Damper and spring suspension settings.

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DaveW
239
Joined: 14 Apr 2009, 12:27

Re: Damper and spring suspension settings.

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ubrben wrote:I'm probably closer to Tom on this. If you look at circuits like Paul Ricard, Lime Rock, Road America, Road Atlanta, Monza, all can warrent having harder tyres on the left-hand side of the car.

Agreed that you rarely see asymmetric springs or dampers, but toe, camber and tyres (pressure and specification) is normal. Running cross weight at places like Long Beach also makes sense because two of the best passing opportunities are braking into 90 degree left handers so some more LF corner weight is useful.
Ben - if you look at my first post, you will see that I agree with your comments on tyres. The problem is that handling can become compromised & inconsistent when tyre "mechanical" properties differ across the vehicle on track. The effect can be minimized by adopting asymmetric suspension settings, given time & the tools, but the task is not a simple one & is, in my opinion, best avoided.

I have more of an issue with static cross weight. The mechanical lateral balance of a vehicle is manipulated by dynamic cross weight in turns, corners, etc., set by suitable selection of springs, bars & tyre pressures. If the vehicle has a good "natural" balance, then adding static cross weight will move balance towards understeer in one direction & oversteer in the other. If it improves max. lateral in one direction, then it will reduce max. lateral in the other. Drivers tend to dislike such inconsistencies & are likely be more conservative as a result.

Much of the above changes, of course, if/when a vehicle is required to turn in just one direction...

Jersey Tom
166
Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Damper and spring suspension settings.

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I'd be all for playing with cross or at a minimum, side weight at Lime Rock... for a road course it might as well be NASCAR in reverse.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

DaveW
239
Joined: 14 Apr 2009, 12:27

Re: Damper and spring suspension settings.

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Postscript (to Ben):

Your specific mention of Long Beach suggests that you are referring to Indy cars? I suspect that engineers in that series have a preference to set up vehicles purely for aero control. As a result they tend to be mechanical under-steerers, in which case adding static cross weight will improve mechanical balance in the (one) chosen direction. In my opinion, the better solution would be to address the basic lack of mechanical balance.....

speedsense
13
Joined: 31 May 2009, 19:11
Location: California, USA

Re: Damper and spring suspension settings.

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Jersey Tom wrote:Braking / accel out of corners happens at the following tracks in NASCAR:

Fontana
Las Vegas
Atlanta
Bristol
Martinsville
Phoenix
Texas
Richmond
Darlington
Dover
Charlotte
Pocono
Michigan
Loudon
Chicago
Indianapolis
Kansas
Homestead.

(Not just Martinsville).

In any event.. there are plenty of options for an asymmetric setup, beyond kinematics. Air pressure, sure. Static cross and left side weight for sure... asymmetric toe... springs... ARB gaps, etc.

Certainly very relevant on road courses.. Lime Rock in the US is the best example. F1 engineers must be very familiar with it as well given that the chassis' themselves have been designed without symmetry.
The main difference is how hard they hit the brakes, the closest braking events (to a road course) are the short flat ovals like Martinsville. While the NCup guys do brake on the ovals, its not a "very hard" braking event and on the higher speed ovals, they actually use different rotors/caliper setups to gain less unsprung weight. The braking events on most ovals is rarely over 1 g. Except the short ones where it approaches road course braking of 1.5-1.7 g's.
One of the hardest things to "learn" for an oval specialist on a road course, is how hard they can attack a brake pedal.
Asymmetrical setup do work on road courses, but most (if not all ) of the time the front springs are the same, due mainly to the braking events. Rear springs however are an effective source of cross weighting as you don't have the high long G of a braking event.
Lime Rock is a common place to run rear springs that are different and cross weight that asymmetrical. Don't know of anyone who has had success with asymmetrical front springs however.
"Driving a car as fast as possible (in a race) is all about maintaining the highest possible acceleration level in the appropriate direction." Peter Wright,Techical Director, Team Lotus