Data Logger - what uses have people found?

Discussion in 'GT6 Tuning' started by bread82, Apr 9, 2014.

  1. bread82

    bread82

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    Hi,

    Now that we've got the data logger, what options does this open up for tuning? Perhaps people's theories will be able to be fleshed out with numbers, or if someone has a handling problem, maybe the logger will give some insight?

    There is certainly more that could be implemented by PD, one of the first things that I noticed was that some readouts have little boxed numbers (e.g. speed), but the G readings and ride height don't. I hope that PD add these relatively small things in, as I've been forced to approach my TV with graph paper or a ruler if I want a figure. Obviously more numbers like tyre temps, dynamic camber etc would also be nice.

    Below are a few early tests/observations I've made.


    1) Vehicle speed vs wheel speed

    On my S13 ~250BHP, CS tyres, I noticed a distinct difference between vehicle speed and rear wheel speed in a straight line under acceleration. Front wheel speed was pretty much always equal to the vehicle speed. for example, on the back straight at tsukuba, 5th gear, 100 MPH vehicle speed, the rear wheels were reading 107 mph (fronts were 100). Therefore it looks like the GT6 tyre model includes slip percentage (i.e. I had a slip percentage of 7%). This is a sensible number for the real world [1], though I was a bit suprised that my 250 BHP car could generate this much at 100 mph in top gear. The wheel speed in general seems to look realistic, if you pull the handbrake the rears drop to zero as you've locked the tyres, and the inside/outside wheels in a turn show a difference (since the outside ones take a longer path in the same time)

    Thoughts:
    a) The driven wheel speeds could be really useful for LSD tuning. With what I thought was a well set LSD (both rear tyres turn red at the same time), the inside wheel was often going a bit faster than the outside. Coming out of a turn, I think you'd want them either rotating at the same speed for straight line accel, or maybe with the outside tyre still rotating a bit faster (since you are just leaving the turn).

    b) The wheel speeds vs vehicle speed could also be useful for seeing how ABS is implemented in the game (i.e. how much negative slip is allowed under braking), likewise for TCS and maybe even ASM.


    [1] http://scholar.lib.vt.edu/theses/available/etd-5440202339731121/unrestricted/CHAP3_DOC.pdf

    2) Ride height telemetry

    This is one setting which I really wish they'd put a numerical indicator on! One brief test I have done is to look at the amount of body roll, i.e. RF vs LF, also RR vs LR ride heights, during cornering. I wanted to know how much one click on the ARBs limits body roll, vs how much spring is needed. Due to having to eyeball the graphs the RHs are probably only accurate to the nearest 5mm, likewise the G force was a nominal 1G, but could have been +/- 5%.

    S13 on CS tyres in a 1G turn

    RH 110/110 (FC sus default)
    Dampers 1/1 (didn't want these complicating things - I measured on a flat portion of the RH graph so the dampers shouldn't be doing anything anyway, since the suspension isn't moving)

    i) Springs stock (3.12/2.97)
    ARB 1/1


    FL -30 FR +60 difference 90
    RL -40 RR +35 difference 75

    Looks like there was some longitudinal accel here that I hadn't noticed (the rears are lower). There's a considerable difference between the front and rear roll, 25mm! I didn't think my measurements would be that inaccurate, could GT6 be modelling chassis flex?!?!

    ii) Same as above except ARB 7/7

    FL -20 FR +50 difference 70
    RL - 25 RR +30 difference 55

    again, front/rear roll is different.

    iii) ARB 1/1, springs max/max (11.61/10.34)

    FL -15 FR +20 difference 35
    RL -15 RR +15 difference 30

    only a slight difference here.

    I'm in the process of analysing the data with some more values, then I can try to work out how much spring one ARB click is worth (it might or might not be linear, so I'm waiting to see what I get before commenting). It does look like the max ARB/default springs isn't as stiff as the max springs/default ARB though.

    Thoughts:

    The RH graphs would be excellent for testing the amount of downforce you get from aero, you could do a run on SSRX and see how much the car gets sucked on to the deck.

    It would also be interesting to see how sharp the changes in RH are when going over bumps, using different damper stiffnesses. If the dampers are stiff and the wheel bumps up off the ground, I wonder whether the RH increases i.e. is it truly body-ground distance. Or is it strut length, which wouldn't change much.

    I'm off to the Eiger or Cape Ring jumps to see if the RH goes to +2000!

