Is Group B 4wd Peugeot 205 T16 handling somehow broken on asphalt surfaces (Spain+Germany)?

[karik_FIN_134]

No matter what I try to change in setup I seem to very often get massive oversteer under braking+turning for corners in this car. I'm driving it with 900degree rotation so it can't be too sensitive steering either. Sometimes in corners/exits I also seem to lose rear grip very easily and spin.

This was my latest setup in Spain when I tried it in Time Trial on Comienzo de Bellriu stage

Peugeot 205 T16 Evo 2 (Spain)
- Alignment: Front: toe 0.00, camber -0.80 / Rear: toe 0.00, camber -1.50
- Brakes: 2,510.00Nm, bias 79%
- Differential: Front: driv 32%, brak 36%, 30.00 / Center: 18kgf-m, tq bias 50% / Rear: driv 32%, brak 24%, 30.00
- Gears: 0.350 (80kph) / 0.505 / 0.660 / 0.821 / 0.985 / FD 0.231 (top speed 225km/h or 139mph)
- Damping: Front: 4.00, 4.00, 0.10mps, 4.00 / Rear: 4.00, 4.00, 0.10mps, 4.00
- Springs: Front: rh -30.00mm, spr 178.58, arb 25.67 / Rear: rh -30.00mm, spr 129.71, arb 30.00

I've tried with lower/higher cambers (example -0.70 and -1.29 / -1.40 and -1.82) no change, brake bias at 55%, 63%, 71% and at max 87% no change. In my eyes this setup should not give much oversteer under braking(and neither on throttle) anymore but it does. I don't normally use toe-setting but maybe with this car it's needed? On gravel+snow handling seems to be better with my own setups.

Anyone have ideas how to get this car handle better on asphalt.

[micone]

ich habe das gleiche Problem, (Bug ♥♥♥♥!!)

[flatdarkmars]

I've driven this car on tarmac and it didn't seem bad to me, but I'd add rear toe-in. Usually I go with about half a degree if I feel a car is generally too oversteery. Without looking in-game I'm not sure how your damper/spring settings compare to the defaults, but I'd run the rear a little softer than the default settings.

On corner exits you really just have to mind the turbo lag. Keep the revs high to minimize its effect.

[AoD_lexandro]

The gearing seems off to me. Second and Third are too close together meaning excess revs in 3rd gear. That makes the rest of the range too short overall again causing excessive revs in higher gears. Then you are overcompensating for that with the final drive ratio.

Also on tarmac you really want more rear power bias, as it helps rotate the car more and give better front end grip from them no having to deliver as much power.

[karik_FIN_134]

Front spring rate is set on firmest possible and rear spring rate is about in the middle of the slider. Surely that difference of almost 50N/mm between front and rear spring rates should give me lot of rear grip and make front tires lose grip earlier and make that understeer happen.

I have too much oversteer under braking and sometimes also on throttle so I don't want to put torque bias towards rear. I almost want to try putting it more front bias, 55-60% of power to the front to see if car becomes more stable under braking and in corner exits.

Gearing is just set with quite equal gaps, 1st gear maxes at 80kph/50mph and every gear change pretty much adds 35kph/22mph more, so 2nd gear maxes at 115kph, 3rd maxes at 150kph. I don't touch final drive because it just makes all the gears shorter/longer so I would still need to tune individual gears to the lengths I want to have them(1st gear to 80kph, 5th gear to max at 225kph).

My question really is that why does this car oversteer under braking with that kind of setup because:

- diff braking locks are set front 36% and rear 24% yet still it gives me oversteer when normally in a 4wd car that kind of values gives massive understeer when on brakes and turning (trailbraking for corners).
- then anti roll-bars are set so that front arb is softer so that should make front lose grip earlier and rear arb is maxed to maintain grip longer(and/or to stabilize the rear).
- even setting brake bias to max front 87% doesn't make it lock front tires more easily and give me that understeer

Compared to Lancia Delta S4 my setup for asphalt isn't nowhere near like this and with that I don't get this kind of issues. Feels like I have worse handling issues in this Peugeot than with Stratos or Lancia 037 on asphalt.

[flatdarkmars]

Originally posted by AoD_lexandro:

Also on tarmac you really want more rear power bias, as it helps rotate the car more and give better front end grip from them no having to deliver as much power.

This advice is really playing with fire on a laggy 1980s turbo-charged car. You will rotate the car more all right, and unpredictably too.

Originally posted by karik_FIN_134:

- then anti roll-bars are set so that front arb is softer so that should make front lose grip earlier and rear arb is maxed to maintain grip longer(and/or to stabilize the rear).

Well THERE'S your problem (or at least a big part of it). You have this exactly backwards.

[karik_FIN_134]

Originally posted by karik_FIN_134:

- then anti roll-bars are set so that front arb is softer so that should make front lose grip earlier and rear arb is maxed to maintain grip longer(and/or to stabilize the rear).

Well THERE'S your problem (or at least a big part of it). You have this exactly backwards.

