H4 Bulb? H7 Bulb?

[Blacklark57]

So I just ordered myself a pair of Xenon headlights last night (since one of stock ones has been burned out since I bought it), and I noticed that the bulbs for either side are different. One is an H4, and the other is an H7. Does anyone know the reason for this? Why not use the same bulb for both sides? Seems kinda silly to me.

 

[champion221elite]

H7 is your low beam, it only has one element inside.

H4 is your high beam bulb and it has two elements inside. This bulb is capable of running high/low beam if you've completed the BD43 mod. I'll try digging up some specs, but I'm fairly sure the H4 is capable of producing FAR more lumens than a H7 bulb can do.


Here's a spec sheet from Osram Sylvania.

http://www.sylvania.com/ConsumerProducts/AutomotiveLighting/Products/Halogen/SilverStarProducts/

Just for quick reference, the H7 bulb puts out approx. 1350 lumens while the H4 puts out approx 910 lumens on low beam, and 1500 on high beam.

 

[necrotimus]

Also be aware that your old H7 bulb has an adapter on it that you will need to use on the new H7 so don't toss it.

 

[Blacklark57]

Good to know about the adapter, I'll be careful when I get to working on it.