What are you guys revalving Koni SA's to, on what spring rates?
After riding in a Moton dampened car, I am now completely disgusted with my stock SA's.
After riding in a Moton dampened car, I am now completely disgusted with my stock SA's.
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A lot of talk in this thread has been about what theoretically happens when you add a large bar to one end of the car. But arent we adding swaybarS, i.e. a paired set of front and rear bars? Am I to think that adding a larger front AND rear bar will decrease grip at both ends?
I have IE3/Konis and I still have too much roll imo yet the front-to-rear balance is good. Should I try moderation and go with a 22/19 setup instead of 25/22?
As time went on, the factory developed the car each year, making it faster, more comfortable, and capable of handling at higher speeds.
You don’t want this. You want the trickiest, most dangerous, oldest model you can find. Only then can you prove to the world that you’re a man.Comment
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You won't necessarily need front and rear bars. The front bar increase may help to make use of the negative camber you have in front, adding grip to the front of the car. And doing nothing to the rear would make the car less prone to understeer and/or more prone to oversteer.....
You maximize the front and then tune the rear to suite imo. Get the response you are after with shocks, and springs, add a swaybar and camber plates to both get, and maintain negative camber, then tune the rear to suite the front.....
This is a HUGE, HUGE if, and I probably shouldn't even say it here, but if the driver doesn't induce UNDERsteer a car that is setup to understeer just a little bit will ALWAYS be faster in an autox (remote exceptions being AWD and FWD cars)sigpic
88 325isComment
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This is the impression i have gotten from this thread as well. why upgrade the size of the swaybars if it is only going to decrease grip? does it only decrease grip on the outside tire because its transferring the load to the inside and you have equal/greater handling, or do you really lose cornering ability?Originally posted by madjurgen View PostComment
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You lose ultimate grip at the expense of increased responsiveness, reduction in roll, less camber change, and increased driver confidence. As long as you don't go stupid wild with the sways bigger can be better.Comment
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Originally posted by 318iSdaniel View Post
Here are some more generalities.
One can go up and down in total roll stiffness and maintain the same chassis balance, so theoretically I could go from a total roll gradient of 5.0 degs/g (standard measure of roll) with a total roll stiffness distribution of 55% front and 45% rear, to a much more sporting (responsive) 3.0 degs/g with that same roll stiffness distribution of 55/45 Fr/Rr. Roll stiffness distribution is only part of the chassis balance equation but we’re talking springs and bars here. In order to really compare the OS/US balance we need to look at an understeer gradient which is a measure of total understeer. The understeer gradient takes into account the roll stiffness distribution, tire, suspension kinematic, and stiffness factors.
Sorry kinda rambling there, but theoretically we could get to the same OS/US balance as we move up and down in roll gradient. The trouble comes in that the hardware that is available to us off the shelf is somewhat limited. Here’s a few calcs to hopefully shed some light on the roll magnitude / chassis balance discussion.
My mad paint skilz are questionable at best, sorry for the fuz. But you can see that the roll gradient has dropped in the 2 examples but the roll stiffness distribution is basically identical.Attached FilesLast edited by JeffRR; 10-07-2008, 09:44 AM.Comment
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can you share this file?Comment
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This maybe obvious, but what is the best way to post a file?Originally posted by xLibelle View PostComment
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If anyone is interested here is the spread sheet that I used for that comparison.
A few notes: This is a compilation of common vehicle dynamics formulas from various text books. What’s in this spreadsheet you’d pick-up in an undergrad vehicle dynamics course.
I use these calcs as a reference only, really only as a A~B comparison using a known set-up as a baseline.
Some of the values in the input section are generic values that I felt were reasonable for comparing spring/bar packages.
Thanks to xLibelle for hosting the file:
Last edited by JeffRR; 10-09-2008, 05:00 AM.Comment
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