    Cheers,

    Bread
     
  2. MrGrado

    MrGrado

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    LSD tuning.

    I can see a tune with a strong LSD setting gain an instant time advantage over one with a weak setting on exits of low speed corners. Also in wide radius turns, a tune with a weak LSD setting can spin up the inside rear wheel, although this doesn't impact on the gap to the other tune.

    Ride height.

    I can see a certain pattern to the ride height on front wheels when the front tyres exceed their grip limit.

    Car speed and time gap.

    Useful to compare Gears and power settings between tunes to optimise straight line speed.

    There's certainly an opportunity for tuners to use the data logger as a tool to analise their tunes and possibly make improvements.
     
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  3. CKVK

    CKVK

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    In 2 separate lap saves in my LFA NUR. Had a 75mph difference in rear tires going through all gears on a straight. Any ideas ?

    Im glad its back. It was the best way for me back in the day before online to learn about tuning my own cars, and it gives me something to do when internet is down for maintenance.
     
  4. Dean

    Dean Premium

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    Wait, isn't it the same data logger as in GT5? :boggled: Sound like a massive improvement.
     
  5. donpost

    donpost

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    156
    You can see ride height for each wheel?!?!? Why did I not know this!? There is so much research to be done! Thank you! :bowdown:

    I'm going to look into if we can detect the phenomenon of hitting the bump-stops when ride height is set too low. Also we can see if ride height really is backwards.

    I like the work you have done so far :tup: I don't think you'll ever see the outside wheel spinning first/faster than the inside. Being able to work out how much the car rolls is going to be helpful.
     
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  6. bread82

    bread82

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    @Dean @donpost

    Yeah, there are a few more parameters than GT5... but they're not displayed by default. I was really happy when I saw these. The settings menu within data logger lets you pick individual wheel ride heights and speeds. At the moment I have my "set 1" window to lat and long G forces, "set 2" to 4x wheel speeds and vehicle speed, "set 3" to 4x RH and sometimes one of the G meters.

    IMO PD have done really well with this, and there is obviously more that could be done (camber values etc). Hopefully a hint of the full 7-poster rig analysis that was mentioned before launch. I'd imagine it's not that big a programming task to get values from the physics model and display them on a graph, and maybe most players won't care, but to people that like crunching numbers and analysing stuff it is hours of fun. Now if only they let us export data to Excel....

    If you like the data logger I've put a thread in the suggestion forum requesting more data options and labels:
    https://www.gtplanet.net/forum/thre...types-and-more-data-types-if-possible.306707/

    @donpost: I jumped my S13 on CS at Eiger, stock suspension. The scale on the RH axis goes weird, I saw -20 but no other numbers. I think the jump messes the scale up. When I landed there was a sharp drop in RH as the strut compressed, and some jagged shock lines at the bottom. I don't know if it was bottoming out or just the dampers arresting movement. Looked very sharp though, gut feeling is that it was something nasty happening.

    @CKVK That sounds crazy, drive wheels 75mph faster than the chassis. Can't have been wheelspin going through all the gears, sounds like someone forgot to code in the correct wheel diameter or something. What tyres were you on, I'd be interested in replicating?

    Cheers,

    Bread
     
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  7. merlinrichards

    merlinrichards

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    :lol:
    WOW :eek: :@:bread82 are u the 1st person ever to say them words on GTP. :lol: I think the different sets u can have and flick between them are great aswell
     
    Last edited: Apr 12, 2014
  8. donpost

    donpost

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    156
    I had a quick blast and it looks promising so far.....

    I took a car to high speed ring and run two laps of data, one with full ride height, one with minimum ride height. Then I paid attention to all four wheel's ride heights during the first long banked corner.

    I noticed that all four springs were compressed much more in that corner when I had the ride height at max. This means I must have been hitting the bump stops in the low ride height car, but I couldn't figure out why all four wheels were showing a consistently lower ride height - then it twigged. The corner is banked so the whole car is being pushed into the track. That must mean that with minimum ride height going around that corner my car is being pressed onto all four bump stops! No wonder it was much slower when slammed, and the g-meter indicated I was pulling far more g's in the max ride height setup.

    We might finally have a way to find the optimum ride height (subject to raising one end to change balance)!

    EDIT - I just saw your comment about chassis flex in the OP. I think it must be in the game, otherwise why have the ability to improve/restore it? I haven't bothered with using it before but now I might...
     
