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[rshon]

I don't know that the line should be that different for power, but I have found that, at least on a race track, having bigger tires, better brakes, and more power allows you to get away with "other lines" without it being so noticeable to other people. Of course, if you take the right line, you should be able to get around quicker.

What I will say is that car setup can definitely affect your approach to a turn. If your car is loose (and more throttle-on torque in a rear-wheel-drive car can contribute to this feeling), you may tend to brake a little earlier (so you don't loop it), make sure you have some margin for the corner, and then accelerate (or coast) through the middle of the corner. If you car is tight (and you have ABS), it is possible to brake later, perhaps even enter the corner a little too fast, and still get away with it by scrubbing some speed off during corner entry (albeit with a somewhat funny line). The most obvious example is a front-wheel-drive car (usually tight) versus a rear-wheel-drive car (if it's an early 911, it's loose), and all-wheel-drive cars can also be a little different (push-me/pull-you). The approach to corner entry, the attitude of the car on exit, and the resulting lines tend to be different.

[Gary Burch]

Higher horsepower cars dont handle any different, they carry momentum just the same. The drivers only think it needs to be driven differently.

Sorry, but I'll have to disagree with that statement, having owned a 944, 911 2.4L, and now a 3.2 in a 73. Everything changes with higher horse power, locations for braking , turn in, throttle on exit, etc etc etc...
Yeah, all cars have to turn in, brake and throttle and carry momentum, but the way you drive a 2.4L and the same car with a 3.2 is quite different...IMHO...
Or am I only thinking I have to drive differently??

Unfortunately I would have to agree with Dan. Momentum is much more important in a 2.2 than, say a 964, or a Boxster, or a'73 with a 3.2. I know everyone who does well at an AX drives on the edge, but in the less powered car you have to drive on the ragged edge with no hope of a horsepower recovery if you screw up or just slightly miss one corner. That's the fun of it.
One thing, you save a lot of money on brakes.

[gocart]

Let's say there is a short strait followed by a 45 deg turn that leads to another straight.
In a high horsepower car you would have gained enough speed so a tap of the brakes would be needed before the turn and back on the throttle through the turn.
In a lower HP car let's say that no braking or maybe not even a lift of the throttle would be needed. That driver could just keep his foot down all the way through the section.
Should the line of both cars be the same?

[Kim Crosser]

I believe the turn-in and apex points should be pretty much the same for all cars. Obviously, the track-out point can vary somewhat with horsepower (a low-HP car - say a "flat out" 944 - may not actually drift to the same track-out point as a high-HP car).
The "mechanics" of the cars will differ. Braking and acceleration can be quite different for each car, based on HP and torque, tires, etc., but I would argue that the turn entry and apexing line should be pretty similar for all cars to maximize the turn exit speed and acceleration.

[Jad]

I think HP make a big difference. It all comes down to available grip. Each tire has a given grip, some of which can be used for turning, the rest for braking/accelerating. In a high HP car, you need the wheel straight to be at full throttle and the car accelerates quickly, with a 944, you can be at full throttle through the corner without breaking a tire lose, but the car does not accelerate well. Thus, a high HP car diamonds a corner to utilize the HP, a lower HP car smooths the arch to maintain momemtum. This is all relative of course. Our high HP cars are momentum cars for professionals, but there are definitely significant differences based on power and car.

[gulf911]

Jad wouldnt admit it publicly, but I think he agrees with me...

[Niraj]

Jad brought up a good point that I've been struggling with. I'm fairly new to this people keep talking about momentum cars vs. 'other' cars. Isn't every car a momentum car? Sincere question - help a newbie out!

[gulf911]

Hi Niraj,
Others can chime in to correct me but my understanding is , as an example, a 944 NA is a momentum car. Because of limited HP and torque with a 2700lb car , you want to maintain as much speed ( through the corner) as you can, because it takes much longer to get back up to speed than with a high HP car/lighter car. You want to limit as much braking or sliding as you can and carry that momentum around the entire course. While the goal is the same on any car in a high HP car the approaching speeds are much greater and require more braking , ie where is the best braking point, how much to brake, but can use torque to get back to speed in a much shorter distance. Not a good explanation unfortunately but my attempt anyway.

