Asymmetric suspension setup in F1?

[DaveW]

Which of those things wouldn't you do and why?

I appear to have dug a large hole for myself mainly because I noted that, personally, I have never seen a asymmetric F1 set-up. I could, by the way, say the same about several other open wheeler series.

Fortunately, I suppose, it is not usually my job to comment on customer set-ups, but it is my job to advise and interpret the messages the vehicle delivers when it is being excited on a rig. It is certainly not my job to compare the set-ups of different teams for the direct benefit of one or another.

So, you can feel free to do anything you like to a race vehicle & I will comment mainly on what my analysis routines tell me. One of the measures is "symmetry rating". That, by the way, has been helpful to me & (I hope) to my customers both for road course & for oval cars (except NASCAR, I admit).

[gixxer_drew]

One of my Indy car customers (i.e. no 3rd springs)

I take it you never saw that funny torsion third springy thingy we had in 2010?

[DaveW]

I take it you never saw that funny torsion third springy thingy we had in 2010?

That could, presumably, have been used to solve the balance issue.

[DaveW]

Which of those things wouldn't you do and why?

Without retracting what I said previously, I would like to expand my reply.

The strategy of setting up a race car tends to be very personal thing, based very much on previous experience of the race engineer and driver preferences. The problem is that many changes affect more than one aspect of performance. In a symmetric vehicle, for example, changing springs can affect roll angle & pitch angle per gn, lateral balance, and also rigid body damping ratios & CPL load variation. All of those can affect performance, & it is often difficult to decide with no other information, which of those, and to what extent, was responsible for a change in performance.

A true story, one right in your own ball park, I think. I was asked to help a US based customer running a GT vehicle a few years ago. The customer complained of "rubbish" rear tyres that wouldn't last a stint. A quick look at a "Daytona" set-up on the rig suggested that stronger rear tyres were required. Alternatively, softer springs (JT's "no brainer") and softer dampers might help. After exploring on the rig different spring combinations, optimizing damper settings for each, we arrived at a set-up that would still benefit from stronger tyres (apparently), but they were now "balanced" (with similar sensitivities to change). Subsequently, the team emailed back to thank us, noting that the vehicle was now more competitive and the tyres, with a "rig set-up", would now certainly last two, & possibly three stints... The alternative might have been harder tyres, I suppose.

The moral, as JT pointed out, is that it is a good idea to get the basics right.

[ubrben]

Which of those things wouldn't you do and why?

Without retracting what I said previously, I would like to expand my reply.

The strategy of setting up a race car tends to be very personal thing, based very much on previous experience of the race engineer and driver preferences. The problem is that many changes affect more than one aspect of performance. In a symmetric vehicle, for example, changing springs can affect roll angle & pitch angle per gn, lateral balance, and also rigid body damping ratios & CPL load variation. All of those can affect performance, & it is often difficult to decide with no other information, which of those, and to what extent, was responsible for a change in performance.

A true story, one right in your own ball park, I think. I was asked to help a US based customer running a GT vehicle a few years ago. The customer complained of "rubbish" rear tyres that wouldn't last a stint. A quick look at a "Daytona" set-up on the rig suggested that stronger rear tyres were required. Alternatively, softer springs (JT's "no brainer") and softer dampers might help. After exploring on the rig different spring combinations, optimizing damper settings for each, we arrived at a set-up that would still benefit from stronger tyres (apparently), but they were now "balanced" (with similar sensitivities to change). Subsequently, the team emailed back to thank us, noting that the vehicle was now more competitive and the tyres, with a "rig set-up", would now certainly last two, & possibly three stints... The alternative might have been harder tyres, I suppose.

The moral, as JT pointed out, is that it is a good idea to get the basics right.

Thanks for the reply Dave. I think (as I alluded to in a previous reply) the situation I've been in is a team that's got the basics very right and then done a huge amount of work on asymmetric setup options to put the cherry on the cake so to speak.

Ben

[cheapracer]

generally assymetrical setups started at Watkins Glen, 1968 thanks to Mario (that helped him to put the Lotus on pole) and were common until later on when serious downforce meant that the car needed to come down evenly all around.

I have certianly seen Chapman in an early 70's film ordering mechanics to weight jack a car when Peterson was complaining about understeer in right handers only.

Just a presumption with no evidence, how much they use, if they use nowadays, would go hand in hand with what downforce they can achieve at different tracks, I suspect Monaco may have some assymetry in their setups for example.

[DaveW]

This is a fascinating subject.

I have certianly seen Chapman in an early 70's film ordering mechanics to weight jack a car when Peterson was complaining about understeer in right handers only.