    Last edited: Apr 10, 2014
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  9. CKVK

    CKVK

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    I was using Rs

    I was using RS. Tires at the time. And it was only 1 drive wheel with the different speed, the other 3 matched eacg other.
     
  10. ShamrockGT

    ShamrockGT (Banned)

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    I've used the data to improve & confirm tuning methods already.

    Steering angle is great paired with ride height for checking F/R body roll.

    I watch to see if a shock is too stiff on the damps, dialling in damps settings are much easier, but surprisingly I was already matching my damps to springs and RH quite well, it's good to get a little data to confirm theories.

    Same with ride height, while this one is tricky to get it all figured out, I can see overly slammed cars ride bump stops. I can see if one end is traveling excessively vs the other. I can see if dive and squat are balanced, or if a side has excessive droop.

    Still testing stuff out on the diff, but wheel speed should prove helpful to that effect.

    I So agree some things like G SHOULD have a numerical read out. Ride height needs a ground reference and maybe some wheel travel clear indication of travel ability and when travel runs out
     
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  11. VeeDubberLow

    VeeDubberLow

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    Really impressed so far.

    I've run laps offline and saved best lap replay and its worked.

    However online with its different physics I couldn't find a save that I could use with data logger. I tried free run and time trial. I'll try a race and see.
     
  12. VeeDubberLow

    VeeDubberLow

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    Just tested it online in practice/race configuration. Saved and worked ok during practice but not during race which is fine.
     
  13. suspension

    suspension

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    OMG!! ●_●
    IM TAKING MY TUNING TO NEW LEVELS FROM NOW ON! THANK YOU PD!!!!!
    ..... NOW PLEASE JUST GIVE US A COURSE MAKER!!!!
     
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  14. DigitalBaka

    DigitalBaka Premium

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    I'd be interested in how this might match up to and/or impact your real world tuning. And for anyone else that has the means to take these sort of diagnostic measurements. :idea:
     
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  15. suspension

    suspension

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    Yes. thank you for your support!
    With DATA LOGGER players will be able to see how "good" a "good car " actually is!
    As far as REAL life, if NISSAN can recruit drivers from a game, I'd better be able to design a better damper or spring. LoL, I would feel I failed if I didn't at least gain knowledge from DATA LOGGER because there is many useful information that has never been known/seen in GT games. I feel like PD is doing good, a bit slow, but good with there updates. I will utilize this tool.

    GPS- forgive me as I know it's not subject matter. But this is no good. Not everyone can access SUZUKA or FUJI in REAL life. This is a feature for "select persons" in a game that says "EVERYONE" this is too "narrow" a feature for such a broad audience and until the whole world moves next to FUJI SPEEDWAY or we all buy TOYOTA 86, this is taking up space on our PS3..
    But I wish I could use the 2 together...
     
    Last edited: Apr 13, 2014
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  16. Ridox2JZGTE

    Ridox2JZGTE

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    I am using it to build some of my latest replicas and tune : FEED RX7 450PS 2007 car and the Superlap Battle Tsukuba 2011 car :), very useful to fine tune suspension and LSD. My 458 Italia GT3 and Camaro GT3 spec cars also used data logger extensively, I have numerous best laps replay from Tsukuba, Silverstone GP, Brands Hatch GP and Bathurst.

    Here's hoping my Oullim Spirra 500PP build will be better when I used the data logger ( got some best laps saved at Tsukuba ) 1:02s, and a couple of low 1:03s on comfort soft.
     
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  17. esoxhntr

    esoxhntr

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    Has anyone been able to save an online lap and view in the logger? Cant seem to get it to work.
     
  18. SCClockDr

    SCClockDr Premium

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    Needs to be a ghost/best lap replay from a garage freerun or a single player time trial. Multi-lap replays do not populate the data logger list.

    EDIT: A seasonal TT might also yield an acceptable file. Though the car choice may be limited when a loaner. I've not tried it though.
     
