During the beta testing phase, the beta team did a lot of experimenting with setups. For a while, we never knew when some major change would appear in the next build. The arrival of a new build was always met with eager anticipation - and a tad of trepidation.
There was a big flurry of activity after Dave Kaemmer added tire temperature response to the tire model. This brought the physics to the point where the cars handled amazingly realistically. This was the last major change in the physics; only relatively minor tweaks followed.
Following are some comments which I snipped from various emails exchanged during that period. Also included are some tips from a couple of folks who weren't on the beta team, but who should know what they are talking about!
Doug points out that most of the stuff is a given.
Start with the front springs: Make them stiff enough to hold up that end of the car.
Front bar is front spring value + 10 lbs.
Rear springs have to bear some resemblance to fronts (combination of weight distrib & wheelbase, but almost always front spring value + 10 or 15 lbs.)
Rear bar is to balance the handling (but basically 70% of value of F bar).
Shox should be same part of spectrum (i.e., stiff spr & bars = stiff shox; this is where I depart from Doug's advice; jounce affects corner-in & droop affects corner-out).
Bumper rubbers & ride hgt are determined by track conditions. Monster trucks @ M.C., Ring & Mosport; Low-rider @ Monza & W.G, etc.
Camber & T.P.s are result of temp readings.
Gears are moved around to maximize acc & minimize wheelspin.
Diff settings. I've never seen anybody seriously suggest anything other than 85 on the power side, and only Doug seems to be able to handle anything more than 45 on the coast side (the benefits, according to Sgt. Arnao, being faster turn-in).
Toe. Zero front toe on tracks where you want minimum rolling resist (Monza, Spa) Slight neg. toe where you want to "assist" turn in (M.C., Mosport, Ring) Slight pos. rear toe to "fine tune" rear bar (say you want soften rear bar for more grip; reducing rear toe will tend back toward oversteer).
All modified by adding slight neg camber [at front?] to enhance camber thrust and slight pos camber @ rear to keep contact patch flat under acceleration.
This is based on information we gleaned early in the beta program. These numbers may or may not be correct in the final build.
I've been doing a lot of testing at the 'Ring, and I'm finding that different cars need different ride heights. The Ferrari I can run the lowest (3.00 / 3.50) the Lotus next (3.75 / 4.25) then the Brabham (4.25 / 4.75)......so far I' ve only tested these three.
If I drop the Lotus down just .25 inches, it starts to get squirrely contacting the bump stops (haven't played with shortening them yet).
Springs are medium stiffness around 80-90 lbs. Interesting.....
Steve: 85/30 + 3 clutches "extreme"? How so? The Ferrari has no traction-busting low-end torque (like the Lotus or Brabham), and Spa has only two traction-busting low-speed turns (La Source, for which you have to feather the throttle anyway, and Haut de la Cote). The 3 clutches works like crazy in fast bends like Burnenville, Stavelot, Cottage, Quarry, and Blanchimont. It means you can even go voll-gaz exiting Malmedy. So what's the problem????
Doug: It Just makes the car push more than it has to here at Spa. Then you have to wait....wait....and you loose almost imperceptable, but valuable, momentum.
Steve: You want extreme? Try Doug's x/45 setups. aheem...that would be x/60 at Spa :) If it's true they "point" faster, it would probably help with the entry to Malmedy and the middle of Masta (there never seems to be enough time to reverse the "point" in the latter; I'm always running out of road...maybe because my setups are systemically too damn soft). The Eagle and Ferrari are "slow" to change direction as it is at the kink. Adding a fully bound-up decell side diff exasperates the problem......wait, wait. Grin
I'm having serious problems wth Kyalami. No effing grip at all. I don't think its the setups.
Did you rear Guru Doug's pontifications on snaking? He was saying you need a scosh of posi static camber, so that when the rear end squats under power, the tires go perpendicular, flattening the contact patch. I know how Big Daddy Don Garlits would do it: he'd move the rear tires closer together.
Since we don't have that option, other pages from the drag racer's book would include:
I dunno; I'm making this up. But you might get lucky trying some of this stuff.
IMO two aspects should be included in the discussion about camber:
As to the first, on slow tracks I'd perhaps use less negative camber, because at low speeds in low gears, with many acceleration and deceleration activities, it is desirable to put the biggest rubber patch down during acceleration (at the rear) or braking (at the front). So, I'd adjust camber according to Doug's guideline, more or less.
On fast tracks, however, it may be more important to have optimum grip in fast corners, i.e. an optimal contact patch at low speeds and full squat may not be that important. At Spa, for example, I use more negative camber at the rear than at the Ring with its many mid-range or low speed corners.
As for camber at the front, I have found that too little negative camber (e.g. 0 deg) may increase the snaking effect. I don't have a theory for this, but -75 seems to work good on both slow and fast tracks at the front, while at the rear, I use either -25 or -50.
As to item two, the driving style, I'd like to mention Curva Grande at Monza. Personally, I find that the grip problem there is at the front rather than at the rear. The corner can't be taken at max speed, because the car understeers first (the corner is too narrow for the car to take it at max speed). Hence, optimum speed there requires that the rear end is used to help the steering, by hanging the tail out in a controlled manner. For this purpose, optimum grip at the rear may not be the optimal solution.
Personally, I did actually reduce the rear end grip at my Monza setup to make it easier to hang the tail out in a controlled manner, without snap-back etc. For Monza it may be worth the while to try and use less negative camber despite the fact that it is a high speed track.
In my experience (going back to ICR2), any tire temp above 120 deg. is okay (for road racing; 180 is about the lower limit for ovals).
