Boxster S vs Nissan 350Z S Tune vs Chrysler SRT-6
03-11-2005, 08:19 PM
#61
Registered User
Originally Posted by JonBoy,Mar 11 2005, 07:56 AM
Do you race?
(For the benefit of lurkers unfamiliar with Detroit cars, a Trans Am is a twin of a Camaro Z28, and like the Camaro has same general front heavy big engine characteristics the Crossfire seems to have.)
[QUOTE]Understeer = less grip at the front than the rear, which means the car pushes.
03-11-2005, 09:20 PM
#62
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Originally Posted by JonBoy,Mar 11 2005, 03:22 PM
With understeer, you can't use throttle (ie, speeding up) to change the attitude of the car (typically) - you have to brake/reduce speed to load up the front wheels enough to where the car will grip. With oversteer you can maintain speed and use the throttle to keep the car pointed where you want. That isn't the fastest way to drive but it's faster than having to hit your brakes to regain grip.
In RWD, increasing power to the drive wheels doesn't necessarily drastically reduce traction to the steering wheels, so a bit of understeer merely means the front drifts to the outside of the corner as you go around. You cannot tell when this is happening (on turn-in, progressively through the corner, or as the vehicle rounds the corner and power is applied on exit) when someone just says "car understeers a bit," but one may generally adjust driving style to make use of, or eliminate, understeering tendency. In my experience, some people have claimed a "perfect" four-wheel drift around a corner was evidence of "understeer," despite the fact the rear wheels were sliding as well, and the whole thing was orchestrated by the driver. I'm not suggesting a four-wheel drift is the fastest way around a curve, just that it is kind of hard to make any kind of assumptions when given a rather vague statement like "the car understeers."
The one mention of "understeer" I found in a quick scan of the article after a long night - "Good thing there is so much power, because it could be used to help counter marked understeer at the track. " Sounds to me like the understeer was not so much of a problem as someone here is making it out to be. A car that understeers, but may also be steered wih the throttle easily, is often called "neutral."
03-12-2005, 07:04 AM
#63
Originally Posted by no_really,Mar 12 2005, 12:20 AM
The one mention of "understeer" I found in a quick scan of the article after a long night - "Good thing there is so much power, because it could be used to help counter marked understeer at the track. " Sounds to me like the understeer was not so much of a problem as someone here is making it out to be. A car that understeers, but may also be steered wih the throttle easily, is often called "neutral."
I submit that it was enough of a problem that they mentioned it...
You are right about the difference between understeer on a FWD and a RWD vehicle, though. I wasn't quite taking into account that difference (though the disadvantage is still there).
03-12-2005, 07:12 AM
#64
Originally Posted by Warren J. Dew,Mar 11 2005, 11:19 PM
"Understeer" does not imply a complete loss of traction. That would be a "skid".
Exiting the turn, you should be accelerating. The Crossfire's understeer will cause the turn rate to diminish. But that's exactly what you want, because you are after all leaving the turn! Meanwhile the Crossfire's 15% acceleration advantage will overwhelm the Boxster's 1% cornering speed advantage well before you've even gotten to the straight or the braking point for the next turn.
At no time do you need to take advantage of oversteer. As you note, using the throttle to keep the car pointed where you want isn't the fastest way to get around a track; if you need oversteer for that, you're not lapping optimally and not getting the best possible lap time.
Exiting the turn, you should be accelerating. The Crossfire's understeer will cause the turn rate to diminish. But that's exactly what you want, because you are after all leaving the turn! Meanwhile the Crossfire's 15% acceleration advantage will overwhelm the Boxster's 1% cornering speed advantage well before you've even gotten to the straight or the braking point for the next turn.
At no time do you need to take advantage of oversteer. As you note, using the throttle to keep the car pointed where you want isn't the fastest way to get around a track; if you need oversteer for that, you're not lapping optimally and not getting the best possible lap time.
On the exit, you say that the Crossfire's understeer will cause the turn rate to diminish. This is true. However, you'll no doubt note that the turn rate will diminish far more quickly than the much more neutral Boxster. What does that mean? You can't really get more power down. The car is pushing to start with and when you put more power down, you're going to lighten the nose and the car will push a whole lot more.
