54 replies to this topic

[NRoshier]

I have found that the dampers on my car are too short for the application, at least in my estimation. I reason this as I have around 10mm droop at the current ride height, which increases to around 20mm with me in the car.
I could of course extend to top damper mount downwards to move the damper into a better position and change the preload to suit, but I thought that I would enquire as to options, as I have never been happy with the AVO dampers mounted on the rear.
So I made a few phone calls and had two very different setups suggested for road and track (6/7 laps sprints around circuits) use. The Koni agent suggested a low rebound setting given the relatively heavy live rear axle in comparison to the rest of the car, whilst the Bilstein agent recommended a standard amount of rebound.
Is there any direct mathematical correlation between the sprung/unsprung weight and the actual valving chosen?

[phantom II]

Droop is when the wheels hang down after you jack the car up on the chassis so I don‘t understand what you are saying about droop. The full extension of the shock is the droop limiter. My first roadster had a live axle. I located it with 3 trailing links and a Watts. I dialed in roll understeer and anti squat geometry which also prevented hop. You never ever pre load shocks on a live axle. Infact, you want the spring to leave its seat under full droop so that the spring isn’t pushing down the axle when the tire leaves the road. There is no suitable way of damping the axle when the rear wheels leave the ground. In other words, if you have a bumpy track, there is no way to control unsprung weight with shock valving, which is of course, the nature of a live axle. There is no point even trying to do so. All you can do, is to allow a free fall droop valve when the tires leave the ground and normal spring damping when they don’t like a motorcross bike rear suspension. Using an ARB can have the same effect as a preloaded spring which will give you some directional control surprises in roll transitions. There is no way to control the movement of that heavy hunk of iron with the shocks.

Originally posted by NRoshier
I have found that the dampers on my car are too short for the application, at least in my estimation. I reason this as I have around 10mm droop at the current ride height, which increases to around 20mm with me in the car.
I could of course extend to top damper mount downwards to move the damper into a better position and change the preload to suit, but I thought that I would enquire as to options, as I have never been happy with the AVO dampers mounted on the rear.
So I made a few phone calls and had two very different setups suggested for road and track (6/7 laps sprints around circuits) use. The Koni agent suggested a low rebound setting given the relatively heavy live rear axle in comparison to the rest of the car, whilst the Bilstein agent recommended a standard amount of rebound.
Is there any direct mathematical correlation between the sprung/unsprung weight and the actual valving chosen?

[NRoshier]

Er, no. Car is at ride height, wheel moves up into bump, wheel moves down in rebound, wheel goes below static ride height into droop.
I do not want the spring leaving it's seat, ever, dampers are coilovers. Preload is required to get static ride height with soft spring rate.
Question is how sprung vs unsprung ratios vary valving and what effects low mass car and high mass axle (relatively speaking of course) would have on damper valving.

[phantom II]

If there is no energy in the spring in droop, there is no preload. You must be able to turn the spring in droop by hand even after you have set corner weights and ride height. Save yourself a big headache and do this. That is why it is crucial to package the car correctly so that the left and right springs are loaded as close to equal as possible. Your question is too complex to answer. The frequency of each bump in the road would require different damping. The inertia of the unsprung mass is impossible to damp practically, you would have to have huge shocks, another reason you can‘t have preloaded springs on a stick axle.
You can’t hide the poor mannors of a live axle, no matter what valving you choose in your dampers.
Let it fall free in rebound and avoid pot holes. Check out motor cross rear wheeldamping.
I gave up and went to IRS.

Originally posted by NRoshier
Er, no. Car is at ride height, wheel moves up into bump, wheel moves down in rebound, wheel goes below static ride height into droop.
I do not want the spring leaving it's seat, ever, dampers are coilovers. Preload is required to get static ride height with soft spring rate.
Question is how sprung vs unsprung ratios vary valving and what effects low mass car and high mass axle (relatively speaking of course) would have on damper valving.

[ben38]

Well, I am no specialist at all of live axle but considering your post about mass relatives to sprung and unsprung weight this comes to my mind.

