Someone recently posted their story of their SUV getting rear ended and the trailer hitch preventing a lot of damage. So...

Is it possible that a heavy steel plate or even a dense carbon fiber reinforcement plate could be fabbed to fit between the chassis and behind the front and rear bumpers (stealthy) to add crash protection? I am thinking it could be about the thickness of the dogbone spacers and maybe the bumber bolts feed through it to hold it in place. For the 1970-74 cars.

Good idea?...Bad idea?

This sounds like creativity.

sounds like my que to stifle it!

I wonder if it it might do more damage to the tub if the gap behind the pumper was filled. In a slow speed crash an un-modified bumper would probably get screwed up but not damage the tub. It may be better to let the bumper take the hit.
I personally have worthless F/G bumpers so I have no clue as to what crash protection is.

When My S-10 blazer got rear ended it got hit on the trailer hitch by a smaller car that was rear ended by an F-350. Initially I thought my rig was OK then realized that all four doors were buggered and the gaps were all off. Since I got hit on my hitch, the force was transmitted to the frame which bent, bowing up in the middle. If I got hit on the bumper I would certainly have body damage but don't think my rig would have been buggered as bad as it was. Also since their was no decelertive absorbtion of energy via a bumper, my neck got buggered more as well.

I've been in & out of the autobody business for 25 years. Back then we saw blood in crashed cars pretty often. Now we almost never see any blood in the cars. The last time I can remember a motorist hit a cyclist and it wasn't the motorist's blood. Crumple zones allow you and your car to decelerate at a more gentle rate. If the car stops and you keep going you get hurt.
I'm not trying to stifle anything, I'm just offering up my observations.

How about filling the bumpers with energy absorbing foam, like polyurethane or
some closed cell expanding foam?

I was wondering what would happen if you filled the longs completely with some
kind of semi rigid expanding foam. Would that increase side impact protection
and would it keep moisture out as well?

The idea would be to allow the bumpers and longs to absorb more energy in a
collision and thus not deform as much in a major impact.

This is not my area of expertise so it could be just a dumb idea.

John

I'm with Steve here...

Rigidly reinforcing the obvious crumple zones in the 914 are a sure way of transmitting greater amounts of energy to the soft and squishy people in the passenger compartment.

I've seen a lot of pictures of crunched up 914's, and most of those, while pretty hurtin' for the car, allowed the driver to walk away. Energy dissipation is CRITICAL. Making a more rigid structure just means less penetration by foreign bodies (other cars, light poles, etc..) but it also means less of that energy is absorbed by the deformation of the chassis, and is then transmitted to the driver.

If you really want to approach it in that vein though, how about foam? Install foam absorbers in the front and rear crumple zones. What you want, is for the crumple zones to do their job, but giving it more material that is capable of energy absorption (as opposed to energy -transmission-), gives the driver more of a safety margin.

-Josh2

When it's been tried before it has had the effect of keeping moisture -in- long after it would otherwise have evaporated. (The factory foam-filled sections of a 914 are a case in point...)

But maybe you have access to a better class of foam than has been available in the past. I wouldn't try it in a moist climate, but go for it if you want.

Other things to be aware of: lots of foams make a lot of toxic fumes in a fire and yes I understand your plan is to evacuate quickly in the event of fire, but you're also planning -not- to have the fire in the first place... (You're also planning not to -ever- need bodywork involving welding...) And most foams expand due to chemical reaction, which sometimes means residual reagent that can set off its own reaction.

Creativity is a wonderful thing. This -has- been tried in the past which means you have the advantage of others' learning experience. You may have techniques and materials not available to the pioneers.

But also consider that (like the 356...) the 914 is from an era when collisions were to be avoided rather than survived, although the 914's crumple zones are way better engineered than any 356. I still plan to drive my 356, but I do so in a -very- heightened sense of situational awareness. They're not (passively) "safe" cars like the multi-air-bagged modern stuff.

This is interesting.

When I was deciding if my son could have a 914 I searched many threads and looked at alot of totaled 914's
The Insurance companies are just right when it comes to boys, under age 24....they are the highest risk group.
I have three male drivers...all had accidents so far.

In stock form, with a spare tire, these cars can take a serious hit and the doors still open.
My son did finally rear end a car with his 914 after driving it for a few years. It dented the bumper, headlight and inner fender buckled (its a 74)

The crash zone stuff in these little cars does work..
I pulled and stretched it all back out again.

Oh, ugly though they may be, the tits focus the crash in exactly the right place.

Rich

I think this the answer here...leave teh car alone, allow teh crumple zones to work, the several crash photos I havew seen testify to their success in saving the occupants and cockpit from damage.

Thanks for the responses!

Add 75'/76' bumpers to the ends.

Seriously, probably the best way to add crash protection.


With more modern materials and knowledge it seems like a lighter, equally or more effective bumper could be designed but resources required and liabililty would be prohibitive.

How about this?

Once the driver and passenger are strapped in, fill the passenger compartment with those little styrafoam "peanuts" used in packages. If nothing else, upon a collission, the peanuts would shoot up into the air a good distance. That'd be pretty cool...

Eric

I think adding the spray foam to the back of the fibreglass bumpers would enhance the "peanut spray" too...

Bang.

Click to view attachment

Pound pound pound paint

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I've often felt if I was more handy with materials fabrication this would be the answer. Utilize modern materials and better shock-absorbers with the existing '75-'76 mounts and create a better looking bumper.

My thoughts about filling the longs with foam are more for absorbing
energy in a side impact collision than a front or rear impact.
It may also reduce flexing by making the longs more rigid without
adding much weight.

I can see the problems with (a) foam should not burn and release toxic
chemicals ( would make further welding repairs more interesting.

I will probably use a weld in roll cage in my car...

John

Roll cages pose their own set of problems. Like being extra very hard metal surfaces for your limbs and head to bounce off of in a collision. It's generally not a good idea to have a full cage in a car that you drive without wearing a full five- or six-point competition harness plus a helmet on.


The 914 has great crumple zones fore and aft. You really do not want to be hit from the side, though, as most cars will go over the strongest part of the side of the 914--the longitudinal running under the door. The later side-impact beams in the doors help a little, but...

--DD

I agree with leaving 914 as is. I was rear ended by a 1971 Mustang Mach 1 doing about 35 MPH at a stoplight. Rear of the car absorbed all the energy and I was only startled. Porsche did an outstanding job building crush zones in the car.

There you go Jeff, the 914 needs bigger and squishier tits to be safer.