I had arb other way too and there's no change. I've had them f36 and r30, f47 and r25 and everything in between. Doesn't having stronger front arb increase front grip and softer rear arb than front allow rear to get more bodyroll(and possibly lose grip earlier)?

I'm trying to reduce oversteer when entering corners. Do you know reason why diff braking locks at F36% and R24% in this Peugeot doesn't give understeer on trailbraking(braking into corners) when in for example Gr A, 2000cc, R5 cars if u have them like this u get understeer (and if they are set opposite F24% and R 36% u get oversteer with hard braking).

[flatdarkmars]

Originally posted by karik_FIN_134:

Doesn't having stronger front arb increase front grip and softer rear arb than front allow rear to get more bodyroll(and possibly lose grip earlier)?

If the whole car is so soft that it is really rolling excessively, then yes, stiffening the ARBs will add grip by reducing weight transfer and preventing the outside tire from exceeding its maximum grip so easily. However this is rarely the case with motorsports cars, which tend to be on this stiff side from the beginning.

For all practical purposes then, it's the other way around. Stiffening the ARBs reduces compliance and allows that end of the car to lose grip more easily.

https://5xracing.com/p-24306-sway-bar-tuning.html
http://iracing.wikidot.com/components:anti-roll-bar-sway-bar

Have you tried this guy's setup?
https://www.youtube.com/watch?v=3SumqCWBc_U
He's fast and a well respected tuner.

To some extent it might just be a matter of adapting your driving style to the car. The 205 is like a go-kart with massive turbo lag, it's inherently a different experience than the modern cars, which tend to be quite docile in comparison.

[karik_FIN_134]

This Peugeot feels quite soft even with everything set very firm, maybe it's all the power just moving car around so much (lateral+longitudinal bodyroll)

I checked GTR technicals tunings for Germany and Spain. They seem quite a bit more oversteering than I have(diff driving and braking locks mainly) so I don't think they help with my issue with having too much oversteer in overall and if he's using lower rotatation like 540degrees or less then catching the slides is easier. He's using toe in settings so maybe it's needed with this car

his setups
Germany
Peugeot 205 T16 Evo 2
- Alignment: Front: toe 0.00, camber -1.70 / Rear: toe 0.20(in), camber -1.50
- Brakes: 2,510.00Nm, bias 63%
- Differential: Front: driv 36%, brak 36%, 90.00 / Center: 22kgf-m, tq bias 49%(front) / Rear: driv 72%, brak 72%, 90.00
- Gears: 0.336 / 0437 / 0.665 / 0.927 / 1.247 / FD 0.225
- Damping: Front: 3.00, 4.00, 0.12mps, 3.00 / Rear: 3.00, 4.00, 0.12mps, 3.00
- Springs: Front: rh -30.00mm, spr 165, arb 58 / Rear: rh -30.00mm, spr 172, arb 22

Spain
Peugeot 205 T16 Evo 2
- Alignment: Front: toe 0.40(in), camber -1.70 / Rear: toe 1.20(in), camber -1.50
- Brakes: 2,510.00Nm, bias 79%
- Differential: Front: driv 32%, brak 32%, 75.00 / Center: 18kgf-m, tq bias 45%(front) / Rear: driv 72%, brak 72%, 80.00
- Gears: 0.336 / 0490 / 0.694 / 0.947 / 1.247 / FD 0.225
- Damping: Front: 4.00, 5.00, 0.12mps, 3.00 / Rear: 4.00, 5.00, 0.12mps, 3.00
- Springs: Front: rh -30.00mm, spr 178, arb 66 / Rear: rh -30.00mm, spr 172, arb 22

[karik_FIN_134]

Okay I may have found the issue. Looks like differential braking locks work wrong way around and having them front 20% and rear 80% reduces oversteer under braking(on Lancia I have them like 36 and 36 and it's good). Also had to rely on some toe in for the front+rear.

It's can still be somtimes a bit too oversteery to my liking when I go very hard on the brakes for corners, sometimes rear just steps out too much and car spins like it has almost no rear grip (almost feels like rear tires lock up under braking or shift-lock happens, but idk). I think there could be some other things in the setup that perhaps work wrong way around(or are bugged) compared to other cars in Gr B 4wd class.

This is now my setup for Spain and Germany

Peugeot 205 T16 Evo 2
- Alignment: Front: toe 0.40(in), camber -0.80 / Rear: toe 1.00(in), camber -1.82
- Brakes: 2,510.00Nm, bias 79%
- Differential: Front: driv 36%, brak 20%, 37.50 / Center: 24kgf-m, tq bias 60%(front) / Rear: driv 32%, brak 80%, 30.00
- Gears: 0.350 (80kph) / 0.486 / 0.631 / 0.802 / 0.985 / FD 0.231 (top speed 225km/h or 139mph)
- Damping: Front: 5.00, 5.00, 0.08mps, 5.00 / Rear: 5.00, 5.00, 0.08mps, 5.00
- Springs: Front: rh -33.75mm, spr 178.58, arb 29.33 / Rear: rh -33.75mm, spr 136.87, arb 30.00

[AoD_lexandro]

Try lowering the brake pressure a bit.