Кейси Рингли: Приготовьтесь. Вышло так, что у нас накопилось много того, что мы можем рассказать о красных машинах...
В качестве бонуса мы подготовили диаграммы зависимости центра крена от высоты дорожного просвета для каждой машины. Это достаточно глубокий взгляд в дебри физической модели, но я полагаю, что для гуру настроек это станет неплохим ориентиром для понимания влияния от изменений клиренса (как в статике, так и в динамике).
Ferrari 250GT Berlinetta SWB
The 250 line of cars is very well documented (and ultimately quite simple in design) so it was easy to put together a model in our systems. Old homologation forms; owner's manuals of similar 250 models; even comparison to its successor, the 250GTO, provided tons of information as a baseline.
Chassis is a simple design with unequal-length A-arm front suspension and solid rear axle on leaf springs. The front end has nothing fancy going on but keeps a relatively stable roll center and little bump steer; most notable thing is that the steering geometry is quite old fashioned, which you would expect for a 1960 car. There is significant scrub radius due to the low kingpin inclination and ball joints being pretty far inboard of the wheel center to make room for fitting the brakes. It makes for informative FFB which helps give clear signals of countersteer when in slides, but it is a very different feel to more modern cars. Our rear end uses a metric four-link setup to approximate the leaf springs, same as we have done for the old Camaro and Escort; technically not the same arrangement, but the roll centre moves in the same way, lateral location, anti-squat and other pros & cons of the design work out almost exactly the same when configured right. Long story short, it does an ace job at putting down power but can feel a little wallowy when cornering.
The SWB was a true GT car; you would buy one, drive it to the circuit, and win various endurance races. The best SWB Competizione models had aluminum bodywork, and that is what we've copied here. Going with aluminum rather than steel dropped the weight from 1100kg to only 957kg. A little heavier than your average sports prototype of the time (DBR1, 250 Testa Rossa), but the coupé bodywork is good for aerodynamic drag meaning more top speed, and the car was generally very well sorted for road use so it did remarkably well in endurance racing.
Gearbox is a very simple 4-speed synchromesh unit with a range of crownwheel & pinion final drive ratios from 4.57:1 (very short tracks) to 3.44:1 (ideal for Le Mans) and a ZF-type limited slip differential. Funny enough, a great deal of the internals were licensed from Porsche. Haven't found any talk about differential setup, but we can be sure it was something like 4 or 6 clutches with symmetrical 40-45° ramp angles for between 30-50% locking factor, as generally everything from this time period used something close to that configuration. Works out well in game, too, with good stability on braking and good traction on power.
Like all Ferraris of this era, the real magic is in the engine. A 3.0L V12 using Colombo design dating back to 1947 and their first race cars, it was a very well-understood design giving good power and great reliability for the time. Engines in the SWB ranged from a quoted 240-280hp depending on state of tune. Ours is set to give 260hp @ 7,200rpm with a super smooth torque curve which peaks at 280Nm @ 6,000rpm but gives 90% of that peak all the way down to 3,200rpm. It has good grunt through the engine's whole range and pulls like a champ out of slow corners.
This is my favorite Ferrari of all time, and it doesn't disappoint after test driving the model in game. Pace is a good match for the DBR1 at all tracks tested so far; the 250GT is a little heavier but has slightly more power and slightly more top speed. Should be some epic racing to be had between this car, the DBR1, and the 250 Testa Rossa.
Ferrari 250 Testa Rossa
I imagined, at first, that this would be more or less a direct copy of the 250GT since cars from this body-on-frame era shared a lot of their underpinnings, but some good information from the restoration of an original 1957 Testa Rossa chassis showed some differences worth including on our model.