Bottom line - you're probably not going to get an acceleration advantage until you're well out of the corner. The Boxster, with it's nose pointed the right way and little to no understeer to exacerbate accelerative squat, is going to be on the gas sooner and harder (same with the 350Z).
So...higher cornering plus better brakes plus better exits...vs power in the straight. I still don't think it adds up to nearly 4s.
03-12-2005, 05:33 PM
#66
Originally Posted by Warren J. Dew,Mar 12 2005, 11:42 AM
It's true that if you're not used to driving an understeering rear drive car on the track, you may be tempted to try to overcontrol the steering. I agree that mistake will limit the power you can put down. I made that mistake myself the first time I was on the track. As the instructor told me, put the hammer down, let the wheel unwind, use the whole width of the track - you'll be much faster.
The Boxster, for instance, would not do this - the front end is lightened by acceleration out of the corner, but since it doesn't inherently understeer, you can put down more power sooner. The front wheels will still push, just not as badly, so you can power out harder.
Make sense?
I've raced Porsche 944 (Turbo S), Datsun Z cars, go karts, Mazda RX-7s, and a few others. I've raced on ice and asphalt (ie, road racing). The Datsun's had V8s in them and tended to push (though you could correct easily with the throttle). Ice racing is, of course, a whole different kettle of fish but the principles are the same.
03-13-2005, 05:21 AM
#68
Originally Posted by Warren J. Dew,Mar 12 2005, 11:13 PM
I'm afraid not. So you lose some grip in the front - you can still put the power down, because the power goes through the rear tires, not the front tires. In fact, to the extent that you're losing grip in the front because of weight transfer to the rear, the drive wheels are actually gaining grip.
None of those sound like they were from Detroit. If the Z cars were 280Zs, they might have handled similarly, though I'd expect a V8 engine replacement to mess up the suspension balance big time. Of course, the fact that an engine replacement was done indicates that power was more important than handling - it seems to me that supports my point.
The principles may be, but the practice is different. In particular, a power advantage should rarely matter on ice, since even a fairly weak engine will be strong enough to break the drive wheels free, making any additional power pointless. I'd expect even a base Boxster to beat the Crossfire on ice, if for no other reason than the extra weight over the drive wheels. I'd guess the magazine's lap times were on pavement, though.
None of those sound like they were from Detroit. If the Z cars were 280Zs, they might have handled similarly, though I'd expect a V8 engine replacement to mess up the suspension balance big time. Of course, the fact that an engine replacement was done indicates that power was more important than handling - it seems to me that supports my point.
The principles may be, but the practice is different. In particular, a power advantage should rarely matter on ice, since even a fairly weak engine will be strong enough to break the drive wheels free, making any additional power pointless. I'd expect even a base Boxster to beat the Crossfire on ice, if for no other reason than the extra weight over the drive wheels. I'd guess the magazine's lap times were on pavement, though.
What does the car coming from Detroit have to do with anything? We're talking about cars that understeer, not specifically cars from Detroit.
On ice, oversteer is a requirement. While a V8 in a Datsun Z may mess up the handling a bit, the fact is that the tail comes around enough that you can control it fairly easily. Ice racing is all about drifting the car. The entire time is spent with the back end drifting or about to drift. Bottom line - we needed power on that car because the stock engine wasn't quite what we wanted. It was underpowered for the application.
You've obviously never raced on ice. In unlimited class, you can put as many bolts as you can fit on your tires. These bolts aren't just sticking out 4mm like studs you put on tires up north - they stick out nearly an inch. They provide a surprising amount of grip and power is definitely important. In limited class, power is less important because you're limited in how many bolts you can have in your tire. I've raced both... Examples of winning cars in the unlimited class are Porsche 911 Turbo, Datsun Z with a V8, Porsche 944 Turbo, and a supercharged CRX with a V6 crammed under the hood. Not exactly "low powered" cars... To race quickly, you have to drift the car to the apex of each corner every time - that requires judicious throttle use but good power. These guys are hitting close to 100mph on the back straight....on ice. Doesn't sound like a lot until you realize that the tracks are a bunch smaller than any road racing track typically used....
Anyways, we disagree, obviously. I'll leave it there...
03-13-2005, 08:54 PM
#69
Registered User
Originally Posted by JonBoy,Mar 13 2005, 06:21 AM
Anyways, we disagree, obviously. I'll leave it there...
03-14-2005, 06:23 AM
#70
