bovellois wrote:
On the new to me 05 Ram 2500 CTD, I note a big difference in lighting compared to Old Faithful (97 Ram), but it's still not perfect. What type of bulb should I use while staying street legal? I've used Sylvania's zXe in the old truck, they are good but pricey. What about SylverStar Ultra?
Instead of dumping a bunch of money into new bulbds perhaps you should break out your volt meter and check the voltage at the bulb socket with bulbs connected and on..
Pretty good chance you will find a 1 or 2 volt drop at the bulb..
Typically I have seen as low as 10.5V at the bulb with engine running, at the battery measured voltage around 13.9V.. or about 3.4V drop..
That is equivalent to about 24% LESS wattage from the bulb!
If you have a bulb rated as 55W you are only getting 41.8W!
Fix that and you WILL have considerably brighter lights.
Vehicle manufacturers tend to use the lightest wire gauge they can possibly use and typically is 18 ga.. While it is acceptable to use for the current drawn through the wire it also adds a lot of resistance which drops the amount of voltage by the time it gets to the bulb..
What I do on my vehicles is I add relays into the headlight circuit.. I feed the relay with 10Ga wire directly from the battery. This shortens the amount of wire the voltage travels and lower the resistance loss of that wire considerably.
With the relays I dropped the voltage loss to less than 1/2V.. The results are nothing short of a miracle and didn't require using extremely higher wattage bulbs which have a shorter life..