Removing the Moonroof
 

I'm thinking about removing my moonroof, maybe later down the line. I rarely use it, and most of the time I can't use it because it doesn't work literally half the time. (For the record, the malfunction is not reproducible for the dealer, and only seems to work in sunlight. Go figure)

I also think removing the moonroof would be good because I'd eventually like to track the car. So the benefits would be lower weight, lower CG, and room for a roll cage.

Basically, is it difficult to remove the moonroof and install maybe a glass or lightweight hatch? What kinds of things would have to be done? Cosmetic things like headliner don't really matter to me, as I could just cut affected portions out and replace it with, I dunno, say plush carpet.

It would probably be fairly costly, but you can surely take out the motor, and fabricate a stationary plexiglass (lightweight) replacement. Some things you should be concerned with however, are the unjustified high costs of pursuing a mod of a rare, and highly customized nature (unless you are doing it yourself). Furthermore it would surely would not help your resale value, for moonroofs are often an option that used car buyers love to see in cars, however a homemade plexiglass replacement is not as highly sought after. A benefit would be that the car is less top heavy, however the LARGEST benefit would surely be headroom, particularly if you plan on tracking the car. I cant see it hindering the structural rigidity in any further way that the original moonroof hadnt already done.

Bottom line is that in my opinion, unless there is NO way you can fit in the car with a helmet, and you are absolutely driven to track your car, then it is not worth the risk, money, nor the potential added depreciation. I think you can track the car fine, despite the slight amount of topheaviness (not too much of an issue). About the moonroof not working, i don't see why you couldnt get your dealer to fix it?

The problem isnt that it never works. It's just that it works only half the time. The 2 or 3 times I've had a mechanic look at it, they said the moonroof worked fine. Subsequently the moonroof returned to its whimsical disposition. So I don't know how valuable it will be to potential buyers, much less how their impression of the car would change when they find out it doesn't work perfectly.

I'm just curious, what do you expect are the major components of the cost of pursuing this?

because they couldnt reproduce the problem. so to them there is no problem and no need for furthur investigation.

I thought that if I had one I would turn it into a scoop. Eventually, I want to pull the AC and most of the other stuff out of the car. I thought a moonroof-to-scoop conversion would be cool in THAT instance.

Aside from the motor, is there really much to be saved by this?

I'd imagine that the vast majority of extra weight involved with having the moonroof comes from stiffening up the spaceframe, and reinforcing the "window" around the moonroof itself (this probably also takes up the bulk of the lost headroom).

Just taking out the glass and putting in plexi might save a pound or so, which won't shift the CG of a 3000 lb car to any noticeable extent (you can probably do more by adjusting the height of the driver's seat, and shifting your body weight lower). It's possible to get rid if the added structural weight, but it would involve an awful lot of cutting, welding and repainting (not to mention fabricating and/or installing a different headliner), and would have your car oof the road for weeks or months, and could probably run into the high 4-figure price range (maybe even 5 figs, depending on the shop). At that point, you might as well get the car chopped and save a little bit of air drag.....

There was a thread on this long ago, someone estimated the entire sunroof mechanism added around 30-35lbs. He then made calculations and commented that the additional weight being situated at the roof line did change the turning characteristics of the car by some degree. Exactly by how much, I don't remember.

I found the thread, not sure if the information is accurate but it does make you ponder roof weight as it pertains to autocrossing.

ROOFWEIGHT AND AUTCROSSING

I'm still shaky on accepting that the 40-50 lb weight difference isn't made up in significant part by the spaceframe reinforcement. I'd guess the glass to weigh 5-7 lb at most, and even with 20 lb of metal in the mechanism, you're barely more than halfway to 50 lb. Throw in that a 20 lb electric motor seems excessive (I found a listing for one at that weight that puts out 12 HP) to open and close a sunroof.

There just doesn't seem to be much room for that much weight in the hardware.

Probably the best "bang for the buck" in lowering the CG is to lower the whole car, and upgrade the sways. Even on a stock suspension, cornering is limited by the tires, and that doesn't get any better with less weight or lower CG. As far as acceleration is concerned, the weight reduction will help, but since the car's a RWD, you're not going to see a benefit from reducing CG height (if anything, you'll see a little loss), but as long as you can do a burnout, then accel is also limited by tires (which may not be an entirely bad thing since replacing blown rubber is cheaper and easier than putting in a new gearbox....)

One other note about the roof structure, and the CG.

Adding a roll cage means the potential to cut out a bunch of weight in the roof (if you're willing to get into the heavy cutting and welding), since the roll cage can take over the structural role of a bunch of that weight.

Of course, adding a cage will likely shift the CG back up to or well past the point where it started with the moonroof installed.....

Here are some pictures of the roof for you...

http://devoid.mine.nu/pictures/20040818%20-%20RX-8/

There are a few others mixed throughout the /pictures directory. They would be in dates after the 18th though. Hope this helps a little.