[Silver BLT]

Greimann

Thanks, I followed (sort of) your directions. Actually I read them once, then completed the 3rd brake light LED conversion. I used a 50 not a 75 Ohm resistor, a bit more power but it would take a long time to burn out the LEDs at that amperage. What a great Idea you had here. Thanks. Took about 45 minuites to complete. (after I found the (somewhat) correct resistor)

Silver BLT

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[Greimann]

Good deal! With a 50 ohm, you will be driving them a little harder, hopefully not above the Vmax. A 75 puts you right on Vf, if you are using the same LED's that I listed. It might also be a good idea to measure the wattage going through the resistor because it might be above the 2 watt limit, requiring a 5 watt, or a pair of 2 watt in parallel.



Either way, I'm sure you were tempted to look at the bulb directly like I did. Bright little suckers. I am still seeing red spots! <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" />



The cab conversion is very similar. You have to add 3 pairs of holes after removing the 4 bulbs and reflectors. The resistor can then go into one lead, instead of on the board. The board is then glued to the lense with some of that GOOP adhesive.

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[Anchorman]

Is there anything the prevents more LEDs from being used in the cab installation? For example, looking at the photo, it appears that another 6 LEDs could easily fit, greatly reducing the 7-point look by having a total of 13 more closely spaced LEDs.



Whatever, though, my goal is to completely eliminate the trunklid-mounted light and integrate a light into the rear panel where the 968 numerals currently reside. My current concept is to install a third brake light from a 996 by having some body work done (basically, cutting the required opening) and then repairing the trunk lid. However, if someone (Dave?) comes up with a simpler approach, I'm all ears.

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[Greimann]

13 lights would be possible. It would just take some tuning of the wiring and resistor values.



With the 996 light option, another thing to consider is beam angle. LEDs are fairly directional and the angle of the 968 body at the point of install may throw the beam off the proper angle to be effective. Something to look into.



A quick idea is to replace the trunk lock cylinder with a small, bright array of LEDs behind a plastic cover. The key socket is redundant anyway with a keyless entry system.



Or maybe a strip of LEDs where the body gasket is that separates the bumper cover from the sheetmetal. There might be clearance issues there though.

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[Anchorman]

I kind of like the idea of replacing the lock cylinder. I seem to remember that the Cadillac Allante had a round emblem as the third brake light, which would be a similar look. Later today, I'll look more closely at the rear of my car - and, hopefully, you'll keep thinking about this as well. C'mon 968Engineering!



Well, after looking at the rear, I don't think the cylinder lock replacement works - it's too low (would certainly not be considered a high-mounted light by anyone). Back to dreaming about the 996 light installation. Right now, all of my bulbs are working (and, yes, $10 apiece - staggering) so I'll see what direction I move in by the time another blows (in two years, two have blown).

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[Scottish968]

Thanks I just read the posting for that and it did look good, your feedback reaffirms my desire to go ahead and 'light up' <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />



[COLOR=red][SIZE=7][FONT=Optima][quote name='insite94' date='Feb 9 2005, 03:49 PM']Consider this a shameless plug for  http://www.968engineering.com/



I just had Dave Greimann redo my 3rd brakelight with LEDs and they look great.  I didn't know it, but I was driving around with 5 of the 7 previously burned out.



I have no affiliation, just a satisfied customer, etc.  But I'm really pleased with the bright "fixed right and shining bright" look of the new LED array...



...reasonable price, fast turnaround, especially valuable for those of us without the time or skills to pull this off.



Thanks, Dave! <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />



Best,



Buzz

[right][post="496"]<{POST_SNAPBACK}>[/post][/right][/quote]

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[SILVY968]

Ever since I added the LED modification to my silver cab I have been thinking about how nice a clear lens would look. In the last few months I have seen several new cars with clear, 3rd brake lenses with red LEDs behind them.



I have decided to try and make a silicon rtv mold of the red lens and create an exact, clear, polyester resin lens from the mold. While I am at it I may remove the stock, round mounts and form in a slot to hold the modified LED PCB.

(If anyone has a spare lens that I could experiment with, it would be a plus, but not necessary.)



If it works out, I may make them available to forum members.

Anyone interested?

Brian

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[968gene]

Brian, I haven't read through the entire post, so forgive any repetition, the cab 3rd brake light is off an 80's corvette (I think the part number is on the cab unit). Finding one might be easier than you think.

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[SILVY968]

I believe that you are correct. An extra lens would be cool to have so that I could work on the project without having to take apart my DD.

Not a blocker, only a thought.

Brian

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[Cloud9...68]

Maybe I'm a little dense here, but I'm confused - what exactly is the purpose of this mod? Is it simply an alternative to the standard bulbs if/when they burn out? Or is it an upgrade of some kind?



My car has had most of the standard 968 problems (except, thankfully, the pinion bearing, or the rear hatch delamination), but I checked recently, and 16 years later, all bulbs in the 3rd light assembly are burning brightly. Thanks; just wondering what the enthusiasm over this mod is all about...

