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WEC | SMP Racing | Technical Analysis

WEC | SMP Racing | Technical Analysis

http://www.racecar-engineering.com/articles/wec-smp-racing-technical-analysis/

SMP Racing LMP1 Technical Analysis

One of the contenders to take the fight to the Toyotas for that final step on the LMP1 podium is the Russian BR Engineering BR1 car. Two cars will be raced by SMP Racing featuring the AER V6 direct injection twin turbo powerplant.

Chassis

The BR Engineering BR1 car has been developed in collaboration with Dallara and together, using the LMP2 car as a baseline, an all new carbon fibre chassis was born. This chassis comes in two slightly different versions to cater for the three different engine configurations available to the LMP1 non hybrids. One variant allows a turbo installation to run with the Mecachrome or AER powerplant, while the other suits the normally aspirated Gibson engine.

Weight was another major consideration as the minimum weight for LMP1 non hybrids is 830Kg plus 3Kg for camera equipment. Compare this to 930Kg for LMP2 and around 100Kg had to be saved which was the main driver behind the chassis design concept.

‘We started from the LMP2 monocoque that was already good, but the name of the game in LMP1 is weight saving, more than anything else,’ says Luca Pignacca, chief designer at Dallara. ‘The car must weigh 100kg less than the LMP2 and that is a lot. Fortunately, we had a good base from which to start, because the LMP2 car carries a lot of ballast with the Gibson engine, but we had to redesign everything to save weight. We had to use different materials for the monocoque, so we went more extreme with everything.’

BR1_SMP_Racing
With the minimum weight for LMP1’s around 100Kg less than that of LMP2, the design of the chassis was very much driven by the need to reduce the weight

The BR Engineering car is somewhere between the two extremes. ‘With LMP2, for example, you need to accommodate gentlemen drivers as well, so some are very tall, and big, and they must fit in an LMP2 monocoque,’ says Pignacca. ‘In LMP1, the size of the monocoque is slightly smaller, and we tailored it around the SMP drivers. We went a little higher with the footbox, but everything must be redesigned or you won’t reach the target with the weight. Someone [Ligier] used expensive materials for LMP2 and for me this was conceptually wrong because LMP2 must not be this much, we used, let’s say, high end materials for LMP1.’

These new materials, together with a revised production process where the overlap between each layer of carbon fibre within the chassis was optimised, helped Dallara to achieve the low weight target.

Engine

SMP Racing’s contenders race with the AER P60B twin turbo V6 direct injection engine, which is based on the original P60 concept that was last raced in the WEC back in 2016. The original P60 was designed from a clean sheet of paper, with the specific intention of exploiting the fuel flow restrictions of LMP1, making the refined P60B perfect for competing in this year’s ‘Super season’. Arguably the best strategy to maximising power in a fuel restricted formula is to use direct injection. Although this has other advantages as well as Mark Ellis, technical director at AER explains. ‘GDI [Gasoline Direct Injection] allows a number of benefits, for example it improves the charge cooling, the mixture distribution within the cylinder and you are able to target the fuel spray interaction more accurately.’ Ellis continues, ‘This improves the homogeneity of the charge and allows more precise control of the fuel added each cycle. This not only brings benefits to the combustion efficiency and BSFC [Brake Specific Fuel Consumption], but also driveability, torque response and traction control.’

SMP_Racing_AER
The baseline concept for the AER P60B was designed from a clean sheet of paper, specifically to optimise fuel flow restrictions

Suspension

The front suspension has also seen some changes, driven by this year’s narrower monocoque at the front as well as the different size of tyres and the need to save weight. The suspension revisions were also due to the IKEA philosophy, says Pignacca. ‘The second time you do the job, you will do it better.’

Although the third element is more sophisticated, the suspension in general has been based on the LMP2 car. ‘We had a good base from LMP2, which we believe is a very good car,’ says Pignacca. ‘We had a small problem with the front splitter, but the rest of the car was a sound car. We didn’t need to change a lot the suspension pick up points; it was a general optimisation. We went lighter, more extreme with the geometry of the monocoque to reduce the drag, and we have used all the possibilities that the regulations gave us, but this was mainly with the aero.’

Xtrac Dallara LMP2 gearbox
The Xtrac gearbox has been carried over from the Dallara LMP2 car into the SMP Racing LMP1 car

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The post WEC | SMP Racing | Technical Analysis appeared first on Racecar Engineering.

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via Racecar Engineering http://www.racecar-engineering.com

June 14, 2018 at 10:19PM
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