Is it true that because carbon fiber hoods do not have a crumple zone like an oem hood, if you are involved in an accident the carbon fiber hood might go through your windshield and injure the occupants. If you are ever involved in accident with a carbon fiber hood, will the hood fly away if i have hood pins? Or will the hood stay in place? Or will it go through the windshield and injure the occupants even with hood pins? I've heard the dangers of a carbon fiber hoods without hood pins? Can anyone elaborate if you have any experience or accidents involving carbon fiber hoods in front end collisions? thanks. I have a no name brand CF hood on my car right now and i'm kind of worried.

 

ive seen a couple accident pics. and the hood was pretty much cracked and broken.

your front windshield is pretty damn strong, i think you will be ok.

i work at a body shop, and every once in a while i would part out a car. i get them it with cracked windshields. and i would grab a big 19mm bolt (kinda like a subframe bolt) and pitch it at the front windshields, wouldnt even break through. im talkin like a 60mph throw like 5 feet away.

im sure an impact is different, but i would think it would break apart rather than go through the windshield. but i could be wrong,

if anyone has pics of a hood through the windshield i wanna see, should be interesting

 

CF is strong, but not that strong. It's tensile strength is high, but as far as withstanding an impact it'll break fairly easily. Especially a no-name hood. CF hoods (of any brand) are built so cheaply it's rediculous. It's more fiberglass and filler the CF.

 

Carbon fiber hoods CAN go through windshields at high speeds. Crumple zones do help but are not a necessity.

 

that's why i'm worried

 

ive HEARD of it happening (injuring people) before but dont know anyone that has had it happen...... but if you have a cheap hood it will break i guarantee just because its not going to be as strong as a high quality layered peice

my friends VIS hood crumpled when he t-boned a car at 50mph so i think you should be ok

 

Interesting topic. I think your question really depends on the type of accident you are talking about. In the right kind of accident that hood can come through the windshield without a doubt. I know for a fact this has been tested by GM. If your hood is built very strong I think the risk goes up. I think it's funny I used to see Fiber Images show one of their hoods being run over by a car to show how strong it was. I think there is such a thing as over-building a hood. Two years ago I worked for the composites company that developed a carbon fiber hood for the production Z06 Corvette. We ended up building the first carbon fiber class "A" body panel for a "production" vehicle and built about 3,000 of them. Anyway after we built the hoods they went on to GM to be tested after each change in the layup. They would crash test them on cars and drop tet them. The drop test involved dragging a hood up to about 30 feet in the air and dropping it on its nose. The hoods would not break even after multiple drops! They were over- built no question. These hoods were built using no fabric but rather uni-directional prepreg carbon and several layers. The hoods were all autoclave cured so they had a much better strength to weight ratio than anything in the aftermarket. What we ended up doing is cutting the plies of carbon that run from the front to the back of the hood. The cut was made in the middle of the hood from left to right. This induced a weakness in the center of the hood so that in a head-on collision the hood would buckle if enough force is applied. This would keep the occupants safe in most cases. As far as I know there are no hoods being made with a buckle point layup. It couldn't really be considered a crumple zone but more like a fold zone since carbon doesn't deform like steel. Adding some Kevlar to aftermarket hoods might help keep them together better and keep them from cracking and sending a chunk of carbon/fibreglass into your body. I'm not trying to scare you but if the right things happen in a wreck you could have a problem hood pins or no hood pins. Even if the hood breaks away up front it doesn't guarantee anything. I am probably going to be building a street/race carbon hood with a fold zone for an Integra soon which will weigh about 8lbs installed.

 

thanks for the insight.i would be interested in purchasing one of your hoods once y ou build it.

 

me too

 

95% of the "Carbon Fiber" hood out on the market are just fiberglass hoods a layer of CF. I've yet to see one fly through a windshield. I've seen accidents where they've bowed up a foot or 2 and cracked, but never seen one sheer off of the mounting points. I don't think it's really anything that you would need to worry about.