Kimi vs. Fisichella (driving styles)

[Guest]

Cyco: Those cars use semi/sequential gearboxes dont they !

Braking to improve turn in is known as trailbraking and can be done by either technique. But I think the layout of corner more than anything else determines how you approach the the corner.

I think you are confusing the two concepts, lfb and trailbraking(tb). They are used to achieve different goals. Tb is used to improve the handling of a car in the first part of a corner and ultimately it is aimed to improve your speed thru that corner. Lfb is used in conjunction with Tb to further improve the handling(weight tranfer) of the car during the entire corner.

RH1300S: I dont agree with lfb improving how you use your tires or rather I dont understand why but plz explain. I but I really believe that it improves the transition from throttle to brake to throttle or rather the weight transfer during a corner, otherwise nobody would use it.

In regards to the gearbox, yes Im aware that a manual gearbox can change gears without the clutch but we are talking or discussing racing situations. The fact that in a WRC car you can mount the seats backwards and have the co driver use his left foot to accelerate the car isnt relevant to me.

/ Fx

[Guest]

RH1300S: I dont mean to be rude but in racing you tend to go for what the fastest and not whats possible.

Cyco: I just want to clearify that I mean that both heel toe(right foot braking) and lfb can be used to trailbrake.

/ Fx

[manchild]

Shifting down without clutch is much easier than shifting up. When shifting down without the clutch you should slightly press lever towards the desired lower gear and than sort of wait until it drops in. I can’t exactly explain it because it is the matter of sense and hint you learn after practicing on specific car. Sounds you get from engine and gearbox are very important for understanding when it is the time to shift down (clutchless).

[RH1300S]

Cyco: Those cars use semi/sequential gearboxes dont they !

Braking to improve turn in is known as trailbraking and can be done by either technique. But I think the layout of corner more than anything else determines how you approach the the corner.

I think you are confusing the two concepts, lfb and trailbraking(tb). They are used to achieve different goals. Tb is used to improve the handling of a car in the first part of a corner and ultimately it is aimed to improve your speed thru that corner. Lfb is used in conjunction with Tb to further improve the handling(weight tranfer) of the car during the entire corner.

RH1300S: I dont agree with lfb improving how you use your tires or rather I dont understand why but plz explain. I but I really believe that it improves the transition from throttle to brake to throttle or rather the weight transfer during a corner, otherwise nobody would use it.

In regards to the gearbox, yes Im aware that a manual gearbox can change gears without the clutch but we are talking or discussing racing situations. The fact that in a WRC car you can mount the seats backwards and have the co driver use his left foot to accelerate the car isnt relevant to me.

/ Fx

I think you explain why lfb & tb work. To my mind lfb is a way to tb BUT with added control as the brakes are tapered off and throttle picked up.

Probably best to google for Friction Circle to get what I am saying about tyre use. Google first - then let's hope I explain this well. The outer edge of the circle is the max grip a tyre can give you and it is shared between lateral and longtitudinal loads (BTW friction circles in real tyres are often oval shaped, giving a tyre bias of more in one direction than another). So, full braking takes you to the outer edge of one side of the longtitudinal grip, leaving nothing "spare" to corner with - as you give up some braking (trail braking) the tyre can give more corner grip (it's a trade) - when you are not braking or accelerating you have max side grip available. The aim is to be able to move between the grip directions, keeping the tyre very close to the outside edge of the circle. By using normal braking, there is more chance of a little bit of "dead" time when the tyre is not being fully used between max braking and max sideways grip.

So, a corner that is long enough to have a full sideways load for a good amount of time it is probably 50/50 between rfb & lfb - but imagine a short corner where you are able (or need) to get back on the throttle sooner - it must be faster to lfb.

Also, F1 cars slow down very quickly just lifting the throttle - so lfb must give better control of speed changes at high speed.

BTW I am not saying the lfb is always faster than rfb - I am just trying to explain why it will be faster more often and

Yes, I agree you will use the fastest technique in racing. Clutchless shifts in a synchro box are probably slower than using the clutch - BUT a downshift is a little easier and gives you lfb control options. Gear changes in a non synchro racing box are fast when clutchless.

[manchild]

Also, F1 cars slow down very quickly just lifting the throttle - so lfb must give better control of speed changes at high speed.

1 g (one gee) with high downforce setup and it is more than what conventional cars achieve with full braking power!
(info is from Williams F1 team)

[manchild]

RH1300S: I dont mean to be rude but in racing you tend to go for what the fastest and not whats possible.
/ Fx

Getting as fast as possible to the end of braking point doesn’t naturally mean that acceleration that follows will be as high as it would be with TB (overall time - from entry to exit from turn).

