"You want to control the hit with extension and then "hold the hit" with the bump. So this tells you that when you adjust one side, you will also likely need to adjust the other to maintain a balance of action and reaction."
So does this mean with looser extension (more hit) the shock needs to be tighter on compression to hold the tire down? Or looser to absorb the inevitable bounce back without launching the car? (Or is somewhere in between depending on the symptom?)
Monte what do you think of the 4th run? Close on tire sidewall hit or do I need more?
How about front shocks.
Thanks a lot by the way for taking time to respond so far.
I have not looked at the videos and was just answering in generalities. But to answer your question........if the extension is pretty loose, it is going to "throw" the housing hard and hammer the tire. With this scenario, if the bump is too stiff, the reaction is going to be too stiff as compared to the action and can make the car "hop" on the springs or on the tire...........Now, how to fix it? and the answer is, it depends. If the tire really NEEDS to be hit that hard, you would need to soften the bump a little to let the housing "settle" easier and keep it from hopping. Most of the time though, the tire should not need to be just pounded into submission at the start and in that case you stiffen the ext. Seldom do you need to just hammer the tire, especially when you have power. You want to control it smoothly. When the car "feels" smooth and slow, is usually when it's fast. When it leaves like a dump truck hit you in the azz, the settings are off.
A radial has a VERY stiff sidewall, so if you actually see it bulge, you are hitting it pretty hard. If you HAMMER it and flatten it out, it WILL spring back, because you will NOT have enough power to hold it there, I guarantee it. So the goal is to bulge it a little and keep it there.
Power is another consideration. If you make a decent pass and decide to go back and "stand on it" power wise, you will most likely need to stiffen the extension. Because more power, will hit the tire harder with the same settings. This is where guys miss it. They go back, hit it hard, it knocks the tires off and they think they overpowered the track. Usually not the case. Usually they overpower the shock, hammer the tire and it bounces back and spins. A more power hit usually requires some attention in the front as well. Hit it too hard too fast, top the fronts quick and it will spin the tire
A certain track surface will maintain a certain g-meter reading, as it relates to your car. Learn to tune by the g-meter and keep detailed logs. When you look at the track, note the condition and determine the Gs you think it will hold, you put in the tune that produced that number in the past. I can usually tell you within a hundredth what our car will 60ft before we go to the line.....provided I have read the track right. I have 1.20 tunes, 1.15 tunes, 1.10 tunes, 1.05 tunes and so on. Each of these will require shock changes to be optimum
