Jason F

I have a couple things I am considering doing to my car (a 1977 911S with 3.2 engine and alot of fiberglass) to further reduce its weight , and would like input. Keep in mind that the car is used 95% for track use.

1. Hollow out the dash area and leave only the guages in a custom mount, and dash top.

2. Remove sheet metal where rear seats used to be and replace with removable lexan or aluminum.

I've seen and heard of cars with these modifications, but I can't find any info on the extent of potential weight loss and complications associated with these modifications.

Does anyone have an idea of what kind of weight loss these mods might yield, and any possible complications that might be encountered.

Thanks,

Jason French

Steve Weiner-Rennsport Systems

Hi Jason:

IMHO, what you propose does not result in much weight loss at all and unless its a full-race car, these are things that we do not do.

Now,.....

Removing the entire wiring harness and adding back the bare minimum does help and is worthwhile.

Cutting out the rear sheet metal is only done where a full roll cage that connects and triangulates the suspension has been installed. This is done for access to the inner trailing arm pivots (camber boxes) are needed for alignment, and easy access for quick engine changes. Sheet aluminum is used and is not structural, of course.

If you have not yet installed a fiberglass or CF hood and fenders, I would do that first,......

Jason F

"If you have not yet installed a fiberglass or CF hood and fenders, I would do that first,...... "

My car has a steel hood, but the front fenders and bumpers are fiberglass, and steel rear flares. The sunroof top has been cut out and CF installed. The driver door is also fiberglass. Sparco Evo seats, stripped and lightly carpeted interior, rs door panels (they could go away, but their light)

I know the things I can buy to make it lighter, like fiberglass passenger door, CF hood, CF engine lit/wing, lexan windows, etc... But I was looking for extrenuous parts of my car that can be deleted fur further lightness. My car has a full custom roll cage that is attached to the rear shock towers, and goes to the front of the passenger compartment (but not to the front shock mounts)

I know what I can buy to make my car lighter, but I want to explore all options for lightening my car.

In your best estimate, what kind of weight loss would result in the removal of the rear seat metal and addition of aluminum or lexan panel (with the added benefit of better access for maintenance). I also recall reading that all of the dash stuff weighs quite a bit. Is 60 to 70 pounds too much to expect to lose with these measures.

Further input is greatly appreciated.

Thanks,

Jason French

JackOlsen

Yes, I think 60-70 pounds of savings is too much to expect. I have an aluminum panel there, and my guess would be the total weight savings is probably 15 pounds or less. Keep in mind, you'll need a new framing piece to weld in to accomodate an aluminum panel.

If you currently have seats and sound deadening back there, you can save a lot more weight. But the sheet metal for the buckets doesn't weigh that much.

The real benefit of this mod is access to the starter, transaxle, axles, camber boxes, etc.

mo_gearhead

Jason,
When we used to build cars for drag racing and (ahem) street racing
(non Porsche) we used metal "hole saws" to remove metal in areas
we wanted to lighten. On your P-car you could probably do this on door panels, dash panel, etc. However you are limited. P-cars are "unibody" construction, (IE: no frame)... as such, cutting out metal in the wrong places can weaken the cars structural integrity. As others suggested, light weight pieces are the best choice. Good luck.

Jason F

Thanks for the input, guys. It is greatly appreciated.

Thanks,

Jason
1977 911S 3.2

911pcars

You have seen this article haven't you?

http://www.early911sregistry.org/jCalzia.html

Sherwood Lee
http://members.rennlist.org/911pcars

Jason F

Sherwood,

That is a light car! Great data!

I haven't previously seen that article. I now have it printed as a handy little reference.

Thanks for the info.

Jason
1977 911S 3.2