PCars 2 : Get to know your ride (1 Viewer)

Taorminator

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Hi everyone!

Every Revolution Cup we drive a different car that you need to learn how to drive and setup. Sometimes you feel the car very quickly, sometimes you'll still be scratching your head at the end of the season wondering how these guys were driving so fast. The important thing is not how good you did but how much you learned.

That process takes time and without return of experience, it's easy to make the same mistakes leading us away from our goal which is ultimately to exploit the full potential of a racecar. I wanted to create a series where I'd share everything I learned from previous cars and reflect on their strengths and weaknesses.

With each episode, I hope to help fellow drivers to consciously adapt to a new combo based on similarities with a previous one. For example, you could use previous experience with a Radical to get up to speed in LMPrototype or from Classic Group A to modern TCR. This is not a setup guide (there is enough high quality content on that matter in Nighttiger's guide) but rather creating efficient ways to squeeze out the pace of the car starting from you, the guy behind the wheel.

See you in episode 1 : our latest combo, the Mercedes 190E DTM
 
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FuBii

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Would be good to tag all members & link 'Tigers setup guide
 

CatchAGlimpse

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You guys are in for a treat - @Taorminator has been making unreal setups for the past two seasons but this season in particular they have been spot on :cool:
 

Taorminator

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Episode 01 : Groupe A Mercedes 190E DTM

Chosen by the community to promote fun and close racing, it is undeniable that this car delivered just that. The first thing that you'll discover though is how challenging it is to keep on the road and even more difficult to drive it fast...

So first thing first, what are we looking at ?

unnamed.jpg


Class :
Group A
Category :
classic TC, very low DF car
Transmission :
manual (h-shifter) RWD
Engine :
front mounted 330 HP @ 8500 rpm
Weight :
980 kg adustable bias from 48 to 52% front
Assists :
ABS
Tyre compounds :
slick, wet

Initial impression :
Some cars are a love at first sight, this one is not (not because it is ugly you silly) and will take time to tame before actually enjoying driving it. The first thing you'll notice when approaching your first corner is the horrific sound of tyres locking and the wall in front coming at you very fast, it feels like it needs a mile to stop. The second thing you'll notice is the understeer mid corner and ultimately the struggle to put the power down. If you have not rage quit yet to yell at the admin for their poor car choice, you might notice the horrible lateral weight transfers that sends you spinning in changes of direction... If this wasn't enough you'll realize after 3 laps that the tyres are overheating... You're still here? Good!

wslr8.jpg


What we can learn from this is that we have a high inertia and low grip to power ratio classic car. This leads us to the next section...

Driving style :
You must be feeling the urge to go to the setup screen and fix this awfully broken car... Don't do that yet, the problem is still behind the wheel. The main concept for the rest of the episode will be "adapt to survive".

As mentionned earlier, we are driving a non-aero low grip to power ratio car with vintage brakes and tyres. Therefore there is a small area in the traction circle (g-force in all 4 directions) that we can exploit in all phases of a corner. A consequence of that is that you clearly can't ask this car to do 2 things at at the same time and you'll have to fight it's inertia...

circle_of_traction.jpg


Braking has to be done in as much a straight line as possible, way earlier than you're used to with modern cars and modulate when you feel/hear the tyres locking up. Turn in is usually ok but you might have to adapt depending on the road camber. Trail brake if you feel accurate enough and able to put the ABS to good use. Mid corner you need to use ALL of the available grip to turn so don't touch any pedal and find where the tyres give up with the wheel. Corner exit is actually the least difficult part, increase throttle progressively, the tyres allow quite a wide slip angle so it's generally ok and safe to slide a little as long as the tyres are not over their operating window of around 105°C.

Talking about it, you will have to adapt your driving style constantly to keep them in the optimal temp range. Your inputs that worked the previous lap might not the next one. So make sure to adjust based on feel for the lap after. You might not be able to be as aggressive on the throttle the first 3 laps as you would at the end, same for ABS you might wanna increase it incrementaly as tyre wear appears. Weight and thus fuel load has a huge impact on tyre temps so adapt to that as well. Overheated tyres at high fuel load might fall back in their optimum window at the end so it would be a shame not to push. Therefore, monitor your temperatures from time to time at least once a lap and don't approach that next corner as you were in quali if your tyres are already at 105°c. Nurse your tyres, they are your main focus here.

In high speed direction changes try to anticipate the violent lateral weight transfer by counter steering or lifting gently a little. FFB is your friend here but don't rely only on it, your anticipation as a driver to apply the correct input based on your knowledge of what's gonna happen a split second next is the difference between spinning or destroying your opponent in a left-right transition.

Of course choose your line and braking references and don't be afraid to adapt them according to the grip levels throughout the race.

You are still off pace? Let's have a look in the next section shall we?

Setting up the car for speed :
Good you made it here! This section is not meant to be definitive, true or science. It is my experience on what I found to squeeze pace out of the car and confidence in driving it at the limit. Disclaimer : a good setup is absolutely no use if the tyres work outside their operating temp window so make sure to get the previous parts of this episode right.

First you have to adapt (again) the car to the track and conditions. The basic things for a 30 min race was to fill 50l of fuel (safe side), radiator opening to reach max 115°C, brake ducts to reach max 600°C and tyres to reach 1.8bars hot pressure. An exeption to that was Texas because the banking loads worked the right tyres hard so I increased it to 1.85-1.9 bars hot on that side. I'd say that if you get this right you already have 90% of the pace that's available in the car, so congratulations!

Next I'll review the parameters that had a big influence on the pace/grip :

Wing : this car doesn't rely much on downforce so I left it at 1 (min) for max speed. Remember that the wing has a balancing effect at high speed so you might wanna add more if you don't have confidence in the rear in fast corners.

