Brighter "P O N T I A C" taillights

Using brighter bulbs - 86-88 GTs only

>I've been told I can use bulb #921, which is twice as bright
>as the standard bulbs to make it more readable.

One of my Pontiac Emblem lights burned out... or so I thought, until I pulled it out. The socket was melted. In fact, all four sockets were deformed. There are 921s in my car that must have been put there by the previous owner. I'd be careful about replacing the standard lamps with a higher wattage.

As a matter of fact, let me pull out my 'GE Lighting Miniature & Sealed Beam Lamp Catalog'...

The 921 is a T5 wedge base lamp. The 'T5' signifies a tubing diameter of 5/8" (5 X 1/8"). It runs on 12.8 volts and consumes 1.40 amps (WOW!). It delivers approximately 21 mean spherical candlepower (don't worry about this, just remember the higher the number, the brighter the lamp output) and is rated for 500 hours of operation. So, the total wattage for four lamps is over 70W, which is more than a high beam filament! Now I'm starting to worry about my ignition switch.

The standard 194 lamp is a T3-1/4 (about .40" dia.), consumes .27A @ 14V, delivers 2 mean spherical candlepower (MSC) and should last 2500 hours. The 168 is also a T3-1/4 lamp, consumes .35A @ 14V, delivers 3 MSC and has a life rating of 1500 hours.

To make the emblem brighter, you need to match the wedge base, operating volts, and increase the MSC. Here are some other T5 suggestions:

Lamp	Volts	Amps	MSC	Life (hours)
904	13.5	0.69	4	5000
906	13.0	0.69	6	1000
912	12.8	1.00	12	1000
916	13.5	0.54	2	10000 (not brighter, but will last forever)
917	12.8	1.20	10	1200
918	12.8	0.56	6.5	500
923	12.8	0.91	12.5	500   (a good compromise?)

There are others, but the life or MSC is less than the standard lamp. The 912, 917 and 923 might be good choices because they increase the light output considerably, and don't run as hot as the 921. With this information, you can make a choice that best fits your needs.

From: Lawrence Mazza

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