eugkim

I just installed a pair of H4s with Hella Optilux 100/80 bulbs. I was a litlle leary of splicing the H4 connector, so I got a 9004 to H4 adapter. The percieved difference in brightness in the garage was substantial; can't wait to check it out on the road tonight.

One thing, though. Does anyone else notice that the bulbs give off a tremendous amount of heat? The instant you turn the lights on, the lights get warm, and they are hot after a minute or so. I didn't bother with a relay, as other posters haven't had an issue with stock wiring and bulbs less than 100w. In addition, the guy from rallylights.com said that Porsche was the only manufacturer that probably assumes that people upgrade the lighting, and have wiring that allows for it. He didn't guarantee that there wouldn't be a problem, instead recommending that I check the voltage drop from the alternator to the socket; if less than 0.5 v, he said I was ok.

Next step is installing Stongard that I've had sitting around.

Rob Edwards

I'll raise your question with a useless answer- another question: What are the thermal insulating properties of Stongard? I totally understand why you'd want to protect the new H4's (my GTS has a beautiful almost new $250 fog lamp lens that was cracked again by a stone...) but if they're already hot will the Stongard make it worse?

SharkSkin

That's about the limit for stock wiring. In fact, I would wire in relays to the jump posts and add a fatter ground wire for 100W. Check and see if the wires are getting hot. Also, you won't want to keep the bulbs on if you're not moving -- it will heat up the housings. This could be especially problematic with Stongard, since that heats up too. IIRC people were cracking fog/driving lights by combining 100W bulbs with stongard.

eugkim

Yes, I recall reading about the driving lights cracking from the Stongard. Kind of ironic. I haven't heard of the headlights having a problem.

I checked the wiring harnesses after the lights were on for a few minutes - they felt like room temperature.

Don't know if it's related, but my driver's window stopped working when I started the car up. Usually, it starts up right away, but it hesitated the first time. Seems ok now, but nothing with the window lift. I'll have to troubleshoot it tonight.

The H4s are definitely an upgrade - the low beams provide better illumination than the H5s, but the high beams really make a huge difference. My adjustment may be a little off, as I didn't have a flat area to aim the headlights correctly, so they're a little low. Still, much closer to the xenons on my Cayenne than the H5s.

Alan

You almost certainly are dropping much more than 0.5v @ 100W - the wiring will be OK but it would be quite a bit brighter with local relays (and hotter though too).

The fixtures get warm because you have upgraded from 55W -> 80W. I have run stongard on H4's for years in Phoenix with no issues and I have 80W low beams. The H4's are better than the fogs in this case because for the same power there is much more dissipation area - most of the bulb dissipation is also to the rear of the glass housing inside the pod covers. There is a little airflow there from the fender area.

Bill Ball

I used 80/100 H4 with stock wiring and Stonegards for 5 years with no problems at all.

SharkSkin

That's right, I forgot you had that setup, Bill. So I guess it's just a problem with the fog/driving lights then.

Bill Ball

I ran stock bulbs in the fog/driving with Stonegards and the left side lens kept breaking. I thought tthe Stonegards just weren't able to absorb the rock hits. If it was trapped bulb heat, then it can happen with stock bulbs.

I should add that I have since switched to el cheapo eBay HID H4s with the pivoting Hi/Lo shield and HID H3s for the driving lights. I'm extremely happy with the HID H4s. The beam pattern is not as defined as halogen H4s, having some scatter, so I had to aim them a bit lower. They still work very well and the high beam is suprisingly good. In fact, it's excellent. I didn't expect that with the silly pivoting shield. The H3s are less successful alone, but together with the H4s they really light up the road.