daltvater

What if these carbon fiber units proved to be just as safe as the aluminum? Hard to believe they could be. We need an engineer to chime in here!

chaoscreature

Daltvater,

Do you still have:
A/C
Carpets
Underlayment
Stereo
Dashboard
Stock seats
Passenger seat
back seats
door panels
glass in doors
stock exhaust
undercoating
Steel undercarriage panels

There are many places to shave weight from the car without getting into the safety bits.
I am an engineer, but I have not done any sort of analysis on the crash bar, but I seriously doubt our friends at Porsche would install a 30lb bar of aluminum in the back without a good reason. It probably helps to distrbute the load of an impact to both of the frame rails and their respective crumple zones. Otherwise a straight on impact with something narrow would just go tearing through the sheet metal. Just a guess.

daltvater

I'm down to 2820 with a half tank of gas and the car is still a fairly comfortable daily driver. (wife would disagree)

Neat video of a Boxster crash. It looks like you can see the crash bar take a hit at 18 seconds.


Not interested in removing my crash bars unless I knew the CF units were safe. If produced correctly could they have the ability be stronger than aluminum? I just noticed Cargraphic calls the units "bumper carrier" I'm guessing that means they were not designed for strength.

NP993

Same for me, although a couple dozen pounds heavier. Would really dig being able to drop 35 more pounds. I wonder what the engineers would say about replacing the aluminum bars by filling up the behind-the-bumper area with crash foam? Would probably be easy to buy a few pieces of foam off any old car at a junkyard and trim it to fit. It weighs nothing but obviously provides tremendous impact absorption.

evoderby

Going for carbon beams also loses the tow points front and rear. This can of course be addressed in alternative ways (CUP tow eyes) but can be rather inconvenient.....

RUF just used to trim away vertical sections of the beam as a means to lighten it. When looking at a standard 944 bumper beam there seems to be ample room to do so whilst keeping OEM integrity:

http://teilecar.com/?449,porsche-944...-beam&sLang=en

V

Sounds good but what do you mean by "trim away vertical sections of the beam"?

evoderby

Easy, have a look at the photo in the link and you'll get the idea....

MDamen

The bumpers and impact absorbers are made to work together to meet the federal standards in place at the time the car was manufactured. Removing or altering any part of that system makes it less safe. Substituing foam or carbon fiber for an aluminum beam would need a lot of data to say it is just as safe. It still may not be un-safe, but you can't make that statement without analyzing the modified design in light of its intended operating conditions. If you plan to use the car on the street, you would be hard pressed to say that using anything other than the federal standards are safe. On the track, you could point to your sanctioning body's rulebook to say their standards result in a safe car.

Mark in Baltimore

Coupla cans of this will do the trick in lieu of bumper foam:

NP993

I was thinking about drilling access holes in the bumper covers and just spraying in a dozen cans of Fix-A-Flat.

Mark in Baltimore

Lightening from the ground up?

jimq

Ok as usual you are correct. Nice to hear how good those highly modified cars protected the occupants.

axl911

Don't know much about what would be the result of a major impact without the bar. But for a 5mph, it would result in an expensive repair as now the dented tub sheetmetal would have to be cut and re-welded in...in addition to the other damages.

Plus, what happens when the insurance adjuster sees the bar that is supposed to protect the tub for these minor fender bender missing?

Definitely NOT worth the 20lbs saving.

race911

Am I? I merely asked if you had specific knowledge based on working in the industry. All I did was relay a couple of incidents that went horribly wrong, both of which I'd heard about because I was involved several layers removed. Not to mention we're talking about 15 and 25 years ago. Lots can change, and I'm always interested in keeping current.

If you want to the details of how I remember each car deviated from as-delivered, I'll try my best to recollect. Briefly, one was a 930 that had a poor seat installation/competition belt install; the other was a first gen Z28 (back when they weren't worth anything) that had a replacement subframe which was substandard. To what extent, I don't know as I'm not a muscle car expert. But I can work my way around a V-8, which is all I'd done to that car. Both were triple digit crashes, and I'm not sure what could have made a difference other than we know the Z28 came apart. The 930, as with 99+% of 930 crashes, was driver error. I harvested a good engine out of it though!

Now that I think about it, my cousin (the one with the Ford GT) was almost killed about 3 years ago when his lifelong buddy took him for a joyride in a heavily modified (Hennessey?) Viper that he'd had for about a week. I know it came from one of the tuner shops. I think they left the pavement well over 100mph; and as I heard the story, this was purely inexperienced driver error. Severe back injury, broken pelvis, etc. etc. Not the easiest thing for a guy in his mid-60's to recover from. I can certainly ask if anything insurance-wise came from that.

MDamen

I think the insurance companies are interested in determining who is at fault for the accident. If it is driver of the modified car who is at fault, they would also be responsible for contributing to the damage and the insurance company has to pay anyway. If the other driver is at fault, but the damage to you or your vehicle was greater because you disabled a safety device, the insurance company might determine you should bear some of the financial responsibility, depending on state law.

The accidents quoted seem to be the fault of the driver of the modified car. I wonder if there are any cases out there where someone removes the bumper supports, gets in a slow speed accident where they are not at fault, but sustains significant damage due to their modifications. Would the other driver's insurance call foul because your car should have sustained minimal damage?