As far as damping is mainly concerned by spring rate and unsprung mass, and your situation is low spring rate and heavy unsprung mass I'd do it like that.
Heavy unsprung mass tends to have low oscillation frequency but with high energy in it.
I'd free quite a lot the high speed damping forces both on bump and rebound. That would allow for better handling over bumps and as far as I know american tracks are bumpy.
Then for low speed damping, the critical factor in here, I'd use quite some bump damping considering the low spring rate and heavy unsprung mass. The energy to dissipate over bumps can be quite huge with a high unsprung mass as soon as the big mass starts to go up faster.
Main problem in that is that bump oriented damping is not comfortable ride and sometimes gives to the driver weird feeling of the car.
Using bump damping mainly in low speed as the main damping solution will of course reduce the need of damping in rebound.
This solution will also help to keep the ride height when a rebound oriented damping on heavy unsprung mass will tend to lower the car.

So the rebound oriented damping will be less sensible to the droop available as your dynamic ride height will be lower than bump oriented (with the same static ride height of course).

I don't know the details of your car and what is the most import for you but here are the factors that I would consider.

Ben

[Fat Boy]

Originally posted by NRoshier
I have found that the dampers on my car are too short for the application, at least in my estimation. I reason this as I have around 10mm droop at the current ride height, which increases to around 20mm with me in the car.
I could of course extend to top damper mount downwards to move the damper into a better position and change the preload to suit, but I thought that I would enquire as to options, as I have never been happy with the AVO dampers mounted on the rear.
So I made a few phone calls and had two very different setups suggested for road and track (6/7 laps sprints around circuits) use. The Koni agent suggested a low rebound setting given the relatively heavy live rear axle in comparison to the rest of the car, whilst the Bilstein agent recommended a standard amount of rebound.
Is there any direct mathematical correlation between the sprung/unsprung weight and the actual valving chosen?

You're kind of all over the place here. I'm not sure what you're really trying to fix.

For a first cut, I calculate damping ratios based off sprung and unsprung masses. I use sprung for rebound and unsprung for compression. This gives you a rebound bias, and as the previous damper thread covered, some people don't care for rebound biased damping. I don't particularly care what the bias is, I tune to the car/track/conditions. The calculations are very rough and just give an idea of the overall forces you need to hit. I know other people have ways of calculating damping target forces in more complex manners than what I have. They get messed up, too.

With this in mind, you need to give us a little information about the car. A high rear rebound setting will usually hurt powerdown/corner exit performance by making wheelspin. A low rear rebound setting is good for traction off the corner, but hurts body control. These are generalizations (because I know someone will chime in with I did this and it went the other way on a street car with my uncle driving 20 years ago....).

Keep in mind, Bilstein spends a lot of time working with live axle cars. They're one of the preferred NASCAR shocks. Koni, to my knowlege, stays mostly in the independent-road racing world.

Also keep in mind that different dampers act completely different on the car even if their F-V dyno curves are perfect overlays. Of course, if you have a good hydraulic dyno, you can see the differences, but most of us don't.

[NRoshier]

OK, to clarify (I hope) I am not really concerned with the rear damper length as if this is an issue I can fix it with new dampers etc.
However I am concerned that learn by going through the process and also by not wasting money by being duped by a saleman who just wants to sell what he has on the shelf. The cars suspension is somewhat typical of the 1959/1960 when the car was made. It comprises of two lower trailing arms, which also locate the dampers at approx 2/3 of their length. There is a shorter top torque reaction arm mounted half way along the axle on the drivers side (in Aust/UK) and the passengers side in the USA. Lateral location is via an angled panhard rod running from near the chassis end of one of the trailing arms, under the nose of the differential to the axle on the other side. This would seem likely to develop some roll steer, but it has not been felt and would be difficult to change to a watts link as the car is a fibreglass monocoque and the structure at the rear is perhaps too weak for the loads. Front suspension is Riley 1.5/Morris Minor torsion bar setup (really!) with sway bar. The diff is open, but I have a Salisbury type Trans-X plate diff on order while the UK pound is weak! When last driven the car had no traction issues in a straight line at all, in fact it seems a strength of the car given the 185 wide tyres that are as wide as can fit, the car has a mildly tuned period engine with approx 150bhp. Accelerating after a low speed left or right 90 produces some wheelspin on the inner tyre for a short period and then oversteer. This wheelspin is naturally greater when going left as my weight (120kg) is on the outside of the corner. Car crashes somewhat on bumpy roads and seems over-sprung. No high speed corners (i.e. over 130kph) have been tried as yet. At this speed the car tends to mild understeer and is stable. Car is upset directionally by mid corner bumps, but has had bump steer reduced since last drive and has 4 wheel alignment on Monday.
Ben, I'm in Australia...and all of our circuits are bumpy...well perhaps Phillip Island is not too bad.
Ben and Fat Boy you are helping.
P2, I understand what you mean about reducing the preload so that it cannot contribute force to the downwards axle movement, however in the current setup with the current length dampers it is not possible to do anything else.

