THE RILEY TRACK DAY CAR I
n 2009 Riley launched what, at first glance, was a
re-styled Daytona Prototype for track day customers, but the MkXXII was a purpose-built machine. ‘We started with the same concept, but pretty much everything is just for this car – the suspension, chassis, everything,’ explains Ron McMahon, Riley Technology’s vice president. ‘The only parts that carried over were the wing mirrors.’
The original car was equipped with a 6.2-litre, 500bhp Chevrolet LS3. But, at the 2011 PRI show, Riley revealed a much more potent version, equipped with a new, 5.0-litre, BMW S85 V10, custom built by Dinan and producing 720bhp. ‘This one was built to order for a customer who plans to use it at a country club track, but it is much faster than the
Daytona Prototype,’ enthuses McMahon. ‘The guy just wanted to do something different, and go a lot faster. As a result, it has a lot of special options on it: it has a six-speed sequential Xtrac transmission in place of the usual EMCO; it has a special crash structure on the front; it has a full carbon fibre body, where a ’glass body comes as standard; and it has a MoTeC ECU rather than an OBR. Also there is no air conditioning. Finally, the aerodynamics are different, with a fair bit more downforce from the bi-plane rear wing and front dive planes. The guy has a special goal in mind, but we cannot yet disclose what that is.’ Whilst this car opens up a
new performance bracket for the MkXXII, it is not a one off, all of the upgrades are available to other customers, at a price.
140,000 CPU hours went into developing the body. Here a pressure map
the safety requirements of a smaller greenhouse and all the clearances and ‘cage dimensions,’ Louth continued. ‘We received the CAD files of the Dallara chassis, and had a similar situation with Bob and Bill Riley. In the end, the bodywork was designed to fit not only the Coyote but the Dallara and Riley [chassis] as well. There’s a few attachment parts that are different from car to car, but all the primary body pieces are identical between all three chassis manufacturers.’ In what could be described
as the reverse of IndyCar’s aero kit concept, GM Racing sought to bring a spec body to multiple chassis and, although the project received positive feedback, Pratt & Miller had to wait until the second quarter of 2011 for the go ahead to bring the Corvette DP to life. ‘The concept of doing this was maybe 18 months old,’ Louth said early last December. ‘The conceptual designs for ‘cage packages, greenhouse sizes, the design work needed to support the rules development, that all occurred from probably October of 2010, and continued all the
way through to when the rules were finally finished on, I believe, April 6 [2011] or so. Prior to that, work was done but almost all of it was, I want to say, ad hoc conceptual stuff to support the regulations development. The real surfacing and design work that ended up as what we have today started, at the earliest, late March of last year. But really, when the rules were finalised, that was the ‘go’ point. ‘And that was the decision
point for Chevrolet. We had come up with a plan for manufacturing and supporting the teams and had estimated target test dates. We knew it was going to be a very short timeframe to actually have the cars on track, or in the wind tunnels, prior to Daytona 2012. So really, it took from April until [mid-November], pretty much eight months.’
VIRTUAL DESIGN As is the case with all racecar development these days, virtual design and testing tools were used extensively throughout the process. Approximately 140,000 CPU hours were spent on the
The revised Riley MkXXII features a new front impact structure and all carbon fibre bodywork
A Dinan-tuned 5.0-litre BMW engine gives this track day special 720bhp. It has been developed for a private customer, but all options are available
February 2012 •
www.racecar-engineering.com 11
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