GP3 Telemetry Guide - Ride Heights - Suspension - Packers - By Charlie "NoCharlie" London - Page 2 of 3
DECISIONS, DECISIONS.
Ok, we've discussed earlier the reasons why we need the car to be low,
so could we not just drop the car until it just flashes away at the end
of long straights? Well the answer is yes but we must remember that the
reasons for lowering the car are to achieve extra grip and extra downforce,
and granted the car will be lower at the end of long straights, but if
we are achieving grip and d/force then we want to put them to the best
use and the best place to use such features is in the corners. This is
where telemetry comes into its own and shortly we will introduce packers
into the equation. Right, how do we get the car as low as possible, and
where do we do it?
If we look at the suspension travel traces at the start of the long straight.
And then compare it to the traces at the end of the long straight.
We see that the front suspension has been crushed from about 28/29mm
down to about 21/22mm and the rear suspension from about 53mm down to
about 44mm or so. It is therefore safe to assume, considering we are
coming out of a relatively fast bend (the Parabolica) that we have at
least 28mm/44mm or more travel in all other corners (as they are all
slower, try using a speed trace alone and scrolling through different
corners to assess the speeds attained). So check on your own travel graph
that this is the case, the only exception to this should be the Curve
Grande where we can see that the left side, under compression has been
reduced to approximately 25mm F and 46mm R. Therefore this is where we
will start to lower our car. Usually you would use a fast corner such
as the Eau Rouge at Spa (Belgium), but seeing as Monza's bends are more
sweeping I will use the Curve Grande purely for demonstration purposes,
but you may like to experiment with the Parabolica, although this will
mean running the Curve Grande on packers as will be seen later, but that's
not necessarily a bad thing, it depends on your overall tyre wear and
personal car setup.
Now we will dispense pretty much with the ride height graph other than
for reference purposes because it is not that easy to read, particularly
on bumpy surfaces. Instead we will use the in car plank warning lamp
and the plank/tyre wear indicator in the pits. The method we will use
is to lower the car so that the plank flashes in the fastest corner and
then carry on jacking up the car by 0.5mm or 1mm until the plank no longer
flashes in that corner,(other than over any large bumps that may be present).
So begin by dropping the front ride heights to 27mm and the rears to
47mm (figures plucked from thin air, use any heights you like.), then
30 laps of fuel and back out on track.
We see almost immediately that the plank is flashing, don't worry, we
are only concerned with the Curve Grande, go through there flat out,
if you have a problem and want to make another run at it you may have
to conserve the plank until you get back round.
Ok obviously 27/47 is too low as we see by the in car warning lamp so
now begin to jack the car up bit by bit, until the plank no longer flashes
in the bend, I have settled on 29.5mm front and 49.5mm rear, but, as
we see, the plank begins flashing quite violently just at the exit and
as you carry on down the main straight. Don't worry carry on with the
lap and see what happens, try to do a few timed laps and then check your
plank wear.
Oooh doctor I've developed a nasty rash on my bottom after a few laps,
any suggestions?
Now it appears that we have a relatively low car, but what use is it?
Well we don't need to worry about the ride height as we have set it so
that we have ground clearance through the fastest corner/bend, and so
we now move onto the suspension travel graph proper, its uses, and how
we can optimise the use of packers and the reasons behind that use.
Firstly, it's all well and good running through a corner low and at speed,
but we must retain some suspension travel, for as we know, the stiffer
the suspension the greater the tyre wear and the less the grip. So regardless
of how soft a spring you are using, if you run through a high speed corner
with no suspension travel left then you are effectively running on the
stiffest suspension available and any changes you make, eg, softer springs
or arb changes are negated as all effective shock absorption has been
removed. However, it is quite acceptable to charge up a straight or maybe
a mild(ish) curve (maybe even the Curve Grande) with absolutely no suspension
travel left as no real steering transitions (changes) are taking place.
For mild curves it is advisable to check tyre wear and speed traces to
see if you are losing out.
You could also use a lateral acceleration graph, but I think we will
leave that for another day for now, although if this tutorial goes down
ok, and demand is sufficient, then I may follow this guide up with whatever
is required in a future article.
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