Best recommendation for headlights
10-29-2011, 01:21 AM
#31
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Time to give an old guy an education. My 928S4 is a Federalized car i.e. it had all of the federal junk required when it came into the US. I think the Sylvania site says I have 9005 bulbs. I see H4 bulbs with balast units for sale on ebay but I suspect there's more to it than this.
Educate me.
Educate me.
10-29-2011, 01:51 AM
#32
Rennlist Member
It is indeed confusing. The "H4" designation is technically a lamp style (as noted above), used in Euro-spec headlights. Euro headlights are characterized by a sharp upper cutoff with low beams, a crisp horizontal line a few degrees below horizontal, with an upward spread to the right (for LHD cars) to light up the deer poised on the shoulder.
The "H5" lamps are used in US-spec headlight assemblies, which basically spray a blob of light down the road, mostly downwards but quite a bit upwards. Two theories on that: It lights up the overhead signs, or just sloppy engineering.
Three different headlights have been used in 928's: early ('78-86) USA cars were fitted with 7" sealed-beam (early DOT) headlights; Euro's of any year were fitted with 8" H4 Euro-spec headlights, with the sharp upper cutoff; and 87+ USA cars were fitted with 8" H5 USA-spec headlights.
And just to confuse things, there are aftermarket (e.g. Cibie) 7" Euro-spec headlights with H4 lamps.
I think the "food chain" for headlights goes like this: 8" H4's (Euro original equipment), 7" aftermarket H4's, 8" H5 (USA original equipment), and 7" sealed-beams (USA original for '78-86).
Brighter lamps are not advised for H5's, it further blinds oncoming traffic and increases the chance that they will do something stupid. Brighter lamps (including HID conversions) in H4's throw more light on the road and (if properly aimed) don't seem to bother oncoming traffic.
The 9005 is an HB4 lamp, used for separate high beam headlights. That doesn't seem likely, can you post a picture?
Cheers,
The "H5" lamps are used in US-spec headlight assemblies, which basically spray a blob of light down the road, mostly downwards but quite a bit upwards. Two theories on that: It lights up the overhead signs, or just sloppy engineering.
Three different headlights have been used in 928's: early ('78-86) USA cars were fitted with 7" sealed-beam (early DOT) headlights; Euro's of any year were fitted with 8" H4 Euro-spec headlights, with the sharp upper cutoff; and 87+ USA cars were fitted with 8" H5 USA-spec headlights.
And just to confuse things, there are aftermarket (e.g. Cibie) 7" Euro-spec headlights with H4 lamps.
I think the "food chain" for headlights goes like this: 8" H4's (Euro original equipment), 7" aftermarket H4's, 8" H5 (USA original equipment), and 7" sealed-beams (USA original for '78-86).
Brighter lamps are not advised for H5's, it further blinds oncoming traffic and increases the chance that they will do something stupid. Brighter lamps (including HID conversions) in H4's throw more light on the road and (if properly aimed) don't seem to bother oncoming traffic.
The 9005 is an HB4 lamp, used for separate high beam headlights. That doesn't seem likely, can you post a picture?
Cheers,
10-29-2011, 08:27 PM
#33
Rennlist Member
HID is the best option for a dramatic improvement in lighting that no standard bulb can match, and the cost has come down considerably.
Unlike many vehicles out there, unfortunately upgrading to HID in a 928 is more than plug & play.
My BMW e30’s 4 headlight system (separate highs & lows) was a piece of cake. I opted for the lower powered low beam 35w kit in the BMW, & the ballasts were easy to install as they're about half the size of the 55w kit. The Ellipsoid low beams are similar to the H4 lenses, so the HID’s have a really nice focused light with a distinct cut-off. The 35w lighting isn’t as good as the 55w kit; so in hindsight, I should have gone with the 55w kit.
I decided to install a kit in my 928. Regardless of whether you have H4 or H5 fixtures, the popup lights in the 928 make HID installation a bit more of a challenge. You have to locate the ballast so that there's enough slack in the wiring when up, and the ballasts don't interfere with the mechanics of the light housing when down.
I went ahead with a low beam 55w kit in my existing H4’s. I needed to install a blocking diode in order to be able to maintain power on both high & low beam setting. Because I’d heard of the crappy beam that H5’s put out, I pulled one of the fixtures and bench tested the beam against a wall in my basement, and sure enough, an uncontained blob of bright light.
However after moving the bulb back a bit, the light became more focused. Still not as much of a cutoff as the H5’s, but acceptable.
I’ve put a large o-ring between the bulb housing and the seat in the fixture which moves the bulb back in the fixture about 1/8" which makes a difference. I wired in the bulb housing as the round twist-on bulb holders won’t work with this o-ring mod. I’ve managed to get a more focused and aimable HID beam out of these H5’s, albeit not quite as good as H4’s.
Unlike many vehicles out there, unfortunately upgrading to HID in a 928 is more than plug & play.
My BMW e30’s 4 headlight system (separate highs & lows) was a piece of cake. I opted for the lower powered low beam 35w kit in the BMW, & the ballasts were easy to install as they're about half the size of the 55w kit. The Ellipsoid low beams are similar to the H4 lenses, so the HID’s have a really nice focused light with a distinct cut-off. The 35w lighting isn’t as good as the 55w kit; so in hindsight, I should have gone with the 55w kit.
I decided to install a kit in my 928. Regardless of whether you have H4 or H5 fixtures, the popup lights in the 928 make HID installation a bit more of a challenge. You have to locate the ballast so that there's enough slack in the wiring when up, and the ballasts don't interfere with the mechanics of the light housing when down.
I went ahead with a low beam 55w kit in my existing H4’s. I needed to install a blocking diode in order to be able to maintain power on both high & low beam setting. Because I’d heard of the crappy beam that H5’s put out, I pulled one of the fixtures and bench tested the beam against a wall in my basement, and sure enough, an uncontained blob of bright light.
However after moving the bulb back a bit, the light became more focused. Still not as much of a cutoff as the H5’s, but acceptable.
I’ve put a large o-ring between the bulb housing and the seat in the fixture which moves the bulb back in the fixture about 1/8" which makes a difference. I wired in the bulb housing as the round twist-on bulb holders won’t work with this o-ring mod. I’ve managed to get a more focused and aimable HID beam out of these H5’s, albeit not quite as good as H4’s.
10-29-2011, 08:52 PM
#34
Drifting
) no matter how I aimed them.As Alan has been saying 8" H4's can NOT be beat. They have the angled lens glass that protects on-coming drivers and with Sylvania Silverstar's they turn night time into daytime and Yes they light up every highway marker, sign AND cop car for miles.
HID's would be cool for other people watching the car on a city street, but would not change much for the driver, they would probably be better used in the fogs.