    Last edited: Apr 14, 2014
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  19. Motor City Hami

    Motor City Hami

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    Ok. So I started playing with the data logger tonight and there are a few useful features. I still wish we had tire temperature at inside, middle and outside of the tire. I could do much, much more with that data. Crosses fingers and hopes that PD will wake up to this data point used all over the world in real life racing and they add it to GT7. Ok. Rant over. I was able to tune as normal on feel and get the car most of the way there. The data logger helped me to fine tune these items:

    1.) Wheel Speed. I am currently tuning FF cars. I found that consistently at every on power through corner exit situation that the inside drive wheel is traveling faster than the outside. This indicates that the LSD Accel setting is too low. I was to the point with the car "on feel" where I was within the sweet spot. There were about four settings that felt good to me; between 12 and 16. I could still sense a bit of wheel spin, but could not identify which wheel was the problem. Normally, I would have stopped here in my tuning. With the data logger, I now have a way to quickly see if the LSD Accel setting is set properly. I cannot yet find a data point for LSD Decel or Initial Torque.

    2.) Speed and RPM. This is great for comparing two tunes or two cars. Change the Display Reference to "Match to Current" and this will place the two tunes in the same location on the track. I think I can use this to tune gear boxes and for exchanging tuning parts. I guess this could help answer the age old question about which is better, horsepower or torque.

    3.) Comparing drivers. This can become a great tool for comparing drivers. I would love to get a lap save and the tune that did it from someone like @R1600Turbo for comparison. I have been trying to become a better driver in the game. This could help me to see his throttle pick up points, braking points, steering input, etc. and allow for me to run lap after lap to improve my driving.

    4.) Time Difference. Many times when testing, I find that my fastest tune was from getting through that one tricky corner with alien like speed. I am not a good enough driver to duplicate alien speeds so I usually clear the lap and start my comparisons again. Using the comparison ability of the data logger, it is really easy to compare the tune in all corners on the track vs. just using the two or three time splits that show up while doing a time trial. I included Speed, RPM, Longitudinal G-Force, Brakes and Time Difference in Set 1. I have two tunes that are virtually on top of each other except for one corner. Car one hit a faster lap time, but car two is more fun to drive. I would have tossed out car two in the past. Now I may go back to car two and refine it a little bit and keep it.

    5.) Ride Height. I think this data is useless in its current form. With wheel speed the MPH is displayed and changes as you move through the lap. Why did they only use a dot for ride height? This could be so much more useful if they would have just used the same method here. Using the L toggle to extend the scale helps, but still useless. Also, if the vertical scale showed more increments, maybe it would become more useful? I thought that this could also be used to tell if the car were bouncing or if the shocks were too soft... nope. Really need this combined with the old load indicator.

    So in conclusion, the data logger is a good start, but could have been so much more. But that is kind of the norm with PD, isn't it?
     
    Last edited: Apr 15, 2014
  20. donpost

    donpost

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    156
    Regarding ride height - we could really do with an indicator that tells us if we are running out of suspension travel or bottoming out the car. It's difficult to tell from the telemetry but here's a method that makes use of what we have:
    1. Run your car at a specific track with ride height at both ends set to maximum. Make the lap as tidy and consistent as you can. Laptime isn't important but at the same time you need to be pushing the car.
    2. Run the same lap with minimum ride height at both ends. You'll have a tonne less grip in the corners but again try to be tidy.
    3. Load the max RH data and compare to the min RH data. I load up set 1 with all four wheel's ride heights. Look for sections where the min RH line goes below the max RH line. These sections represent parts of the track where your car is running out of suspension travel/bottoming out.
    4. Increase the ride height from minimum and run another lap. Compare this to the max ride height lap and see if the sections noted above still show the max ride height setup compressing more. If they do, increase ride height and try again. If they don't then you have found the lowest ride height that doesn't cause suspension problems.
     
  21. donpost

    donpost

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    156
    Sorry for the double post but I just did some research that I wanted to write up in here.

    I broke out the McLaren F1 (this was an expensive test) and took it down to Daytona. I gave the car medium-stiff springs and recorded data from three flying laps, one at min ride height, one at max RH and one slap bang in the middle.

    Max vs. Min RH
    [​IMG]

    The blue line is max, the white line is min. You can clearly see two sections where the springs are compressed much more with max RH. These two sections are the two main banked turns, where you have the weight of the car plus aero plus a force generated by the banking pushing the car into the road. With minimum ride height I was clearly running out of suspension travel and it killed the handling.

    Max vs. Med RH
    [​IMG]

    Again blue is max and this time white is medium ride height. The big differences in the corner have gone away so I know I can safely use this ride height without causing suspension problems. My lap was 0.2s faster as well, this could be co-incidence or it could be the lower ride height improving my cornering speeds.

