Formula-Retro drivability

What do you guys think about this?

 

Last night I drove the Lotus, Mclaren and Brabham in Brands Hatch. It actually went really well and was lots of fun. Treating the Throttle pedal and Brake pedal with lots of love did the trick for me

 

1. Brake sensitivity to 50? I run it at 90... seems fine to me. Wouldnt you lose a lot of braking performance if you set it to 50?

2. What do you mean you "restrict your turn in on brakes"?

3. I feel like in the vid, he's got the weight loaded forward and turning and the car turns until it exceeds the grip of the tires, then it goes to where momentum is taking the car. That makes sense. What is odd is that I do feel like the back end should break away at some point in that process. But I also know that I intentionally brake very hard while turning to get the car to rotate and there are definitely times the rear end has come around on me (Acque Minerali I'm looking at you!), but thats with a very loose coast side diff setting. Even with a more typical coast diff setting I dont think the car should snap back to straight, seems like it should snap around and spin.

 

I am not that sure, without looking at telemetry (is there any for AMS2?) whether any of these cars generate significant enough overbody aero load to make high speed pitch sensitivity as much of an an issue as it is in more heavily aero focused cars. Whilst I've tended to maintain a healthy rake, the medium speed aero load is so low that the suspension setup is far more crucial with management of yaw on power over crests.

Management of the cars performance over crests needs to be managed really by working the available travel, allied to spring strength and good slow damper setup. In AMS2 the Lotus 72E default setup had 11mm bump stops all round which limits the available suspension travel.

In terms of realism and accuracy, IRL the 72 uses torsion bars with a custom linkage, which gave the suspension rising rate characteristics, a design created to prevent bottoming on heavy tanks. The dampers used on the car, according to the suspension design docs (Lotus part no. 72-2031), fully extend at 13.20 inches with a compressed length of 9.25 inches, leaving 3.95 inches of throw (almost 10cm). Digging up a setup sheet here it looks like no bump rubbers were used on that particular test, but this was for a modern historic event on more modern tyres. I've really no idea if any of this accuracy is reproduced in AMS2.

Personally I have found that I have softened springs and reduced bump stops in all of my work with the M23 and 72E, the defaults seem far stiffer than a beginner in the cars would want. It's possible as one grows in experience then maybe stiffening up a little more will be the case, but I'd say I would need 15-20 hours of seat time before feeling like I am comfortable there.

The other big problem can be the way power is delivered by the Cosworth DFV. As we've seen in many other sims (predominantly in the Lotus 49) the power delivery around 4500-5000 RPM is like a grenade and if you're hopping over a crest at that point you're going to spin things up.

As mentioned in a previous post, on some tracks it will be very rare to find full throttle too often.

Seems prudent to me that more travel and stronger springs would be beneficial yes, followed by careful slow damper setup. Higher and stiffer, though mileage may vary with ARB stiffness.

Note of course also that these were the very cars that had the Nordschleife removed from the F1 calendar due to the inherent dangers of driving them there.

Good luck out there.

(Sorry for the long and boring post).

 

I agree, but is that because of weight balance or aero? Hard to tell, the other question is whether the aero load leads to full compression or not. Which is why I'd like to see telemetry.

Yep, I've only tested really at Kyalami so far. I am not sure I will run these cars on any non-historic tracks.

The chicane at Kyalami has been fine for me. I should add that really I have found the car far more compliant in general being softer than the default setup offers. I think personal driving style comes into this too.

The very idea sends shivers down the spine

 

The very idea [of driving these cars at Nords]....

 

So that leads me to my next big question... what tracks are you guys liking with these? So far I feel like an "AMS 2 season" for Formula Retro would look something like...

1. Brands Hatch
2. Interlagos (crazy version)
3. Kyalami 76
4. Kansai GP
5. Imola 72
6. Ibarra (I just love this track, it definitely feels old school and seems to have the right atmosphere and doesn't get enough love.)
7. Spielberg historic
8. Nordschleife (I would be super excited to have a historic version with the Sudkehre!)
9. Hockenheim historic (when available)
10. Silverstone historic (Is there going to be a historic version of that?)

I ask because it'd be nice to get an idea what tracks I can optimize for and stay more or less period correct. I was surprised to see so many lap times at Bathurst for these on the TT boards... and none at Kansai. Suzuka has been mostly unchanged for 50 years... it definitely fits the era.

 

Yep, perfectly do-able. I've driven the Lotus 49 there in a sim so the 72 should be more stable than that.

I was just using a little hyperbole, apologies.

 

Confirm, it wasn't easy in real life and it shouldn't be easy in AMS. But having (the feeling of) aquaplaning on a light damp track with rain tires is a little bit too much.
I was running at Estoril and I let the car rolling on the back straight, it was wet, and suddenly the car turned around and I hit the barriers. No chance to avoid. Cornering, is difficult but controlable, braking the same, but accelerating on a straight, and it doesn't matter if full throttle or not, the back of the car gets round without any chance of avoiding. I tried different LSD settings because I thought it's because one side looses grip and the otherside still have and I could fix this issue with higher LSD. But it didn't help. Doing the same in lowering LSD, not really a difference.
I really can't compare this rain behauvior with any other car. I'm driving much in rain because I always use random weather and the chance of rain is about 90% (it seems that Reiza loves raining otherwise they programmed another random weather generator...).
Sure, the rain tires weren't the best that time, but they should have a positive effect compared to unprofiled tires under damp, wet or flooded conditions.

 

Ah yes. Well, tbh I am not sure I am having as much of a problem with the way the car is over crests as you seem to be (though I note from the Kylami TT board your pace isn't struggling!). Next time I head out on Osterreichring or Interlagos I will think more about it whether it is an overall issue with tyre load sensitivity and maybe form an opinion on it.

 

Same to me, maybe on thursday next time for testing...