It's time for another one of "Tristan's annoying, yet slightly technical threads about real racing". You know you want to ignore them, but as they are pretty much the only technical threads on this forum you just can't help yourself, can you?

Anyway. This week/month/year I'm asking about datalogging...

Only the geeky may apply, and those willing to download software and my datalogger file that goes with it.

1. Race Technology V7 Analysis software - download here 26MB

2. Snetterton weekend datalogging processed run file - download here 45MB

Once it's installed you can double click on the .raf file to open it. It should have lap markers, variables and vehicle data in it already, as well as a screen layout, so you shouldn't need to configure much/anything. Tabs along the bottom are preset for various bits of data (yes, I know the water and oil get a bit hot), and you can play with graphs, tables and all sorts.

You can't open these .raf files in F1Perfview or similar (as far as I know!)

The challenge - using this data (and it's all I have of Snetterton - no WRs to compare it to in real life!!!) work out where and why I am losing time, and what I should do first of all to improve. I have my own theory(ies) on a few, but I won't state them yet in case I influence your thinking.

I appreciate that most of you won't bother to download 70 off MB of stuff just to look at datalogging, but I'm hoping one or two of you clever lot might take a lookie.

I will give it a closer look =)

i tried, but the analysis software crashed when trying to open the raf file. also, it defaults to asking for a .run file, not a .raf file. did i load the file wrong?

EDIT: nvm, figured it out. RTFM.

Good point - If you open from within the software, you need to Load All, not Load Run (or whatever it's called). Run files are the raw datalogger outputs, whilst Raf files include all the extra stuff added afterwards...

Edit: I'm not expected really quick answers, because the analysis software will be new to everyone (mostly), and it'll take a bit of time to work out how to extract information from the data... So take your time if you are kind enough to have a lookie.

Edit: Oooh, time to go home and fit some more kitchen

I'll have a look purely for the learning exercise, does that make me geeky?

I'll need a day or two to look at it (inbetween work and house reno's) probably want be of much help to you though

Well I've just opened the file and the first thing that hit me was that your average max RPM was 200 higher than on your fastest lap, it may be worth trying to work out where the power is in your engine and when you should be shifting. You also had 11 gear changes on your fastest lap but 13 on average, maybe you were making unnecessary time consuming shifts? As for consistency did you have some slow laps (first lap, yellow and red flags) or something to make the average time 8 seconds off your fastest, which isn't slow at all for Snett

I haven't got time to look into full detail now but I'll take a look some time. That program looks so much nicer than the prehistoric datalogging system one of our cars has got.

The data includes the warm-up and slow down laps, which probably messes with the average lap speeds. And, because it includes all 4 sessions of the weekend, it includes slow laps in practice (warming up the engine), and a couple of small spins whilst hunting for 'The Limit' into Russell's Chicane.

Interesting about the 200rpm thing - I'm pretty sure I know where the power is, because we had the engine dyno'd - how accurate that is I don't really know (it came up with silly power figures that we don't believe). I might just be that I didn't shift at the right point out of a slower corner or something, but I'll have a closer look at that anyway...

Waded through the data a bit and it's actually quite fun learning how to interpret this data

First pic is a gear overlay of your fastest lap (Sunday race, lap 10). It clearly shows that 3rd gear through The Esses is quite fine, so I'd stick with that. Though on the second pic we also see that you simply carried much more speed through it (huge time gain of about 0.5 sec!), which is probably the reason you stayed in 3rd. So for future races, if you have to shift down to 2nd, you were too slow

Second pic is a speed/time slip graph over the fastest laps of each day's practice and race. I've added corner markers with a dotted line for entry and exit. On the time slip graph, your fastest lap (black line) is the zero-line, the basis of the time slip. The coloured lines of the other laps show where they faster (below, or going down) or slower (above, or raising up).

Compared to your second fastest lap, you can clearly see that you "messed up" Sear Corner, losing about 0.2 sec over the Revett Straight. The orange line interestingly demonstrates how slow-in fast-out works, seeing that it had the slowest corner speed (60mph, opposed to ~65mph on the other laps), but you hit the throttle earliest, clearly resulting in the fastest speed over the straight.

Then comes the most important time saver on your fast lap, The Esses. On the speed graph you can see how you braked considerably later and harder than on all the other laps, and even the slowest speed throughout the chicane is 3mph faster than on the practice runs.

Next we approach Coram Curve, where the Sunday laps show that you didn't slow down through it, whereas the Saturday ones show a clear dip in corner speed, costing you about 0.05 - 0.1 seconds.

Last point of interest is the Russell Bend, where the spike shows us that you went in too hot braking too late. The spike means that initially you were faster (because you braked later) but you quickly lost that gain due to the slow exit, resulting in a net loss of about 0.04 seconds compared to your 2nd fastest lap.


Now all you need is to steal the log data from your fastest opponent, then you can see where you're losing time compared to HIS best lap

Thanks Android.

I was thinking I lost most of my time on the brakes - not braking late or hard enough, so it's interesting to see that the slow-in fast-out approach into Sear helped a lot overall. 3rd through the esses has also surprised me, and it's probably better balanced in the higher gear, as well as less gear changes, making me able to concentrate on speed/lines etc more, hence more speed.

Regarding Coram, that's just bravery really - you know it's fast, but it's really hard to not lift off the throttle a bit, but by the end of the weekend I was managing it!

Russells is a nasty chicane. It sucks you in, and you think you can brake later and later, but it suddently turns left and bites your enthusiasm. The fact that my latest/hardest braking attempts resulted in slower overall times, despite them obvious being (and feeling) quicker on the way in.

The moral - slow-in fast-out always beats fast-in sort-it-out slow-out

The hardest corner is actually the Bombhole. So difficult to find a turning point (little reference points), and judging the entry speed is hard too. I think I could go quicker there, but it's really nasty on the exit so I don't want to try too much.

Snetterton is the first race meeting next year (with radials too, so direct comparisons will be difficult as I doubt we'll have as good a balance on the new tyres straight away), hence wanting more input on my driving this time around... Hopefully I'll also go testing at Snetterton before the race so we can try and get the car balanced in time

Edit: Average time without out/in laps, parade laps etc was 1m13.18, just 2.44 seconds off my best lap of the weekend, which isn't bad considering I hadn't turned a wheel in the dry at Snetterton before.