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/DRIVE Who is your Chassis and What Does it Do?

Posted: Mon Oct 12, 2015 2:25 pm
by kevm14
https://www.youtube.com/watch?v=xYYGkWVy32I

I guess I should have put /ENGINEERED in the subject line. I'm just glad that content creators (and the viewers) are realizing you don't have to just do superficial or typical car stuff on the web. We live in a wonderful time. That may be the codeine talking.

Anyway, this may be a good compliment to Pobst's series, since this will probably discuss the vehicle itself. Would be interesting if they covered the kind of things/tricks that OEMs can use to get handling and ride quality at the same time.

Shock damping is just one piece, since you also have to know how to TUNE the shock. Clicking a knob on a set of Konis won't do it though it will be serviceable at least. MR shocks also (and again, critically, tuning them). The algorithm in the controller is just as important (or more important) than the technology itself. You take inputs, do some processing, and that drives some outputs. That's the magic part.

Lightweight suspension components. Less unsprung weight is always better unless you're off-roading.

European-style bushing solutions. Compliant bushings that absorb NVH in one direction and geometry that provides stiffness in another direction. The liability is lots of bushings and rubber stuff can wear out and make the car feel awful vs a simpler design that probably keeps its stock characteristics over a longer period.

Trick geometry like passive rear wheel steering. The difference between my CTS-V and cars that preceded it is that you can coax whatever slip angle out of it that you want. Somehow the rear can bite and hold a slip angle without resorting to spinning out. Less sophisticated handlers fail here. I'm looking at you, F-body.

Re: /DRIVE Who is your Chassis and What Does it Do?

Posted: Mon Oct 12, 2015 2:31 pm
by kevm14
Still haven't started the vid for some reason but I forgot a big one:
Overall chassis rigidity. This is actually huge, because the benefit is better ride AND handling, all else equal. It allows the suspension to be tuned to do its job, and not be stiffer than necessary to compensate for unwanted flex in some direction (or directions).

The road to good handling is basically maximum suspension compliance for non-smooth surfaces while also damping all unnecessary body motions. This is kind of how I feel about the FG2 shocks in my CTS-V though I know a lot of progress has been made since 2005...

Re: /DRIVE Who is your Chassis and What Does it Do?

Posted: Mon Oct 12, 2015 2:38 pm
by kevm14
I learned some of this from Dan Edmunds on those suspension deep dives on their fleet vehicles. Does anyone remember that?

Re: /DRIVE Who is your Chassis and What Does it Do?

Posted: Mon Oct 12, 2015 2:46 pm
by kevm14
Ok so my expectations were way off. When they say chassis, I think they mean frame or unibody. Literally just the frame. Anybody who is going to actually build their own chassis isn't using this video. I think identifying good street car chassis and suspension characteristics, and then what makes them tick (a la Dan Edmunds) would be more interesting.

Re: /DRIVE Who is your Chassis and What Does it Do?

Posted: Thu Oct 22, 2015 3:16 pm
by Bob
kevm14 wrote:I learned some of this from Dan Edmunds on those suspension deep dives on their fleet vehicles. Does anyone remember that?
I do remember those. I always enjoyed seeing those. This was back when Inside Line was doing its best work, IMO.