What do these things in the setup actually do?

[Ethan Bass]

A few weeks ago, I was racing with some guys in a RaceDepartment session, "WTCC 08 @ Anneau du Rhin - Sun July 11th 2010"

While chatting with some of the guys on TS while during practice, about setups. I was running in the BMW. After little chatting about the diff, they suggested locking it nice and tight, so the setup that I then used in the two races, they were, Lock : 40%, Coast : 100%, and Preload : 5.

After doing that with the diff, the BMW became very neutral on that track, the rear would stick alot more, and would only really swing out on badly worn tires, and if I remember correctly, this setup didn't manage it's rear's very well.

So what I'm wondering is, once I know the track, what will these settings listed below do to my car (or any car of any class) in terms of characteristics, and in what circumstances should I change them i.e., bumpy braking zones not letting me brake as late as other.

Lock, Coast and Preload settings

Fast Bump, Slow Bump settings

Fast Rebound, Slow Rebound settings

Caster settings

Thanks for any help people can give.


Ethan Bass

 

[Ivo Simons]

Can you take a look at this guide maybe. Most of your answers you can find there.

http://www.racedepartment.com/gtr-evolution/3511-racedepartment-setup-guide.html

 

[Ethan Bass]

I have been using that setup sheet for a few months now, and it does help, but unfortunatly, it doesn't go too in-depth.

Also, it says if a FWD is understeering on turn-entry, that you should - power. Or if if the same happens in a RWD, you should + power. Does this apply to when and how much throttle I should be using?

Then there is the fact that the guide never mentions "Lock and "Preload". I can't see why they wouldbe in the setup screen and either a) should never be touched, or b) nobody seems to know what they do to a setup.

What I was hoping was for someone who has exstensive knowledge of the main WTCC tracks to be able to tell me if changing thing like the "Lock" and "Preload" in the diff can help to solve an un-wanted characteristic in the car, and if maybe different values help different driving styles. I say the bit on the driving style becasue, no matter what WTCC car I'm in, I seem to destroy the tires after about 5 to 8 laps, so if I could do something to help me maintain my tyres better that would be awsome.


Ethan Bass.

 

[Bram Hengeveld]

WTCC tyres should not last longer than 25 minutes (race distance).

For a RWD, reducing the differential lock it will make your car less oversteery. Increasing it will oversteer more. But 100 coast i would never use. The lower the coast the harder your car brakes (though it gets unstable under breaking).

For a WTCC E90 BMW i mostly uses the default differential or something around 30/10/1.

 

[UMC 22]

Rather than using the setup sheet in that thread, try the downloadable PDF setup guide above it. Did a decent job of explaining most of what I wasn't sure about. There's also the Engineers Handbook which I found useful.

 

[Koray Can]

Then there is the fact that the guide never mentions "Lock and "Preload". I can't see why they wouldbe in the setup screen and either a) should never be touched, or b) nobody seems to know what they do to a setup.

The guide does mention lock & preload (page 6; differential).

The reality is there are whole books written on vehicle dynamics. Short setup guides really oversimplify this stuff. Most importantly,

The challenging part of racing set-up is that everything affects everything else - Race Car Vehicle Dynamics - Milliken & Milliken

You can follow the guide and get rid of the understeer and end up with a perfectly slow car. It's really about an education, and people who seem to know what they're doing have spent quite a bit of time on it.

 

[Yves Larose]

the lock is rather simple, take for exemple a drag car, they all have a fully lock differential cause when they accelerate off the line they want the power to be delievered equaly to each wheel, the down side with a full lock differential is that the car won't turn when applying throttle cause it pushes the front wheel forward even if they are turned. so for a road racing car you want a balance between turning and wheel spin, to much lock and the car will want to go straight when you apply some throttle and not enuff lock and the car will become very slow coming out of a corner. i always drive the BMW when racing the WTCC and on a bumpy track i normally use about 10 of lock and on a rather smooth track between 20 and 30 depending the type of the track, fast track or slow track.

as for the coast i usualy use between 30 to 50 cause i prefer to have more stability when braking hard, the down side is that the car gets harder to turn in and it tend to eat more the rear tyres.

as for the preload i almost always use 1 but on a really fast track a higher preload might be more in order.

but keep in mind that that alone won,t make a fast car or a slow car, a setup is a whole and everything affect something so when you change something you might need to change something else, the more you'll drive the car the more you,ll be able to identify its behavior and how to correct it so it will go where you want it to go. many says that driving the WTCC BMW is an art and one of the most diffecult car to drive so be patient with it and start slowly.

 

[Günthar Rowe]

I love driving the E90, but I hate how it is very very easily spun when the lightest tap to the rear end The same or worse to the back of the WTCC FWDs can often be pulled off with some quick steering and a heavy foot...

In the E90, I have used 30/30/1to3.. I like the higher coast on the rear to cause some stepout in the rear under heavier braking that I use as turn-in

 

[Ethan Bass]

Thanks for the posts guys, I've been religiously reading the RD pdf setup guide (only part that is confusing is the toe-in bit quote; "For the front wheels, the preferred setting is a slight amount of toe-out (negative setting), which helps turning in." I always thought toe-in was negative and toe-out, was positive ), and have been using it in the past few RD events. It definitely helps (unless the track is wet, can't drive quickly in the wet in this game, yet), so all I need to do now is, 1) pick A car for each class/year, i.e. Alfa 156 for WTCC O7, (why nobody use it in O8 :frown then 2) run around EVERY track to learn it's flow.

Thanks for the help, and sooner or later, you'l see my tail-lights dissapear into the distance. :tongue:


Ethan Bass