Fiberglass v. Factory Bumpers: Weight v. Safety?

A lot of you have posted great looking post-74 cars with aftermarket front and rear fiberglass bumbers. I think the RUF narrow body bumpers would look great on my 78SC. I haven't weighed the factory bellow-type bumbers but I'm sure you save a ton of weight. Question, how if the bumpers function compromised by this converstion. Obviously the steel factory bumpers provide more protection, but are the factory bumper shocks retained? Thanks in advance.
---------------------
Paul
78SC Targa

I can only answer for my application. All of the stock bumper equipment was removed. All that remains is the original mounting area. Wieght lost is about 150 pounds. You can fabricate a nice steel bar that will fit behind your new bumper attaching to the original mounts if you wish.

As far as safety is concerned I am much more worried about a side impact than front or rear. The front tub and rear engine will buffer the impact in a substantial crash. A smaller "fender bender" will destroy the glass bumpers. Obviously damage to the engine and front tub are much more likely, but this gamble is the price paid for light weight and asthetics.

You stand a good chance of major fuel leakage in the event of front impact with a glass front "bumper" the factory steel bumper tends to distribute impact loads across the front of the car and offers some protection to the very exposed fuel tank. The after market glass bumpers look cool but are a risk! one reason why fuel cells are mandatory on the track in many groups.

I always pick up a set of 964 inner bumpers and modify them to fit under whatever bumper cover I am putting on. They will bolt directly to the factory bumper shocks and are made of aluminum, so they are considerably lighter.

David

I too am really curious about the weight savings potential. I've heard different numbers ranging from maybe 40 lbs up to (now) 150 lbs!

I've had both the front and rear bumpers off and in my hands. Unfortunately I didn't weigh them, but I'm guessing the rear was 30 - 40 lbs, the front 25-35 lbs. Those rubber bumpers on the rear are heavy, maybe 7 lbs each. The sheet metal weighs nothing. I haven't had the bumper shocks off but might guess they weigh 10 lbs each? If I'm right the whole thing weighs about 130 lbs on the high end, maybe 110 lbs on the low end.

I'm told those rear fiberglass bumpers weigh 10 lbs, the front 20 lbs. This would yield a savings of 80-100 lbs if you don't put any impact protection behind them. Can anyone sanity check my numbers?

On the safety side, consider that all the pre '74 cars had essentially no bumpers. And few people would list that as the reason not to own one.

------------------
'86 Cab, '77 Targa, '85 toyota 4wd rain mobile http://www.cheaterswayside.com/911/

When I removed the stock bumpers I removed EVERYTHING. All the plastic trim doodaddys, license plate stuff, shields, brackets, shocks, everything. This is where the 150 pound figure came from. There is a lot of crap associated with the bumpers. The items removed were placed in a scrap basket and weighed on a set of bathroom scales. Not NIST accurate, but it gives you a good idea. I need to weigh the car as it sits now to get the final tally on the diet.

I wouldn't recommend removing safety equipment to anyone. This is my pleasure car, not the family car. You rolls your dice you takes your chances.

The following is from my spreadsheat on weight reduction from my '76 Carrera 3.0

Front Al bumper w rubber spats -19lbs
Front valance w fogs -13lbs
Rear Al bumper w valance & rubber -24lbs
Rear steel spats -8lbs
total -64lbs
Front f/g bumper cap with grill +5lbs
Rear f/g bumper cap with plate & lights +5lbs
front nerf bar under f/g +4lbs
rear nerf bar nder fg +4lbs
total +13lbs
I like Dave's idea of the 964 pieces, I never thought of them, I just made mine from some short pieces of channel iron welded onto the oem bumper mounts(non-hydraulic) the back ones were switched to the front, and the front ones were shortened and put in the back.
Have you got any pics of the 964 pieces Dave?