19 replies to this topic

[rwiddi]

Hi, If I were to replace my steel with carbon fibre a-panels and keep a steel front end would there be be a reduction in strength or any other problems that i'm overlooking? the work would be done by a bodyshop not me so would be done properly

[rally1380]

How are carbon A panels fitted to the door pillars?? Steel ones are bend round to form the trailing edge...can't see how carbon ones can be formed in such a way. Interested to find out how its done though.

Not too sure how carbon A panels will fit to a steel wing either???

That said.....carbon fibre and steel have very different properties in terms of strength. Carbon shatters on impact, whereas steel will fold and bend and absorb the impact.

[Andy!]

Carbon fibre is stronger than steel, so i doubt you'd have any reduction in strength at all, if anything you'd gain strength, one question though.... why? is it an ultra lightweight track machine?? if not, i ask again... why :s

[sonikk4]

Not only is a steel A panel folded around the A post it is also spot welded in a couple of places as well. A carbon fibre A panel will need to be bonded to the A post.

Considering no mini panels use adhesive to attach them then there will always be a question mark with regards to strength. Its the initial argument about the original design etc etc.

Modern adhesives are very very effective and i know this from experience as this technology is used extensively in modern Civil aircraft construction. However this is designed from scratch with this in mind. A mini was built and passed for use using welding technology.

[Alex_B]

As said carbon fiber is stronger in some ways than steel but in a car that was designed to use steel swapping bits for another material with completely different properties is likely to void your insurance and also create unecessasy risk, why do you want to swap the a panels for carbon fiber anyway? seems a bit pointless

[rally1380]

why do you want to swap the a panels for carbon fiber anyway? seems a bit pointless

Doesn't rust?

[Alex_B]

why do you want to swap the a panels for carbon fiber anyway? seems a bit pointless

Doesn't rust?

No but if its all repaired correctly with new metal then protected properly and arch liners installed it shouldnt need doing for a very long time and that would still be cheaper than carbon a panels i would imagine

Plus you still have the front wings and front panel which are steel which will rust plus the sills etc etc

Edited by Alex_B, 23 April 2013 - 08:19 PM.

[rally1380]

why do you want to swap the a panels for carbon fiber anyway? seems a bit pointless

Doesn't rust?

No but if its all repaired correctly with new metal then protected properly and arch liners installed it shouldnt need doing for a very long time and that would still be cheaper than carbon a panels i would imagine

Plus you still have the front wings and front panel which are steel which will rust plus the sills etc etc

Yeh...i was being sarcastic....i'm with you though.....do it properly in steel and you can forget about it. And it'll be strong and behave well (as well as can be expected) in an impact. I'm thinking the carbon A panel idea is for cosmetic reasons....get stick on stuff...boy racers don't know the difference!.

[rwiddi]

the idea is mostly that I hope to go down cf bumpers and just thinking with the a-panels done to carry through the car. didn't want to go down the wrap route

[Alex_B]

Save your money imo, carbon fiber as styling is a bit naff anyway to be honest, yes if you are making a car that is an out and out lightweight special then Cf is perfect provided its designed correctly but as styling parts its expensive and pointless as you really dont save much weight at all

[Tamworthbay]

Carbon fibre is stronger than steel, so i doubt you'd have any reduction in strength at all, if anything you'd gain strength, one question though.... why? is it an ultra lightweight track machine?? if not, i ask again... why :s

So is spiders silk but you can't make a car from it! CF is brilliant when it is used in the way it is designed to be used. That is very different to how a mini is put together. It would take too long to explain fully but just replacing the A panel would result in a significant loss of strength if done in a like for like fashion. Even with a full structural adhesive such as DP410 the way it would be loaded in a crash is totally wrong. This comes from experience in designing and building CF monocoques for endurance racing. You have to throw away all your steel monocoque knowledge and do it a completely different way. CF A panels are good for looking nice (if you like that sort of thing) and saving weight - hardly relevant on a road car as there are a thousand better ways to save weight.

[petey81]

I fitted fibreglass A panels a year ago and bonded them to the A pillar then to the fibreglass front end. all ok still.

[Alex_B]

Ok yeah its all ok at the moment but you have lost a lot of structural ridgity and in the event of an accident you could find yourself in a bit of a pickle!

Fiberglass is similar to CF in the way it deforms in an accident ie it doesnt it simply shatters and the front end provides all what little crash protection the mini has, I wouldnt have any legs or at the very least broken legs if my car had a grp front end after my accident in november

[petey81]

Ok yeah its all ok at the moment but you have lost a lot of structural ridgity and in the event of an accident you could find yourself in a bit of a pickle!

Fiberglass is similar to CF in the way it deforms in an accident ie it doesnt it simply shatters and the front end provides all what little crash protection the mini has, I wouldnt have any legs or at the very least broken legs if my car had a grp front end after my accident in november

Yeah very true, I am a biker and have been for many years so not bothered about protection and I don't take passengers in my car.

Edited by petey81, 23 April 2013 - 09:41 PM.

[tiger99]

Carbon fibre is an MOT failure. Only properly welded in steel panels are acceptable. It also would require an IVA, as it is a modification to the monocoque. And, as stated rather well above in at least two posts, carbon fibre is woefully inadequate in that position as far as impact protection is concerned, and would void your insurance unless declared.

Also, the pitifully small amount of weight reduction is utterly pointless. You could get much more by just polishing the rough skin off the engine block, without weakening anything.

And, on the basis of dimensions, carbon fibre is NOT as strong as steel, i.e. if it is 0.9mm thick, it does not have the strength, and even more so, stiffness of the standard Mini panel. On the basis of weight, it is stronger, but still less stiff than steel.

If you must waste money on CF, and it is a complete waste on a road car, let it be somewhere harmless like the boot lid, or maybe the roof skin, although a steel roof will be better in some uncommon types of accident.