Papy hasn't told us about operating ranges for these old tires, so I don't know for sure, but I would think 140-180 would be about optimum, and over 200 should be getting greasy. I've spiked them at 450, which seems to be as high as the GPL "pyrometer" goes.
Those old tires were different. I once owned one of the three Corvettes that Briggs Cunningham raced at Le Mans in 1960. It still had the original Firestones (with about half the original tread). They not only wore like iron, they handled as if they were ferrous, too. I drove the beast in open practice at the old Thompson (CT) track, and after much slewing around (the car was an oinker...to be charitable), they finally developed some stiction. But not much.
Alison: The optimum would be having the car just reach redline in top gear.
Steve: I do it slightly differently. First I do what you do, but then I try a gear or two on either side and see which one pulls the highest Vmax (top speed). In the 6-9 build, I could get a mph or two more than your top. This matters the most at a track like Spa, where if you can carry a mph or two all the way down the Masta straight, you can save a second or two a lap. (You want to make sure, however, that you're not losing any speed pulling up the hill towards Blanchimont.)
Alison: The idea is to put the power where you need it most, which is at high speed. Both Smith and Van Valkenburgh agree with this.
Steve: Not this Smith. Think of the Ring. It's basically Monte Carlo with an added two-mile straight; so you want a close-ratio 3-speed for the first 18 km, and an incredibly long G5 for the straight; then fit G4 somewhere in the middle.
At Monza, you set up 1st gear for the start only; 2nd gear where wheelspin won't mess you up getting the power down coming off the Parabolica, a 3rd gear long enough that you don't incur two extra shifts between the Lesmos (up & down), and a 4th gear that will either just see you through the Seraglio, or - if you like taking the Curva Grande in 4th - through the Vialone.
Don't tell me about gears. It's the one area where I'm bulletproof. (I was the only guy with a 5-speed Speedster in 1968. Yes, it was illegal, but we won a lot of trophies. Unfortunately, I was the wrench, not the shoe).
I think we know enough about the engines as is.....the true race engines are all a bit peaky and the Repco isn't :-).
If you look at the max RPM you can extrapolate from there......a 10,500 rpm engine is gonna make max torque around 8500 rpm and a 9000 rpm engine is gonna come in around 7500. The Repco is in about 5500.
I'm allways talking about the loaded side of the car. Usually the left side in a road race car. I tend to ignore the right side for reasons of lack of turns loading that side. (except Monza and Limerock....special road race cases). The right just gets what ever the left gets, essentially....and inside means towards the center of the car.
On the subject of camber thrust : A tire is like an eraser on the end of a pencil. If you stand a pencil straight upright (zero camber) on a table, push down on it then pull it across the surface, the eraser will deform away from the direction of travel and sort of "chatter" with out much resistence (grip). If you then try it tilting the pencil a few degrees away from the the direction of travel (negative camber), and push again....this time the eraser deforms starting at the inner edge and forces the flat top down square to the table and provides noticably more resistence. The inside edge is under more pressure for this higher grip condition to exist and this causes more friction and heat at the inner edge.
This essentially is camber thrust and why a car handles better with it.
This is also why on a real race car we like to see the tires hotter on the inner edges than the outer. It tells us our tires are working properly. If GPL models this correctly, then I am very impressed once again....:)
Alison: I think it is probably safe to assume that the car will roll a bit more as it gets more sideways.
Steve: Not true. The maximum cornering thrust (grip) for bias-ply tires is about 8-12 deg. of slip (for modern racing radials, about 4-8 deg.), beyond which it drops off, so that at, say, 45 deg., you'd actually have_less_roll.
Besides which, the suspension geometry starts working against you, too. That is, at 180 deg., the formerly "lateral" grip is now actually producing nose-up pitch, not roll.
If the original T2 driver routine doesn't work, try to install your T2 as a custom four button, three axis controller or as a four-button, two-axis controller, depending on how it has been wired or depending on whether you use the 2/3 axis adapter TM delivers with some of their products.
You might also try to install it as two two-button controllers, using the buttons on the wheel for the wheel, and using the buttons on the right hand side (or the gear shifter) for calibrating the pedals. The pedals would then either be a one-axis or a two-axis controller, depending on how you wired them and on whether you use the abforementioned adapter.
If that doesn't help, I'd look at the electrical values the controller produces. ICR2 is very good for that. If it displays values of let's say 3000, then there's something electrically wrong with your controller, i.e. they produce too high voltages. If that's the case, check the following: Are you sure you: - used the right pots with the correct electrical specifications
There may be other possible errors I have not in this list, but this list is something to begin with, I'd say.
Rich: Setup really doesn't help too much here - I've found very little difference in my lap times based on setup, although it is important to have tight ratios since the vast majority of the circuit is done in the first two gears.
The big thing here is patience. Almost always, my fastest laps here don't "feel" fast at all, probably because since the damn thing is so tight any type of sliding really hurts you here.
Anyway, the old adage "slow down to go faster" definitely applies. I think you'll find being able to hurtle through the chicane will help your times tremendously.
Steve: Thanks for the advice. Tried it yesterday (2+ hours); didn't go any faster, but had a lot more fun. M.C. definitely requires a different mindset that, say, Monza (which is more like an oval; Louden, say) or Spa (where you can "give the car its head," like a horse).
Don't quite agree with you about setups, though. Tried Ferrari (for its short w.b., meagre low-end torque) with a very tall, very soft setup (derived, oddly, from Mike Laskey's very low, very stiff W.G. setup), with very stiff shocks, and found it a lot easier to drive than the BT24, which I'd chosen earlier for its small size and easy pointability (too much torque; never could find the right gearing; it should have had a 2-speed and a torque converter, like the Chaparral).