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Ever since the G8X M cars arrived with customers, Tom Wrigley at Tom Wrigley Performance has been developing and pushing the limits of what the chassis is capable of in terms of outright power and speed. Working alongside multiple partners such as Precision Turbos and MHD Tuning, the ultimate packages are being comprised to turn an already fast BMW into a blisteringly quick record setter. However, as Tom is also a current pro racing driver within the British GT at the helm of a BMW G82 M4 GT4 car he knows that all that power is ultimately nothing without control.
Tom knew that in order to turn this outright speed machine into a genuine record setter there would need to be some suspension modifications to keep the car stable at high speeds, put the traction down off the line and transfer all of that power down to the ground and through the tarmac with as little wheel spin as physical possible. This is when our phone rang…
With the mission understood and the record setting capabilities in mind we landed on 3 specific components to target traction and stability directly in a straight line.
First of all was a focus on getting the car off the line as this was a standing half mile run, meaning that the car starts from a complete standstill and must launch off as fast as possible. One issue encountered with the stock suspension was a wheel hop off the line where the rear axle effectively jumps up and down as it tries to manage the power and grip. To solve this, we supplied a set of our Suspension Secrets Adjustable Rear Traction Arms. With the traction arms fitted to a specific length longer than the standard arm, the rear axle kinematics are altered in such a way that generates much more mechanical grip from the chassis.
Kinematics is the interaction of the different arc patterns that each suspension component travels through during the compression and extension of the suspension assembly. Put simply, each arm has a pushing and pulling motion on the wheel when the suspension is travelling up and down. How these pushing and pulling forces interact with each other decides how much grip and stability is available at the axle. With the alteration in length of the rear traction arm by installing our adjustable arm, we are able to alter this interaction to rotate the upright forwards and down as the wheel goes into compression. This means that as the throttle is applied, the rear wheels go into compression and the leading edge of the tyre is mechanically pushed into the ground to increase traction levels substantially. This downward traction force also loads the tyre to a point that help to remove the wheel hop that the car suffered with initially. With the hop removed, the tyre has a more consistent level of grip, allowing a much faster getaway from the line.
With the car off the line with much more traction than before, attention now needed to be turned to increasing the overall levels of grip and stability as the car continued at full throttle down the drag strip. For this we installed a set of our Suspension Secrets Adjustable Rear Toe Arms. With the toe arms fitted we unlocked two benefits. The first being the ability to set the toe exactly where we wanted it to ensure the car has the perfect toe settings to no only increase grip but so that the settings aren’t so aggressive that they impact top speed as both factors are important for this record breaking run. The second bonus is more consistent levels of traction due to the solid rose joints that the arms feature. The standard rear toe arm links feature rubber bushes that flex under load. As they felt the rear toe settings change leading to instability in grip under extreme conditions when pushing hard on the drag strip, race track or out on the roads. In fact the effects are even larger when cornering due to the lateral G forces but we will go into more depth on that in a future article.
With the flex in the rear toe links removed, it means that the toe settings that are installed on the rear axle, stay on the rear axle leading to more consistent and reliable levels of grip, allowing Tom to keep the throttle pressed hard down with plenty of trust that the rear axle is going to stay perfectly planted and arrow straight for the record setting run.
Now that we have got the car off the line with maximum traction and stable grip levels as it accelerates down the drag strip, the final piece of the puzzle is to keep the chassis arrow straight and stable as Tom rockets towards 200 MPH in a very short space of time. Enter our Suspension Secrets Solid Front Caster Bushes.
Like the rear toe arms, the solid front control arm caster bushes have two major benefits when it comes to keep the chassis stable at high speed. The first and most obvious is the increase in caster. The caster change is caused by our solid bushes having an off-centre hole machined in an exact position to increase the caster angle by 2 degrees compared to the standard bush. Adding caster increases an aspect of geometry called mechanical trail. Mechanical trail is effectively a lever arm that takes effect upon the steering meaning that the larger the mechanical trail, the firmer the steering is and the more that the steering wants to remain straight. This not only adds steering feel in to the car (which is much needed over standard) but creates a huge amount of stability at high speeds as the wheel remains naturally straight leaving Tom to focus on breaking the record in stead of hanging onto the steering wheel fighting to keep it straight.
The second benefit is once the run is completed. A lot of focus is often put on the high speed run (and quite rightly so) but at the end of it, the brakes need to be pressed and the heavy 1800Kg car needs to be stopped from over 200 MPH. The removal of the standard rubber bushing means that the braking is much more stable and direct, again keeping the chassis much more stable as it slows down from such high speeds.
With all of these components fitted, Tom took to the drag strip and laid down an incredible run. The combination of all the work that has gone into the build by the team at Tom Wrigley Performance has created a monster, putting down an incredible run to break not only the record for the standing 1/2 mile for the G8X chassis worldwide but the all time fastest BMW ever to run the standing 1/2 mile which is a seriously impressive feat! The 1/2 mile was completed in just 14.28 seconds at a top speed of 203 MPH. Check out the video the run below.
If you would like any further information on the products fitted or would like to see how we can improve your chassis then head over to the link below to see our product range and get in touch.
