RIIIDEHEIGHTTTS, uh, wassamatta, huh, uh…..oh! It's you Doc, sorry 'bout that,
musta been dreaming, what! Visitors. Oh righto, thanks doc
Where was I before I dozed off? Oh yes, pillow height, right, a pil…. Oh, before
that. Yes of course, of course, sorry.
In part 1 we discussed ride heights, suspension travel etc. We saw that by testing
our car and then reading the telemetry that we could pinpoint exact locations
on track. We could take realistic measurements and make specific adjustments thus
removing guesswork. Well ok, we all know that the telemetry works, lovely, we
can now read and understand the rideheight telemetry, splendid, even the suspension
travel telemetry, marvellous, we even know where to poke our packers, brilliant.
Well what else can it show us? Let's see
In my opinion, it is always best to find a base setting from which we can work.
I have noticed in various forums that the question of brake balance often arises.
We know that if the brake balance is set too far back, then rear brake lockup
& oversteer can result. Equally we know that if the brake balance is set too far
forward then front brake lockup and understeer (the most common) will result.
Well what is too far?
What we need to understand and accept is that the brakes will always lock up
at some point if adjustments are not made to the brake pedal whilst braking is
taking place. This is true even if all braking is done in a perfectly straight
line. As the car slows down the effort required to stop it is reduced, therefore
the pressure applied to the brake pedal must be reduced in accordance with the
speed reduction to prevent the brakes from locking. Regardless of the brake
balance setting, a brake lockup of some description will ensue if this requirement
is not met.
This is particularly true when cornering and braking at the same time, where we
have the outside wheel "loaded/heavy", and the inside wheel "unloaded/light",
you will have noticed that it is always the inside (unloaded/light) wheel that
locks up first. The stopping efficiency of four wheels will always be greater
than the stopping efficiency of three wheels. Subsequently, for front/rear brake
lockup, understeer/oversteer, increased stopping distances and slower lap times
will result.
The Doc has had loads of people in his surgery complaining of brake balance blues.
I've heard them. Ooh Doctor, I've got skidmarks in…… Sorry Doc, what's that? Nothing
to do with GP3. Oh, err, maybe I'd better move on, client confidentiality and
all that. Suffice to say, his usual remedy for brake balance blues is a lightening
of the clubfoot that is applying them.
We shall prove this to ourselves shortly. Brake balance, as with every other aspect
of the car, is peculiar to -
A - You, the driver.
B - The track at which you are driving.
Brake balance/bias should therefore be set accordingly.
There is no "correct" balance. The best balance is the one that works best for
you. The problems arise when you make a change, test, but notice no difference.
In braking terms, it may mean braking a metre later. Even one metre per braking
point will mean you have been on the throttle that bit longer per lap. Net result
- faster lap. Unless you read, interpret and understand the telemetry it will
be difficult to know if a change has been effective.
As a demonstration, and as an aid to new comers, what we shall now do, with the
aid of telemetry, is find a point towards the end of the main straight at which
maximum braking, and therefore optimum balance for that part of the track,
is achieved, from full speed. The shorter the stopping distance, the later you
can safely apply the brakes, then the longer you can stay on the throttle. Obviously
this will reduce laptimes.
Personally I like to find the shortest stopping distance from the highest speed
that I can. This is my method, it may not suit everyone. It may be technically
incorrect, I don't know. Whatever method you prefer is fine. But try to find a
reference point of braking.
Once the driver has this point of reference, he can then make adjustments to suit
his particular driving style and braking points for the rest of the corners of
the track.
Once again, this is purely a demonstration, to get you used to reading, interpreting
and measuring the relevant telemetry traces, usually you will have some steering
input, but you will get a good idea of what we are talking about.
Something you may like to consider.- If you are trying to achieve the shortest
distance, from the highest speed that you can. If your top speed is attained on
a slight bend or whatever Then you could take your car setup to a track with a
very long straight and do your testing there.
Once again we will use Monza as our test track. Let's make a start. Move brake
balance completely forward, using rookie mode with all aids enabled carry out
the "out lap". You will notice immediately that the AI driver, regardless of ability,
is locking his brakes at virtually all braking points, don't worry. Also it doesn't
matter if you go off, we are not interested in lap times, only the telemetry at
a given point. Right, at the start of the Parabolica, pull up….. Ok now you're
going to get a very graphic demonstration of how difficult it is to drive with
brake balance too far forward. Ooooerrr. Doc's got various sprays and ointments
ready, cos you're gonna go off and its gonna be a bumpy ride.
Now press F1 to remove brake help, this is important. Try not to fall off through
the Parabolica, if you do, then press F3, turn around and go back to the start
of the curve. Get a clean run through, hit top speed, then, when you hit the 300
metre mark hit your brakes full on, do not lift off the brake until the car
is stationery, try to keep the steering as straight as possible without going
onto the grass. Don't worry about the brakes locking. You must now complete
the lap, without brake help, crossing the start and finish line again to get
a timed lap that you can graph**. You must not re enable brake help
as this will confuse GP3 and it will not record the lap.
You will now fall off while braking into corners, oops, there you go, byee.
Now try to just feather the brake pedal, try to prevent front lockup as much as
possible. You can now see, that, dependant upon brake balance, the pedal now has
to be applied in a very different fashion to what you may have thought or have
been used to. Try to do a lap or two like this, try to get used to the different
pedal application. Don't worry about your laptime. When you pass the start line,
press "shift Q" to return you to the pits.
**You may have to disable brake assist ( F1) prior to leaving the pits,
thereby forcing you to do both your out lap and your flying laps without brake
help. This is because GP3 sometimes becomes confused if aids are enabled or disabled
on track, and subsequently refuses to record/graph them.
Now, as per usual, reselect the tyres you have just used, then, fetch, view, copy,
blah blah. Lets now graph the lap and see what we can do to make it as easy as
possible for us to understand, whilst giving us all the information that we require.
Firstly, we shall keep information to a minimum. Then, as we understand more of
what is going on, we shall begin to introduce different traces and see if we can
then fit them into the scheme. This will allow us to collect more information
at once, give us a mental picture of what is happening within the car, and then
make sensible adjustments based on fact for either cure or comparison purposes.
So……
Once more……"Unto the graphs dear friends"
As we are working on brakes we will need a brake trace, choose the colour of your
choice and introduce it. We will also need something by which to measure this,
other than distance. Well, as this is a comparison exercise we will need to know
that we are braking from the same speeds. So introduce a speed trace. Remove anything
else on screen. We will now move step by step, to show you some things that you
may not have realised and to get you used to optimising the graphs for the job
in hand.
Find the start of braking, and then increase the x-axis to show 100 feet intervals
with the complete braking operation, from start to finish on screen. If you wish
to have the map displayed, feel free. Let's study this for a moment.
Ok, that's plenty long enough, now let's return to car set up.
This time set brake balance completely to the rear. Now follow the same procedures
as before and carry out one more not so flying lap, try your hardest to adjust
your braking, hit your brakes very hard on the straights, very feathery while
turning, so that you can stay on track, again, try to do a lap or two. Return,
and then fetch your data etc. Ensure you have this lap recorded, and then go back
to car set up. Now set brake balance to dead centre. Do one or two more flying
laps, return and carry out the same procedures. It was important that you carry
out the braking operations for yourself. You should now have an understanding
of how you have to use the brake pedal differently for different brake bias settings.
You should now have three recorded laps from which to choose, the only difference
to the car being the brake balance.