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[SILVY968]

[quote name='Cloud9...68' post='45164' date='Jan 1 2008, 12:14 PM']Maybe I'm a little dense here, but I'm confused - what exactly is the purpose of this mod? Is it simply an alternative to the standard bulbs if/when they burn out? Or is it an upgrade of some kind?



My car has had most of the standard 968 problems (except, thankfully, the pinion bearing, or the rear hatch delamination), but I checked recently, and 16 years later, all bulbs in the 3rd light assembly are burning brightly. Thanks; just wondering what the enthusiasm over this mod is all about...[/quote]



You are lucky, or the previous owner has replaced bulbs. Filament lamps do not last 16 years, especially when they are on a lid that is closed by dropping it down, or "gently" slamming it into place.



Also, the lamps, # 94163191120 are $12.25 each at Pelican.



The LED upgrade is a long term fix for filament lamps, are brighter, are red and are a cool project that takes very little time or money.



I would not say that it is required, but more of a cool, small project. I am just taking it one step further with the clear lens assembly; somewhat on the same scale as the quest for clear front turn signals that has been discussed on this forum.

Both are simply a matter of choice and quality, not necessity. Whenever anything goes out on my 968, I try to upgrade the part, if possible and affordable, much the same as your upgrades, the 3rd brake light mod was simply one of them.



Brian

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[Cloud9...68]

Thanks for the explanation. I didn't realize the replacement bulbs are so expensive. I'll keep an eye on mine, but given that my car isn't a daily driver, they may last awhile. But when they start to go, I'll consider this upgrade.

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[SILVY968]

If anyone needs bulbs, I have 3.

I need the small lamps from the instrument cluster that have a small black twist mount base. They are used to light up the "parking lights" green display.

Brian

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[saxman]

it's worth mentioning that led brake lights do make a noticeable safety increase to the vehicle...



they come up to brightness much quicker than incandescent bulbs, and when factored in to human reaction times, make for a noticeable stopping difference that adds up to a couple car lengths for someone traveling behind you.





silvy... if you're thinking of making your own lenses, give this a read



http://www.alumilite.com/index.php?page=info&type=HOWS

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[Ryan]

Saxman, that site is pretty cool. It looks like you could make a new lens within reason. Some of these lenses have compound curves that would be hard to mold, but the brake lite looks doable.

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[SILVY968]

Saxman,



Thanks for the link, most helpful.

TAP Plastics is in my area, and so I used their site. http://www.tapplastics.com/info/video.php



I went by today, but they were short of material. Got plex scrap and a bag of rice to make the box and measure how much silicon rtv I'll need. Will try to make the mold this weekend.



Brian

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[saxman]

[quote name='SILVY968' post='45216' date='Jan 2 2008, 06:20 PM']Saxman,



Thanks for the link, most helpful.

TAP Plastics is in my area, and so I used their site. http://www.tapplastics.com/info/video.php



I went by today, but they were short of material. Got plex scrap and a bag of rice to make the box and measure how much silicon rtv I'll need. Will try to make the mold this weekend.



Brian[/quote]

I've visited tap many times... have a few out here...



are you trying to make a clear plastic lens, or something kinda cloudy?



a clear lens without bubbles is a bit difficult without a vacuum chamber to degas the resin before pouring.

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[SILVY968]

The lens will be clear. It will be cast in polyester resin.



I do not have a vacuum chamber, so I'll try the "bombs away" method.

The guys at TAP tell me that if I pour at the edge of the mold that I should not get any bubbles.



If the bubbles end up forming and I do not like the look, I guess that I could always cloud-up the inside of the lens to hide them and defuse the light. It may end up that even with a bubble-free lens some clouding would be desirable to defuse the light and keep you from seeing the PCB, wires and LED's inside the housing.

Brian

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[968gene]

Brian, I may have missed this, have you located LEDs in red that are bright enough?

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[jfrahm]

The bulbs for the Cabrio can be found quite cheaply, packaged for low voltage lighting at Home Depot, Lowes, etc. LEDs would be a nice upgrade if they are adequately bright, as the old-timey incandescent bulbs take a bit of time to warm up. If you back up to a garage door and watch in your rearview you can see the delay between your foot hitting the brake and the bulbs getting going. The downside with LEDs is that they do not emit a great deal of light unless you get a bunch of them. I see a lot of cars and bikes with LED marker lighting and they are pretty dim, especially in daylight.



After changing the bulbs in my old S2 Cab rear lamp I hit on the idea of soldering 3-4 LEDs together and installing them in place of the center bulbs in such a way as to be able to press the group of LEDs into the bipin bulb socket. I don't think I'd do all of them as I know the bulbs work and are quite bright, but having some LEDs come on faster might be a benefit. It might also produce an interesting effect, the LEDs flashing on and then the outer incandescent bulbs warming up afterwards. A group of four high power LEDs to replace one bulb might work pretty well. Maybe I'll try it this weekend.



-Joel.

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