Car physics and real life car setup - do LFS fast setups use unnatural exploits?

Hi car setup people :0) I've been trying to figure out the setups used by the fastest hotlappers in Live For Speed. It seems to me that their setups are "unnatural" in that they wouldn't work in real life... it reminds me of the 48% front brake balances in GPL setups - they're exploiting the extremes of the physics engine. But I need help in understanding what's happening! Here's the low-down: The LFS GTi is a FWD hatch, 920 kg, 110 bhp, with a 59% front static weight distribution. The hotlapper setups use typical values close to these: front spring: 60 kN/m rear spring: 47 kN/m front ARB: 70 kN/m rear ARB: zero limited slip diff is set to "10"... ie max locking, minimum slip. Now, with this setup this front wheel drive car will *oversteer* when power is applied exiting a corner. The front ARB is so stiff that the inside front wheel is lifted off the ground when cornering and when exiting the corner. The diff is fully locked, so the outside front can put down the power and the lifted inside front doesn't spin the power away. So my question is... is this natural behaviour? Or is this an exploit where hotlappers are gaining an advantage by brutalising the car or tyres? Would this technique work on a real life race car? Only time I've ever seen a stiff front rollbar cause a car to oversteer. :0) Cheers all Jim

I did a search on RSC forums and Scawen says there's no load sensitivity in LFS yet: "At the current moment in time (9/10/02) the grip-load characteristic is not modelled correctly. At the moment, doubling the load does result in double the available grip (the peak of the friction curve)." My best guess is that the whack hotlap setups are taking advantage of this by super-loading the offside front, which currently maximises traction. Once load sensitivity is modelled I guess this technique will cause the offside front to "wash out" and we'll get understeer. Or something. :0) "Jim Seamus" <[email hidden]> wrote in message news:xzBD9.517$[email hidden]... > Hi car setup people :0) > > I've been trying to figure out the setups used by the fastest hotlappersin

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> Live For Speed. It seems to me that their setups are "unnatural" in that > they wouldn't work in real life... it reminds me of the 48% front brake > balances in GPL setups - they're exploiting the extremes of the physics > engine. But I need help in understanding what's happening! Here's the > low-down: > > The LFS GTi is a FWD hatch, 920 kg, 110 bhp, with a 59% front static

weight

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> distribution. > > The hotlapper setups use typical values close to these: > > front spring: 60 kN/m > rear spring: 47 kN/m > > front ARB: 70 kN/m > rear ARB: zero > > limited slip diff is set to "10"... ie max locking, minimum slip. > > Now, with this setup this front wheel drive car will *oversteer* when

power > is applied exiting a corner. The front ARB is so stiff that the insidefront > wheel is lifted off the ground when cornering and when exiting the corner. > The diff is fully locked, so the outside front can put down the power and > the lifted inside front doesn't spin the power away. > > So my question is... is this natural behaviour? Or is this an exploitwhere > hotlappers are gaining an advantage by brutalising the car or tyres? Would > this technique work on a real life race car? > > Only time I've ever seen a stiff front rollbar cause a car to oversteer.:0) > > Cheers all > Jim > >

AFAIK in real life fwd racers use a huge rear bar and the inside rear comes off the ground in a hard corner, not the front. Seen many pictures of that. So I would say what they are doing is unrealistic. "Jim Seamus" <[email hidden]> wrote in message news:xzBD9.517$[email hidden]... > Hi car setup people :0) > > I've been trying to figure out the setups used by the fastesthotlappers in > Live For Speed. It seems to me that their setups are "unnatural" inthat > they wouldn't work in real life... it reminds me of the 48% frontbrake > balances in GPL setups - they're exploiting the extremes of thephysics > engine. But I need help in understanding what's happening! Here's the > low-down: > > The LFS GTi is a FWD hatch, 920 kg, 110 bhp, with a 59% front staticweight

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> distribution. > > The hotlapper setups use typical values close to these: > > front spring: 60 kN/m > rear spring: 47 kN/m > > front ARB: 70 kN/m > rear ARB: zero > > limited slip diff is set to "10"... ie max locking, minimum slip. > > Now, with this setup this front wheel drive car will *oversteer* when

power > is applied exiting a corner. The front ARB is so stiff that the insidefront > wheel is lifted off the ground when cornering and when exiting thecorner. > The diff is fully locked, so the outside front can put down the powerand > the lifted inside front doesn't spin the power away. > > So my question is... is this natural behaviour? Or is this an exploitwhere > hotlappers are gaining an advantage by brutalising the car or tyres?Would > this technique work on a real life race car? > > Only time I've ever seen a stiff front rollbar cause a car tooversteer. :0) > > Cheers all > Jim > >

Yep. In my memory, you ran more bar on the back than the front to get rid of the push, and my old Scirocco would always lift the inside rear if you were really on it. Great fun, chop the throttle to get the tail out, then step back into it for a nice drifting turn. Darned thing practically drove itself... ;-) SB "Haqsau" <[email hidden]> wrote in message news:arogep$k8v52$[email hidden]...

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> AFAIK in real life fwd racers use a huge rear bar and the inside rear > comes off the ground in a hard corner, not the front. Seen many > pictures of that. So I would say what they are doing is unrealistic. > > > "Jim Seamus" <[email hidden]> wrote in message > news:xzBD9.517$[email hidden]... > > Hi car setup people :0) > > > > I've been trying to figure out the setups used by the fastest > hotlappers in > > Live For Speed. It seems to me that their setups are "unnatural" in > that > > they wouldn't work in real life... it reminds me of the 48% front > brake > > balances in GPL setups - they're exploiting the extremes of the > physics > > engine. But I need help in understanding what's happening! Here's the > > low-down: > > > > The LFS GTi is a FWD hatch, 920 kg, 110 bhp, with a 59% front static > weight > > distribution. > > > > The hotlapper setups use typical values close to these: > > > > front spring: 60 kN/m > > rear spring: 47 kN/m > > > > front ARB: 70 kN/m > > rear ARB: zero > > > > limited slip diff is set to "10"... ie max locking, minimum slip. > > > > Now, with this setup this front wheel drive car will *oversteer* when > power > > is applied exiting a corner. The front ARB is so stiff that the inside > front > > wheel is lifted off the ground when cornering and when exiting the > corner. > > The diff is fully locked, so the outside front can put down the power > and > > the lifted inside front doesn't spin the power away. > > > > So my question is... is this natural behaviour? Or is this an exploit > where > > hotlappers are gaining an advantage by brutalising the car or tyres? > Would > > this technique work on a real life race car? > > > > Only time I've ever seen a stiff front rollbar cause a car to > oversteer. :0) > > > > Cheers all > > Jim > > > > >