Engine and gearbox are a very similar 3.0L Colombo V12 base as the 250GT SWB with the main difference being higher-compression pistons and tuning changes which bring the power level up to 295hp @ 7,200rpm. Gearbox is the same 4-speed with limited slip differential. They combine with the roadster's aerodynamics (more drag) for a similar top speed in the neighborhood of 165mph. The race-tuned engine was durable at high rpm, even if there was no real power advantage in doing so. There is at least one report of a driver at Le Mans being ordered to stick to 7,500rpm maximum on the Mulsanne straight but instead ignoring that order and letting the car run up to 9,500rpm between shifts...without any race-ending consequences.
That roadster bodywork helps the car weigh in almost 100kg lighter than the lightest 250GT at only 880kg - slightly more than the Aston DBR1 - with a nice weight distribution near 50:50 when the driver is onboard. A unique feature in the 1957 car are the 'pontoon' front fenders, added to help airflow for cooling the drum brakes but creating a not-insignificant drag penalty in doing so. Later updates to the 250 Testa Rossa (TR59, TR60, etc.) abandoned this design and moved to disc brakes for easier cooling. The drums are a good bit behind the performance of discs as used on 250GT SWB and Aston Martin DBR1, so while this one has the power advantage and gets up to speed more quickly, it is also more work to get it slowed back down.
Front suspension is similar to the 250GT in using unequal-length wishbones on a primitive steering geometry with small caster and kingpin angles, resulting in large scrub radius and little mechanical trail. This gives good self-centering to the steering feel (makes catching slides easy) but hurts cornering feel (harder to feel the grip limit) and is just kind of a trait of these older cars with their simpler designs. Makes an interesting comparison to the modern GT3 machines where so much has been learned about design in regard to using the kinematics to improve handling AND give the driver good information through steering feel.
Rear suspension takes a different design approach to the 250GT and it's semi-elliptical leaf springs. Here the solid axle is supported with upper trailing links and a triangulated lower link attached to a pivot on the differential gear housing. We found some dimensioned blueprints from chassis restoration work which was a huge help in getting these linkages correct. What it means, in practice, is that the 250GT rear roll center moves in sync with changes in the rear ride height at almost a 1:1 ratio while 250 Testa Rossa has a rear roll center which moves much less and in the opposite direction of suspension travel (i.e. the roll center raises as the rear end squats down). Both approaches work and are pretty dang good at controlling the rear end, but the general handling feel when braking and cornering is quite a strong contrast from one to the other. 250GT tightens up under braking for a comfortable, stable feel while 250TR loosens to get ready for a sharp turn-in that requires full attention. Kinda neat that two cars which, at first glance, seemed like they might be near clones with only bodywork changes have instead ended up offering very different driving experiences while also balancing nicely for performance on track.
Jussi’s default setup notes:
For the 250 TR/GT I had to think about whether I wanted to keep the setups more historically accurate as per Casey's research, or go for a more modern sensibility that would probably improve performance. In the end I decided that historical accuracy was the better idea. The main issue there really is just that if you drive like a real hooligan the cars can lean on the rear suspension quite a bit. Really like these two cars; they're similar but very different in how they handle, with the GT being much more stable as a platform and the TR wanting to dart in more. Or at least it wants to get sideways a bit more, at any rate. =)
This is another one where there is a mountain of good reference material available - detailed owner's & workshop manuals, independent tests and measurements from private-owner cars, FerrariChat discussions, etc. - which made putting together an accurate model quite a straightforward process. Being one of the best-known and most popular road cars of all time worked very much in our favor.
Engine is the street-tuned version of the same 2.94L twin-turbo V8 as we have in the F40 LM. It was one of the first turbocharged engines to use ECU management of boost pressure to shape the torque curve; spiking boost pressure to the peak 22psi at mid-range rpm range and then bleeding some off at high rpm for smooth torque delivery up to the power peak. Quoted at 480hp@7000rpm, it was generally considered to be quite underrated and most tests I've seen have cars producing nearly that number at the wheels. What's probably the case is that boost bleed-off wasn't really active in test cars and owners easily tuned around it to hold near the maximum boost pressure right up through the full rpm range for just north of 500hp total. Ours defaults to that setup at 100% boost and the 'official' boost curve for 480hp at 75% boost.