[DaveW]

I don't have much to add to comments on the original question, given the lack of information, although reducing the damping overall of a road vehicle (if that was the suggestion) doesn't sound like an inspired idea.

On other posts, with apologies, I can't think that NASCAR experience would provide a solid base for good a mechanical set-up, but OzV8 experience might (fewer aero constraints & spurious rules to negotiate).

Two properties that can be important & haven't been mentioned yet are tyre stiffness & damper "top mounts". Both affect set-up "boundaries", particularly for live axle vehicles. It follows that useful, but perhaps simplistic, set-up "rules" might not translate too well when unsprung masses (and/or tyres) are changed significantly.

[NRoshier]

Well it seems I need to learn first what is enough information, fair enough. So what is required - as far as information - for a question on damper setup?
DaveW I am genuinely interested in why you consider the V8Supercars a relevant example for me to consider? They do have a live axle, but they are a 600bhp, 1650kg racecar running fairly massive spring rates. Could you also tell me what you mean by damper top mounts?

[NRoshier]

It seems that I can borrow a set of 'pots' and a data recorder, which I assume could assist with the required data, though I have the feeling that this could get bigger than ben hur!
Assuming that such materials become available, what is an advisable (simplified given the scope of the project) test procedure to collect data?

[ben38]

Well, first of all I did not understand that we were talking about vintage car.

One thing could be quite determinent for your choice I believe. It is linked to the caracteristics of the chassis.
You quote a fiber glass structure about 50 years old...
I believe that chassis torsional or even overall stiffness is not at its best and was never that high anyway.
Soft springs are definetly the way to go. As for damping, bump oriented will be equivalent to a harder set up of springs on dynamic ride (what makes it feel more uncomfortable generaly), so this construction might feel a lot better with rebound oriented damping.

One very simple solution would be to go for adjustable dampers (the ones with clics). Then you could easily try both ways. Drawback is the cost of such dampers but that depends on what you want to spend.

About suspension pots and data, that is the best way to go definetively. But that needs adjustable dampers too or it will just be a constatation of what you got.

About that contact me by mail I'll give you some infos on it.

[phantom II]

What is the car? Lotus 11? Westfield kit? What frame/chassis? 150hp is high for a vintage Ford engine even with Lotus heads.
Have you got any of these books? Carrol Smith, Herb Adam's 'Chassis Engineering', Fred Puhn's 'How to Make Your Car Handle' and Don Alexander's 'Performance Suspensions' and for good basic info. Milliken's 'Race Car Vehicle Dynamics'
What is your car doing? What do you want it to do? Does your spring rate match wheel rate? Wheel freqency (undamped natural frequency) is important with spring selection, that is the most basic component of any spring-mass vibration system and the part that you should give the most focus and attention in stick axle handeling. Do you have photos? What are some specifications: Total weight, split, corner? Dimensions of spring location on trailing arm? Is the spring vertical?
If you really want to get technical, you need to figure in the spring constant (probably non-linear) and damping coefficients for the tire, and all the bushings in a suspension, along with the elastic give that the components have. It can become quite a non-trivial problem if you want it to.
While you are experimenting, leave the diff open. Keep it open if you can get away with it. Your soft springs minimizes inside wheel spin where the shocks are located.
The springs mounted on the trailing links present problems especially accurate calculation of spring rates. The result is often that the effective wheel rate under cornering is different than it is under acceleration and braking and raises the roll center and causes adverse jacking. It can be minimized by locating the spring as close to the wheel as possible on top of the axle. You would have roll control without jacking and could go to harder springs. This makes spring and shock selection and tuning pretty easy and you can almost use rates suitable for IRS except for high frequency rebound valving. Never ever get adjustable shocks. They do not work except for Penskes$$$$$. How much surgery is permitted and how much are you prepared to do?
Oh yeah, one more thing. Get rid of that preload. You won't know your ass to your elbow.

