Operation Brown Bear

Our plans to get a single make championship/series off the ground for the SC09 V8’s has been hindered due to lack of commitment. We still very much plan to run with the idea, however it will certainly require more time and effort and we hope that throughout the 2016 season more people commit and get stuck in. The general feedback from everyone is that it is something people want to be a part of, there really is nothing like this in the UK and let's be honest nothing beats the sound of a roaring V8, let alone a whole grid of them! We will still be racing this season, but we will be joining in with other grids until everything falls into place. We have recently been undergoing a project with one of the SC09 race cars and would like to take this opportunity to share our plans with you. A more competitive package is required to enable a front running car in a GT4 class in events such as Britcar, GT Cup, 750MC and MSVR. Perhaps the most easily identifiable issue with the standard SC09 is the vehicle mass. Currently at 1550kg these are on the heavy side for a race car. As much as we would like to think they are Aussie V8 super cars they are quite a long way off. They are in essence a GT4 version of a Vauxhall VXR8/Chevy Lumina/Holden Commodore.
How it all started
As you can see a relatively substantial cage is in place currently
There are two avenues to investigate to deal with its current power to weight ratio; add more power to the engine, or, remove as much weight as possible making a more nimble package. Removing weight was the route dictated to be initially investigated. A combination of the both may prove to be the optimal route in terms of performance, perhaps not for cost though. Starting at the current weight, a loss of 300-350Kgs is required to be removed in order to put the car in the power to weight ratio of where we are aiming to be. Getting that much additional weight out of an already stripped vehicle is difficult, time consuming and costly. However if the more than capable power-train ends up in  a lighter car the rewards will soon become apparent; it will accelerate faster, brake faster and corner faster.
Weighing the chassis.
As a starting point we stripped one of the cars down to a bare shell and recorded the weight of each component to assess the weight saving possibilities. Not surprisingly the chassis is the largest mass at around 700Kg. This is obviously an area of concern as things like the engine and drive train are not going to change much. For example the front end assembly as a group weight is nearly 520Kg, these items won’t change therefore this is a known mass of the final vehicle.
A reasonable chunk of weight was in the car from the standard bar and brackets, another bar is going to be welded across the bulkhead with mountings for the dash and steering wheel.
Front sub frame assembly fresh out of the car, it needs a lot of TLC.
Moving onto the shell; there is already a substantial roll cage which extends to the front suspension struts; by altering this structure to be more like a space framed chassis vehicle we can remove most of the floor pan, transmission tunnel and bulkhead. These can then have bracing areas welded back in and lightweight flooring bonded and riveted. All the current bodywork is heavy, even items such as the bonnet and front bumper that are already moulded from GRP are heavy; this is mainly due to poor manufacture from the original supplier. There is a substantial amount of resin incorporated into these panels which is totally unnecessary weight. The doors and a lot of the other body work have had a lot of body filler put on them in the past along with many layers of paint. With this in mind we will be planning to replace these panels with new vac moulded GRP pieces and only minimal paint applied. Just the doors come in at around 100kg total! The suspension components are modified standard units for the most part. Upper and lower control arms on the front and rear are bulky cast metal with in some cases large machined housings made to be inserted into the standard bush holes to accept plain spherical bearings. A more long term plan is to redesign these components and make them from tubular equivalent with the correct housing sizing for the bearings required from the start. Machined uprights would also be another consideration as all of these OEM style parts are very heavy.
Rear Subframe assembly with gearbox stored on-top. These both will undergo full rebuilds.
The sub-frames are modified standard items. They have been seam welded for the most part and have solid bushes machined to fit in the standard bush holes. More weight can be saved by once again making these from a tubular equivalent, along with adding more adjustment for suspension geometry.
Stripped front subframe, cleaned and repainted.
As you can see we have a lot to think about and design, but once we have the shell sorted and we can start testing we can then think about the further development of these other items.
08/03/16 – Update
We are currently part way through the project. The rear shell of the vehicle has now been removed, weighing in at nearly 160Kg including; the boot lid, glass and rear doors. This is going to be sent off to Production Glass Fibre to have a rear clam shell made. The new fibreglass shell will come in at somewhere around a third of the weight, we expect it to be below 50Kg. The boot lid and rear doors have been tack welded onto the metal shell and the whole rear section will be moulded as one piece. The rear light clusters are also being incorporated into the mould with a much less expensive lighting solution being produced for the final build. Light clusters on these cars are ludicrously expensive from HSV and in racing it is quite likely they are going to be damaged, so provisions for overly expensive items like lights are being taken into consideration. Along with the rear shell, the floor pan has been removed; this was not only to try and save some weight, but this will also mean we can make a customised transmission tunnel which will allow us to tuck up the exhaust with the prop-shaft to give us a bit more freedom with regards to ride heights. The fuel tank is planned to be moved more inbound into the vehicle, inside the crash structure in a more favourable position. Weight split of the new vehicle is going to be an interesting point for discussion, most of the weight being removed is from the rear of the vehicle, and it will not be possible to take the same amount out of the front due to things that cannot be changed or altered i.e. the cast iron blocked LSX engine. There are a few ways to try and deal with this; add some ballast to the rear of the vehicle or bring the weight from the front inbound, i.e. move the engine into the bulkhead. There really is very little weight over the rear axle and the car will just want to spin during cornering. We will need a relatively good aero package to push it down so it doesn't float around under acceleration also.
Almost ready to send up for a mould to be produced.
The state of the chassis currently, still a lot of work ahead.
Suspension will need to be thoroughly looked into, even corner weighting the car is not going to be enough to help the split. But also removing the weight means that the dampers and spring rates are not going to be correct for the new vehicle mass. A new exhaust system is going to have to be produced to bring the exits out of both sides of the car this will help us with our noise levels. That is it for now, watch this space for more updates about this project. UKV8S
Shot of the pedal box that requires a refresh