prana

how does that transfer to the WRX and its various AWD models ?

Specifically, with LFB you transfer weight to front by using the engine torque to unbalance the braking to the rear, at extreme, the rear wheels lock. Obviously that principle is different in an AWD. What really happens and when is it you use lfb in a AWD such as our WRX's? Maybe, lets say a slalom course, at what point would u use lfb over simply throttle control in the awd setup ?

ta - looks like more techniques to practise on the next track day woohooo

Claudius

Personally, LFB helps in tight corners to get the front "in" when the natural tendency would be to understeer. Talking about my 97 model with no LSDs.

ScoobySport (SdB)

Hi prana

Slalom is a good suggestion.

Left foot braking will be of most use during the point at which you transition from one direction to the other. LFB is useful when you want to give the front tyres more grip than the back (under normal conditions) without lifting the throttle too much (and losing boost), and by allowing you to have very precise control over the amount of transfer, plus keep drive going to the tyres.

All the best

Simon

Claudius

That's what I meant

DaveW

Well I use it going round small roundabouts.

Hard on the brakes to the point you need to turn, off the brakes, turn, then left foot brake and accelerate whilst turning. Moderating both to keep the car neutral. Then while your straightening the steering wheel ready for the exit, off with the left foot and plant the throttle

Dave.

Subie Gal

i find the LFB is the only way for me to keep my WRX going
in the twisties during a rally...

it's a Stock Class WRX so the engine is totally OE

hard to keep the turbo spooled up with a 32mm restrictor in place!!!

Basically use LFB to get the car rotated, whilst remaining on the gas thus keeping the turbo spooled and the power on

it's a great way to set the car up for nasty corners
tho not meant to SLOW OR STOP the car...
merely to pitch it properly into the corners...

example:
http://www.subiegal.com/images/ralli...rx_wagon99.jpg

cheers
Jamie
SubieGal.com

prana

Thanks for all your replies. Appreciate learning new things everyday.
I suppose I can ask more questions, but I would fair better going to the track and learning

I would love to hear how the machanics of this work. I mean , in terms of the drivetrain specific rather than weight shifting. Very cool indeed I wish I could do that.

prana

Simon, I will try this when I get a chance to go to EC skidpan and jump at a chance at the slalom Hopefully soon !

ScoobySport (SdB)

mechanics wise, there are some interesting side effects of LFB.

Be aware that the main benefit in performance driving of LFB is the load transfer.. you effectively use LFB for turning the car. But...

There are also some interesting torque split effects.

Imagine you are understeering due to spinning up the front wheels... this effectively means you're loosing a load of torque through the diffs, so adding a bit of resistance to the front wheels can increase the torque output of the whole system and move driver rearwards.

So the mechanical side tends to work in conjunction with the dynamic load transfer side.

All the best

Simon

StickyMicky

intresting, ive never tried this

i will experiment next time it rains or sumthing, or maybe wait for snow

prana

please dont try it on the street, especially in the snow if its your first time round. This is not at you StickMicky, but to anyone reading this thread who are curious and have never tried it before.

The first time I ever tried lfb, I nearly flew thru the windscreen. Now that my left foot is sensitive enough, I am beginning to explore the use of it.

Sorry to sound like a nag...... I just dont want ppl to get hurt.

Andy Gough

Please tell me how applying the brakes mid flight will cause the front of the car to dip.

johnfelstead

just backing off the throttle has that effect too.

When the car is in the air, the gyroscopic efect of the wheels spinning maintains a steady flight path, if you LFB or back off the throttle the wheel speed drops and this alters its gyroscopic steady state causing the car to nose dive.

StickyMicky

dont worry about it

ive tried LFB b4 but never in the ways mentioned, i nearly went through the screen as well

it was in my dads citroen zx thing and the brakes are a bit off and on in them to start with

ScoobySport (SdB)

Not quite John.

What causes the nose to dive (when braking in mid air) is the transfer of energy from the spinning wheel through the brakes, mounting and finally into the chassis. Lifting off, can cause this effect, but it is GREATLY reduced.


Good advice from prana

All the best

simon

AvalancheS8

O.T but maybe interesting:
Moto-X bikes and off road radio-controlled cars use this effect to control mid air attitude. Their relatively high wheel weight to vehicle weight ratio and plenty of power (also ability to get loooots of air time) allows it to be done the opposite way too, lots of throttle will lift the front. Know from experience that RC cars can be put entirely upside down with the throttle and then brought back by braking hard to land wheels down, also seen backflips done. Combine steering with use of the throttle and you can effect the roll attitude....

ScoobySport (SdB)

hehe

I'd love to see the RC car back flip thing

The steering also works for cars controlling the roll attitude, and this IS by utilising the gyroscopic effects of the front wheels.

Adding throttle does help too, but again it's not as effective.

In reality you only really have one shot at it.. If you take off a little crossed up and pointing at the sky...

Get your steering done as best you can, then hit the brakes, and back on the gas again.

AvalancheS8

Et Voila:

Backflip

And what happens when you misjudge:

Oops

Lots more here:

Traxxas video vault