vanduker

I am trying to sort out exactly what need to be done when upgrading to 50 watt bulbs for the fog lamps. I have read the tech tip but apparently several things changed during the production lifecycle.

As an example the Tip shows replacing the 10A Tail Lamp fuse with a 15A but on the 96 the Tail Lamp fuse is already 15A.

The tip also mentions that some models ground the fog lamps through the high beams but that also seems not to be the case on the 1996.

Has anyone researched our what changes need to be made to support the higher draw of the 50 watt bulbs and/or how best to change things so the lamps will stay on with the high beams on?

Mark

FoolCrzy

I have the 50W bulbs. I didn't change any fuses, and never had a problem.

:cheers:

tkrussell

Agree. Just put in the new bulbs. The wiring, switches, fuses, etc. all are up to the load. I've had no problems in 3 years of using them full time.

If you are compulsive, recheck the aim on a garage door before and after the bulb switch. Usually it does not change.

You can also upgrade the cornering lamps to 50 W for a little more light. The bulb is the same as the 50 W backup bulb sold by Ecklers, etc.

vanduker

Do yours work with the high beams or just with the low?

Mark

tkrussell

The fog lamps are wired from Chevy in the European style, ie, on with parking lamps or low beams only. They turn off on high beam. Makes sense in general, since the fog lamps are limited in range.

Cibie has a good illustration of the relative pattern and range of fog lamps, low and high beams, driving lights, and pencil beams on their web site. On the Vette, the best combo for the least work is European pattern headlamps (Hella, etc) with 55w/60w "Plus 30%" bulbs (also Hella), combined with the 50 W fogs.
Works with the standard wiring. You can go to hotter bulbs (100w) , but you need a wiring upgrade and relays to do it right.

For night racing, fog lamps are often used as cornering lamps by angling the light to each side by 30 degrees or so. In that case you could rewire the lamps to stay on with the high beams. In the Vette's case, the lamps don't adjust for aim to the side, so you would have to do some work on the mounting brackets.

96CollectorLT4

[QUOTE]
Works with the standard wiring. You can go to hotter bulbs (100w) , but you need a wiring upgrade and relays to do it right.
________________________________________ ________________________

just wondering, I put a new set of headlights in my 96. Bosch with 80/100w bulbs, now do I need to change anything like your saying here? Have not had it out and about yet, but I don't want to bugger anything up in the process either, like melting some wire harnesses or relays.

tkrussell

With the 80/100 w bulbs you are living on the edge. The Vette routes all current to the headlamps through the switch on the dash. For weight saving reasons, the wiring is sized just adequate for the standard wattage bulbs, with just a bit of extra capacity.

The hotter bulbs draw over 50% more current, so one of two things will happen: 1) the bulbs don't get quite enough voltage because of the small wiring so they do not shine at full brightness, (and fail sooner) or 2) the small wiring overheats, melts, and bad things happen. The fuses/ breakers may or may not save you. The headlamp switch may similarly overheat and go bad ($$) or melt.

European cars (BMW, etc) use relays so that the switch sees only control currents. A better design, but more expensive. Susquehanna Motorsports has a good website explaining all this, and sells relays, etc if you want to do the job right. http://www.rallylights.com Installing the relays is rather straightforward, and they can mount on the radiator shroud with the other relays.

The Hella "plus50%" bulbs (they make both plus 30 and plus 50) are high tech wonders that use halogen gas at high pressure to get greater efficiency: more light, same current. The plus 50 is equivalent to a 83/90w bulb and uses standard wiring. http://www.rallylights.com sells them.

I think the plus 50's are the easiest way to go. No wiring changes needed, and no worries of possible overloads. This will work on all c3- c4 Vettes.

HTRK-1

I could be wrong, but don't all 91-96's already have the 50w fog lamps?


[Modified by HTRK-1, 8:14 AM 2/21/2003]

Ramrod92

From tkrussel in an earlier post ........................................ .................. The stock bulbs are # 896 37.5 W 940 Lumens
A drop in replacement is the # 886 bulb 50W 1255 Lumens
a 33% increase in brightness!
Philips, Wagner and others make this bulb. It should be available at an auto store such as NAPA.
Before you begin, shine the fog lights on a garage door from 2 or 3 feet and mark the upper limit of the beams.
Access the bulbs from under the front bumper (2 access panels).
It is a tight fit for large hands, but do-able with patience. The connectors twist off from the housing by rotating 45 degrees. Unplug the wiring harness after the bulb is out of the housing and hanging down.
The bulbs are halogen- do not touch them with fingers or greasy rags!
After the bulbs are in place, double check the aim. The beam upper limits should be the same.
The combined bulb currents at 12V go from 6.25A to 8.33A, but this is within the fused limits and so should not be a problem.

A similar upgrade can be done with the cornering lamps.
The stock bulb is # 1156 27W
MidAmerica and others sell a 50W "backup Bulb" that is a drop-in.
Again, a substantial increase in brightness.
I've upgraded the foglights on mine and I'm pleased with the results.


:thumbs: :thumbs:

96CollectorLT4

Thanks for the tips and websites, read over the info and got a good idea what I have to do, thanks again!

:seeya

rcolling

I would be very careful with 100 watt bulbs. Stay off those high beams. A better choice would be the Silverstars with their 60/70w.