SHIFT 2 UNLEASHED Tuning Tips: Spring
Continuing from where I left off last week, I thought I would finish the Springs category. Sway Bars deserved their own blog because I feel they have a far greater impact on handling than the rest. That being said, once you have your sway bars tuned properly, adjusting spring rates and bump stops can act as a complement to them.
I’ll come right out and say it: I love the GUMPERT apollo. I’m not sure if it’s the looks, or the absurd Performance Index the Works conversion gives it (2354!), but I love it as an alternative to all the Lamborghinis and Paganis I see. That being said, I spend about half of my energy just trying to keep the car on the track. The back end simply has a mind of its own.
Adjusting the sway bars helped, but there was still more to do. I needed to tone down the movement of the rear-end, while still maintaining the ability to turn into the corners.
Stiffening both springs to 6.00 essentially turns the car into twitchy, uncontrollable jackhammer. Trying to hit a high-speed sweeping corner with stiff springs will send you shooting into the wall due the wheels having zero give. Every bump in the road is felt, and you’ll find yourself skipping outwards consistently as the tires lose contact with the pavement.
Softening both springs to 0.00 will cure the twitchy feeling, making it easier to control on the straights, but the turn-in becomes much more difficult since there is a lack of responsiveness and slight increase in body-roll.
My personal preference is that I’d rather have to catch the tail trying to step-out, than wait for it come around in a turn. I found comfort in a setting that gives me a responsive front spring rate 4-5.00, and 3.00 in the rear. If you don’t like trying to tame oversteer, set the rear a bit softer.
With that fixed, I moved onto bump stops which cured one of my biggest annoyances with the apollo: Bottoming out. With the Works package, the GUMPERT sits extremely low, and constantly scrapes on rough sections of the track. By setting the bump stops at 15.00 in the front, and 20.00 in the rear, I fixed bottoming out altogether.
The trade-off here is that I gained precious MPH, but the car becomes a little bit squirrely. If you find sparks shooting out from underneath your car regularly, increase your bump stop on the front and rear until they stop, just remember that the higher you go, the less control you have. I would only recommend adjusting bump stops if your car rides extremely low.
A well-balanced car like the BMW 135i Coupe has a ride height that’s fine, negating the need for bump stops (or a change in ride height itself). That being said, it really isn’t as responsive as I’d like in corners. After playing with the sway bars (Front at 6.00 and Rear at 3.00), I set both Springs at 3.00 which resulted keeping the car balanced, giving me a little bit more turn-in, a touch of controllable oversteer, and more speed out of the corners.
If all else fails, keep remembering the three parts to a corner: Entry, Apex, and Exit. Each needs to be smooth in order to be fast.
General Rules:
Stiff Springs - responsive, but twitchy
Soft Springs - Less responsive, easier to control
Bump Stop - Raise it only to the point where you stop bottoming out, any more than that and it becomes extremely difficult to control