I think people react instinctively in a "pit lane" situation ("don't know" is not an answer). An obvious question to ask (and probably look for an answer later) is why the balance was like that in the first place. I am reminded of a reply I received from a GP2 race engineer to my question about asymmetric set-ups: "only if we are lost".

[Eager Learner]

Has anyone heard of any top teams running asymmetric damping on road courses? As in left side dampers set at different bump or rebound force via the adjusters, different from the right side? To me it would seem that it would make the car difficult to handle especially on braking.

I have heard a garage owner claim this but they have never done anything great in terms of racing.

[DaveW]

Has anyone heard of any top teams running asymmetric damping on road courses? As in left side dampers set at different bump or rebound force via the adjusters, different from the right side? To me it would seem that it would make the car difficult to handle especially on braking.

I think your comment is well made. It would also make road inputs change the (transient) balance of a car.

I do see teams running different settings left & right in an attempt to match dampers. This is normally done with the aid of a dyno. It is sometimes not successful (at least according to multi-post rig tests - the vehicle often appears to be behave more symmetrically with "square" settings than it does with adjusted settings).

[Belatti]

I do see teams running different settings left & right in an attempt to match dampers. This is normally done with the aid of a dyno. It is sometimes not successful (at least according to multi-post rig tests - the vehicle often appears to be behave more symmetrically with "square" settings than it does with adjusted settings).

Are you talking about dampers that, even with the same shim config the dyno ouput is different? Like low quality dampers?

Now that I remember I saw a slightly biased damper setup (only oil) in a car with "in line" engine. The right damper worked 30C hotter because of the exhaust...

[DaveW]

Are you talking about dampers that, even with the same shim config the dyno ouput is different? Like low quality dampers?

Yes, & not always that cheap.

Now that I remember I saw a slightly biased damper setup (only oil) in a car with "in line" engine. The right damper worked 30C hotter because of the exhaust...

Ouch! That would require temperature stable dampers, or protection, I suppose..

[Eager Learner]

Has anyone heard of any top teams running asymmetric damping on road courses? As in left side dampers set at different bump or rebound force via the adjusters, different from the right side? To me it would seem that it would make the car difficult to handle especially on braking.

I have heard a garage owner claim this but they have never done anything great in terms of racing.

Thanks Dave. I forgot to mention that this was in GT and touring cars. Is there any reason to run asymmetric (left to right) damping when the lateral mass distribution is not perfectly 50%?

Formula cars are usually much closer to perfect 50% left-right weight.

[xpensive]

...
I have certianly seen Chapman in an early 70's film ordering mechanics to weight jack a car when Peterson was complaining about understeer in right handers only.
...

I wouldn't read too much into that really, when Ronnie's feed-back was somewhat unclear at best. Legend has it that he once complained of a terrible oversteer and Peter Warr went out on the track to see for himself, when it proved that the 72 was actually badly understeering, why the driver intuitively set it up with an opposite lock before the corner to cope.

[Belatti]

Are you talking about dampers that, even with the same shim config the dyno ouput is different? Like low quality dampers?

Yes, & not always that cheap.

Then I would suspect of the dyno measurement, the purge and some other details, etc.. Even more if dampers are non presurized bi-tube. I have seen dampers measurements "normalize" after cycling them at different speeds, when recently assembled. I attribute the problem to shim+oil layer friction effects.
I would not be surprised if in the post rig test actually you were not testing symetric dampers in some of those cases.

Now that I remember I saw a slightly biased damper setup (only oil) in a car with "in line" engine. The right damper worked 30C hotter because of the exhaust...

Ouch! That would require temperature stable dampers, or protection, I suppose..

Its a problem when you are allowed to only use a defined damper type, very common cost control measure arround here. Thermal insulation doesnt work either...

[DaveW]

Is there any reason to run asymmetric (left to right) damping when the lateral mass distribution is not perfectly 50%?

Probably. I have often though about that as a solution for offset c.g.'s, but never had the confidence to suggest it seriously. It does appear to work for "oval" vehicles, but the "low risk" solution for me (and the best, I think), is to suggest moving ballast around. We often play with that to prove the cause of asymmetric response. Incidentally, the solution probably also requires asymmetric springs...

p.s. By ballast I mean anything that is not "fixed by function" e.g. batteries, electronics boxes, etc.

Then I would suspect of the dyno measurement, the purge and some other details, etc.. Even more if dampers are non presurized bi-tube. I have seen dampers measurements "normalize" after cycling them at different speeds, when recently assembled. I attribute the problem to shim+oil layer friction effects.

Perhaps. I think however that dampers are impedance sensitive, especially when their response is characterised by "peak load peak velocity" plots. There is a very large difference between the impedance presented by a dyno (when the trajectory is forced) & that presented by a car (where the damper can make its own trajectory)....