Originally posted by NRoshier
It seems that I can borrow a set of 'pots' and a data recorder, which I assume could assist with the required data, though I have the feeling that this could get bigger than ben hur!
Assuming that such materials become available, what is an advisable (simplified given the scope of the project) test procedure to collect data?

[Fat Boy]

Originally posted by ben38
Well, first of all I did not understand that we were talking about vintage car.

Same here. What are the fastest cars in your class doing?

[Greg Locock]

The damper top mount is the bush, or sandwich of bushes and washers , between the damper and the structure. Tuning them is surprisingly important for shake/secondary ride, but for a circuit car I find it hard to believe that anything other than a spherical joint is optimal. (ie stiff in translation, free in rotation). If you have room then the lower front shock bush in a current Falcon or Territory is a good example of a rubber bush that has the appropriate characteristics. You can just use a spherical joint, it is cheap light and does the job, but it will rattle quite quickly.

[NRoshier]

Greg, thank you, it is what I thought, but I just wanted to be sure. I have a couple of sets of Dynamic Suspension dampers from a defunct Shelby project (the 'Series One') which come complete with hyperco 200lb/in springs. These dampers have spherical bearings top and bottom.
P2 the car is a Rochdale Olympic http://www.rochdale-....uk/olympic.htm and the engine is a Fiat twin cam - a popular conversion in the 1970's, as in the UK the rest of the Fiat generally dissolved around what is otherwise quite good running gear. I would stress that my car has been considerably reinforced over a standard Olympic in virtually all areas and now includes a 6 point CDS roll cage and foam filled box sections.
Ben the car originally tested at over 4,000lb/ft per degree in torsion and I have added approximately 40kg of fibreglass in upgrading it, plus the roll cage. I hope that it would test around that figure now, which if local advice is correct is substantially better than say the period equivalents of an MGB/TR3/Healey.
The rear damper is mounted via a rubber isolator at the top. The monocoque is approximately 12mm thick at this point and the main roll hoop attaches via the same bolts as the damper mount. I would respectfully ask what difference the car's structure/age would make WRT the damper settings as they relate to mass? - many a Caterham style car would have a similar sprung/unsprung mass ratio are of similar vintage.
P2 the damper cannot be moved as the car's structure is not designed for the loads.
Fat Boy I am not quite sure how to answer your question: my car will compete against other sports cars in circuit sprints and hillclimbs and I am not sure how I can equate their speeds in a meaningful manner. I aim to compete against cars such as early RX-7's, early 911's etc. Top speed will be limited more by my bravery (heck I know I'm driving an old egg shell), but top speed will be around 120mph.

[ben38]

So the damper top mounting points at the rear are safe!
But what about those from the live axle? You said above that the chassis wouldn't have the strengh required for additional bars in the live axle.
I believe in this case the limitation is more the rigidity of the mounting points of the suspensions which can be problematic rather than overall stiffness.

For the front I strongly advice you to use A shaped sturcture to fit on the cage to reinforce the front dampers top mounting points.
(see fia rule book Art 253 drawing 253-25)
This combined to drawings 253-17, 253-18, 253-9 should give you real stiffness from the cage.
Not really expensive if you do it yourself but time consuming.
Continuous effort lines through the cage are obvious.
This will be accepted by the scrutineer if your 6 points actual cage is on FIA standards dimensions (like 99% of 6 points cages)
This done you could save weight by taking off the possible overload of fiberglass.

The rigidy problem fixed, just remain the damping question.
If you had put your hands on a dynamic adjustable set, the best and most effective way would be a small data logger able to record 4 suspensions pots at something like 500Hz and tune it on track. (basic oscillation speed calculation and histograms with driver feed back are powerfull tool)
You could then try both rebound and bump oriented and get what actually suits you best.

Ps: Drawing number 253-27 could go directly on rear live axle mounting and help too.

[ben38]

Originally posted by NRoshier
I would respectfully ask what difference the car's structure/age would make WRT the damper settings as they relate to mass? - many a Caterham style car would have a similar sprung/unsprung mass ratio are of similar vintage.

