My sunroof is getting cancelled!
 

While I've always been obsessed with getting the best power out of the 911 motors, ever since I've been tracking and autocrossing my cars for the past 15 years, I've also been weight obsessed too. After all, didn't Colin Chapman say 'Adding power makes you faster, but adding lightness makes you faster everywhere'? So with that in mind, when I read in these forums that deleting the sunroof saved anywhere from 20 to 55 lbs. I was enticed, but what is the reality? After all I also deleted the sunroof in my 997 GT3, and before I did it, heard the same embellishments, claims of anywhere from 20 to 47 lbs. I weighted everything pulled out and put back in and the net in reality was something like 23-24 lbs. savings. So I had to take the claims of 55 lb savings on our aircooled 911s with a grain of salt, but I was still optimistic as it came from some very prominent posters on this forum, some of whom are no longer with us, and others who are still active today.

So in the pursuit of science, and for the brain trust here, last year I ordered a new non sunroof steel replacement Dansk roof panel, details of which I posted in this thread here:
http://forums.pelicanparts.com/porsche-911-technical-forum/1048937-dansk-roof-panel-91150308712grv.html

http://forums.pelicanparts.com/uploa...1721357405.jpg

http://forums.pelicanparts.com/uploa...1721357405.jpg

Pelican lists the roof in their catalog here: https://www.pelicanparts.com/More_Info/1682001000DSK.htm?pn=1682001000-DSK


When it was received, I weighted it at 20 lbs +/- 0.25, so that already dispelled the myth of claims that it was 8 lbs. The metal is 0.95mm thick, standard sheet metal thickness for the roof, and frankly I can't see how anyone measured 8 lbs unless their scale was broken, or the roof was made of steel foil. For the size of the roof, it would have to be made of fiberglass or carbon to get it that light with any structure to it. And I've felt a 911 with a finished carbon roof and the thing deflected like a plastic trampoline, so that was a no go for me.

This is the subject car, an 86 3.2 pretty much all stock before any changes:

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After a bit of dieting, and a few hundred lbs lost, the car weighted something like this, with full AC, stereo, etc, with myself (170 lbs) in the driver's seat and probably about 50 lbs of gas. Subtracting for that the car likely is something like 2450 lbs by itself:

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And looked like this:

http://forums.pelicanparts.com/uploa...1755830111.jpg

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So along with a collection of fiberglass bumpers, front hood, rear decklid, and tail, most of which are from Getty Design, who makes I believe some of the best parts with their use of woven fiberglass and first time fit that requires the least amount of body work to fit, I brought everything over to Alex and Joel at Perfect Lines in North Hollywood, CA to have everything fitted and painted, including cancelling the sunroof! I chose them as most all they do is high quality restorations and body work for 911s for many years. They have two Cellete benches for 911s - not sure why they have two.

Anyways, after dropping the car off, a few days later they removed all the windows and cut the old roof out carefully right at the fold line just before the gutters, and separated it from the spot welds around the windscreen frames. This is the removed roof section, minus the sunroof lid, minus the motor assembly, and minus the sunroof deflector and slider hardware:



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On my non scientific weight scales the above assembly weighted about 28.5 lbs. with the steel rain deflector still welded in the roof vent (probably about .75 lbs)
The sunroof lid alone weighed 13.7 lbs
And the sunroof motor and cover weighted 3.0 lbs
I'm guessing the deflector and hardware probably doesn't weigh much, maybe about 1 lb.

I didn't bother with weighing the headliner and rods, as we need to put in back a non-sunroof headliner and rods, so that would be a wash.

So some quick math I did on the back of a napkin comes to:

Original sunroof roof assembly (not including headliner): 28.5 + 13.7 + 3.0 + 1 = 46.2 lbs.

New Dansk non sunroof lid plus adding the steel rain deflector (not including headliner): 20.0 + 0.75 = 20.75 lbs.

Net savings comes to 25.45 lbs. or something like that. Not exactly the 55 lbs I wished for but I'll take it.

