Q: “I’ve been told to work on my driving before making mods and tuning my car, and I’ve taken that advice. But my car understeers badly. No matter what I do, I just can’t seem to get it to turn. Can you tell me what I can do with my driving to help this? And then, what should I do to my car to make it understeer less?”
A: I’m going to turn your questions around and answer them in the opposite order – what to do with your car first, and then what to do with your driving.
As I wrote about in my How to Tune Your Car’s Handling eBook (free to download at https://speedsecrets.com/tune-car-handling/), start tuning your car by using the tools you have. So, if the only tool you have is a tire pressure gauge, then adjust tire pressures; if you have camber gauges and can adjust camber angles, do that; if you have aero devices on your car (splitter, rear wing), then use them.
Understeer is simply that the front tires have less grip than the rear tires, so your goal is to give them more traction. In terms of tuning your car, start with softening the front roll stiffness. You can do that by changing the front springs to softer ones, softening the front anti-roll bar, or reducing compression and/or rebound on the front shocks. You could also lower the front ride height. Oh, and back to the tire pressure gauge… either reduce tire pressures, or increase them. Yup, there’s no way of knowing for sure which way to go without trying and testing different pressures. If your tires are already slightly over-pressured, then lowering them will help; if they’re under-pressured, then increasing the pressures will help. Make some reasonably big changes – at least 4 psi – in both directions to get a “read” on which direction you want to go before fine-tuning with smaller adjustments.
As for your driving, you can manage understeer by either loading the front tires more, or less. So, you could trail brake further into the corners to keep load on the front tires. However, the understeer could be caused by overloading the front tires, so you could release the brakes earlier to reduce understeer. There’s only way to find out which one works, and that’s to try them both. However, if I had to start with just one option, I’d trail brake more to load the fronts more, as that will work more often than the opposite approach.
You could also drive the line through corners that allow you to begin to unwind (straighten) the steering wheel sooner, to reduce the amount of time you spend turning the steering wheel. I’d also try being a bit more gentle with the initial turn of the steering wheel entering corners, so it gives the front tires more time to change direction of the car.