Häl o Tå revisited!

Det har varit på tapeten förr men kan alltid diskuteras igen

Den här texten hittade jag på "Ringers list" och tyckte den var kul läsning. Kommentarer????

First of all, let's look at why HT makes you faster. When approaching a corner at a speed greater than traction will allow you to traverse it, and the speed at which you must enter the turn is best handled by a lower gear, several things must happen. I think it goes without saying (even though I'm gonna say it) that everyone knows it's best to have the appropriate gear selected before you enter the turn. Thus the whole reason for the existence of HT. If you don't know this, then there are other discussions you need to participate in on car balance and acceleration prior to taking on HT.

OK.
First - you've got to slow down. Obviously using the brakes accomplishes this. There has been discussion on engine braking but in this situation engine braking offers so little in the scope of things that its effect is negligeable. There are those who would even say that engine braking shoud never be done. I say it's another tool to be used when appropriate. Usually between corners that are very near to one another and your speed is already relatively low, as is your gear selection - thus increasing the effect. But ultimately, if there is a downshift involved, this is the area in which you want to accomplish it - in the braking zone. To get your driveline set up for optimal travesal of the turn with the highest exit speed.

Second - This is a turn, so you've gotta do just that...apply steering to turn the car in (hopefully ) the correct direction. Not much else needs to be said here...right?

Third - To keep the back end planted as well as to gain speed out of the turn, you have to accelerate. We're talking "maintenance throttle" and "rolling" here. I see many people say that they "nail it" at the apex of a turn. I certainly hope this is not really the case, and that you are speaking figuratiely. If you "nail it" [in a high-bph RWD car] at the apex of just about any turn other than high speed sweepers (and even then it can be dicey) and you're in the appropriate gear you are going to go for a theme park ride. A transition at the apex of a turn from maintenence throttle to suddenly foot-on-the-floor like a light switch is usually so upsetting and so overpowering that throttle oversteer is almost ceratin. And once you're there (To) there is little to no recovery that will save that lap - you're toast. Anyway, stepping back off my soap box and back to the chalk board...

You must apply some acceleration to this equation to keep traction on the back end - even if it's a turn that requires rotation (another discussion).

So now, we have braking, steering and throttle applications. The fastest way through a turn is not necessarily defined as the highest speed way through it. What we're really looking for is the most efficient way through the turn. Through efficiency comes speed and decreased lap times. The way to attain maximum efficiency is to play at the limit of traction at all times - effectively maximizing the amount of traction you can maintain for any given situation. This is driving at the edge but not going over it.

The only way to do that is by using all the aforementioned techniques/controls at the same time. Braking, steering, and acceleration. And to accelerate most efficiently for the turn you need to have the driveline at the most effective gear ratio, which usually involves shifting. So now, in order to take the hypothetical turn, one's two feet must be doing three jobs. Let's consider my slightly altered graphic from Ross Bentley's great book Speed Secrets, a recommended must read:

(please visit Smartgroups->Pictures->Temporary->speedsecrets.jpg)


If you try to ....

forts...

If you try to cheat, you lose efficiency. That "split second" you mention actually covers a lot of distance when you're in a moving vehicle, especially on a race track. You just gave up that distance to your competitor who is using proper HT technique - in every turn. Not to mention that in that split second, you have taken the weight off the back end by not applying throttle and thus changing the balance of the car - doubtfully for the good. Next you engage the driveline at a lower speed than the rotation of the diff gear, further upsetting the balance while the driveline and diff are forced to negotiate a truce. Now you have a nose heavy situation, as well as a less than flat side-to-side weight distribution (due to upsetting the driveline) at or even beyond the turn-in. Not optimal.

If you look at the above graphic, it becomes obvious that the most efficient way through the turn is actually braking through the turn-in and even into the turn, gradually decreasing the braking force along the way. At the same time, you are rolling into the throttle. This requires HT foot placement for your right foot, even if you don't shift. Furthermore, acceleration should begin long before the apex (another old bad habit) to both keep the rear planted but also begin ramping up your exit speed. Usually, by the time you get to the apex, you should be at or approching full throttle. Again, one must use proper judgement when driving a high HP car - full throttle depends on gear, speed, and turn ratio.

So to draw this epic to a close (and hopefully I've answered your question in all this), You bleed off the majority of your speed in the straight braking zone prior to turn in; if you don't have enough time to do so you either waited too late to brake (go get bigger clamps or extend your BZ) or were simply not braking hard enough. This is also the point at which you need to get your gear selection completed, gracefully and smoothly. Smoothness is the key to all of this. If you are not smooth (i.e. you force your driveline to argue with itself) and efficient (i.e. you lose energy that could be applied to going faster to spinning up the front side of the driveline to match that of the diff) then you will not traverse a turn optimally. Not to mention the added wear and tear to you wonderful car...


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Någon här på Ringerslistan som förstod vem som skrivit det hela?

Som jag tolkade det så var det ngn på en Corvette-site.

Jag tycker det är för mkt generaliseringar och dessutom en del missuppfattningar.