Mainly on the limit of stiffness you can use efficiently on springs and damping.
Resine used in fiberglass composites tends to delaminate with time, sun, humidity etc
All this will lower the stiffness a lot.
It might reduce more local strength rather than overall. Drama is that the most stressed points, the suspensions' mountings will be the weakest ones over time.

Loss in rigidity will interfer with the overall stiffness of suspensions and accuracy of suspensions mouvments.
(imagine one side softer than the other in the pick up points).
If you consider bump steer and the difference that it can make for such a small adjustment then you get my point.

Bump oriented damping results in a harder equivalent spring stiffness in dynamic so a softened mounting point will be more of a problem with this style of damper setting.
Rebound damping will be less sensitive to that.

Once again, I don't know your car and I haven't seen it but on a 50 year old car these are for me important points to consider.

And the suspensions'pick up points on a catheram are on the steel frame!

(edit: should have posted this one before the one above : )

[Fat Boy]

Originally posted by Fat Boy


Same here. What are the fastest cars in your class doing?

I meant in terms of dampers. What manufacturers are popular? What type of valving seems to work the best?

[Fat Boy]

Originally posted by DaveW
On other posts, with apologies, I can't think that NASCAR experience would provide a solid base for good a mechanical set-up, but OzV8 experience might (fewer aero constraints & spurious rules to negotiate).

Do they play their crazy 'damper jacking the ride height around' games on road courses as well? I always assumed that for a couple races a year they put that aside.

[phantom II]

Why don’t F1 cars have adjustable shocks? I defy you to get any two adjustable shocks the same. The repeatability of results determined on a shock dyno is not achievable yet the believers of adjustable shocks have their adherents. The only way to adjust your shocks properly is to build them according to suspension velocity histograms. 65% of critical damping in the 0-3 in/sec range will almost always be accurate. Adjustable shocks are an act of desperation.
Ofcourse, to match the ideal curve with the actual curve is something else. Its best to match the low speed curve if you can’t match both. I don’t know what Roshier's is trying to achieve, but in view of his cars platform and it's ‘shifting’ natural frequencies and unknown chassis and suspension rigidity, it seems he had better acquire driving skills to drive around the problem, what ever it may be. He hasn’t stated it yet, but he wouldn't be posting if he didnt have a problem.
Sometimes it is impossible to get a car right if it wasn’t designed right.

Originally posted by ben38
The rigidy problem fixed, just remain the damping question.
If you had put your hands on a dynamic adjustable set, the best and most effective way would be a small data logger able to record 4 suspensions pots at something like 500Hz and tune it on track. (basic oscillation speed calculation and histograms with driver feed back are powerfull tool)
You could then try both rebound and bump oriented and get what actually suits you best.

Ps: Drawing number 253-27 could go directly on rear live axle mounting and help too.

[phantom II]

That’s the coolest looking car. I gave up on my stick axle mostly because of damping difficulties. Physics is physics. I can make no further contribution to this thread other than to hijack it a bit, if you don’t mind?
My main interest in cars is the way they look. They should go the way they look though. There are actually a few Rochdales in the States. I havent seen one for years. They look like a cross between the French Panhard and the South African GSM Flamingo, the designer of which, designed the Daimler 250SP Dart. Daimler prevented GSM from using the name Dart in the UK, and Chrysler prevented Daimler from using the name Dart in the US.
Anyway, I’m sure you will have a blast sorting out your car and you must share your adventures with the rest of us car lovers. Please post detailed pictures.

Originally posted by NRoshier
P2 the car is a Rochdale Olympic http://www.rochdale-....uk/olympic.htm and the engine is a Fiat twin cam - a popular conversion in the 1970's, as in the UK the rest of the Fiat generally dissolved around what is otherwise quite good running gear. I would stress that my car has been considerably reinforced over a standard Olympic in virtually all areas and now includes a 6 point CDS roll cage and foam filled box sections.
P2 the damper cannot be moved as the car's structure is not designed for the loads.
Top speed will be limited more by my bravery (heck I know I'm driving an old egg shell), but top speed will be around 120mph.