    Looking at the time difference graph, I gained most of my time in the corners so maybe so.
    [​IMG]


    Here is another cool screenshot. This is max vs. medium again, but this time I have focused on the telemetry from the back straight. It's difficult to see, but the medium ride height is running slightly lower at the front and slightly higher at the rear. The lower ride height means that less weight is transferred rearward under acceleration, so the rear springs compress less and the front springs extend less while I'm accelerating up the straight. I'm a self confessed nerd and I make no apology for being excited about seeing the physics in action :p

    [​IMG]


    So the data analyser has some uses it seems! It might be harder to do the above on other circuits where there are less obvious signs that you are running out of suspension travel in the telemetry.

    Anyone know a way to use telemetry with the skid pan at Willow Springs? If I try in free run it invalidates the lap and I can only get it to save a best lap.
     
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  22. rams1de

    rams1de

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    451
    I took my first proper look at the data logger tonight after spending some time adjusting my Integra for a race at the Ring this weekend.

    It was great to see I could home in on any part of the track in tiny steps using L1 and R1 and could observe what was happening at any corner down to a few yards I would guess. It would be better if I could understand what it's telling me :O

    It was interesting to see the variation in wheel speed under acceleration and deceleration. It got me wondering what might be the ideal. The drive wheels speeds could get to about 4% faster than car speed when accelerating and similarly ~4% slower under decel/braking.

    There were bigger and more varied differences between inside and outside wheel speeds during cornering and I guess the ideal would be to narrow those variations as much as possible?

    I assume the Ride Height scale is in 20mm increments above and below 0, the scale showed 0, 20 and 40. Should we assume 0 is the set RH whether 100mm, 70mm or any other setting and the graph displays the amount of travel?

    At one point the Integra, which is running 95mm RH, registered just short of -60mm (bottom of the graph). I loaded a lap from the BMW seasonal which was slammed at 70mm iirc and the maximum amount of travel it registered was +/-40mm approx. Again just guessing, but the BMW must have been bottoming out at that level since it reached the mark a few times under different braking levels and cornering speeds.

    It would be great if there was a perfect lap we could use as a benchmark, would make the learning curve less severe.
     
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  23. FussyFez

    FussyFez

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    Some great stuff starting to emerge here.


    I've managed to debunk a long standing myth regarding fully locked, or 'welded' diffs here.
     
  24. Motor City Hami

    Motor City Hami

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    @donpost I would suggest adding speed to the bottom of your ride height chart. Did the bottom out effect also reduce speed?
     
  25. Aussie_HSV

    Aussie_HSV (Banned)

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    This is a great thread.
    I love to read the tips, try my own tests, and learn from what you guys write, so thanks all.

    @donpost
    I'm curious as to why you suggest in your 3rd point that if the min. RH is lower the suspension is bottoming out.
    Understandable if the max. RH is near it's full travel, but if there is still travel available wouldn't that allow the min. RH to be below and still not bottom out?

    Would you mind expanding on your thoughts for your 3rd point?
    Cheers.
     
  26. GTP_CargoRatt

    GTP_CargoRatt

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    I have started doing just this in the Seasonal TT's. Taking the replay from the #1 guy and comparing it to my own best lap. You can really learn a lot if you have the time and patience to study everything and make the proper comparisons. I spent about 4 hours alone today making comparisons and taking notes from one of the Seasonal TT's. I went out and practiced what I learned and what do you know, improved my time by over .300. What a great tool and glad it was finally released.
     
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  27. NoizeboyMugen

    NoizeboyMugen

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    Sorry to be the bearer of bad news but for now DL can only be used offline.
     
  28. GTP_CargoRatt

    GTP_CargoRatt

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    I have used it numerous times loading replays from the online Seasonal TT's. Works just fine in that aspect.
     
  29. FussyFez

    FussyFez

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    Done a little test on downforce.

    R34 GTR Touring Car, max power, max gearing, max downforce, max ride height, softest suspension on all settings.

    One lap of route X.

    Test ride height at 0mph and crawling at 2mph shows all ride heights at 0mm.

    At 220mph I had - 20mm front and - 60mm rear (full throttle, didn't think to test part and off throttle)


    This was only a quick test, but it proves that downforce is acting on the body rather than the tyres.
     
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  30. Nish

    Nish

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    Anyone know as of yet if different shaped wings have different effects on airflow or not?