On South City, maybe except S01 and SO2, RB4 has an advantage:

in the slow section, you don't need much efforts to block your opponents if you are quick enough. Just keep to your racing line. At the exit of the slow part, you just run away from them. FXO can't accelerate in a slow turn, either XRT (hard to keep it under control). Then, if you were quick enough, you've made a gap that they can't make up at the straights.

Quote from Ball Bearing Turbo :

When has anyone shot at you for mentioning flaws in turbocharger modelling?

I started a thread on it ages ago and it went quite well. (search for a thread called "boost modelling questions")

And I really seriously doubt that "they've struggled this long" rubbish. It's simply not at the top of the priority list, and hasn't been to our knowledge for ages. I'd be dissappointed if it wasn't addressed before S2 final, but who knows. Scawen has directly said that he knows the boost modeling has issues, so it's not like he doesn't know - he just has chosen to deal with other things.

Yes, I DID get shot down quite a lot for mentioning about turbo engine behavior in LFS IN THE PAST, not in this thread. And some guys here developed a knack for picking on me for this, but they were people who obviously didn't know much and had much experience with RL turbo cars. Anyway, enough of the past and on to the present topic...

Don't get me wrong, I respect the devs (believe it or not) and I'm sure they could get the turbo boost and powerbands working properly if they spent a reasonable amount of time on the physics modeling, implementation and testing it. If this is just something trivial like say "want more bling in the graphics" or "want fancier user inteface" I wouldn't even bother.

But LFS is a SIMULATOR and physics make the simulator. The current problems such as lack of antidive/squat and dynamic toe (lack of 3d suspension geometry) aren't so terrible problem yet since the 2D suspensions still manage to behave as 2D suspensions are supposed to behave. But this long neglected turbo modeling problem IS an obvious physics flaw that stares one in the face whenever one drives a turbo car in LFS.

And no one in their right mind can deny that it's seriously affecting racing in LFS, especially whenever TBOs are concerned. I applaud the devs for adding a ballast and air restrictor system to help balance things out, but it's very much a band aid solution for now and still completely neglects the underlying physics problem. Ballast and air intake restriction are good for fine tuning performance equivalence but CAN NOT be used to eliminate fundamental physics flaws. And to be absolutely blunt the adjustment range for intake restriction is just ridiculous. Why on earth would anyone want to drive a 103hp RB4/XRT? Those thing don't even move! Even when one pushes the throttle past the firewall!

Oh, let's see, we've got 80kph...86....91...95...98...100kph!!!!!

Great fun if you're a retired landspeed record breaker.

Well I guess the air intake restriction was meant more to the GTR class, it's a bandage but keeping in mind that the next incompatible patch might be several months away, it's worth it. But there should definitely be a fix for the turbo model, I hope it's on the list to do for patch Y.

Quote from Jamexing :

FYI, auto diff locks are known as detroit lockers. Their default operating mode is as a locked diff. When one wheel is forced to turn faster on a sticky surface like tarmac, the faster outside wheel is allowed to disengage and freewheel whilst all power is sent to the inside wheel. But if one applies torque to the detroit locker again (e.g. flooring the throttle) it'll return to its normal locked diff mode of operation after about 15 degrees of wheelslip.

Detroit lockers are somewhat strange to those not used to them as they change the cars behavior from super tight and stable to absolutely loose whilst cornering. Turn in will feel tight, but as the vehicle starts to turn and the diff unlocks, there's a relatively sudden increase in yaw rate. But if one gets used to them, they do in a sense provide the ultimate performance as they have the traction of a locked diff without the mid corner speed penalties.
...

Cheers, I've always wondered how the detriot locker worked... only ever used ARB air lockers.