StockSH

my coworker(other department) has a Supra and he told me that his car pulls much higher g force than my s2k so it handles better.

I don't know how much Supra weights (3600lb?) but my question is
If both our cars to pull same 1.00 g , then my car(lighter) should be hitting middle apex at higher speed than supra's speed right?

here's a formura for centrifugal force I remember: F = m* ( v^2/r)
this mean force is proportional to the mass...
oh well.. then I wonder how much more speed Elise could carry into the corner..

pantyraider

Yes, all else being equal your car should be going faster even though it is pulling the same g's. The formula you mentioned shows that his velocity must be less than your's to come out with the same g's because his car is so porky

Elistan

If both cars pull 1g in cornering, then they will both be going at the same speed.

Remember, 1g is simply 9.8 m/s per second. If you accelerate at 1g for one second, your speed is 9.8 m/s. If you accelerate at 1g for 2 seconds, your speed will be 19.6 m/s. Doesn't matter how much your car weighs.

Now, the amount of force required to achieve this acceleration is directly proportional to the mass. F=m/a. So if you double the mass of the car, you will need twice the force to maintaine the same acceleration.

So, to sum up - if both Supra and S2000 corner at 1g, they corner equally. The Supra takes 1.29 times the force to achieve this, however. (Bigger tires, stickier tires, whatever.)

FO2K

His car may pull more g's, thus be faster on a skid pad, but it does not mean his car "handles" better. A skid pad measures a relatively static condition where tire size and rubber compound play a large role.

I "real world" dynamic conditions, other factors come into play such as the ability of the car to respond to changes - going thru the esses, braking, accelerating, etc.

Zoran

What Elistan said.

Latteral G is the cornering ACCELERATION, not the cornering FORCE. Mass has nothing to do with it.

If you drop two metal spheres of the same size but different mass from a top of the building, they will hit the ground at the same time and with the same speed.

Same with cars. Cornering at 1.0 G means going at a speed of 9.81 m/s around a corner with 9.81 meter radius. No mass involved.

Now to the other things. Cornering at a higher G does not mean "handling better". You can stick some 11 inch wide wheels with R compound tires and some super-hard springs on a Chevy Tahoe and it will pull more than 1.0 G's when cornering. That doesn't mean it "handles better" than any of the cars pulling less than 1.0 G. As a matter of fact it will handle horribly.

Anyway, tell your coworker that he is full of it and that he doesn't know what he's talking about. First of all, unless he has some serious suspension modifications, his Supra won't have much higher latteral acceleration than your S2000, if any at all. S2000 does 0.92 G, and I doubt a stock Supra can do much better than that. Second, tell him that "good handling" is a much more complex goal than simply putting sticky wide tires and stiff springs on a car. Invite him to your local autocross so he can see what good handling really means. When a Miata with less than half the power he has and only 0.86 cornering ability posts a 5 second better lap time than his "better handling" Supra, he might begin to understand.

pantyraider

I was thinking of lateral force , not acceleration

Caffeinated21

to much time raiding the sorority houses and not enough time in class, i thinks....

vroom

But as stated above - lateral accel does not necessarily indicate good handling. It is not a measure of a cars transitional ability for example, which might be a better indication of 'handling'. Equal spaced slaloms, decreasing and increasing slaloms - these can give a better idea of a car's handling - especially when then teamed with lateral G figures.

Part of the beauty of a Miata in an autocross is how small and narrow it is. They can straight line sections even S2000's have to turn (and slow) for.

You can get a feel for a cars handling by judging it on all aspects - street, track, autocross - it's what makes a Z06 so great - it's a class winner at stock class ax, on track, SCCA racing (not really stock), on the street - heck even the drag strip. A SS (soloII) Z06 can conceivably be driven daily, win on Saturday at an ax, dominate a HPDE on Sunday, and be driven to work again on Monday. Excellent.

Penforhire

Elistan has it right. But skidpad g-force is not meaningless. Put it this way, your co-worker is correct in that his car (if skidpad g is higher than yours) will go around that diameter traction circle faster than yours. No doubt about it. One G (peak) on street tires is really impressive. Not a huge deal on full-on race tires.

Zoran has a more complete answer. Real-world handling is about transitions. The funny thing is most cars, even the Z06 and Miata mentioned, come with compromised suspensions in terms of best transition ability. Really high performance suspensions are very expensive (go price some serious Penske shocks) and not so comfortable on city streets.

Officer_down

A stock Supra used to pull higher g's than a stock RX7, which was in the same range as an S2000, but no way in hell do I think a Supra could handle better than an RX7. No way!