Hope it helped a little,
Dan

[Jad]

Jad brought up a good point that I've been struggling with. I'm fairly new to this people keep talking about momentum cars vs. 'other' cars. Isn't every car a momentum car? Sincere question - help a newbie out!

In racing, everything is a give and take and shades of gray. In a momentum car, you must maintain the maximum speed at all times as you can not excelerate to make back time/speed but can be at full throttle in corner exits. In a high hp car, you can slow down more, turn sharper, straighten the wheels and get back to full throttle much sooner which allows you to gain back the time you lost slowing down more to turn sharper. If you get on the gas while turning, like in more of a momentum car, you will spin or have to maintain partial throttle for a long way (effectively becoming a momemtum car). The example in the DE school of the different drivers and their approaches to corners 1 & 2 at Pahrump illustrated this very well. The more power you have, the straighter the steering must be to accelerate "flat out " and you drive sharper diamond corners whereas the less hp you have, the more you round corners.

Does that make any sense or am I as bad as Dan .

[Niraj]

Maybe I'm just repeating what you said. Maybe not though.

So it's faster to take a sharper turn (and brake more for it), straighten the wheel and hammer the throttle in an HP car than brake less, go partial throttle with a wider arc? I would imagine this depends on the turn in question and if the straightaway after the turn is long enough to justify the extra 5-10-15 yards of full accelerration versus carrying more speed throughout the turn but a lower exit speed because of the "momentum" approach.

Maybe you should just be my instructor at Buttonwillow. I would like the red group please.

[gulf911]

So it's faster to take a sharper turn (and brake more for it)

Its out of necessity you have to brake more because your entry speed is potentially much greater, than in a 944 that will brake less and carry the speed through the corner...., you want to have the car straight as soon as possible to get on the gas as soon as possible, hammering the throttle in a new mid engined (read forgiving) car may work for you, but hammer the throttle in my car or a lot of higher HP (lighter) cars and you will end up looking sideways out the window in a hurry, or just burning up the tires....

[Niraj]

Are we just talking physics and available grip like Jad mentioned? Maybe that is what's confusing me. When you say carrying more speed through a corner, that speed is relative to the car and it's available grip. i.e. a GT3 on street tires maybe take the HP approach for a particular turn, whereas a GT3 on full slicks may be able to take the momentum approach?

[Kim Crosser]

Isn't every car a momentum car?

YES - every car is a momentum car. This goes back to an earlier post - once you are on the track you can only lose time AND MOMENTUM. It doesn't matter how much HP you have, if you lose some momentum in a turn and another driver doesn't lose that same momentum, in relatively similar cars the other guy is going to beat you.
Having high HP can help a driver hide the occasional loss of momentum - at least until they meet up with a better driver in a similar car.
What is true is that for a low-HP car to compete with a high-HP car effectively (on raw times), the lower-HP car needs to be much better at maintaining momentum. If the high-HP guy is over-braking in the turns and then using the HP to drag race out of the slow corner, the lower-HP car can beat him by driving smoothly and not losing momentum in the turns.
If it is a low-HP guy against a high-HP guy and both are effective at maintaining their relative momentums (momenti? ), the high-HP guy will always win...

[Mmagus]

Interesting side topic we have going here. I can't resist chiming in with something I have noticed regarding a HUGE line choice difference while working corners.


While observing the slalom section a few AX's back I was surprised at some cars taking what I thought to be the "wrong" line...even more they were entering it on "the wrong side" of the first cone, in my thinking. When I talked it over with Paul Y. he agreed that was not the side he would take. Then as we discussed it more we realized the higher horsepower cars were taking the side that allowed them biggest straight going OUT of the section, while the lower horsepower cars were taking the side that allowed them to carry as much speed as far IN to the section as they could.

[Niraj]

Having high HP can help a driver hide the occasional loss of momentum - at least until they meet up with a better driver in a similar car.

Dan, Jad and Kim - I have seen the light... now if only I can use that light. Thanks guys.