[NRoshier]

That is reasonably august company for a Rochdale Olympic. I found the car one day in a book in the local library when I was 14 and was taken by the shape. I always thought that I would like one, though I liked the Lotus Elite even more. However as it happened I found one when working in the UK and it had three benefits over the Elite: the olympic was much more rugged, it was 1/10 of the price and most importantly as a 2+2 GT car I could be made to fit (I'm tall) with a helmet (I cannot fit in any Lotus). The car is a challenge to get running well for two reasons - they well never as well developed as something like the Lotus and they were mostly a self-build car like the Elite - so they suffered from not only the vagaries of 1960's British car manufacturing but also from the skills of those who built and since owned the car. The only advantage I have over the other cars that will be in the same class is that I can get it 150 - 200kg lighter, which is worth a lot in a hill climb!
Fatboy the dampers commonly in use are the usual brands in bilstein/koni etc. and usually a revalved road damper. I think that this is one area where my car can greatly improve and I have a strong belief in the importance of dampers vs more power (for my application), though I admit that even after reading Milliken/Phun/Staniforth etc I seem to know far less that I need to to make a start on a choice.
Ben yes I have researched the embrittlement of ester based resins and am resigned to eventually replacing the whole shell at some stage. In defence of the material, at least it cannot rust and I hate rust! I will have a look at how I could tie in the steel to the front suspension, though I suspect that I cannot really do so in any meaningful manner. I checked the Dynamics last night and I cannot use them as they are too long.

[DaveW]

P2, the F4 was a fantastic aircraft, even if it was developed from a prototype built largely of spare parts. However, the aviation world has moved on since then. Ditto the damper world. Fifteen years ago I would have have agreed with your sentiments about dampers, but it is possible now to find adjustable dampers (shocks) that are matched to within the odd couple of percent setting on setting throughout the adjustment range.

F1 teams might use non-adjustable dampers at race weekends, but that is not a virtue. It is simply a statement that mechanical performance is not high on (or even on) the agenda for most teams, and F1 designers will sacrifice everything to save the odd milligram. They do, however, carry more than one set of dampers and often invoke the alternative option of having a circuit modified when they encounter track-related problems.

Elsewhere, damping levels and "style" are important (if sometimes misused) tuning tools at both track tests and race weekends because an "optimal" mechanical set-up is a compromise that will depend upon circuit, driver, tyres, surface and ambient conditions. Cockpit-adjustable dampers are used (wisely or otherwise) in at least one race series. Look inside a NASCAR truck & you will probably see wall-wall shocks neatly labelled and ready for use, mainly because they are allowed only a single adjuster per shock.

Fat Boy may be correct about NASCAR road course vehicles but, with the greatest respect, I wouldn't like to bet my house on it. In any case, I suspect road course events are not considered to be "real" races in NC. OzV8's, by way of contrast, have fairly "pure" mechanical set-ups and use dampers with 3, 4 or even 5 (!) adjusters.

Having said that, adjustable dampers provide the ability to engineer a vehicle away from a good "generic" set-up and to arrive at "magic" solutions that, mysteriously, work only the once. In that context, earlier posts on this topic do contain wise advice, even though I would question some of the details (e.g. P2's 65% of critical is not true universally).

[Fat Boy]

Originally posted by Fat Boy


Do they play their crazy 'damper jacking the ride height around' games on road courses as well? I always assumed that for a couple races a year they put that aside.

This was a question, not a statement. I've never raced NASCAR.

[Ross Stonefeld]

I didn't want to miss the chance to share a photo

[NRoshier]

well it is difficult to imagine a better front splitter/road match than that !

[ben38]

Originally posted by NRoshier
well it is difficult to imagine a better front splitter/road match than that !

Well that's true!
But what about your damper problem? What are you gonna do?

[NRoshier]

Well I have been offered some generous support to help select dampers. So I have booked the car in to get a wheel alignment/corner weight session from an ex-F1 mechanic who now has his own workshop and does FF work. I'll pass on this detail and discuss it further and then I will follow up the advice I get and get some new dampers to suit. The rear open/closed lengths may preclude a monotube damper, but I will fully investigate the matter further when I calm down...I installed new 45 webers and it ran very poorly, so is also in line for a tune-up. However the real surprise was the electrical problems - strangely all the original Lucas gear was fine, but all the Bosch gear needed to be fettled and I now need a new electric fan.

[RDV]

PII-Why don’t F1 cars have adjustable shocks?

