the light from a standard bulb is side light. So if you can find some sort of LED that produces lots of side light go for it and try them but don't waist time or money on the LEDs that just shoot light straight ahead.

I have also tried placing LEDs inside the clock like Hollywood Speedo does and this approach seems to work OK but still not as bright as the 5W Xenon. I also concluded that if you are going to crack your gauges open and place LEDs all around the bezel internally you are much better off just giving the job to NH Speedo for $400.00. So this left me back to the first approach of improving the lighting without craking te gauges.

In conclussion of your question I see no issue placing LEDs in these gauges, they just don't get that hot.

[scarceller]

Originally posted by Walt Fricke
Sal

I agree with you about the high quality of the headlamp switch. But Porsche seems at times to ignore the simple stuff, like what can handle what current. My switch quit providing power to the headlamps because they drew too much current (well, perhaps I had been experimenting with higher wattage bulbs, to be fair). I took it apart and was awed. However, one of the silvered (or so it appeared) runs on a ceramic core had blackened and pitted where it ran past its contact. And cleaning and a coat of solder was no long term fix. The fix was a "good" used switch and the use of relays for both highs and lows.

Inspired by this discussion I hunted around in my bulb box. Found some bulbs that fit and were brighter. Installed one. Then found I had no light from that bulb - must have been a 6 volter from a VW, and it promptly burned out. I have a bunch of bulb holders from VWs that fit nicely in the holes. Maybe I can convert one of those to hold the better bulbs. Lots of work, but speedo and tach are all I need to brighten. Speedo especially, as you have to interpolate with it and it is smaller and harder to see (I have mine rotated about 90 degrees to the left due to a small steering wheel).

Walt Fricke

Walt, I agree 100% about placing relays on the headlights. Not sure why Porsche failed to do this? They use relays many other places. I will be doing this to my 84 soon and I think it's a great modification for these cars. It will also extend the life of the headlight switch and the parts for the mod cost less than the switch it's a no brainer. As for the wear on the dimmer reostat I'd have to just say many of these switches are 20+ years old. I suspect most of the dimmers last forever because most folks don't dim the dash. If the dimmer is fully turned clock wise then it does not put any current through the reostat at all.

[scarceller]

Originally posted by Mysterytrain
Sal..what is the resistance of the dimmer?

Ron, I measured 0-5ohms resistance for the dimmer. This dimmer is very low resistance dimmer because it dims the dash by dropping the voltage to the gauges because the dimmer is wired in series with all the dash lights and forms a voltage devider so that as you turn the dimmer counterclockwise (towards the 5ohm side) the voltage drop across the dimmer starts to increase from 0v to say 6v, I have not tested the voltage drop so I'm guessing here. Anyway this 0-5ohm reostat may be tough to use with the modules you are researching since I suspect most of those want a potentiometer of 1kohms or more, just guessing here.

[scarceller]

Originally posted by Walt Fricke
Sal
Inspired by this discussion I hunted around in my bulb box. Found some bulbs that fit and were brighter. Installed one. Then found I had no light from that bulb - must have been a 6 volter from a VW, and it promptly burned out. I have a bunch of bulb holders from VWs that fit nicely in the holes. Maybe I can convert one of those to hold the better bulbs. Lots of work, but speedo and tach are all I need to brighten. Speedo especially, as you have to interpolate with it and it is smaller and harder to see (I have mine rotated about 90 degrees to the left due to a small steering wheel).

Walt Fricke

Walt,
Are the VW bulb holders diffrent than the 911? what bulbs do the VW gauges use, BA7S bulbs like the 911 gauges? Would love to find simpler way to put the 5W bulbs in the 911 gauges. Could you take pics of the VW bulb holder?

Thanks.

[gatotom]

Scarceller.... it was my pleasure to donate to the cause, great work.

You were right the new switch did nothing for my car other than the piece of mind that it is now new, it should last till the wheels fall off.

My 2 gauges that have the weakest light are tach and speedo, tach being the weakest with the hi beam light hard to see. The other 3 gauges are great no problems. So them replace the 2 gauges, right, should cause no problems with the current wiring.

Is there anyone out there that wants to start a cottage industry and build these lights???? I don't even have a solder gun.

[SCWDP911]

Originally posted by gatotom
Scarceller.... it was my pleasure to donate to the cause, great work.

You were right the new switch did nothing for my car other than the piece of mind that it is now new, it should last till the wheels fall off.

My 2 gauges that have the weakest light are tach and speedo, tach being the weakest with the hi beam light hard to see. The other 3 gauges are great no problems. So them replace the 2 gauges, right, should cause no problems with the current wiring.

Is there anyone out there that wants to start a cottage industry and build these lights???? I don't even have a solder gun.

Hmmmm.......

[SCWDP911]

Sal,

great work continuing here. I have been away a bit. We just aquired two new plants and I have been busy with that. Look forward to trying these out soon. I believe I will go the non-dimmer route myself.

Cheers,
Shane

[Walt Fricke]

Originally posted by scarceller
Walt,
Are the VW bulb holders diffrent than the 911? what bulbs do the VW gauges use, BA7S bulbs like the 911 gauges? Would love to find simpler way to put the 5W bulbs in the 911 gauges. Could you take pics of the VW bulb holder?

OK. I'll take a picture. I'm guessing these are VW parts. These bulb holders are the same diameter as the Porsche ones. My Porsche holders have the wire integrated into the holder assembly. These have a spade lug extending from the plastic insulation. Like the Porsche they have a lip with two notches, and the positive terminal is spring loaded.

The bulbs I had fit both holders, though in the Porsche they were a bit looser. They had lengthwise protrusions formed into each side of the base to hold them in when rotated. I'll see if they have any markings.

I kind of wish Porsche had used spade lug connectors on its bulb holders, though making up an entire loom, or part of one, isn't that much work (and we have no choice). Or did some models/years of 911s come with spade lug positive bulb holder connectors?

Let's see - can I crush a bulb, solder a replacement into place in the old base, strengthen the gap for insulation and support, and just use the stock holders? Tedious, but so is the alternative?

Walt