b'TECH TIP PAGE Tech Tip 61:The good, bad & ugly with aero. Diffusers need airflow to work well & provide downforce. If you have a well designed rear diffuser (and belly pan) that can seriously help airflow evacuate out from under the car at a high rate, your splitter needs to step up in the front. This is to allow airflow to continue flowing under the carright in the middleand out the diffuser. Or your diffuser is non-functional. On the other hand, if you have no diffuser, or a poorly designed diffuser (for looks) and/or no smooth belly panthe under carriage isnt going to produce much downforce anyway. In this situation, having a flat splitter that seals off the undercarriage & forces all the airflow up & over the cars body, or around) is better. The ugly:Aero is dependent on the car going forward, making smooth, gentle changes. If you get the car in a state of yaw, the downforce disappears. The more downforce you haveor had I should saythe more dramatic the result is with this loss of downforce at speed. This is especially dangerous if you run a smooth belly pan & diffuser. When that airflow is no longer going the length of the car, that downforce evaporates instantly. Can you say oh hell?Sure you can. LOL The old phrase live by the sword, die by the sword is very applicable here. If you have a boatload of aero downforcesay 50% or more of your cars weightand it disappears when you have the car in a 10+state of yawits going to be a 90-180 state of yaw until you hit something. Tech Tip 62: Grip creates harmonics. Period. Anytime we create more grip in a race car, wewill have more harmonics. Higher spring rates?More harmonics. Higher sway bar rates?More harmonics. Stiffer valving to control the springs & bars? More harmonics. Shorter sidewall tires? More harmonics. Wider wheels & more tire pressure? More harmonics. Big aero creating downforce and load on those springs & tires? More harmonics.Ok. Ok. There are exceptions to the rule. Eliminating chassis bind reduces harmonics. So doeseliminating stiction throughout the suspension. But, for the most part, creating race car with a high level of grip, brings a high level of harmonics with it. This is not comfortable in the car. In fact, it is downright uncomfortable & will wear out the average driver in a shorter time. If the goal is to build a winning race car, the driver & crew need to embrace harmonics as a side effect of going faster. The driver needs to be in better shape & not complain about the harmonics to the crew. Because the only cure is to reduce grip& slow the car down. Now, if you have a track car, and driving is all about fun, you need to decide what level of harmonics are you willing to live with to outrun all of your friends. Thank goodness track days only run 5-15 laps, then you get a break. 1080'