..as basic setup is done on a seven poster rig, it is already in the ballpark...secondly same track testing brings the settings to the ideal(sort of) before the race....it will be interesting to see how his develops with less testing this year. And they still have alternate set dampers at hand if needed.Thirdly F1 is a bad example as running on huge balloon tyres, which changes the parameters somewhat, plus being 80% dependent on aero....again this year with reduced aero should see some changes.

I defy you to get any two adjustable shocks the same. The repeatability of results determined on a shock dyno is not achievable yet the believers of adjustable shocks have their adherents.

I would say that in the past yes, present dampers can be very repeatable, from some suppliers.

The only way to adjust your shocks properly is to build them according to suspension velocity histograms. 65% of critical damping in the 0-3 in/sec range will almost always be accurate. Adjustable shocks are an act of desperation.

Yes, not a bad approach, as there is a strong tendency for racing cars to be overdamped.The adjustability will help in trimming the car for different track and temperature conditions and a very good tool for platform control, very important for aero balance.

[Fat Boy]

Originally posted by RDV

Yes, not a bad approach, as there is a strong tendency for racing cars to be overdamped. The adjustability will help in trimming the car for different track and temperature conditions and a very good tool for platform control, very important for aero balance.

I'm waiting for the day when you see an F-1 car run into pit lane, they pop the shock cover off, the engineer hops off the timing stand with a screwdriver and clicks the dampers, they button it up and the car rolls back on the track.

I'll probably have to wait quite a while for that.

Incidently, didn't Villenueve ask Williams re-introduce front flap adjusters? Even with all the aero knowledge out there, these seem to be pretty common. Why not on the dampers?

FWIW, all the modern dampers I've worked on match nicely when built properly. Old Spax or Koni or whatever are all over the place, but those are strictly vintage material now.

[Ross Stonefeld]

I think we'll see mid-session shock adjustments shortly after someone removes a rear wicker during a pitstop.

With the shape of rear wings and specifically their endplates, can an F1 wing even be adjusted these days? Or do you just put on new bodywork.

http://www.autosport...737_HiRes.jpg-2

[Ray Bell]

When you're looking for a longer stroke compared to an overall length, so you get the maximum out of a given length of damper, I'd think a monotube design would be best... but I might be wrong there...

One thing I think you'll find with increasing your rear droop capability is that you'll get more consistent adhesion in the rear in cornering. I think you're right when you suggested you might need more preload... certainly, in a design in which the damper is the droop restraint, you need to have spring load on the damper at full droop.

[NRoshier]

I always thought it would be the opposite given the monotube has to have the gas and contra piston taking up room.
Anyway everything is on hold as the bosch electrical maladies have spread to the ign system and it bogs at 2500rpm and I cannot drive it anywhere like this.

[Powersteer]

With my current race experience being zero, nil and none I would go for a softer tyre(depending on the sprung only mass to unsprung ratio), lots of anti-roll bar, less spring load (squat baby, squat! Get that CoG low) and lots of compression damping to tame that wild axle.

Never have I written a more honest 2¢ in my life.

[Tony Matthews]

[macoran]

Hiding one of your best from us at TNF ? Tony, did you paint it ?....."#hint#

[Tony Matthews]

Don't know about best, Marc - I just thought it might be of interest on a thread about adjustable dampers! Admittedly it's not easy to make out the salient features of the valves and adjusters, but I only have a 10"x8" transparency, which I can't scan, I've tried, and a very small Polaroid-type (actually Fuji) print, so this is the best I can do in colour.

[NRoshier]

Triple adjustable Penske's...I wish!
BTW it might be a good idea to wipe some of the phone numbers in the sketch?

[IrishMariner]

Oi! Tony - I Hope you're not going to make a habit of scattering crackers like this in threads all over the forums????

[Tony Matthews]

Originally posted by IrishMariner
Oi! Tony - I Hope you're not going to make a habit of scattering crackers like this in threads all over the forums????

sorry

[cheapracer]

Originally posted by NRoshier
Triple adjustable Penske's...I wish!
BTW it might be a good idea to wipe some of the phone numbers in the sketch?

2 of my mates racing a Viper at Willowbank bolted in 4 Penskes and went 1 second quicker immediately.

