Works style rally car preperation for the clubman budget

The Running Gear

      The first step for the running gear was a good steam clean followed by an inspection from top to bottom to see what needed replacing and then a long list of parts were drawn up to source from various suppliers. One of the things on top of this list was a complete set of harder suspension bushes. These are made by a few different manufacturers and range in price, but the ones we choose were made by Polyflex, the reason being we've used them before and were happy with the quality. Shown below are the complete set of bushes we purchased for the BM. The reason for changing to these bushes are fairly straight forward, as previously shown in this build we've gone to quite a bit of effort to stiffen up the shell of this car with the idea being to enhance the handling. The suspension bushes play a large part in this role also. A badly worn suspension bush  will leave the car handling poor and loose and the driver will not have as much feeback from the car as to what it's going to do next when pushed hard. As opposed to a car which is stiffened and has no excess play in the suspension components, then the driver starts to get a feel for the car and how much it can be pushed in certain situations. The steering geometry of a given car, that is the toe-in, toe-out, castor and camber angles of the wheels plays the biggest part in how a car will handle when driven hard and if the suspension bushes are worn then these angles are allowed to change slightly when driven hard and as such have an adverse effect on the handling. We could have just changed all the worn bushes for new BMW ones but the new Polyflex bushes are made from a hard substance called polyurathene and offer a large improvement over standard items, as they remove all unwanted flexability and still allow the joints to work correctly.


  The pic to the left shows some of the bushes fitted to the rear beam and wishbone. These were quite easy to fit as the suspension was already removed from the car from earlier. The 2 inner bushes shown fitted to the wishbone greatly reduce the rear wheels ability to flex in and out altering the rear wheels toe settings, while the outside verticle bush shown which mounts the beam axle to the car ensures that the beam which everything hangs off is solid.

The bush shown here is probably the most important one on the whole car as far as handling is concerned and its the pivot bush for the front wishbone. If this bush is badly worn and allowed to flex the front wheels can actually turn in and out a small amount all on there own and dramitically effect the steering. The whole strut will also be able to move forward while accelerating and rearward when braking giving a horribily unstable feel to the car.


          With the bushes all fitted a few standard genuine BMW  items were then fitted to the car to replace some worn items, new front wishbones, new innar and outer steering ball joints and new bottom ball joints all helping to tighten things up nicley. Brakes were next on the list and as the budget is to be kept as reasonably low as possible on this build it was decided that the standard size items would suffice after a good overhaul. So the worn disc's were renewed for new Tarox aftermarket jobs and standard rear pads were fitted. For the front pads however we decided to upgrade to some competition spec items and the reason for this is when the car is to be used, it's going to be driven hard and as such braked hard and standard pads can quite often fade as a result. This is a situation where the material the standard pad is made from can't cope with the excess heat created when the bakes are repeatedly hammered and the result is a hard pedal that when pressed doesn't actually slow the car down much. Not a nice situation I'm sure you'll agree! The uprated pads are made from a different material able to cope with the higher temperature and should provide good brakes during all situations. The only other thing left to do was to overhaul the calipers, making sure the pistons were free and caliper sliding pins were also free to do there job and cover all with a nice coat of the appropriate grease to ensure they stay that way.
         Next up will be the engine work and what was involved in transforming this..........


                                                         into this.................


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