Gearbox uses the Euro-spec ratios with 2.727:1 final drive ratio for hitting the 200mph top speed. Differential is a clutch & ramp type with default set to only around 25% lock in both directions (4 clutches + 50° ramps); the car has so much rear tire (335/35R17!) that it doesn't need a great deal of differential lock to handle the power and too much can shift the car into power understeer since there is so much grip at the back from the 335s.
Double-wishbone suspension is largely a carryover from the F40 LM and is built from detailed, dimensioned blueprints of the chassis, with adjustments for the road car ride height. Funny enough, the road car's suspension could be adjusted for ride height and track use but it required unbolting the whole thing and moving each suspension arm to a different set of attachment points. Ferrari were happy to let you adjust the car, but don't screw around with the roll center design. F40 owners have measured their own cars with spring rates at 480lb/in (83N/mm) front and 325lb/in (57N/mm) rear, which gives the factory setup a 12% stiffness bias to the front for a nice, stable, GT race car kind of setup.
Brakes were derived from Group C racing parts and the aerodynamics produce some useful downforce to keep the car stable at high speed. Real car had no driver aids, not even power brakes and steering. It really was a racing car for the road.
Overall, it's surprising how easy and predictable the F40 is to drive. You'd expect the wildest, fastest supercar of the late-1980s to be a handful that requires constant attention to turn fast laps. 480-500hp isn't really all that much by modern standards, though, and the general balance of the car was designed for stability and inspiring confidence in the driver to be fast around a track. Some old magazine tests of the car mention how it "edges into a nice, modest, deliberate understeer" and that comes across in our model too. Push the car too hard and it smoothly informs you about it without upsetting the chassis; a little trail braking or throttle lift usually is enough to pull the front end into the apex and then you are met with just the right amount of power oversteer on corner exit as the turbo boost comes on. It really feels like the car is working with you, and it pays off; I'm running the F40 around Fiorano within 1s of my 458 Specialé times despite a 100hp deficit.
Jussi’s default setup notes:
The F40 is an interesting car to drive, with some clear foibles to it that would be done differently today. The insane power output (for the day) made them put really wide rear tyres on it, especially compared to the fronts, which on modern rubber, like we primarily simulate, makes it feel like it has a surplus of grip at the rear end, and less at the front end. Think of it this way, the Chevy C7 Z06 has the same width rear tyres with more than 150 hp more power, and 4 cm wider fronts. The turbo lag is humongous by today's standards, and the gearing has big gaps to it (2nd gear pulls all the way to 150 km/h, whereas 3rd gear in the 458 SA pulls to a bit over 130 km/h), which makes efficient power usage a bit tricky. On controller this lead to some issues with getting the car to turn well at certain speeds, when the long gearing gaps prevent good engine braking. It's an interesting experience driving this car, very much of its time period, but definitely a capable machine.
The 458 SA on the other hand is a fully modern car with modern sensibilities to it (aside from the engine, since it's an NA one). The front to rear grip balance is perfectly thought out, the chassis balance is excellent, the NA engine gives you instant access to power, the gearing is really well spaced... This is just an awesome car to drive, my favorite road car currently.
Ferrari 458 Specialé A
It's just about as good as I imagine a road car can get. Power, handling and speed are all abundant and in a perfect balance.
The engine is Ferrari's F136 4.5L naturally-aspirated V8 in its ultimate form, producing just over 600hp at the 9000rpm rev limit and 565Nm all the way down at 5200rpm. Dyno test references show just how strong this engine is above 4000rpm, holding over 90% of peak torque all the way from 4000-8000rpm and then only falling off gradually to make that top 25hp. It revs freely and is always ready to pull hard without needing you to work through the gearbox excessively (or at all, really).