[NRoshier]

I sold mine to a friend with a sports sedan...he is very happy with them...I am not very happy with the currency conversion!
BTW I found this funny, not relevant but amusing and since I started this thread I feel I can go off topic at least once:

[phantom II]

It would be nice if we could see a pro business message from the media for once.
I saw a bumper sticker yesterday, 'Who is John Galt?'
If you buy into this stuff, you must also reject the wisdom of George Washington, Thomas Jefferson, Thomas Paine, Adam Smith, Aristotle, Blake, etc.

I urge you to purchase this book by Mark Levin: Liberty and Tyranny." A Conservative Manifesto."



George Washington: "The best means of forming a manly, virtuous, and happy people will be found in the right education of youth. Without this foundation, every other means, in my opinion, must fail." "Our cause is noble; it is the cause of mankind!"
"Enlighten the people, generally, and tyranny and oppressions of body and mind will vanish like spirits at the dawn of day. ... If a nation expects to be ignorant -- and free -- in a state of civilization, it expects what never was and never will be."

"The country is headed toward a single and splendid government of an aristocracy founded on banking institutions and monied corporations, and if this tendency continues it will be the end of freedom and democracy, the few will be ruling and riding over the plundered plowman and the beggar...
I believe that banking institutions are more dangerous to our liberties than standing armies. Already they have raised up a moneyed aristocracy that has set the Government at defiance. The issuing power should be taken from the banks and restored to the people to whom it properly belongs." -- Thomas Jefferson (1743-1826), US Founding Father, drafted the Declaration of Independence, 3rd US President

Now back to your dampers. What's the story so far?





[QUOTE]Originally posted by NRoshier
[B]I sold mine to a friend with a sports sedan...he is very happy with them...I am not very happy with the currency conversion!
BTW I found this funny, not relevant but amusing and since I started this thread I feel I can go off topic at least once:

[gruntguru]

Originally posted by IrishMariner
Oi! Tony - I Hope you're not going to make a habit of scattering crackers like this in threads all over the forums????

Post them wherever you like Tony (although preferably somewhere easy to find) - just don't stop posting them!

[NRoshier]

Story so far:
Webers now balanced but need some idle jets, main jets and air bleeds, need to make new carbon airbox and ducted filter to in front of rad.
Dampers: trying to get some new springs with a shorter free length.
Trying to find some reasonably priced coil-over dampers - NOT easy locally. Local Bilstein agent says 'these will do, or if you want to revalve to make the work properly then another $200ea' and Koni not an awful lot better. Will keep working on it.
Trying to get car mobile enough to get it corner weighted and wheel aligned.
Electrical maladies mostly sorted, need to get some dialectic grease for contacts.
Thermo fan spat the dummy and stopped working - more to do there.

[Ray Bell]

I think I could help Konis look more attractive to you, Neil...

You know my email address.

[phantom II]

Try these folks. http://www.qa1.net/ They will customize a coil/over profile to your liking cheap.

Originally posted by NRoshier
Story so far:
Webers now balanced but need some idle jets, main jets and air bleeds, need to make new carbon airbox and ducted filter to in front of rad.
Dampers: trying to get some new springs with a shorter free length.
Trying to find some reasonably priced coil-over dampers - NOT easy locally. Local Bilstein agent says 'these will do, or if you want to revalve to make the work properly then another $200ea' and Koni not an awful lot better. Will keep working on it.
Trying to get car mobile enough to get it corner weighted and wheel aligned.
Electrical maladies mostly sorted, need to get some dialectic grease for contacts.
Thermo fan spat the dummy and stopped working - more to do there.

[NRoshier]

Ray you have mail.
P2 I expect I will need to work with someone to get the car where it needs to be and as such I have an aversion to products not supported locally, though I have no doubt QA1 do a do product for what they are.
The local market has Drummond Motor Sport dampers, which seem based on a bilstein. Koni, Proflex, Penske, Bilstein, AVO and a few other brands.
Do you have a view on the monotube vs twin tube debate?

[Greg Locock]

Neil, are you aware of a guy called Deon Beattie? I know he builds off road shocks to spec. He used to be my mechanic, or I used to be his engineer or however the hell that works.

[NRoshier]

No Sorry, have not heard of him. By 'off road' do you mean buggy racing etc?