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you are using a new roof or just an inlay for the sun-roof hole? federleichte-elfer.de has a carbon unit that fits as a replacement for the sun-roof itself and weights nothing..
Hi Thilo,
I think the carbon roof or panel are not safe for road,
best is the full steel roof, but steel panel is ok if welded, bonded very well and all the parts cut delete well,
I am going for the steel panel ,
Will buy a kit from Feen lane in U.K.
The kit inc
steel panel, perforated trim , foam, 2 special steel wires.
^^ agreed altho not sure how much the roof skin does - the pillars would save you in a roll rather than a skin I think - anyway the weight saving is very small v the Fenn Lane panel which is 2.2kg I think
With the skin there is absolutely no risk for the weld seam or bonding to show with time,
I will take a chance with the panel , I may do the gutters delete at the same time.
And the DP plexi , 1/4 windows with 993 seals and flush plexi rear window.
Regarding saving weight , the engine surrounding cooling panels replaced with fibre glass are good too, plus they're rust free, I have a set a side, Will fit them next winter.
964 Thin Glass-rear window
- with electric. Heating (connections as original)
- no hole for windshield wipers
- 4900 G Series: Easy (6700 G)
- 3 MM THICK (4 MM)
Price: 390,- plus VAT
not so sure about gutter delete .. loved the idea at first but cooling off on it looks and function wise
Do it!
Cosmetics aside, like the look or not, no question, done right, it makes the 911 more rigid structurally and a better package aerodynamically. (you can start with the Porsche published 935 #s of 3% less drag and 23 less lift sans gutters)
Only reason Porsche didn't do it on the earlier 911s was to cut manufacturing costs. Check out how they built the 356.
From Paul Frere in PORSCHE RACING CARS of the '70s.
"Porsche shaved the rain gutters off of a 935 and did some wind tunnel tests of the aero impact. There was a 3% drag reduction and a 23% increase in rear down force. That's pretty signficant.."
The A pillar accounts for 3% in drag reduction. The rest of the rain gutter accounts for that 23% of lift. This on the 935 aero package and at speeds we aren't driving on public highways. The rain gutter delete was not an aero enhancement originally for Porsche race cars. It was done to make the cars more rigid. The aero effects are a benefit of that intent.
Good info JETTA,
well yes not a surprise, but it cost 2500 euros.... problem is , its very tempting when doing the sunroof delete, this is what I am doing at the moment,
wonder if it would reduces some wind noise in the cabin..
mind you you can't realy compare a 964 to a 935, and we are not really reaching often height speeds with our cars ...
please excuse my scarce contrib or replies of late ... been a very busy 3 months!
ok so I took my rear screen out for the headliner replacement (yes, still road use/GF friendly) and it weighs 8kg WITH the seal attached!
Looking into the plexi or lexan .. seems lexan is used in the cup cars as its less likely to scratch and better for UV.
Good news is both C2 and C4 sunroofless now ... spent another 3 hours paneling the roof for the second one and it meant very little filler needed .. also made extentions for the spot welder which meant I could do many more spots and get it nice and tight without any warping.
Black C4 is now 1300kg w/o spare and qtr tank which I think is pretty good for a c4 with bigger sway bars and brakes and full interior ex rear seats but has CF front seats and CF techart RS wing.
I have added 11.3kg chomoly rear cage to the White C2 and I'm pretty confident it'll be 1150kg with reserve fuel .. feels very composed now with the cage and less weight.
spot then etch
sound proof (1.4kg)
heat proof - very airy silver foil over plastic foam (400g)
fennlane headliner .. superb quality and price
cage in 11.3kg coated
extra weight necessary sometimes!
rather spend an extra day paneling than use filler
HiWind - use Lexan not plexiglass. Lexan is much stronger and much less likely to develop cracks at drilled hole points. I used ⅛ inch or 3 mm thick Lexan. I have mounted the Lexan 2 ways, first I used the standard rubber seal ( which worked fine), second I made another rear window out of Lexan, but fit it directly to the metal (my case fiberglass) open. I then drilled holes about ever 8 inches and mounted the window with stews and nuts using fiber washers. I also sealed the edge with clear sealant. I additionally made 2 aluminum straps to insure window stays in place. Do not these would’ve necessary if only street driving.
I will probably make one more window, larger than earlier to lift the window so it is level with top, sides and back for a more aerodynamic fit. Have to make up fittings and spacers for this.Cars looking good.
Great advice Gus thanks ... everything I've found and more in one post ... can you hear/feel that it isn't glass amymore? I mean from a comforr/useability/road trip perspective?
HiWind - have to think back when I did the first rear window and used the stock seal to install as this was when my car was closer to stock than now. If I recall correctly there was very little difference. The noise seemed to be marginally louder. The one thing that you will notice in the inside rear view mirror is that the Lexan does move in the center some, just because it is a large flexible area. This had no affect on the mounting nor security of the rear window.
Once I mounted the 2 aluminum straps on either side, fasten to car body and window this flexing was reduced significantly. Think a lot of this may be in how you secure the window as now that mine is mounted by screws and not the stock rubber seal it is tighter which makes sense. The one think that I did not do with the rubber seal was use the rubber weatherstripping cement/glue to hold the Lexan in place as I knew I would be making further modifications and wanted to be able to remove easily.I also replaced the side windows and the forward vent windows with Lexan - the sides are real easy. The vents you have to take the frame work apart after you remove from door and it is not much of a weight savings. Really don’t recommend this route.Side note - the forward vent window frames are made of brass and very heavy - need to make window slides /frames out of aluminum channel to save weight. Lot easier said than done.
The endless debate about weight.
I had my blue 964 on the scales this week and this was frustrating:
I had the car at (other) scales several times over the last years.. I started with >1400kg and have a list about weight savings, i had done from year to year.. when the car went back on scales, i compared the results (done with math and done with the scales) together and was quite close and had a good feeling.. now, i removed round about 40kg last winter and the car was at a motorsport shop for corner balancing and alignment...
I expected the car down to 1200kg (the heavy wheel were fitted, with the 996 5Spoke wheel, i expect 12 kg less) with an nearly empty fuel tank... I refilled the fuel tank absolutely, 100m besides the workshop to have a clear situation with the fuel...
Theoreticaly, the car should have 1260kg with the load of fuel, but....
i am a little bit disappointed...
I have light headers, carbon hood/bonnet, bucket seats, rennline lower dash, no airbargs, AC removed, no stereo, RS door cards, euro RS thin rear glas, no sound insulation anymore (inside nor in the engine bay), bumper beam removed, no spare wheel nor anything else in the trunk, carbon undertray (everything underneath is carbon, 2kg lifepo battery, lightweight starter, RS lwfw with gt3 clutch, 993 RS alloy topmounts, RS thin carpet, cup floor boards...The car started in the 141x kg ballpark 8 years ago (with half tank of fuel) which should had been ~1450 with a full fuel tank...
I searched for every single weight from every part, i removed or added and did the math over 8 years... Result is a loss of 154,2kg... With my now meassured 1325 this would mean, a C4 weights ~1500kg without much optional stuff inside (my car was quite naked when i started).
The good thing is, that the corner balancing job was done excellent...
06-17-2017, 07:11 PM
- I've bolded the stuff that actually impacts weight materially