That gearbox is a 7-speed dual-clutch unit like other 458 models with ratios spaced perfectly across all seven gears; no wasted top gear on fuel economy here, they are evenly-spaced up to the top speed of 320kph. The differential uses our approximation of Ferrari's e-diff similar to what you'll find on the LaFerrari or FXX-K, blending aspects of geared, clutch & ramp, and viscous to help guide the rear axle in various conditions.
Ferrari make some aerodynamic claims for the 458 Specialé which are quite credible. The car has an array of active flaps; some close at 105mph to reduce drag and others in the rear diffuser adjust above 137mph to shift aero balance 20% to the rear for high speed stability. Our model copies this in the same way with speed-sensitive elements front and rear. In total, they produce around 500lb of downforce at 150mph with the front balance moving somewhere between 12-32% depending on your speed. It's enough to aid cornering performance, but not so much that it feels like an extreme, high-downforce car that can only be driven fast or falls over if not driven on tidy racing lines. This car loves holding a bit of a drift through turns.
Suspension uses a design family common to just about every Ferrari for the last decade - double wishbone front and multi-link rear - which we have good reference for and it just does a great job. Plotting out the roll centers and roll axis motion is a textbook example of how to design a car for good handling behavior. The 5th link of the multi-link rear is a neat little thing between the lower control arm and upright to triangulate with the toe link and prevent axial motion. Makes it work almost exactly like a double wishbone design, but with lighter components and tighter packaging...cool stuff. Springs and dampers in the 458SA are pretty dang stiff and with a similar balance to the LaFerrari: slight front stiffness bias for steady, predictable, mid-corner understeer which can easily be defeated using power. We've included adjustment range here to take it down to standard 458 Italia stiffness or right up to Challenge-spec GT stiffness if you want.
The real 458 Specialé (not Aperta) turned a 1:23.5 at Fiorano. Ours is right in that ballpark on Corsa tires if you can restrain yourself from drifting through the corners too much. You can sorta kinda mimic Ferrari's side slip control to some very fun results too. Turn stability control off and take traction control up to 25-30% slip allowed. Does a great job of hanging the rear end out with throttle planted and still leaves good control over the car through the steering wheel. Massively fun car.
This might be my favorite car in game. I totally expected the 1035hp monster to be more difficult than it is fun, but it handles that power wonderfully. The base is 90% the same as the LaFerrari, so that car also received a few fixes/updates in the process of building up this one. The differences between the two largely boil down to just a few performance enhancements in the engine, drivetrain and aerodynamics.
The LaFerrari 6.3L V12 is tweaked and tuned to bring power up from 790hp to 850hp at a whopping 9200rpm. It is a very smooth torque curve with 90% of peak available at 4000rpm, a smooth rise up to 750Nm@6500rpm, and then a smooth drop off for increasing power right up to the fuel cut. Immediate and smooth throttle response in a way that even the best turbo engine can’t achieve. Augmenting the V12 is an e-motor adding 142kW on the rear axle. Ferrari haven't mentioned specifics about the system but do hint that it changes a lot of the road car parts out for their F1 systems. We've run with that idea and increased the charging rate by 60% over the road car, to levels in line with what works on the LM P1H cars, and send it to the same 2.3kW-h (8.3MJ) battery as in the LaFerrari.
Gear ratios are shortened in the FXX-K to hit the rev limit in 7th at 350km/h instead of 405 of the LaFerrari. Not that there is ever a bad gear to be in with all that power on hand, but it does feel great on track having the gearing matched so closely to the aero-limit. The differential uses our blend of Geared+Clutch+Viscous effects to emulate Ferrari's e-diff, just as in the 458SA and LaFerrari.
For fun, I've added in some engine maps to the Lean/Normal/Rich function so you can run it on different power levels like the Aston Vulcan. The lean one holds it at 600hp, which is surprisingly easy to manage, and won't activate the e-motor assist so you get faster re-charging. Rich puts everything to max for 1035hp total at peak and 'normal' is halfway between for about 720hp from the V12 and 71kW from the e-motor.
