belewis01

iTrader: (5)

So a general question for body mounting such as a touring car, or a pan car ...

Is it better to allow the body to float a bit, or should it be held on to prevent it from moving?

I generally make the mounting holes slightly oversize, and clip the body mount pin so the body can float up a millimeter or so. My thinking was to isolate any potential body twist from the chassis.

Last race someone suggested I use the foam body mount rings and pin the body tighter against the mounts ....... as that someone is much faster than me I thought it worthwhile to investigate

Thanks,
Bruce

WagwanBumba

iTrader: (1)

I let it float a little to eliminate the body affecting the chassis twist/tweak
I used to use foam body mounts too but then got rid of them cos the slightly loose nature of the body was lost and also any downforce generated by the body would be compressed in to the foam rather than into the chassis

WheelNut

iTrader: (5)

The downforce the body is generating is not lost through the foam. All that force is still translated into the chassis. The foam cushions the body, but that just means that the area through which the body translate force to the chassis is spread out over a larger area. Some tiny amount of energy would be lost to heat from the internal friction of the foam, but that amount would be very small. Imagine if you were lying on the couch and a kid throws a large pillow on top of you and then proceeds to jump on top of the pillow. The weight (force) of that kid is still squashing you, but its over a larger surface area.

To answer the OP: I would recommend over sizing your body post holes by 1-2mm so that the body doesn't affect the chassis flexing and try to position your clips, posts, supports so that there is 1-2mm of vertical play as well. Less chance of tweak and it will let the body move around a bit if it starts to rub on the track.

belewis01

iTrader: (5)

Thanks guys, seems we are of the same thinking - slightly loose mounting to prevent the body from tweaking the chassis.