Thank you! And no, not sliding - feels like it’s on rails for a bit, typically towards the corner. It’s great.
I always set the decel so that the car doesn’t resist turn in, no more nor less. It’s a mistake to try and use the decel to tune out a problem that might lie elsewhere.
From the OP the problem is just trying to keep the back of the car docile under deceleration and downshift. That’s going to be moving the brake bias rearward, raising the decel diff, stiffening the front end, softening the rear arb - in any number, combination or order.
With a heavy, front engined car, the biggest problem is likely to be dive under brakes, and the corresponding massive weight shift onto the front wheels, so stiffening up the front and moving the brake bias rearward will probably help the most. The object is to keep the rear settled and planted enough on entry so that the drivetrain shock of downshift doesn’t simply unhook the rears.
That’s tuning.
Driving techniques that can be used are to brake earlier or more progressively, keep a trailing throttle, exploit the oversteer to your advantage, or blip the throttle on downshift.
Or just go slower.
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Who said that he was slowing down? Can’t find at any point in the OP where he’s talking about the oversteer when slowing down. So, without knowing exactly when, where and what is causing this, suggesting tuning tips isn’t going to help, unless he wants to spend hours messing around with settings!!
Actually it would be better messing around with the settings because he might learn more! - Messing around with the settings is what all the best tuners do to understand what is happening.
Once knowing this information for tuning, you can adjust your car without having to spend too much time. Quite a few people who say they know how to tune actually don’t. I don’t know what everything does but you learn from it by reading it up and/or messing around with the settings.
Next time someone who says they can tune anything ask them to answer this, “If you decrease the front suspension in relation to the rear, what characteristics will this show?”
And if they say “more oversteer” they’re right, but they don’t actually know the actual characteristics, just a general idea.
Sorry for the little rant but it’s true! =P
Anyway, as soon as he answers what I posted we can all then help, No point tuning blind it solves nothing except more problems popping up!
=]
RR
Yeah, it’s not slowing down that’s the issue. Although, I do appreciate the feedback. Clearly, my engineering knowledge alone is not enough to master in-game tuning. All tips from fast(er) drivers is a good thing.
“Anyways … I still can’t fully counter corner entry snap-oversteer when a gear change is necessary.”
That’s from the OP. If you’re NOT slowing down then I think have found your problem!
We need to see your build, and maybe even knock one up and run it. On turn 2 at RA are you dropping one, or two gears, and are you trail braking at the same time? Are you using the inside kerb? That’s one of the greediest corners in the game with a mean camber and a lot of lateral loading. Do you have any other examples?
Oops…should clarify more. It’s more the mid corner from corner entry zone. The spot where you start speeding up again. Should have been more clear. I meant BEYOND the corner entry portion. I do slow down for corner entry, yes. lol. Not sure why I just typed “corner entry” (maybe it was a little late at night for me. ha ha).
O.K. open source tune time:
A 700 class: (high speed track build)
SLK55 (I’ll just do this one for now)
Upgrades:
All race handling/gearing upgrades added (exception: no clutch upgrade due to manual + clutch use) with power added after to balance it out.
Tune set-up:
Tires:
Front: 29 psi
Rear: 29 psi (I always start off at this number and increase if necessary. Not for this car)
Gearing:
Final Drive: 3.33 (other gears normal. Allows for 200.4 mph top speed)
Alignment:
Chamber front: -1.0
Chamber rear: -0.5
Toe front: 0.1
Toe rear: -0.2 (worked on this quite a bit. seems like the best setting)
Caster: 5.0
ARB’s:
Front: 29.22
Rear: 23.11 (been thinking of dropping these quite a bit but haven’t yet)
Springs:
Front: 700.2
Rear: 700.2
Ride height:
Front: 4.2"
Rear: 4.5" (standard setting for me. Rear is always .3" higher than Front, at least)
Damping:
Rebound front: 8.4
rear: 8.2 (tweaked these a bit)
Bump front: 6.3
rear: 6.1 (probably not soft enough)
Aero:
front: 75 (stock)
rear: 143 (slightly adjusted higher for added grip)
Brakes:
towards front: %55 (apparently still backwards? Actually 45% rear. Helps counter default understeer in most cars)
pressure: %100 (I don’t touch this due to using ABS)
Diff:
Accel: %74 (definitely thinking of decreasing quite a bit but not sure)
Decel: %74
O.K…that’s it…umm…be gentle…ha ha.
