Shhh... don't tell The Frog

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Chalk line test is great... if you're on the track or autocross. It really helps dial in hot pressures for max grip. But those pressures may not be safe for the street. 

Posted by: NottaMiata

I am looking for lateral stiffness. At least thats what I think I want.

I put some air in the rear last night, but still not satisfied. Not done tweaking pressure yet, though.

So, is there any opinion as to my camber? Would it help that rolling-under feeling if I increased it a bit more (more negative)?

Is that half-degree reduction from the recent alignment significant?

Before starting down this path the best thing you can do is get the car evaluated by a experienced member or by a tuner shop that has experience for track. 

It is the single best thing you can do so you can  save  a lot of time and money getting your car to perform to your satisfaction. 

Suspension and tires are not a very simple subject that can be understood on an Internet forum. I had a lot of frustration with those that were full of half knowledge   but claimed to know what they were doing because they AutoX or raced their car but had nothing to show for it.    There were a few members like Randy Chase that had very good  logical explanations that were spot on because what he wrote added up.  I decide long ago that internet forums are not the best source of information when I was trying to build my car to be a handling monster so I turned to books written by authorities on the subject that had very nice illustrations and explanations that were referenced and edited for accuracy. I suggest  that would be the best way to go but I warn you once you figure it out you will start to find errors in what others write.  

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As I said previously the dampers will not be noticeable to be bad to most for straight line driving but when you performance  drive they will be shot to hell. 

Most people with really old passenger  cars probably have shot suspension and they don't know it or even care because the feeling is progressive until it reaches  a point of being obvious where its crashing. 

The only way you can know this is to drive a low millage Spyder and feel the difference. Brand new the car handles very well until it reaches 40k miles where the mid-corner float becomes obvious. 

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Dampers don't have to be leaking to be bad or bounce excessively like those old time suspension tests suggest.  Dampers can just go bad from its characteristics of dynamic damping. The only way to know this is if an experienced person drives your car or a shock dyno.   

The struts that were provided for this car are made by KYB and its not the same struts that is sold by KYB as a replacement.  The consensus was and my own observations are that the original KYB had less gas charge in the bladder and I observed this by pressing down on a sock damper that only had 10k miles on it where the piston will retract slowly.  The replacements have more gas charge in them. 

 They also ride slightly different as well.  The OEM damper when brand new is better but unfortunately very short lived where as the KYB replacement can last a lot longer.   

You see this kind of thing in advanced suspension where there is a trade in performance  for longevity especially with some of the  mono tube options which requires frequent rebuilds.   

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 Adding more and more air will give you the illusion of the car driving better and being more responsive.  This might be a good feeling but it is in no way optimal for two reasons. You will not have an optimal tire contact and you will actually lose sensation of knowing what the tire is doing near or at the limits. 

 Some people do this especially those that have shot suspension components  or tires that have a soft sidewall to get more repose and more of a BMW kind of ride but it is counterintuitive.   

There was an owner that asked me to evaluate his car and it was scary because I could not feel what it was doing. The owner made an over generalized complaint about how the Spyders handling sucked and I disagreed with him on the board and I offered to evaluate his car. 

 The owner added brand new KYB struts so that was not the problem as it was well dampened and although the car would perform well  without diving or any indication of something being mechanically wrong it was terrible.   I could not put my finger on why but I asked him what his inflation pressures were and he said over 40psi. 

I stoped him right there and politely mentioned that is the reason and if we lower the air pressure it will dramatically improve.  He didn't believe me and was adamant I was wrong and said it shouldn't matter and could not make that much difference.  

After lowering the pressures to stock it was night and day.  He was pretty amazed as cynical as he was.    This is why making assumptions about suspension will lead you on the wrong path. There are many that have a poor suspension  and don't even know it.   When accident avoidance comes into the picture then the car will flip out on them when they least expect it.  

Suspension tuning  is a precision instrument that cannot be taken lightly.    For normal passenger cars it doesn't matter a whole lot because as they get older, the softer suspension is forgiving but when you get a boy racer adding stuff that stiffens the car then it becomes a danger.   

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Posted by: NottaMiata

LOL, Dev, you sure do have a lot of stories about trying to help stubborn people that are "smarter than you". I hope I don't come off as one of those people.

 

 Most people are pretty responsive and are surprised that it was something so simple that it can be fixed in 10 minutes.  A few have been a real pain but I believe in what I write and that is why I stress it.  I have been around these cars a very long time and have driven many examples to the point where I can diagnose a car in five minutes of driving unless its really throwing me for a loop. 

This is nothing new, you are not giving me anything different than what most people assume because its typical. 

Sometimes there is a right thing to do that is done blindly  however the explanation why  is a bit more complex a contradiction of sorts. Understanding the nuances and rational is the only way to fully understand otherwise it is someone else  repeating the same old  answer but without the explanation behind it.  

 Everything you do to this car has consequences. How much you are willing to give up is on you but well spend money on this hobby for quality parts tends to  solve a lot of compromises but unfortunately most throw money at the car. 

...never mind...