Ride height variation due to damper configurations.

[Caito]

Does anybody know if any F1 team uses dampers to reduce ride height?

What I mean is, if you have a strong rebound, and soft compression, after a lot of irregulrities the height would be lowered due to the strong rebound of the damper.


Bye


Caito.-

[Jersey Tom]

Pro race teams use extensive 7-post testing to determine what setup combination produces the best compromise of things, yes.

Lowering ride height isn't everything.

[silente]

I know for sure some high level formula 3 teams do it.

The thing is normally tuned on 7-post rigs, as JT said.

I don't agree completely with this technique, anyway they decide to deliberately have a very non symetric tuning of dampers (above all front) to help the car to pitch more during straights because of road irregularities.

[DaveW]

I think it is true to state that heavily rebound-biased damping is always a fix for a problem. Intractable problems include damper architecture & a minimum static ride ride height rule.

Dampers are "free" in many F3 series, & none has a minimum static ride rule (so far as I'm aware). The reason commonly given for rebound-biased front damping in F3 is to counter power-on under-steer, but I suspect there is a better way to overcome that characteristic.

[silente]

completely agree with Dave, very often who use very rebound biased front dampers settings claims to do it to solve an understeer problem, more often in corner exit.

It's my opinion as well that this is nearly always a wrong way to try to fix the problem.

But some high level teams are more and more using dampers to influence aerodynamics in some extent more than mechanich grip.

TO be honest, in my experience with Formula 3 cars, although i worked a lot on dampers settings in the past years, i have seen they are a less important area of development than other things.

[marcush.]

I would not agree to this latest statement.
Dampers are very important but in many cars with issues in installation stiffness or other things completely wrong you will very unlikely be in a position to maximise the damper potential.
Dampers are very important for driver confidence according to my experience.As they are effectively timing device for things to happen .as stated above you can tune otransient over or understeer characteristics into the car by dampersetups ,you can help aero and you can help mechanical grip.to a degree you can compensate for flaws in the original design of the car but of course curing the weakness has to be still the main objective.

[Sayshina]

Marcush, I admit I haven't followed F3 in decades, but I was under the impression that Dallara had a stranglehold on car manufacturing. Installation stiffness would largely be a common problem. Also, I think what the poster above you was refering to was that damping takes a back seat to front wing placement, which seams to be the direction all open wheel cars are currently going in.

I think what the OP is refering to is biasing compression vs. rebound so heavily that the suspension can't recover between bumps, thus lowering the car. First OP, you would very quickly bottom out and then effectively have no suspension. Since you're not actually required to have any suspension, and yet all cars do, you can assume having useful suspension travel is an advantage. Bottoming out suspension in bump tends to result in a sudden loss of traction. It's also a horrible feeling for the driver, as it feels like you've just lost all control. As a rule freaking your driver out is bad for lap time.

Also, the regs limit ride height by a solid object on the car, the "plank". This is regulated by mandating a maximum amount of allowable wear to said plank, and years ago Ferrari was actually penalized for running too low and getting too much wear.

What teams have been trying to do in the last couple of years is get the front wing to ride closer to the track while keeping the ride height the same. Red Bull and Ferrari clearly managed exactly that last year, and nobody else seems to understand how they did it, and were clearly unable to stop them. It's against the rules, but aparently incredibly hard to police. It's also clearly worth a lot of lap time, as a number of knowledgable people have said the gap between Red Bull and Ferrari was down to other things but the gap between Ferrari and McClaren was mostly the wing.

[marcush.]

understood.
excessive rebound damping is not the same as bottoming out..wich is a really nasty thing at the limit.
the question is if you would do this with the dampers anyways.There are some trick bumpstops on the market whih have a lot of hysteresis so these will show some of the described rebound heavy characteristic... and it would create a system which is position sensitive in its behaviour .So you could possibly have less rebound in your lowspeed corners but a lot of rebound damping at higher speeds with high downforce(when the car lowers itself onto the bumprubbers)

[Sayshina]

understood.
excessive rebound damping is not the same as bottoming out..wich is a really nasty thing at the limit.
the question is if you would do this with the dampers anyways.There are some trick bumpstops on the market whih have a lot of hysteresis...

I intentionally failed to mention bumpstops because I didn't want to complicate the picture. From the OP's original wording I was led to believe he didn't have an in depth knowledge of the subject and bumpstops are pretty complex considering what they are. After all, there have been cars designed to ride the stops.

And I know that excess rebound damping isn't the same as bottoming, but if your damping is such that you're permanently lowering the ride height you're going to either bottom out or need some seriously high rising rate, which will end up giving you a lot of the same problems.

I was just trying to give the OP an idea of how nasty that is.

[DaveW]

I agree with your sentiments, Sayshina, but don't forget that springs will also (try to) control the dampers, & that driver inputs will (can) also affect dynamic ride height variations.

My view remains that the only logical reason to manipulate dynamic ride height with dampers is to compensate for a minimum static ride height rule, when the aero benefits of reducing ride height may over power the reduction in mechanical grip (NASCAR on ovals, for example).

[marcush.]

why not use the bumprubber to cater for the lowered rideheight? You could use a high hysteresis elastomer for this and not too much compromise on damper characteristics -effectively a position sensitive damping.

[DaveW]

You certainly could, Marcus, & I know one race series that does. They use dampers set-up to work with fairly long & low hysteresis bump rubbers, however, & I suspect the vehicles are not checked post-run.

I think the problem with high hysteresis bump rubbers is heat dissipation when they are used continuously. Polymer technology is becoming very sophisticated, but I have yet to see one that claims to have good heat extraction properties. I have, however, seen one that appeared to have been through a "melt down" cycle, gluing itself to a damper shaft in the process.

[marcush.]

without a doubt you should not fool around with things without knowing what is going to happen...
Heat buildup surely is getting in your ways so it seems unlikely you can maintain a setup over a race distance.But on the other hand ..with lower fuellloads after some laps the reduced performance of the bumprubber maybe even an advantage,who knows?

[Sayshina]

I agree with your sentiments, Sayshina, but don't forget that springs will also (try to) control the dampers, & that driver inputs will (can) also affect dynamic ride height variations.

My view remains that the only logical reason to manipulate dynamic ride height with dampers is to compensate for a minimum static ride yheight rule, when the aero benefits of reducing ride height may over power the reduction in mechanical grip (NASCAR on ovals, for example).

Agreed on all points, though I would add that drivers tend to be largely uneffected by variables created by their own inputs. Hmm, let me try that one again. Anything that the driver can trace back to something he did doesn't scare him, and will tend to have a relatively small effect on laptime.

I was actually thinking of NASCAR myself when I mentioned riding the bumpstops, though I'm not a fan and couldn't say if they still do. At any rate, it is my understanding that you normally use rather soft springing and damping and that there's no F1 style load put on the chassis during ride height testing. So the car only rides the stops during cornering, and as you mentioned does so purely for aero reasons.

Oh, I would also add that this whole concept seems to be about cheating. When we say the reduction in ride height provides an aero benefit we should probably say a reduction below the minimum allowed. I don't see any reason whatsoever for doing any of this if you can get the ride height you want legally.