Project RADBUL: Power Is Nothing Without Control

Watch part three of The Making of RADBUL
© Brad Lord
By Brad Lord

Last episode’s revelation that a four-rotor, twin turbo engine capable of producing well in excess of 1,200 horsepower will power Mad Mike Whidddett’s Project RADBUL, took the Mazda MX-5 pro drift car build to an all-new level of awesome. Or perhaps ‘insanity’ is a better word, taking the car’s short wheelbase and expected power-to-weight ratio into consideration.

Either way, ensuring that the little Mazda can harness, and most importantly, use all the power to its advantage is now more important than ever. Over the course of the past few weeks at Townsend Brotherz Racing (TBR) ‘Metal House Compound’ there’s been a lot of progress made in the car’s suspension and steering departments.

RADBUL’s new KW 3A Competition coilovers © Brad Lord

Like any racecar, the way a car rides has a direct impact on overall performance, so handling an area of utmost importance. That said, for the Mad Mike Motorsports team, having prestigious racing suspension specialist KW come on-board with RADBUL is a major coup.

The purple and yellow 3A Competition coilovers that have found their way into the Mazda were custom-built for the application at KW’s race department in Germany. Not only do they have ability to alter the car’s ride height, but offer up three-way adjustability for compression, rebound, and both high and low-speed valving. In other words, they can be fine-tuned to suit different track layouts with quick and simple adjustments.

TBR’s in-house CAD design process © Brad Lord

Given this pro-spec drift car’s unconventional base platform and rotary engine conversion, custom-made components feature heavily throughout the chassis. They’ve all been designed in-house at TBR by the project’s lead engineer Kaz Townsend using computer aided drawing (CAD) software. It’s a solution being applied directly into the suspension and steering too, with TBR-developed arms, rods and links, working with what will be a completely custom knuckle setup at the front end.

Scratch-built steering knuckles for big angle © Brad Lord

To go sideways you need steering angle - and the more of it the better. It’s common practice in drift car builds to modify factory knuckles to increase this angle, but there are drawbacks in doing so. By designing a knuckle from scratch, however, there are no compromises - just benefits.

Along with near 90-degree lock, another gain - by Kaz’s design - is a 45mm drop, which essentially allows the wheels to sit up higher into the body. That effectively lowers the chassis without messing with the suspension geometry, so the car can have a low ride height and look good, while retaining full functionality. This TBR knuckle is Prototype V1.0 assembled and ready to be welded up.

An every-way adjustable rear end © Brad Lord

At the rear of the MX-5 the focus is on transferring power to the ground efficiently as possible. You might think that less grip would be more beneficial in drifting, and while that might be true for low-powered cars at a grassroots level, for maximum control a pro-spec machine actually needs it. Side and forward ‘bite’ is achieved through various components, and with KW coilovers and a full spread of Megan Racing rose-jointed arms in the mix, full adjustability is a big advantage here.

Final chassis fabrication at TBR © Brad Lord

Kaz is now in the final stages of chassis fabrication, which means that the Mazda will soon be leaving the TBR workshop to be fully painted before final reassembly can begin. That includes its 26B engine package that’s currently being prepared for assembly at Pulse Performance Race Engineering (PPRE). Completion is in sight for RADBUL - look out for another update very soon...

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