105 replies to this topic

[James_1]

Some of the FEA testing that I have been running on a series of models based on both tried designs and new ones. I am applying a load of 1500N to the frame in one place which is far higher than it is likely to be subjected to under normal use but this should give a good factor of safety. Under heavy braking the total force excerted by the engine on the frame will be around 1000N spread over the three mounts. The suspension loads are taken by the subframe as originally intended. The model shown above is the most promising so far, only deflecting by 2.6mm. By comparison the models made from plate (assumed to be 16swg) were deflecting by 10mm+. The frame above is 30x30 16swg.The total weight of the new metal comes to under 9kg.

[al_reidy]

looking good

[James_1]

Plot of VonMises stresses in the frame with the same loads applied.There is a single spike but that is down to the mesh which needs a control applied too. I need to finalise the drawings and check all the dimensions when I get home next week but it's promising.

Edited by James_1, 15 May 2012 - 03:58 PM.

[Artstu]

Clever stuff, however it doesn't look anything like any subframe I've seen before on a Mini?

[James_1]

It is designed to be welded onto the two turrets, hense the funny shape. The lower crossbrace helps increase the ridigity should the car bottom out and to protect the sump.

Worlds worst photoshop http://s961.photobuc...=Untitled-1.png

Edited by James_1, 15 May 2012 - 06:32 PM.

[Artstu]

Is there room for the bottom arms and tie bars? won't those front mounts be sticking out through the grille as well?

[James_1]

No, like I said, it's a terrible photoshop! :) The new frame is welded to the front of the turret just below the top arm bolt and welded to the base of the turret under lower wishbone. The arms are well out of the way. The tie rod is also clear and will mount to a bracket as per the standard frame. The frame is almost exactly the same length as a standard frame, just giving more clearance for the manifold. The design is not finalised by any means. :)


Turrets shown in red, not to scale

Edited by James_1, 15 May 2012 - 06:49 PM.

[.998TANGO.]

Looking goood! any estimates on when its likely to be available?

[SA MINI]

Would these be available for an auto micra box ?

Edited by SA MINI, 20 May 2012 - 08:27 PM.

[l_jonez]

Looks good, does look like the tie rods will be a problem tho.

[James_1]

.998TANGO: It's still some way from getting a full idea of the costings but it's designed so that I'll be able to make them on a jig at home. I won't be trying to get any money back for the time developing it so it'll just be the cost of materials and the time to cut and weld the chassis. I'm currently waiting on a new welder my old SIP has given up. I'll hopefully be replacing it with a Portamig 185 :)

SA MINI: I couldn't say without actually trying it but having looked at some on eBay it doesn't look much bigger although the shape is different.

l_jonez: Thanks, yours looks great! A very nice build. I've been messing about with the design a bit more recently and have been able to bring in the front reinforcement a fair bit without compromising the strength to clear the tie rods now.

[batespeed]

jeepers creepers you are going about this the PROPER way, a lot more design has gone into this than the original mini front subframe.
i just cut bits off and welded in whatever i had had lying about . (i seem to remember using part of a heavy duty transit roof rack)
i take it you are planning going into full scale production then ?

[jonny f]

Interesting i like where this is going.

followed.

[chris211083]

Looking good mate, I am waiting for these to go into production for the wifes mini.

Chris.

[EspMini30]

Could you put a micra k11 gearbox on a rb20det from a gtir