[Guest]

RH1300S: Maybe I dont express myself very clearly but I agree almost completely. Im a software student so I dont really know alot about gearboxes but what I have seen from onbard footage is that depending on the type of car different types of techniques are used in regard to gearchanges. That has to be because of the gearboxdesign, or the drivers really suck, but in leauge racing I dont think they do.

Manchild: Of course not, that is why generally fastest means the highest average speed for the given distance.

/ Fx

[Cyco]

Braking to improve turn in is known as trailbraking and can be done by either technique. But I think the layout of corner more than anything else determines how you approach the the corner.

I think you are confusing the two concepts, lfb and trailbraking(tb). They are used to achieve different goals. Tb is used to improve the handling of a car in the first part of a corner and ultimately it is aimed to improve your speed thru that corner. Lfb is used in conjunction with Tb to further improve the handling(weight tranfer) of the car during the entire corner.

I completely agree with what you are saying here, but you are missing some of the other points LFB gives you an advantage. These are not so obvious on a F1 track, but on road rallys and tracks like the 'ring and Bathurst these work well.

Tapping the brake when the throttle is wide open will transfer weight to the front wheels and result in the suspension squatting. When cresting a hill the car will normally get very light and can drift on road camber. The lfb here will keep the car on the road in much more control. This lfb will also work where the kick/corner is very fast, but the car will run wide without some extra front bite.

Do not worry if you do find this in traditional driving books, it is more likly to be taught at rally schools, but even then not all have the sensivity on their left foot (or choose to learn it) and it is considered an advanced technique, but I found it quite easy to pick up and use it regularly.

[Guest]

I see what you are getting at. Of course I agree. I understand that to improve front end grip you shift weight forward. Of course you can use the left foot to tab the brake in any car clutch or no clutch(asuming cardesign and other parameters allow for it), what I meant by lfb was F1 style lfb were you use the lfb to improve tb(weight transition) and the exit of a corner. That I dont think you can do with a gearbox that has a manually operated clutch.

/ Fx

[Cyco]

Guest, Let me also add that these techniques work much better in a turbo car than in a NA car as it helps to keep the turbos spooled up and on boost

[Guest]

Why would lfb improve the latency of the turbo ? The pressure is directly linked to the rpm of the engine isnt it ? If thats the case then either the clutch or the rearwheels needs to slip and to me that seems counter productive.

Im not saying you are wrong I just cant see why lfb would decrease the latency of the turbo.

/ Fx

[RH1300S]

Why would lfb improve the latency of the turbo ? The pressure is directly linked to the rpm of the engine isnt it ? If thats the case then either the clutch or the rearwheels needs to slip and to me that seems counter productive.

Im not saying you are wrong I just cant see why lfb would decrease the latency of the turbo.

/ Fx

It creates a demand in the intake, so the turbo begins to spool up.

[manchild]

Braking with left foot without completely removing right foot from the accelerator could perhaps benefit turbo engine because the pressure in the intake would be different and that would probably (in certain amount) prevent vacuum sensors to activate water injection (or other fluid/mixture) - Engine would still get real fuel mixture instead of water mixture whose purpose is to keep revs of turbine during downshifting and braking.

[DaveKillens]

Turbos in modern race cars have progressed and evolved a lot since Renault first introduced a turbo to F1. Back then, turbo lag was a very large issue, but as we witness in WRC, it is now almost non-existant. These days, they pump more air than needed, and use the wastegate to dump excess pressure. This keeps boost pressure much higher at lower RPM's than in previous generations.
As far as upshifting and downshifting in Formula One cars, it must be emphasised that the engine, transmission, and associated drivetrain controls are integrated and controlled by a computer. And correct me if I am wrong, but they use drive-by-wire in the throttle, where the throttle is no longer mechanically linked to the fuel control and intake, but instead is a form of potentiometer, where the driver's pedal depression on the throttle is fed as an electrical signal to the previously mentioned drivetrain computer controls. As an example, when a driver comands an upshift, the computer cuts the throttle back, and when the RPM conditions are appropriate, the shift sequence is initiated. This gives a synchronization between the gears that a human would find almost impossible to do on a consistent and regular basis. The engagement between the gears is much less abusive than a human could attain. This reduces the reliance on the clutch.
In previous posts, much discussion has been about the use of the brake and throttle in roles additional to just simple acceleration and deceleration. There is the goal of using as much as the traction circle, and also, to balance the suspension in anticipation of an upcoming road event. And as I have put forward, to be used to add stability in a hard braking situation. So when we discuss the use of the throttle and brake, they are used in many scenarios, and we must try to correctly identify their intended result.

[Guest]

It creates a demand in the intake, so the turbo begins to spool up.

What happens in the intake when you push the accelerator ? I thought you just cooled the air to the intake.

The system that the WRC cars are using burns/uses fuel in some way to keep the rpm up doesnt it ?

/ Fx