Real World Test: Yaris vs Yaris

[cleong]

nurburgring's (henceforth Marc) got our setups pretty well memorized. I'll only add on that I have tire pressures set at 230kPa front and 210 kPa rear.

Our test circuit is a curvy section of downhill road about 2 miles long. The gradient is generally less than 5%. We did descents as well as hillclimbs.

I took each car down at an approximately-constant 45mph(60-70kph), since one is manual and the other is auto. That helps take transmission out of the equation and we can concentrate on the handling.

Between the two cars, I feel that Marc's car has higher sustained cornering limits due to the footwear. However my car (as said) has a better turn-in and tires are more progressive. I can "convert" the neutral attitude toward planting throttle earlier to set up for the corner exit.

I cannot objectively judge Michelin Pilot Precedas for their grip levels (no basis for comparison to others) but their transition from grip to slide and back is the best I've tried so far (I've got time on Yokohama Aspec DBs, Falken Ziex, Bridgestone GR80).

Dunlop SportMaxx are new to me, and it took me a while to learn their limits. They are impressively high, and appeared to take more lateral Gs before losing traction. Marc complained about the sidewalls rolling; I have to say I can't feel it. I do know that the grip does fade more rapidly the harder you corner. The wider tires give better grip, and also gave the steering a nicely weighted feel that was less "woolly" than my own car.

The fact that the TTE springs are lower in the front are probably an important factor in the handling difference. I've said before that the difference in ride height shifts the CG forward a little. I like how the car pivots nicely around the front wheels when I turn in. That sort of sensation was picked up by Marc as feeling like the rear end was a little unweighted.

The front end of my car received attention from the setup guy who put in the camber and took out the toe. The net effect is that the car grips pretty well under hard cornering, and it has a generally darty pointy feel if you like that sort of thing.

It is probably hard to say which single factor contributes to the differing feel (as described by Marc). Could be all of them. But car setup is a pretty personal thing, some people like the security of understeer, I prefer to drive the front end of the car and let the rear follow. I can use the throttle to control the initial turn-in pointyness to turn it into productive understeer out of the corner.

That being said, we drive at fairly sensible speeds (less than 60mph) to learn the mechanical grip limits of the cars. As such there isn't much hard braking to unsettle the rear end. Driven at 10/10ths my car would probably be quite prone to spinning out going into bends.

I would look to dial out some front grip if I was going to bring my car to the racetracks.

[CASTREX]

Originally Posted by cleong

I'll only add on that I have tire pressures set at 230kPa front and 210 kPa rear.

By the way... can someone plz translate this to PSI???