Extra wings and aero parts are added front and rear on the FXX-K, with the claimed gains being about 40% more downforce over the LaFerrari for as much as 520kg @ 200km/h. That is A LOT of downforce - greater than GT3 levels - and refers to the highest downforce mode of all the active flaps when at maximum braking effort. The official claims also note a number of 675kg downforce at maximum speed, which means more than 50% of the maximum downforce is removed when the active aero elements are in their low-drag positions. Our active aero model copies this by looking at brake pedal force, speed, and cornering effort to blend between those downforce targets with the bulk of the maximum downforce load going to the rear - roughly a 10% rearward shift in aero balance for stability when it detects you need it.
Suspension tuning proved to be very simple. We had accurate stiffness values for the springs and anti-roll bars of LaFerrari and known weight reduction for the FXX-K. FXX-K has a quoted 'dry' weight of 1165kg but has been tested at 1495kg 'with fluids'...that's a lot of ‘fluid’. Still, it's a good 100kg less than the LaFerrari, and the road car being racecar-stiff to start with meant that its springs work well here. Damper valving from the road car units gives nice control too. All it needed was some extra front anti-roll bar to handle the increase in cornering load from slick tires - 300% stiffer, effectively changing from a 27.5x2.5mm bar to 35.0x4.0mm. Either way, it relies very little on the ARBs compared to the corner springs, and this appears to be a design philosophy across all Ferraris for some time now: anti-roll bar as a fine-tuning device only.
It's real fast. They've lapped Fiorano in the real thing at 1:14 and I've done a couple laps in ours at 1:13. Close enough for rock and roll considering we don't know the exact slick rubber compound they were using. Comfortably in the 6:20s at the Ring (Jussi is even dipping below into the 6:teens).
Jussi’s default setup notes:
Over 300 kg of "fluid"... I think some of those fluids might be the battery bank, since I doubt they've managed to fit in 4-5 full beer kegs anywhere in the car... =)
The FXX-K is indeed a really dang fast car, and the development on it helped a few other Ferraris too via shared components. If anything the car was "too good" as Casey delivered it, his setup essentially straight up going in as the Stable setup and I had to adjust it a decent bit before it started getting towards "loose" territory for that one, which sounds right for a 1000+ hp car they're selling to amateurs instead of proper racing drivers. The P1 GTR ain't much slower (due to much higher DF it can be faster too), but it certainly isn't as friendly as this.
Almost seems a bit too fast really, there's like nothing bad about how the car performs (you might drive it and say "braking distances", but considering it'll probably be approaching any given corner at least 50, maybe 80 km/h faster than a GT3 or GTE car, that's not really true), after my first lap around Nords to verify that, yes, it does run out of boost around half a lap in, I did a 6:15 from almost a standing start. Compared to this the Vulcan , Zonda Revolucion and P1 GTR are ferocious beasts, this is a cheetah that behaves like an adorable kitten.
Ferrari F355 Challenge
Very happy with how this turned out! You typically read about how the F355 was beautiful, very fast, even more expensive, but pretty dang difficult to drive at the limit. Perhaps the road models hit that last point, but the Challenge kit certainly fixes any handling issues and makes for a wonderful gentleman's racer. FerrariChat, again, proved immensely useful as some smart people with experience racing and building the F355CH were very open with sharing technical details about the car.
Any F355 could be converted to Challenge with a $30k kit which included the usual safety upgrades required for racing: better brakes, race wheels, suspension upgrades, and a rear wing. Perhaps the most important change was swapping out brakes from the F40 (which, in turn, came from Group C racing) and the wider, slick race tires measuring 245mm at the front and a beefy 305mm at the rear. We have also included a 'Street' tire option in addition to the race slick and rain tires. The Challenge was still a street car at its core, and some have converted their F355s to Challenge spec for street use, so it's a fun option to have.
