Data Loggers (Spec DL1) - Getting Started and using them for Driver Analysis

[Maxx]

SAVE YOUR COMPLETE WORKSPACE

One quick thing, if you are using the DL1 analysis software, you have some stuff up on screen, graphs etc. and you've arranged them and such but you need to close the programme, you can save that session, exactly where you are and what you have on screen.

Just do File->Save All give it a name and save it. It gets saved in the default DL1 directory and you can just load it back up by loading up the program and doing a File->Load All and picking the same file.

These file contain all the customisation you may have done as well as all of the RUN files you have loaded.

Maxx

[Maxx]

Latest Correspondence following re3cipt of the race data

I have just taken an initial look at the data. The really good news is that you went quicker in that last
sector (the last corner followed by the main s/f straight) and that fastest sector was the ONLY fastest
sector in your fastest race lap.

I had to redo the s/f line and this time your fastest quali came in at 17.26 and your fastest race lap
came in at 17.47, so a couple of 10th slower. You were however a bit more consistent and had many more
laps in the 1:17s than in quali.

You actually improved your best time on every sector, except one which was Sector 3 (turns 3/4 + chicane)
where you were consistently a little slower. The fastest being only .08 slower than your best from quali
though.

Your best theoretical has gone down from 1:16.87 to 1:16.51 which is a worthwhile improvement. I imagine
you must have been doing a fair bit of overtaking so overall I think your performance was definitely
better, can't see any evidence of improved tyre grip, did you fit new tyres? if so they probably were
not needed and, in fact, if they are treaded, fitting new ones before a race is usually a bad idea.

To give you some idea what i'm talking about below is the trackmap showing sectors and then the
sector times. Sector 1 to 6 are just the track slip up into 6 sectors.

Sector 7 is from the entry to the last turn until the braking point for T1 (Marker 1)



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As I said, it's difficult to get a picture of exactly what is possible from the data, on the
face of it your laps look pretty consistent but when you look at some of the detail you do see some
remarkable differences.

I took a look at T1 with all my special custom graphs (g-circle and various xy graphs, speed, lat/long
accel etc.).

I can definitely see that you have made improvements in the last turn, lets just look at your fastest
Sector 1 in the race versus the fastest Sector 1 in quali. On the face of it, not much difference.
18.32 in Race v 18.46 is Quali, just 0.14 BUT looking at speed we see a big difference, on your best
S1 in quali you where at 83.2 mph just at your braking point, whereas in Race you were 100.2, that 17
mph different!! which is huge!!

Your braking point is the SAME yet you still manage to get to what is possibly your turn-point within
70mtr and be at the same speed 56.5 mph. That just shows you definitely had brakes to spare as I suggested.
In fact your maximum braking G on the 100mph entry lap was 1.251 g versus 0.883 g for your 83 mph approach.

Problem was you came off the brakes too early (and looks like quite abruptly) and ran a little wide in the
corner which slowed you down and you lost 3 mph on the exit. You were actually 6 x 10th up at one point
on the other lap but ended up .14 behind by the exit.


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This is not just an isolated incident, on EVERY LAP bar one you were considerably quicker into T1. I can
only summise at this stage that the improvements we made on the last corner have led to 10mph+ at the
end of the main straight, you've braked in the same place, harder but have yet to develop the skill to
trail-brake effectively and lost that extra speed in mid-corner and exit.

From your view in the cockpit does that sound feasible?

There is probably lots to learn here but it will have to wait a couple of days till I get some time,
I took a look round elsewhere and you are consistently braking harder (making better use of the brakes)
but I have a suspicion that this is making you mess the corner entries up a bit, from what I can
see we need to do some work on braking when we eventually get together. My suspicion is, and I may
be able to see this when I look more into the data, you are braking hard for a bit too long (the
really hard braking come between 10% in to 80% into the corner then bleeding back gradually lower
depending on if you need to trail-brake.

If you look at the big screengrab and the speed graph, you will see the speed tails off at a higher
rate as you continue to brake. And you can see the extra dip at the end on the Accel/Braking Graph.

That's all for now. When you have recovered, let me know your thoughts.

[Maxx]

Attached is the jpg for the last grpah which is hard to read, even when double-clicked.

[Maxx]

Wasn't going to post anything else here for a while but i've just been doing some
work on a Silverstone Session and it has highlighted an important point.

I think I may have mentioned before that you can look at a friction circle diagram
of a particular corner and just by looking at the shape of it you can determine which
was the best one.

It's still generally true but it's also very important to look at at least the speed
graph as well. My favoured layout is as was posted earlier, showing the g-circle graph,
the speed graph and the long g [accel/brake] and lat g [cornering] graphs. This was
you can really see what's happening and when.

The following screen was a great example of this and demonstrates and old coaching
adage "slow in, fast out".



It's Copse Corner at Silverstone, looking at the g-circle graph first of all we see
that the RED run used the available grip more fully. What the g-circle doesn't show
us though was the TIMING of it all. For that we look at the left hand side.

Look at the top graph first, the long g graph (braking/accel]. This shows that the
RED run actually braked later than the BLACK. Braking needed to be harder (hence
the steeper slope to the line).

If we look at the bottom left graph (speed) we can see that we were already arriving
at the corner at higher speed also, so, we arrive going faster (so we get there quicker)
we brake later and we use the OVERALL available grip "better" (or more precisely, fuller)
All this you would think would lead to a quicker run through this sector. In fact the
RED run was 12.94 and the BLACK run was 12.79 that's 0.15 quicker.

We can see that we didn't brake as hard on the BLACK run, we can also see from the lat g
graph that we turned a fraction earlier (and more smoothly) and didn't take off so much
speed in. We carried better approach speed (whilst still not overloading cornering g) and
were also able to achieve a slightly higher apex speed (where the 2 lines get close again
is the apex).

Looks like this was the limit however as we see a bit of a shimmy (slide correction) in
the BLACK run (also visible but not so severe in the RED run).

The big difference however is at the end of that sector where the BLACK run has been able
to unwind the steering more and reduce lateral g (middle graph) and thus GAIN SPEED on the
exit (bottom graph). The difference is actually 1.5mph but of course that gain is going
to last right up until braking for Becketts.

SO, the BLACK run is quicker by .15 of a second AND carries 1.5mph extra on the exit
which I would think would "potentially" gain another .05 or more into Becketts, so .20
in just one corner. The thing to remember also is that this is not doing something
new, it's just deducing which of the various slightly different things you did for
Copse works best. You do that for the other corners, you go out and drive them again
using what you've learnt. Some won't work, more will and you will likely get one or
two that are better (as you are practicing the "better" way more, so stand a chance at
getting even better at it).

<Screen as an attachment below, had to resize smaller though as run out of attachment space>

[m3Chris]

Maxx - any chance you could upload another datafile (or tell me the extension so I can allow them to be uploaded on here).

Thanks.

[Maxx]

Chris,

File extensions are .RUN but main problem I would have is that I have reached my upload limit for attachments (all on this thread I think).

M.

PS. I can zip them up easily enough. Most data files are between about 5-10Mb, zip will usually decrease this by 50%

[m3Chris]

I can increase upload limits no problem and will set a 10MB limit per file.

Have actually found a file from a Corvette in the states.

[Captain Slow]

It looks complicated - but I guess that is where the value is.

[Maxx]

I'll post up some sample data files tomorrow.

[m3Chris]

Cheers.