Just built this. Don’t know quite where to start. The pressures are too high and the rears overheat within the first couple of hundred meters. The back of the car is too stiff and will come around at the slightest provocation. The brake bias is turning it into a pendulum even under relatively light pressure. You definitely CANNOT trail brake at all. In fact the brakes have a hard time doing anything useful whatsoever. The setup you have is very close to default, but with dollops of added power. I will tune up one and post it up later. It may be that it will never be great, but I’ll do what I can.
Shared a tune as SLK 55. Could probably be polished a little but you’ll get the idea. Same build as yours but spring rates 550 front and rear, tyres 27.5, dampers 10 and 3.8, ride height 4.3, arbs 21.6 front and 19.4 rear, aero 80/170, brakes 48% and 149%, diff 25/15, gears final drive 4.06 and 2.14,1.62,1.26,1.02,0.84,0.71,0.62. You still need to respect the power on such a little car, but it flows quite a bit better and does everything pretty much how you would expect.
Whoa…just tried this. One thing is for sure…our driving styles are very different. This build feels very stiff, however, does a better job at eliminating the snap oversteer. Thanks for that. I’m still not sure what contributes to the better snap oversteer control. What do you think it is? That was my original question, of course.
Increased brake pressure is very helpful for this car, so that’s good.
The other issue I have is that this build is almost 2 full seconds slower around Road America West Alt. but definitely more “flow” as you say.
Another thing I’ve noticed:
The extreme difference between the 10 rebound and the 3.8 bump (I assumed both front/rear rebound are 10 and front/rear bump are 3.8). I’ve noticed a few people applying this to their open source tunes on here. This is something I’ve never practiced before. Seems to add to the overall control through corners.
Stiff? You lost me there. I have it as soft as it will get, 150 pounds less than your build. It will still ping the dampers slightly approaching the left hander before the carousel, but that tends to happen with a lot of cars. I forgot to add that I set camber to 2.6/2.4, and no Toe. The bump has been set to the bare minimum for the car.
Not sure why it would be slower either. Did you apply my tune or just add the settings to your build? You didn’t go into tyres, wheels or engine upgrades in your listing so I winged it. I have the accel diff set fairly low which might drop a little speed. I set it this way as another measure to help keep the rear end in check.
As for the snap oversteer, there isn’t any in my set-up. You can unhook the back of the car if you tramp on the accelerator, but that is perfectly normal with 500+ hp.
I explained your ‘snap oversteer’ problem in an earlier post. Your rear tyres had just about no grip the way you had built up the car. They heated up to over 35 degrees almost immediately, and because the back of the car was skittering around, they just kept getting hotter. With the front bias on the brakes, coming into a braking zone, or even brushing the brakes coming into turn 2 on RA, the back was simply letting go.
Softening the arbs front and rear and softening the springs makes the car more compliant and helps it take a better stance through corners. Lowering the tyre pressures helps them stay within an acceptable range. The hi-lo damping settings benefit most cars, although mid 3s would not be considered low in many circles.
Looking at RR’s and Mick’s feedback, I can definitely see areas of improvement. Thanks guys.
Just to confirm, I only lift the throttle and shift while cornering and nowhere else (if needed). So, yeah, I get that.
Mick, I just applied your settings to confirm. I’m trying to learn on my own. Your feedback makes sense when it comes to snap-oversteer (tires, brakes). I’ll add some more tweaks.
What I meant by stiff is REALLY grippy. I’m used to a little more loose build.
RR, yeah I’ve been playing with lower damping for a bit but I like Mick’s current locations (10, 3.8). My alignment has been tweaked as you said (been playing with that for awhile).
@RR - Dude, he posted his tune for the SLK. Build it up and run it. Your conclusions and subsequent advice might well differ from mine, and neither of us can account for his driving style, but there’s not much point in running with responses to an abstract questionnaire when you can get your hands on the problem car itself.
Case in point, you recommend raising the decel based on his responses. If you looked at the build you would see he already had it at 74%. The car was almost impossible to stop because excessive front brake bias was destabilising the rear end, yet based on his response you tell him he doesn’t need to adjust the brake bias. I could go on, but you get the picture.
Anyway that’s me out. I think I’ve given enough time to this one.
I would say biasing your spring rates a bit towards the front should help with the rear traction as your start to put the power down.
Right now you have them 50/50, try going to around 51.5/48.5 or 52/48
Example 51.5/48.5
Front: 721
Rear: 679