The engine and gearbox were largely unchanged from the road car. You get a 3.5L flat-crank V8 producing 375hp @ 8250rpm and a very wide power band with the 365Nm torque peak being more of a plateau between 4500-7500rpm. Dyno tests show very little power drop off right up to fuel cut at 9000rpm. Power runs through a 6-speed H-pattern gearbox (later cars could run the F1 sequential) and the usual clutch & ramp limited-slip differential. The Challenge has some big, sticky slick tires at the rear which make differential tuning a powerful setup tool in controlling the turn-in under/oversteer balance. Gearing is evenly-spaced and runs out right around the 300km/h top speed; perfect for track use.
The F355 went through an intensive wind tunnel program and the claim is that it produces 220lb downforce at 183mph thanks to the flat floor and various air management tricks. The Challenge kit then adds a rear wing which, according to those who know the car well, doesn't do a whole lot. Positioning it behind a vertical rear window and above a slew of engine vents put the wing in some dirty up-wash flow...a recipe for wing stall. Still, it will have a small effect and the combination of its light downforce and drag can be useful as a fine-tuning tool, shifting the aero balance about 20% rearward for stability at the maximum setting.
Suspension design has been well studied by the folks at FerrariChat and we used dimensioned blueprints to clone the behavior of roll centers and everything into our model. The most notable aspects are how the roll axis shifts some load forward when cornering for a smooth, comfortable understeer as you approach the limit and also that the rear roll center is quite responsive to ride height changes. This makes ride height one of your primary tools for adjusting chassis balance: higher rear=more oversteer, lower rear=more understeer. Changes at the front have a similar-but-opposite effect and with smaller impact; the rear end is your prime dial in this car. Rear ride height, camber, and toe angle on this one have a stronger effect on handling than just about any other parts of the setup. The other notable thing about the F355CH suspension is just how crazy stiff it was. Teams were allowed to use two sets of springs best described as ‘Stiff’ (1800lb/in front, 700lb/in rear) and ‘Super Stiff’ (2200/900). That's about 8x stiffer than the road car springs - it even required beefing up the chassis mounts to handle the suspension loads as part of the kit - and in the range you might expect a modern GT3 car to run with their large aero loads and lower ride height. Can't argue with results, though, and the setup gives nice, easy, predictable handling when combined with the light anti-roll bars this car used.
I think this will make an excellent league racing car, which was the whole point of it after all. Very easy to get up to 95% of its performance potential and getting the last few tenths takes a lot of effort and skill but without it ever feeling like it's going to bite your head off. Fun car.
Jussi’s default setup notes:
The F355 Challenge is an interesting design from somewhat of a bygone era. The springs, especially at the front, are super duper stiff for what it is, we're talking about a slightly modified road car without any real aero running on springs rivaling some modern prototype racers. This type of design was seen in a few Group A/DTM cars in the late 80s/early 90s, so I guess that's where Ferrari got the idea back in the day. What it tends to lead to is a car where the front responds quickly, but isn't very progressive, the car has basically no need for ARBs, and generally has some understeer tendencies, which makes it a good fit for gentleman racers. Camber, ride height and tyre pressures do allow a decent control over the handling balance, and I do find it quite satisfying to drive, but with my engineering hat on I would still like to try it with softer fronts/stiffer rears for a more naturally neutral spring balance.
This was originally on the GTO tyre set but after some testing we found that with the quite low power output of the engine it was better to limit the car to the hard compound to make it a bit more lively and interesting to drive. There's still plenty of grip but the car doesn't just feel like it's on rails now and is more fun to drive, the hard compound works better with the understeer tendencies in reducing front end wear. And since it's essentially a modified road car we put in some road rubber as an option too (some people have made their Challenge cars road legal, it'd be interesting to see how harsh the ride feels like with those massive spring rates).
