More ?? on 9007 vs 9004 bulbs rebuttal

Todd Young auditodd at
Wed Mar 5 23:14:26 EST 2003

Funny, I like the headlights on my '93 90S...
If the road is unfamilar, I just flick on the fogs in addition to the
normal headlights. The regular headlights project down the road, the
fogs fill in the space in front of the car and off to the side of the road.

One thing I've noticed, since I had to have one head light replaced due
to rock damage, the new headlight does a much better job of dispersing
the light. Oh, and they are US spec lights.

First, I trust what Dan Stern has to say.
Second, I run Sylvania Xtra bulbs in my car. They don't have the cheesy
"blue" tint, just a little different gas mix to give them a little more
light output.
Third, if I wanted more light, I would relay the bulbs to ensure they
were getting a solid 12+ volts at ALL times.

Have some fun. With the engine off (but the key on, so the headlights
will actually light), measure the voltage at the headlight bulb. You
should be getting around 13 volts. Now start the engine, and turn on the
heater and the rear window defroster. Now go back and measure the
voltage at the headlight. I'll bet you will be lucky to get 11 volts.
That's a difference of probably 2 volts. You've lost 15% of the voltage
going to the bulb, that translates to lost light output from the bulb.

Don't fall for the marketing hype, don't waste your money on any
headlight bulb with a blue tint on it, you are just reducing the light
output from the bulb.

If you want to really have better lights, either invest in Euro
headlights, or get a set of the Sylvania Xenarc (true Xenon) driving
lights and rig them up in place of the OEM fog lights.

Just my $0.02.;

John Stanton wrote:
> Ok, more fuel for the fire.  I was kind of intrigued about getting better
> head lights on my 95 90q and decided to do some independent research.  Here
> is what I found.  Im confused now any truth to this?
> BrickBoard Archives
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> ----
> Re: 9007 headlight bulbs[200/1988] posted by Daniel Stern on
> Sunday, 8 November 1998, at 6:55 p.m.
> The 9004 and 9007 are not interchangeable for several reasons:
> 1) The filaments are in a different position, and oriented differently. The
> 9004 filaments are transverse to the bulb axis, and the 9007 filaments are
> in line with the bulb axis. This is important because the reflector and lens
> optics of a particular headlamp are based on specific filament position and
> orientations. The US headlamp beam pattern is bad enough as it is--messing
> with the filament orientation can only worsen it.
> 2) The pinout is different. The high feed, low feed and common (ground)
> terminals are rearranged in the 9007 compared to the 9004.
> 3) The keying on the base is different, so a 9007 cannot be inserted into a
> 9004 headlamp or vice versa.
> To answer your implied question, you don't have a wattage problem, you have
> an objection to the US beam pattern, which doesn't generally do a very good
> job of lighting up the foreground (road near the vehicle) and which tends to
> produce a narrow, rather dim tunnel of light on the road with a "black hole"
> directly in front of the car. European headlamp beams don't have this
> deficiency at all, but US regulators at NHTSA like to pretend they know
> better than the rest of the world, so we're stuck with this kind of junk
> unless we're rich (to install the very expensive, but very good '86-'93 240
> European lamp assemblies) or own a car with sealed beams that can easily and
> economically be converted to European (H4 type) headlamps. "ten more watts"
> would not help your headlamps a bit. 100/80w 9004s wouldn't either, for
> electrical, mechanical and optical reasons which you can read all about at
> in the "overwattage bulb" section.
> If you're interested in more information about all of the different bulbs
> used in headlamps and fog lamps, I've put up a comprehensive chart at
> --Daniel Stern
> Stern Automotive Lighting Consultation
> Automotive Lighting Technical Info Centre

Todd Young
7079 Dawn Ave. E.
Inver Grove Heights, MN 55076

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