Keep hearing about frame twist with 440s
I know you know a lot...But no. Uncle Tony isn’t making it up as he goes along. I may have misrepresented his comments. If you’re interested, check out the video.
Don’t get me wrong. I don’t think that a more flexible chassis is better, at least not for the kind of driving that I enjoy. That said, some compliance in the system can absolutely make a car more forgiving and it doesn’t mean that the flex will be unpredictable. A lot of that comes from the driver knowing the car. Chassis flex doesn’t tend to present like slop from worn ball joints or a worn track bar bushings on a solid front axle vehicle that can surprise you (usually not in a good way).
On most roads in the USA these days when the rich people own everything and don’t pay taxes (eff you, Jeff Bezos) the roads are going to hell. Our infrastructure is crumbling everywhere. A stretch of road without potholes, cracks, cheap patch jobs, etc is pretty rare in most parts of the country. As a result, you could bring the 2019 SCCA Solo2 champion modified whatever car out to some local rural back roads and it might get dusted by the same driver in a bone stock Miata- some actual suspension travel and compliance in the system from shocks chassis flex, etc. might be a huge advantage depending on the surface where none of that is helpful in the controlled environment of a sanctioned autocross lot. Is it better if you can get all of that compliance from the suspension? I would say yes as someone who plans to keep cars for decades but flex can be engineered to be part of the system, not unlike the wings on any passenger plane.
As for Tony’s example of maintaining control on the drag strip in car with drag tires, probably no oil in the front shocks, slant 6 sway bars, etc; I can at least imagine that extra slop of a non-reinforced chassis might give you a tiny bit more of a warning and save you from smacking the wall. I haven’t been horsing around with muscle cars since the late 70s like Uncle Tony so I’m not able to report on my own experiences but intuitively, that sounds plausible.
I’ve seen Tony’s first video on chassis reinforcement. It was completely wrong. Not a little wrong, not wrong for some applications, but a complete misrepresentation of physics, metallurgy, engineering and science.
Sure, a lot of what he says “sounds intuitive”. That’s not science. He has a lot of experience, that’s true. But anecdotal evidence does not change the science. If what “sounds intuitive” was reality anybody off the street could design airplanes and bridges and everything else. That’s not how it works.
Your example of back roads isn’t accurate. The “SCCA 2019 Solo2 champion” isn’t at a disadvantage because the chassis is too stiff. It’s at a disadvantage because it’s suspension is set up for a smooth road and super grippy tires. Dial back the suspension for a road tire and the stiff chassis isn’t a problem at all. That example has nothing to do with chassis stiffness and 100% to do with suspension tuning. Those are VERY different things, and you’re interchanging them. So does Tony. That’s not experience, that’s oversimplifying what’s actually happening so it sounds good on YouTube.
Even the drag race example is backward. “Extra slop” doesn’t give you more warning, it gives you LESS. Your chassis gets more out of shape before you notice it. And when you do react your inputs are lost into that slop. That’s lag time where your chassis is stepping out further. That’s not helping you recover, it’s fighting your recovery.
Yes, chassis flex is different than a worn out ball joint. And it is somewhat predictable, but that doesn’t mean it’s good. If your flexible chassis has loaded up in a left hand corner and you have to immediately turn right, well, that’s stored energy in your chassis that’s fighting your input for the upcoming right hand corner. If it unloads quickly, you’re toast.
Like I said, Tony knows a lot, and he’s definitely an authority in a lot of things. But he’s completely out of his depth on chassis reinforcement, and he’s putting out bad information.