The engine is another iteration of the LaFerrari 6.3L V12, here in F140FG spec giving slightly less power (still a whopping 769bhp) and ever-so-slightly more torque at a lower 6,250rpm. Really there's very little in it between the two; both being buttery-smooth sledgehammers of power. The 7-speed dual clutch gearbox is also very similar to the LaFerrari (and F12berlinetta) but with ratios shortened by 6% for sharper acceleration. We've again approximated Ferrari's active e-diff with a combination of Salisbury, Torsen, and viscous effects as on the others. You can fiddle with this to tighten the handling with a stronger diff (and make power-oversteer breakaway sharper) but, while we're approximating drive modes/aids, I've found adjusting the traction control strength does the best job at something like the different modes you get via Ferrari's Manettino dial. The default settings are pretty conservative, but take it up to 20-25% slip allowed and the car will comfortably hang out the rear end through corners while you hold throttle to the floor. Fun stuff.
Suspension is in the same design family as the other modern Ferrari's with the only real difference being spring rates to suit the front-mid engine layout. They push that big V12 as far back as possible so, despite the engine being up front, weight distribution is a solid 54% rear with the driver's seating position pushing it back even a bit more; not all that different from the mid-engined models. The big thing differentiating F12tdf here is that they've given it more front tire and less rear tire, so it has no problems at all with turn-in or kicking the rear out on power.
Some very bold claims are made about the car's aerodynamics, quoting 230kg downforce at 200km/h for a lift:drag efficiency of 1.6; that's as high as your average GT3 car. The drag value this equates to makes perfect sense and puts top speed right around 340km/h as it should, but the downforce number kinda sends up a flag of being CFD numbers (these typically overestimate by about 20%) or picking an optimum, non-standard, very low ride height. They have done amazing things with the air management on F12tdf and have a very clean underbody plus diffuser...that said, I don't see it doing GT3+ levels of work at double the ride height. It still gives you some strong downforce with useful balance even at typical ride heights seen during a fast lap; impressive stuff for a car with no ugly wings or spoilers bolted on.
I'll admit I was a little worried this one would end up being too wild to be fun. Read/watch any road test and they make it sound like the F12tdf is this untamed beast that you must tiptoe around or you will Face the Consequences(tm). And, yeah, it does work out to more of an aggressive, oversteer balance than something like the LaFerrari, but it's still following that modern Ferrari architecture which is very nice and rewarding to control while being stupid fast around a lap. Jussi and I were guessing which class it would fit into before hitting the track; best guesses being top of Road C or barely into Road B just because it would be too oversteer-biased to be fast. Turns out it is a strong Road A contender. The real Fiorano lap time of 1:21 on Corsa tires totally jives, and putting Trofeos on it in game put it comfortably below the 1:20 mark. Crazy fast.
Jussi’s default setup notes:
This thing turned out quite different from how I envisioned it. I was looking forward to an overpowered GT car, mostly capable of ripping its tyres apart with the insane power, heading somewhere in the Road B rankings. What I got was a very capable and fast sports car, with good grip and balance, and even the power isn't that overwhelming when you have modern tyres capable of putting it down.
Casey and I were expecting it to land in either Road C or Road B initially, but after testing it out it drives so well (actually has decent DF too!) and is powerful enough that it ended up being very similar pace to the 720S, clearly in the Road A category.
And it really does drive well for a front-engined car. It's stiff but not overtly so, and the dampers are more traditional and not as bump biased as Macca usually makes their cars, which suits me better. The car has poise and purpose in its driving and despite the power output it's actually not that hard to handle on the throttle, at least on Trofeo R tyres. Corsas are a bit more of a challenge. The handling balance makes the car feel like it's lighter than it actually is.
You definitely can ruin your tyres handily even with the Trofeo Rs, but the car has enough balance (and our modeling of the Ferrari diff is subtle enough) that it's not terribly hard to avoid it if you can keep your right foot in check. With Corsas it does become more of an actual effort to keep the power under control.
