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[h=2]IMSA 2017 Prototype Tech Profile: Riley/Multimatic Mk 30[/h] Tuesday, 24 January 2017


Marshall Pruett (words & images)








ORIGINS AND PERFORMANCE:

The North American combination of Riley Technologies and Multimatic have come together to produce the only P2-based 2017 model built in a collaboration between two manufacturers.
With Multimatic's large-scale composites capabilities in Canada, the firm took responsibility for the Mk 30's carbon fiber tub, bodywork and aerodynamics. From its base in North Carolina, Riley Technologies designed and manufactured the majority of the mechanical components on the WEC P2 Mk 30 chassis. From the Mk 30, the partners also produce the RT24-P Daytona Prototype international variant for Mazda.
With one team using the Mk 30 in IMSA, the primary development for the WEC-spec P2 is taking place in with Visit Florida Racing. Although the Mazda Racing team is able to help with feedback on the non-DPi aspects of the car, that leaves VFR to explore the Mk 30's WEC aerodynamics and learn how its impacts the car's overall performance with the spec Gibson V8 motor in the back of the car. Together, Mazda and VFR have kept each other abreast of any chassis-related problems, which proved to be valuable when a right-front suspension control arm failure on the Mazda at Daytona led to sharing the information and the immediate stoppage of testing. New, fortified pieces were then sent by the manufacturer for both teams to use and testing resumed.
One development issue – gearbox cooling – hampered the Mk 30 and RT24-Ps in testing, but those issues were reported to be resolved before the end of the Roar.
Of the three WEC P2 models and the three DPis, the Mk 30 stands out for its highly conventional shape among 2017 cars. Riley's cars have always placed a higher value on straightforward, user-friendly designs, than pushing the outer conceptual limits, and with that core philosophy in mind, almost everything about the Mk 30 appears to adhere to that standard.
Like many IMSA Prototype teams, the late arrival of 2017 cars has left entrants like VFR with a significant learning curve to overcome and very little time to reach the peak before the green flag waves at Daytona. The Mk 30's performance at the mid-December Daytona test and again at the three-day Roar Before the 24 test spoke to the new-car discovery process taking place, and while the car has yet to demonstrate class-leading speed, valuable gains were made by the end of the Roar.
Of the six prototype models, the Mk 30 ranked fifth among fastest laps at the test (only Nissan, with its newborn DPi, was slower). Although being the fifth-fastest chassis is far from optimal, the gap to the class-leading model, ORECA's 07, was reduced to 0.579s by VFR on Day 3 at the Roar. Prior to that session, the margin ranged from 0.9 s to 2.4s.
What remains unclear is how much faster the Mk 30 can run at a unique track like Daytona, where the ability to make extreme drag and downforce reductions plays a major role in saving time on the long banking sections.
One commonly held belief in the paddock is the car's base downforce and drag levels are higher than the other models, meaning it could be a challenge for the Mk 30 to reach down to the same level of slipperiness the other cars can achieve.
An interesting example of this was temporarily seen with IMSA's initial Balance of Performance tables for the Roar. The Mk 30, in that first BoP document, was granted a few aerodynamic options that spoke to improving its straightline and top speed performance against the other WEC P2s. Owing to an agreement with the ACO/FIA to perform zero performance balancing among WEC P2s, a second BoP document soon followed with the Mk 30's special aero allowances removed.
With the revised BoP in place, the Mk 30 recorded the slowest top speed of any model at the Roar. In an interesting twist, the Mk 30-based Mazda, with its custom DPi bodywork, was fastest.
Considering the overall lap time achieved by the car, the Mk 30's performance on the infield road course – where higher downforce helps – allowed the VFR car to shine. Under braking, and while cornering, the Mk 30 is hard to match. Once the season moves from the missile-like aero needs of Daytona to circuits like Sebring, Monterey, Detroit, and other venues where higher downforce is a benefit, the VFR team should have a car contends for wins.
DAYTONA TEST PERFORMANCE NUMBERS
The aforementioned six prototype models were represented by 12 cars entered at the Roar (3 x ORECA 03, 3 x Cadillac DPi.V-R, 2x Mazda RT24-P, 2 x Nissan Onroak DPi, 1 x Ligier JS P217 and 1 x Riley/Multimatic Mk30).
MK 30's Fastest Roar Lap: 1m38. 922s (P5 among the six models, P7 of the 12 cars, -0.579s to the fastest lap set by the ORECA 07)
MK 30's Best Roar Top Speed: P12, 188.3 mph (-8.8 mph to the top 197.1 mph set by Mazda's RT24-P)
NAMES AND SPECIFIC VEHICLE DATA
Lead Chassis Designer(s): Bob and Bill Riley
Lead Aerodynamicist(s): Mark Handford
Transmission Vendor: Xtrac
Brake Package Vendor: Brembo Calipers with carbon Hitco discs and pads
Data and ECU Electronics Package Vendor: Cosworth (spec)
Engine displacement and cylinder count: 4.2-liter V8 by Gibson Technology (spec)
Engine air induction system: Naturally-aspirated
SPEC 2017 P2-BASED DATA FOR EVERY PROTOTYPE MODEL
Minimum Weight: All WEC P2s and DPis have a minimum of 930 kilos (2050 pounds) with no fuel or driver for the Rolex 24. 930 kg is also the minimum in the WEC.
Maximum Length: 4750 mm (187 in.), which is 100 mm/4 in. longer than the previous LMP2 max length.
Maximum/Minimum Width: 1900 mm max (approx. 75 in.) to 1800 mm min (approx. 71 in.), which is narrower than the previous maximum of 2000 mm/75-3/4 in.
Maximum Height: 1050 mm (approx. 41.5 in.), slightly up from the previous 1030 mm (40.5 in.) standard.
Wheel Size: 18x12.5 in. fronts and 18x13 in. rears.
Tires: All supplied by Continental. Unique use of DP-derived Daytona specification for the Rolex 24, only. Brand-new 2017-spec Continental tires will be used from Round 2 at Sebring onward.
Transmissions: Six-speeds are required for every car. In the WEC, P2 teams are severely limited on the number of gear ratios that may be used (three sets), which will compromise the ability to perfect power and torque curves at some tracks. IMSA has removed the restriction for WEC P2s running in the WeatherTech Championship, and there are no limitations for DPis.