P21W alternatives

[GT17V]

Of course, a lot of people (including myself) use 1156 as the alternative. There is another alternative, 3497.

Quick specs:

P21W
Watts: 21
Lumens: 465.09
Life: 150 hours

1156
Watts: 27
Lumens: 402.24
Life: 1200 hours

3497
Watts: 27
Lumens: 565.65
Life: 600 hours

Result?
1156 are dimmer then P21W, but have substancial more life
3497 are brighter than P21W, 4x more life, but costs me $9 for a twin pack.

[whatnxt]

Since you have a Golf, do the 5th brake light mod and get even more light.

[A2B4guy]

1156 is a great alternative, excpet it is slightly longer and will "bottom out" in some tail light units, IOW the glass hits the front of the lens before the back plate snaps in place. If there's room, use the 1156.

[dennisgli]

Quote, originally posted by GT17V »

Quick specs: P21W Watts: 21 Lumens: 465.09 Life: 150 hours 1156 Watts: 27 Lumens: 402.24 Life: 1200 hours 3497 Watts: 27 Lumens: 565.65 Life: 600 hours

Are all these ratings at the same voltage?

[GT17V]

12V for P21W
12.8 for the rest

[dennisgli]

Not much of a comparison if the ratings are at different voltages - power, light output, and service life will all vary with voltage.

[GT17V]

If you're assuming everything is linear... bump up the voltage to by .8, P21W will still not as bright (estimated 494 lumens) and will have even less life

Of course, if you ask the beloved Daniel Stern what he recommends for MKIV tail lights..... He'll tell you:

Brake & Turn = go with 3497 instead of P21W
Reverse = 796 (which is a 35W Halogen) instead of P21W

[rains]

thanks for this