And here is the car with the replacement Dansk roof placed on top for fitment check after removing the original roof. The original gutters are still on the car, and Alex will later unfold them, remove the residual of the old roof, and insert and recrimp the new roof back on just like original, with his special gutter recrimping tool:

http://forums.pelicanparts.com/uploa...1755832559.jpg

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Nice.

I often wish I could go back in time and slap whoever ordered my car with a sunroof, and change it to no sunroof. I have no real clue as to what you are spending for the sunroof delete, but that is not a cheap project. I am guessing 15 to 20K if you do a full repaint on the roof.

In the 30 years I have owned my 911 I have opened the sunroof three times. In Acadia national park in Maine, In San Diego and Monterey, CA. Any other time the windows are up and the heat or AC is on.

My car is a fat pig at 2,741 pounds with full carpet and floor mats, and full OEM heater and four AC condensers and leather seats, a gallon of water in the washer bottle, huge battery. tool kit, and spare.

Very interesting project and presentation. The small opening and the lost headroom that comes with the sunroof make it less desirable than some other options, so I don't think that you've lost much with your change, except the weight.

Costly, but if I were looking for another 911, I would prefer the sunroof delete. Great project and being done right. Good luck Steve. :)

Just curious, why not just remove the sunroof panel, motor and other equipment and weld in or bond in one of the readily available metal or carbon fiber panels designed to simply replace the existing sunroof panel? Seems like it would be a lot quicker, easier and less costly than replacing the entire roof.

Steve, that looks amazing. And it’s nice to see someone doing the work who knows to re-pinch the roof together, use spot, welds, etc. Very clean job.

I’m glad my 1975 911 S was one of the few cars that came to the United States ordered as a slick top from the factory. It made for a very happy day when we pulled the headliner out during the recent 15 month restoration and discovered that it was an original no sunroof car. Welcome to the Slick Top Club.

The inner structure is fairly heavy, see SW's above posted weights and the roof is a highly visible part, welds tend to print through the paint.

On my 993 I got 48# removed on a bathroom scale
sunroof roof and internal structure 33
sunroof o/I panels 15.00
headliner, bows, trim, motors, sliders, lights 14.00

That's the million dollar question right? I thought about all those options. Such as just replacing the sunroof lid with a fiberglass or carbon piece, saving about 10 lbs, and it would still be operational. But if you remove the motor and hardware, an additional 3 lbs but would not be functional anymore - not that i ever used it. That would be the least invasive, and everything could be brought back to original if needed.

Or as you say, gut everything and bond/weld in a steel panels available online. I discussed it with Alex and he wasn't crazy about the idea, saying the roof would likely end up with bunch of bodywork, filler and shop time to get it perfect, plus you still need to prime and paint the whole roof. vs the complete replacement roof piece cost about $2000, so how much more did it end up costing? I don't really know - the back of my napkin has run out of room!

I may be shooting you an email when I am ready to bite this bullet. Exactly what I want to do on my 87!

So Bill, your 48 lbs aligns with the 46.2 I weighed, except you weighed it with the headliner, bows, and light, but I didn't, correct? If so then with a replacement roof, I'm assuming steel, your net savings was something like 28, plus the weight of some kind of headliner, bringing you to somewhere around 25 lbs?

Sure, you're welcome to see the results when it's all completed and see if it meets your expectations.

Nice work so far Steve.

I can't remember what my net loss was. I think I remember the inner structure, motor, and everything that went with to be on the upper side of that weight estimation you made. I did a fennlane weld in panel.

I wish you luck on your headliner install. :-)

I glued in a panel and you can see a faint line under the paint when the light is just right. If I had to do over, I'd still glue in the panel. Not enough of a line for me to worry about.

Losing 25lb is nice, even better losing 25lb from the roof!

Alex and Joel from Perfect lines are great. They straightened out my yellow car and installed all new front structural metal, suspension pan, along with a backdated front hood latch section. You're in good hands.

My metal panel was 6.24 lbs so if your whole roof section is 20 lbs, that's really good.

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