And speaking of the Trofeo Rs, I've been reading up on my Sport Auto magazines and checking their tests. The development of these tyres today is insane. The Michelin Pilot Sport Cup 2 tyres started out as roughly P Zero Corsa equivalents, but these days they're right up there, perhaps even higher grip than the Trofeo R tyres, and the grip levels are such that even the drivers of Sport Auto, a magazine only loaning the car and unable to do that many runs of the track for their test, took the Porsche 991 GT2 RS around Nords in under 7 minutes. When Sport Auto tested the 918 in 2014 they were almost 20 seconds slower than Porsche's factory effort, and now they are going under 7 minutes with these things. Seeing these cars driven around Nords with these ludicrous tyres that were never used just a couple of years ago is further proof that our grip levels for these things were pretty much spot on, despite really good references and some arguments to the contrary. Modern tyres really are amazing things.
Really pleasantly surprised by this car, was expecting much more of a sledgehammer, something like a Corvette with a Vulcan engine, ended up with a seriously well balanced supercar.
Ferrari 512BB LM
This car never really got any respect for its performance in period, and that is largely down to how it used the regulations to race in a class where it never stood a chance. The 512BB LM did not meet production requirements to run in FIA Group 4, so instead it used a loophole in the regulations to enter races in the IMSA GTX (GT Experimental) class, putting it directly against a cavalcade of Gr.5 Porsches 935 Turbo. 512BB LM was a nice racecar, particularly for endurance events or in the rain, but was vastly outmatched by cars weighing 200kg less with 300hp more power. Winning its class and finishing 5th overall in the 1981 Le Mans 24h is quite a remarkable achievement considering the raw performance disadvantage it faced.
To give better competition in races less than 24hr long, we've placed it in the Gr.4 class alongside the BMW M1 Procar and Porsche 924 GTP. All three get performance in very different ways, but the overall balance is quite good and each one can shine at the right track with the right driver.
The heart of the car is a 4943cc F110A flat-12. They call it the Berlinetta Boxer, but really it is a 180° V12; Aaron found an article which claims the BB naming was actually a development codename in honor of Brigette Bardot! With mechanical fuel injection producing, in race tune, about 475hp @ 7250rpm and a healthy torque peak of 535Nm down at 5000rpm. It was enough extra power over the road model 512BBi that they had to redesign the gearbox internals for 1979 with straight-cut gears and everything strengthened for endurance.
Ironically, the flat-12’s design intent was to lower the center of gravity, but installation here required it to be placed above the gearbox. This pushed the whole unit upward 15-20cm, which is not at all what you want to do with a 250-odd kg lump of metal at the back of a car. This had a negative effect on the handling, making the car somewhat wayward and tough to predict. Most cars, including the reference car we scanned, appear to have addressed this by running narrow front tires - only 215mm tread width against 330mm rears - to keep the car in balance. It's a solution which appears to work quite well on our model too; the car loses some overall grip, perhaps, but the general balance is good and controllable. Do keep an eye on your tire temperatures with this one as the extra weight and narrow fronts mean it works the rubber at both ends more than the other Gr.4 cars. Hard slicks can often be the better choice here in a race as it will let you push harder for longer.
Our reference car had all the suspension links measured to copy into our model. The design there is all standard, double wishbone stuff with front roll center near the ground, rear RC about 8cm higher and similar motion up/down with chassis motion. Only noteworthy thing is that the steering geometry does follow the older design theory of large scrub radius with little mechanical trail; great for self-centering when catching slides but it does give a little 'delay' to the feel of mid-corner steering forces.
The real standout feature of 512BB LM is that bodywork. The angular shapes of the road car made for pretty poor top speed, and so it went to the Pininfarina wind tunnel for extensive redesign. The body was lengthened by 40cm, lines smoothed out and pulled down to the floor level, and a rear wing from the 312T2 F1 car added on for stability. Result of this work - aside from being, IMO, one of the most graceful GT car designs ever - were top speeds in the neighborhood of 195mph at Le Mans, a good 12-15mph up on the BMW M1 with similar power. 512BB LM may carry an extra 150kg, but it carries it up to a handy Vmax. Use that top speed to your advantage and it can compete well with the lighter-but-slower BMW M1 and the even-better-handling-but-even-slower Porsche 924 GTP.