Ride height : beware this parameter is linked to your chassis stifness so be careful of bottoming out. For me it was pretty straightforward, I dropped the rear as low as I could (70mm) and balanced the front (60mm) to have zero rake at top speed for minimal drag. I left it there the whole season, I know rake is a powerful parameter for balance but I didn't want to compromise speed.

Camber : this one had a huge impact on grip actually. In Bathurst for example it was night and day between -2.0° and -3.0° in the forest section (high speed corners). I find the rule of thumb to be that when there are critical high speed corners, don't be shy to bump up the camber as long as you respect the 10°c spread rule. This season I went up to -3.2° at Texas. You can also balance high speed behaviour by altering the ratio between front and rear camber, for me it was generally 0.5° bias toward the front exept Bathurst where I had more camber at the rear than the front.

Gearing : other than having a long enough ratio to not hit limiter when in slipstream you have to set it up so you are at the best rpm at critical parts of the track. Example : when you hit the banking at Texas, in 6th you are at engine revs that give you 310hp but with a slightly longer ratio you hit it at revs in peak power band (330hp) in 5th, that's a huge advantage! Another benefit of a longer gearing ratio was to help put the power down without spinning wheel and conserving tyres. Do not underestimate that factor.

Differential : there wasn't a good rule here, many different LSD combinations felt great and awful. What I applied was mostly around 80 to 100Nm preload on a 50° power ramp and 25° coast ramp on most tracks. NB : engine brake was at 8. On twisty tracks I used something around 40Nm preload on 75° power ramp and 35° coast ramp. Again you could achieve a good diff setup with totally different values so don't take that as holy bread.

Chassis and dampers :
Now the techie part! You could improve the behaviour quite a lot by finding the good combination for a track. For this I used Jussi's Suspension Calculator. This subject could have it's own episode so more on that later. Depending on the track I found the behaviour was better with a chassis on the stiffer side with a roll frequency of 3.2 up to 4Hz. A bias of 33% towards the front worked best for me. Dampers could give you excellent curb behaviour, mitigating the sucking effect that we all fear. Values are track layout and chassis stiffness specific so you'll have to adjust them but the calculator makes it easy to explore the possibilities and not fall into handling killing values. I'd suggest we go more in depth in the next episode.

unnamed (1).jpg


ABS : this is one I totally overlooked until the end of the season! I started with the default setting and wasn't very confident with the braking. What worked best for me in quali was around 40-45% and up to 75% at the end of a race on worn out tyres.

ARBs : I didn't adjust them much other than to correct roll frequency and balance. Stiffening the front to 110Nm was a good way to improve front end responsiveness

Final thoughts :
The Mercedes 190E DTM suffered a lot from it's low grip and high inertia. It rewarded drivers when accurate and disciplined with their basic driving skills such as the traction circle. The car worked best when stiffly sprung and with quite a lot of camber. Dampers played a big role to achieve a predictable and forgiving behaviour. What drivers will remember for sure is the fun this car delivered driving it sideways and next to other mad men.

If you have your own tips on this car or would like a certain section to be discussed more in depth, feel free to do so by replying to the original post!

I hope you liked this first episode :)
 

FuBii

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A trick I picked up from my Formula Student days....
If setting up for a track with long straights & minimal corners, eg, the real Hockenheim..
Inflate those front tyres to bursting to minimise contact patch with the road, reducing rolling resistance, & decrease the rear pressures slightly to maximise contact patch on the rears to get the best traction as possible. You can take this further by fiddling with the toe in/ out settings front rear as well as the camber.
If memory serves, the maximum downforce you could get from the Merc was only 15kg (please correct me if wrong, I can't find the article I read this from) but it did force BMW to build a new wind-tunnel for their cars.
Your diff settings for this car were miles off from mine @Taorminator but then again, you used a much lower gear ratio than me throughout the season lol
 

Taorminator

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A trick I picked up from my Formula Student days....
If setting up for a track with long straights & minimal corners, eg, the real Hockenheim..
Inflate those front tyres to bursting to minimise contact patch with the road, reducing rolling resistance, & decrease the rear pressures slightly to maximise contact patch on the rears to get the best traction as possible. You can take this further by fiddling with the toe in/ out settings front rear as well as the camber.
If memory serves, the maximum downforce you could get from the Merc was only 15kg (please correct me if wrong, I can't find the article I read this from) but it did force BMW to build a new wind-tunnel for their cars.
Your diff settings for this car were miles off from mine @Taorminator but then again, you used a much lower gear ratio than me throughout the season lol
That's an excellent trick! I indeed did it at Hockenheim but both front and rear so I might have lost some traction because of that, good point! I remember my main setup goal for this track was to be able to eat these huge curbs like they weren't there and survive the overheat in the last sector. I didn't know you participated in Formula Student, that's awesome! :) I'd be glad to chat about it because I still struggle to find the correct alignement and almost everytime overlook it but I keep hearing that it is a critical in motorsport articles. So yeah I could use some teaching :)

About he LSD setting, it's really funny because 2 totally different settings will sometimes give similar result with small subtilities that suit the driver's style more. So yeah I'm not surprised to hear that :) What I usually do is to have the maximum power locking effect I can get away with but also when I want to be easy on one of the tyres. Usually lap time is the best judge so it's usually best to explore the range and see if more or less lock gives best result (define best results first, it could be uniform tyre temp, good handling according to driving style, shear lap time, ...). You can also get away with a much aggressive LSD setup that kills the tyres in quali

EDIT : about downforce, yeah I didn't see much effect of the wings and splitter but driving the BMW 320TCR now I should have used it to stabilize the balance in high speed corners. Would have been easier on the tyres which were most the time the limiting factor. But yeah top speed is greatly impacted
 
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