Up Close And Personal: The Formula Renault 3.5

Project CARS Vehicle Lead Casey Ringley Gets Under The Formula Renault 3.5 And Finds A Seriously Quick Runner.

This was a cool project to work on as we ramped up to the IndyCar Dallara. The FR3.5 chassis is made by Dallara, and the underbody with full tunnels isn’t all that different from the Dallara DW12. We were given extensive data for what this kind of underbody does over a wide range of ride heights, and matched the game model to it in seriously minute detail.

The changes in downforce level and center of pressure balance are much larger than you might expect. Getting your ride height wrong by 10mm can mean a loss of 10 percent of total downforce, and a shift in balance that is enough to push it from understeer to oversteer. Fascinating stuff, and always a dream to work with real data like this.

In general, the Formula Renault 3.5 wants to be low—as in really low—and you tend to run it as stiff as you can to get that aero’ working.

The aero’ package also includes DRS, but it works in a very different way to what most of you are probably used to. Rather than reduce the angle of the second wing element, it flips up a small flap at the trailing edge of the main element. This closes the slot gap, and causes flow separation on the suction surfaces of the wing, stalling it out and reducing both downforce and drag. This is similar in theory to how the old F-duct worked on certain F1 cars back before they added the DRS systems as we know them now.

Suspension geometry is taken directly from CAD. We did have to make one compromise, though: the real car uses a monoshock front end. What this means, essentially, is that there’s one spring that holds the car up, plus an anti-roll bar for lateral movements. Our current chassis solver, however, doesn’t handle this elegantly. It works perfectly—right up until it doesn’t—and then the car explodes off into space. As a compromise, we’ve matched a traditional configuration of four ride springs plus anti-roll bars to the standard setup on the real Formula Renault 3.5 as closely as possible.

The engine is yet another 4.0-litre flat-plane V8 based on a Nissan block. The lump is good for 530hp @ at a tasty 9,200rpm, and is supplied by Gibson Technologies: for the record, the engine is the Gibson ZRS03.

The gearbox, meanwhile, is the typical six-speed sequential with flat shifting. In this case, the same Ricardo unit as used in Indy Lights—somewhat interesting! Overall, it’s like driving the IndyCar with 60 percent of the power and downforce, which is actually a lot of fun, and asolid challenge.

It’ll take you a good three laps to get the tyres up to full temperature from cold, as the car—due to its light-weight—doesn’t work them very hard.

Top speed at Monza approaches 298-300kmh with another 10-15kmh added via DRS. Lap-times are close to what they’re running in the real-world: 1:34s at Monza, 1:41s at the ’Ring GP, 1:59s at Spa. Pretty quick car for the specs!

Motion Ratio: Front= 1.0/Rear= 1.0

Damper Transitions: 50mm/s bump, 80mm/s rebound (front and rear)

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