Hetmann

What items can go on a 911CS to get the weight down?

Bill Gregory

Removing the entire a/c system is good for 50-60 lbs. That includes the compressor, hoses, front and rear condensors, drier, and component in the front boot. Of course if you're really lightweight serious, your strip it - carpeting, interior, insulation, inside side treatments, underbody rustproofing, trunk sound/heat pad, front trunk carpeting, replace stock seats with lighter fiberglass, pitch the spare tire (keep in mind the spare is an integral part of the front crash protection), etc. If you're racing lightweight serious, you start replacing metal body panels and bumpers with carbon or fiberglass parts.

Ed Bighi

Here is what I removed from mine. AC system, power windows, mirrors which I first replaced with RUF units, but now run none, factory seats (replaced with race units), carpeting, interior insulation, stereo, ventilation system in the front (doesan't weigh much though), sunroof parts, heat exchanger shielding, parking brake system (cup cars don't have them, so why should I), fog-lights, spare tire, undercoating and a few other interior things. I did leave the factory bumpers and am glad I did. I have to parallel park sometimes and just the other day witnessed someone back into it. Needless to say no trip to the body shop was needed since those bumpers work very well. I am sure there were other love taps that happened when I wasn't looking. I also decided to leave them on since the car already weighs in at just under 2,300 lbs.

This weight reduction makes a big difference in comparison to conventional means of improvement as in bigger this and that. You are not improving one area of the car like the motor which places other areas like brakes and suspension out of sych with that improvement and vice-versa. The best part is that I did it all in one day. Though I must admit that cleaning the interior up for paint prep took a long time. So did the undercoating and would not do that one again. Reducing weight makes every system of the car work better in unison. The only catch is that the majority of the weight comes out towards the front of the car. This though, when overcome with skill, makes for a razor sharp car that starts to resemble the nimble early cars. Very effective on a track, even though mechanically it is stock. I did this years ago, and still drive the car in this configuration daily since life is too short to drive civilized cars.
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Alan Herod

Ed, Could you elaborate a little more on the configuration of your car. Mine is going in that direction -- I first started with removing the stuff that was somewhat ineffective or cosmetic, like the A/C compressor, back seats, and rocker panels. Prior to removing the above items this 1983 Euro SC weighed 2605 pounds without driver or spare, but with 14 gallons of fuel. At present no cage or roll bar. I have worked the scales over the past three years at PCA club race, so the weight should be close, but not certified. In weighing some of the cars for compliance some of the benefits of race seats and lighter wheels become apparent, but with SCs we generally do not start with power seats.

Does "removed undercoating" mean the body colored & textured "Body Schutz" or that black tar-like spray that US dealers are fond of? I did not have the latter to contend with, but have noticed during hundreds of inspections that it is fairly universal on US cars.

Sunroof parts? Does that mean motor? or complete sunroof replaced with welded in panel.

Electric windows? Replaced with windup glass, or replaced with pull-up lexan/plexi-glass.

One of the persons in our region has his SC down to close to 2000 lbs with full cage, one Kirkey seat, fuel cell, fiberglass fenders and bumpers, no muffler, lexan/plexi windows, and gutted interior, but BIG brakes and 17 inch wheels with 245/275 combination.

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Elephant Chuck

A lightweight dry cell battery is a big bang-for-buck weight savings. The factory battery on the SC is huge, over 60 lbs! It's capacity is overkill for most.

Here are some lightweight dry cells <a href="http://www.elephantracing.com/battery/batterymain.htm" target="_blank">http://www.elephantracing.com/battery/batterymain.htm</a>. I am affiliated with Elephant Racing.

I use the 15.7 lbs model daily on the street as well as the track.

You are looking at a savings of 45 lbs or so, it is easily reversible and very little effort to install.

