In the last few years we spent a lot of time testing the position of the differentials in the XB4.
Moving the differential up or down has a major influence on the handling of the car.
For carpet tracks we typically need to decrease the ride height to a minimum so the chassis is as low as possible, which means we need to put the differential higher.
For dirt tracks the opposite combination usually works best.
Last year we used shims to adjust the diff position by raising the bulkhead which moved not only the differential, but the entire suspension assembly.
Raising all of the weight up also means a higher CG that is not what you want.
Our goal was to adjust only the differential height and to keep the bulkheads in place.
At the same time we wanted a wider range of different height adjustments, not just up or down position.
We came up with a solution to redesign the bulkheads and integrate eccentric bushings.
This allows to change the differential position without moving the bulkhead.
The front of the car features 3 different height settings and the rear has 6 different settings.
The first tests were positive but we were not satisfied with the improper angle of the central drive shaft when the differential was in a higher position.
As a solution we redesigned the bulkhead and integrated another eccentric bushing for the central drive shaft with different angle alternatives.
So now when raising the differential higher, you can also change the central drive shaft angle which provides maximum drive train efficiency.
This unique feature is something we are really proud about and I am sure you will like it too.
And I forgot to mention that to make working on the car easier, we have the all new horizontal split design.
Now when you want to take out the differential or adjust height, you only need to remove 4 screws, take off the upper half of the bulkhead and you can easily remove the differential and adjust the eccentrics.
Smart and easy.
One of the main areas of the XB4 we wanted to significantly improve was the slipper clutch.
As every track is different, we wanted to have more fine tuning options for the slipper adjustment.
We felt we can gain more efficiency from the car after a landing, and found that we preferred one slippage setting on the front tires and a separate slippage setting on the rear tires.
The ratio between the front and rear slippage needs to be adjustable as the track conditions change constantly and of course every tire has different grip too.
So we needed one slipper clutch that is fully adjustable and will work in all conditions.
The solution is our Multi-Adjustable Slipper Clutch.
We have completely redesigned the standard slipper and made the front and rear separately adjustable.
We have tested plenty of different slipper pad materials, many different thickness slipper discs and of course we have tested plenty of different springs to find the best combination.
Now for the high traction carpet you can set higher slippage in front and less in rear so the car accelerate faster after the jumps but is still easy to drive.
For the low traction dirt tracks you can set equal slippage in the front and rear, so the front tires will still keep traction after landing and pull out of the corner while the rear will accelerate exactly to your input.
And as the track conditions change, you can adjust the slippage accordingly and separately in front and rear.
I am sure you will enjoy this new unique slipper clutch, the first in a shaft driven 4WD buggy.
With the all new split design of the XB4 bulkheads we had to completely redesign and change all of the related parts:
We completely redesigned the rear suspension holders so they can be installed in an upward or downward orientation.
This results in extra roll center positions and allows moving the entire suspension up or down.
Typically, the downward position will be used for dirt tracks and the upward position is for carpet tracks.
The chassis was redesigned to fit the new bulkheads, the new suspension holders and also features the new tweak-free Quick Battery Holder.
This smart system allows for adjustment of holder’s height for different battery sizes.
But most importantly this system is completely tweak free and reduces the effects of the battery and the holder on chassis flex.
This tweak-free design makes the XB4 more predictable and easier to drive.
The all-new XB4 shock towers feature an updated design to fit the new split bulkheads and extra denser shock mounting positions.
The new rear shock tower has more roll center positions and more wing mounting positions than the previous towers.
To improve the stability and to increase the corner speed the front shock bodies and shock shafts are now 2mm shorter.
In the rear, the body post holder was redesigned to fit the new split bulkheads and with easy screws access.
In the front we have redesigned the steering system to fit the new bulkheads and differential height adjustment.
The side guards were also redesigned to work with the new Quick Battery Holder system.
Now the central drive shafts are longer in front and rear to move the CV joint closer to the differential to improve drive train efficiency.
All these small details make a big difference on the track.
With the increasing expectations of performance we spent a lot of time working on the body design.
We had specific goals of the characteristics to change to improve the performance but the main struggles were the compromises needed to achieve those targets.
The initial idea was to continue with one body for all track conditions, but we found that approach would result in a performance compromise either for carpet or dirt conditions.
As such, we made the decision to make two bodies, one specifically designed for carpet and the other one for dirt tracks.
The bodies were designed in combination with the different wing designs, so the entire effect of the body is perfectly paired with the wing design.
The main downforce area is moved to the rear of the body.
As usual, we first made clay moulds that were modified for multiple design alternatives.
These hand moulds were rough but good enough for quick testing of the different concepts.
The first tests showed great performance improvements but we still worked on more small details.
In the final results, we were able to lower both bodies and we changed the front windows to make the flow lines smoother.After
all the design changes were selected, we made one more handmade mould.
With a great result of the final prototype we finished the last small details and created the final production mould.
After the extensive work of our R&D team and plenty of testing of all the prototypes on both carpet and dirt tracks, here is the final pre-production prototype that was built a few months ago.
At this moment the production is running and you can expect your all-new XB4 very soon.
I hope you enjoyed our exclusive story about designing and making of the XB4.
We did our best to make the best XB4 even better, and I hope you will love the new car as we do.
Thank you for your time and see you on the track.