7 replies to this topic

[PIIIOWW]

Hi,

I'm considering fitting a carbon front and have read some of the posted discussions about safety and MOT inspection etc.

Q: Does anyone know if you can retain the full inner wing and still add the Mini Spares style brace bars(?) or does the inner wing have to be chopped where most people do, just in front of the shocker mounts, for the bars to fit?

For background info., my main concern with a removable front is the reduction of the inherant strength of the front end by removing all the spot welded panels. Much like the strength added to an egg carton by its solid intricate underside, I believe the front gains a lot of structural strength from the intricate shape that's spot welded together at possibly as many as 75-100 locations.

I've watched videos of race minis in accidents and the removable fronts just spring straight off as they're only pinned on at a few points (leading edge of A-panel and simply suspended at the leading edge of the subframe). The front therefore barely absorbs any impact protection.

To me, the brace bars also only seem beneficial in impact absorption if they're hit longitudinally (i.e. head-on) but this still adds some rigidity.

I'm interested in the benefit of the lightweight front but not at the detriment of structural safety. I'd like to maintain the full inner wing and tag this to the carbon front at the front panel and down the bonnet gutter with a number of M4 setscrews and add the brace bar if it will fit.

Of course, racing minis will be travelling at higher speeds and more likely to have impacts but they also benefit from multipoint cages. Whilst I have a 6-point cage with a dash bar, I don't think this should be fully relied upon for safety.

Any comments or advice on my approach are welcome.

Thanks
Howard

[Sprocket]

In my opinion (and thats all it is, an opinion, of which you will likely have many), I wouldn't fit a removable front of any kind on a road car. Been there, Done that and welded all the front back on again.

 

The fit was horrid, rattled around, chaffed the paintwork and never looked the same . For a road car, it was the worst thing I ever did. I'm not even sure the miniscule weight saving is even worth it. the car will never be the same.

 

I personally don't think its right (another reason I went back to a welded steel front) as the pedestrian impact and general frontal impact are drastically altered. if youve seen a mini with a welded steel front thats been involved in a frontal impact you'll see it folds up quite a bit. Consider that with a floppy fibre front and what little bracing provided.

 

Like i said, this is just an opinion, I would at least like to get out of the car with limbs mostly intact in the event that it all goes wrong

[sonikk4]

There is nothing to stop you from keeping the full inner wings, but think outside of the box here. The inner wing not being attached to the front is a flexible beast and as such as much use as a chocolate teapot. So reinforcement needed.

Can you weld and fabricate?? If so think about making some purpose built reinforcement. Look at the contour of the inner wings at the top and think of what you can add to that to stiffen it all up. It would need to be tied into the bulkhead and suitable reinforcement added there.

A lot of work?? Yup but you can be individual as to what you want to achieve.

Yes I agree with sprocket, flip fronts equal even less protection (as much as you get with a mini) plus all of the issues with fitment, finish etc. Not my cup of tea and as such would not be inclined to ever fit one, my choice.

If you are after a bit more room working on the engine then fit some Minivation Articulated Hinges. No more banged heads.

[nicklouse]

First point. One piece front ends are a waste of time they make every little thing a pain in the but and every like thing involves scratching the front.

Been there with road and race cars. A two piece front end is a different issue it can also be more solidly fitted.


But back to your question sure and if you can weld you can do an even better job.

[Will16]

As said above, if you crash a welded front mini it sort of folds up to absorb the impact (been there, done that!), if you put a composite front on it, it will shatter, even with full inner wings and bracebars they would just bend and probably wouldn't be much safer than having no inner wings

[6joshh6]

I've bought a mini with a steel flip front and I'm going back to standard. The standard front is strong in spite of the thin sheet metal because of the shape of involved. Short of making a space frame it's about as good as it gets really, everything supports something else, and the subframe stiffens up the sheet metal where it's liable to bend on the front mounts. You lose this when you get a flip front. Some people advocate brace bars which are about as good as a chocolate fireguard, if there is any force applied to them the point where they join the body will give out first as the strength in the monocoque lies in the area over which the force is applied, while brace bars, at least the ones I've got, are 20mm box section which lacks triangulation and doesn't have much in the way of bracing where they attach at each end. I suspect the bars would probably just break loose before they failed, and they aren't that tough to start with. 

 

Now your idea of replacing the spot welds with bolts has plenty of potential providing the bolts can provide similar strength to a spot weld, otherwise we've lost strength before we've even started. M4 isn't going to cut it, I would want M8 as a direct replacement for a spot weld, although that doesn't stop you from simply using more M4s. The standard spot welds are around 8mm in diameter, so providing you have the same surface area acting on the same or better material (even 8.8 grade bolts are streets ahead of spot welded mild steel in terms of tensile strength) you should have sufficient strength. Washers will naturally be essential for this as you need to dissipate the load over a larger area. I would also use a strong body adhesive to glue the panels in and keep flex between the bolts to a minimum. 

 

However since we're doing this to lose weight it seems like a lot of effort. I've got a carbon bonnet and a steel one and the difference is not a huge as you might think once you've got all the furniture on there. I personally would seek to lose as much unsprung weight as possible, this has a much bigger effect than losing sprung weight and will make your suspension much more effective, which makes stopping faster, gives better grip off the line and of course through the corners. Wheels are well worth lightening as they have a similar effect to a flywheel in that they absorb power due to inertia which could be helping acceleration, as well as being unsprung weight. Even better, you can do things in stages so the car isn't off the road while you sort the body out. 

 

Hope this helps you out a bit, and feel free to ask away if you'd like to know anything else.

[PIIIOWW]

Thanks everyone for all the input on this. I agree with most of the comments and logic on this and will most likely stay with a full steel front.

Another question off the back of the first: has anyone had any experience fitting an electric water pump on a normal fronted car? I believe they're supposed to be a very tight fit against the radiator and inner wings and are normally best suited to a front mounted radiator.

Cheers,
Howard

[nicklouse]

rad position as little to do with it. removing the pump has issues as you then have problems with the fan drive and alternator drive.

 

so why would you do it?