Note: Chuck works for Elephant Racing

Ed Bighi

Ok Alan, here are the basics. The interior is bare. I never used door panels since I liked the look without them. My wife doesan't mind when she rides in it for the occasional road trip to California, so I left them out. The dashboard pad is in but all the other trim on the dashboard is gone. Everything else is gone, but I still have the glove box compartment, minus a door. I need that bit of storage. The sunroof was a project. I replaced the entire sheetmetal with one from a non-sunroof car. It is very expensive to do and should only be done by a very, very good body shop. Of course, with that, all the frames, motors and all are gone from the highest part of the car. Great weight savings in a crucial part. Were I to strip another car, I would do it differently. I would remove all the frames and reinforcements and save the small sunroof panel. I would then put in one of those fiberglass ones they have available. Simply because it is complex job to replace the sheetmetal. Anybody that does it by cutting at the pillars is not doing it properly. The frame should never be disturbed. Another one I would not do again is the undercoating. I do have the body schutz kind that is next to impossible to remove. But I still have some to remove and have to do it since most of it is already gone. But now I have found the right tool for the job. It is made by Wurth and works well. Before I tried everything including heatguns and such, with almost no success. I stress that this is a very very hard job. The interior takes work too since you want to remove all that junk, glue and insulation to prep it for painting in the body color. But that can be done with patience. Undercoating is a bear and another bear of a job. I don't know if one could mold sheetmetal in the exact shape of the roof, but if that could be done it would be great. That is why you should save the sunroof piece just in case. I left the bumbers since they don't weigh as much as people think and I would have been through a few figerglass bumpers by now. If I were backdating my car to a 73rs or IROC, that is different. But I am happy with them on. Besides, I run against guys with fiberglass bumpers and we go just as fast. No difference there. Again, removing the undercoating does not make the difference necessary to make it worthwhile. The weight you mentioned for your car sounds about right. Tough most sc's I have weighed come up around at just under 2,600. They are light cars to beging with, especially among the current crop of new sports cars weighing almost what my wife's 300E weighs. Let me know what your intentions are and I will try to give you some guidance.
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Ed Bighi

Chuck, where did you mount that battery and how do you have it attached?

richard glickel

Ed,

In an Excellence article, about a year ago, I recall a sunroof project car where the roof panel was removed and replaced with Lexan (fixed in place)instead of sheet metal. Looked okay. Do you think the the Lexan is lighter than your metal work?

Does replacing the sunroof with sheet metal increase body rigidity? Any other benefits to removing the sunroof?

Richard
'87 Carrera-3.6L

Elephant Chuck

[quote]Originally posted by Ed Bighi:
<strong>Chuck, where did you mount that battery and how do you have it attached?</strong><hr></blockquote>

In my '77 I have the battery laying on its side in the stock location. I am using a rubber battery strap obtained from a local parts house to hold it down.

On my '73 it's in the driver side battery box on its side. The PC680 battery I'm using is very small, so I fabed a metal tie down strap. I am going to relocate this to the smuggler's box shortly and will use a fabed metal strap.

The larger size PC1200 battery fits the pre '74 box perfectly even using the factory strap.

ledyard

I have upgraded to big brakes, so my spare will not fit any more. I was thinking of removing it, but I heard that it is also intended to play a role in front crash protection. Does the spare really make a difference? Is the car unsafe without it?

Also, is a weight reduction - removal of spare, use of dry cell battery, fibre glass bumpers w/o shocks - noticeable on a street driven car? I have an '88 cab that is about to get a euro vario 3.6. My goal is to have a somewhat modern German version of a Cobra.

Any thoughts?

Lew

Ed Bighi

I don't think you would get a noticeable increase in body rigidity from welding up the sunroof or doing a resheetmetal job of the roof like I did. The reason I spend the money in that department is that I wanted no trace of there ever being a sunroof up there. And there is none in my car since the welding is hidden under the frame. I'm just a nitpicker about some things. And crazy about others. For example, I never stripped my car for weight reduction. I was sick and tired of seeing interiors go bad in previous cars and wanted none of it in my 911. Besides, I liked the stripped rsr/cup car look. I wanted to remove weight from the top of the car, but not so much to care about using something lighter like fiberglass or lexan. Though that would be easier. Most people just use a fiberglass panel or the original sunroof panel up there.

Ted Drake

Hope this helps.

<a href="http://www.early911sregistry.org/jCalzia.html" target="_blank">http://www.early911sregistry.org/jCalzia.html</a>

Would'nt keeping the weight towards the center of the car improve the moment of polar interia. My 911 has a light wieght battery in "smuggler's box" where your steering joints are located. Push the battery towards the passenger side to help offset the drivers weight.