RPM limiter

Discussion in 'Gran Turismo Sport' started by bil coz, May 22, 2019.

  1. bil coz

    bil coz

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    Does anyone know why in GT games it's possible to push the car to higher RPMs when in the highest gear of the box. This is happening with all the cars and is even apparent on every gear graph, with different cars allowing more or less of it.
    I really don't know much about cars in general, and maybe that's a feature to be expected on every real car engine/transmission?
    Please enlighten.



    to make things clear:
    If you have a 5 speed transmission and you do 2 different gearbox tunes t1 and t2
    you set 4th in t1 at 1.000 and 5th in t2 at 1.000, same final gear for both tunes.
    On the track you will be able to reach a higher speed in 5th using t2 than in 4th using t1 (which will bang at the limit RPM)
     
    Last edited: May 22, 2019
  2. Vegard

    Vegard

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    With identical final drive ratios?
     
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  3. TurboTacho

    TurboTacho

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    Theoretically, if you set 4th and 5th gear at 1.000, the car will eventually hit the same speed at the set RPM (i.e. x km/h at y rpm).

    However, by setting the ratio at 1.000 at a later gear, you are providing faster acceleration to 4th gear, which helps to bring the car closer to the top speed. Despite the fact that you set the same ratio at 4th gear, you are not providing any acceleration between 3rd and 4th due to the ratio gap, which takes a longer time for the car to reach the speed you expected.
     
  4. bil coz

    bil coz

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    Please read my post and understand it. This is completely off topic.
     
  5. TurboTacho

    TurboTacho

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    Sorry but your question seems a little confusing. Firstly you were referring to engine revs at top speed in virtual compared to reality, followed by maximum speed at different gear ratios.

    Would it be possible if you could rephrase the exact question in whole? This should give us at least a better understanding on what you're seeking.
     
  6. ROCKET JOE

    ROCKET JOE

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    Just for clearness, again :
    One car is faster than the other while gear ratios, final gear AND RPM ! are the same ?
     
  7. bil coz

    bil coz

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    I'm saying:
    All the cars can be pushed to higher RPM when in the last gear of their gearbox.

    Question:
    Is this something that can be done in real world?

    No.
    I'm saying in 4th it will not go higher than say 7000 RPM.
    But in 5th it'll let you go to 7500.

    And it's EVERY car.

    This is irrelevant Dude.
     
    Last edited by a moderator: May 24, 2019
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  8. Illum_Concept

    Illum_Concept

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    I did read somewhere that PD did a "fix" a few patches back which is probably causing this. Apparently everyone was bumping off the rev limiter in top gear (@ la Sarthe I think), so races were a battle of who could best feather the throttle at top speed to avoid this.

    The fix might have included increasing the final gear rev limiter. Perhaps check back through the text for each update for more info.

    FYI, I used to hit the rev limiter in my road car during my early driving career (so going back quite a few years). You would genuinely "bump" back down a few mph as power is cut back, however I expect technology has moved on a lot since then.
     
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  9. bil coz

    bil coz

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    I don't think it's a new thing in GT, as I remember seeing the same type of gears graph in GT6 and GT5, with the last gear bar/line crossing the RPM limit line.
    I just always saw it and thought nothing of it. But recently I moved the gears of one of my drift cars down 1 level (make 5th become 4th, 4th become 3rd etc), and to my surprise, it couldn't be drifted the same because of this.
    Then I also realized that if you just compare the kph/ratios on the settings sheet, it's there for anyone to see. If you multiply ratio*speed for every gear you get the same result (small gaps because top speed is rounded) but when you do it for the last gear you get a decidedly higher number, meaning it climbs to higher RPMs.
    I understand that technology has come a long way but this behavior is there on every car in the game, old or recent, stock transmission or custom transmission.
     
  10. Vegard

    Vegard

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    No, man, it's not. New information has come to light; The gear ratio and final drive ratio combined decides the 'engine speed' to 'drive wheel speed' ratio. Check the final drive ratios for t1 and t2 again.
     
  11. bil coz

    bil coz

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    loooool

    Alright but seriously please stop spamming this thread unless you reread my post until you get it.
     
  12. praiano63

    praiano63 Premium

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    Since the beginning there is a bug with ratio number and speed in GTS.
    But it concern only the last gear of any gearbox , custom or stock.

    If the graphic is showing you a reachable top speed at rev limiter , it will match perfectly for all the gears except the last gear , with a gearbox 3 or 4 or ..... 8 gears , always the last gear will reach around 5% less speed than showed on the graphic.

    Let's take an example with the PORSCHE 356 stock gearbox

    SHOWED ON SETTING PANEL
    1st gear ratio = 3,091 top speed at 6800 rpm = 59 kmh
    2d gear ratio = 1,765 top speed at 6800 rpm = 104 kmh
    3rd gear ratio = 1,227 top speed at 6800 rpm = 149 kmh
    4th gear ratio = 0,960 top speed at 6800 rpm = 197 kmh

    TESTED ON TRACK
    1st gear ratio = 3,091 top speed at 6800 rpm = 59 kmh
    2d gear ratio = 1,765 top speed at 6800 rpm = 104 kmh
    3rd gear ratio = 1,227 top speed at 6800 rpm = 149 kmh
    4th gear ratio = 0,960 top speed at 6800 rpm = 191 kmh

    The problem is the last gear ratio number. All the others 1st , 2d and 3rd gear ratio numbers are corresponding mathematically and on track but again , not the last.
    For corresponding with the speed indicated on the setting panel , this 4th gear ratio number must be 0,930 not 0,960.

    If you want to do the calculation by yourself , you can take a tire perimeter of 2,00 meters as a base.

    EDITED : 2 meters tire perimeter sorry


    gears porsche 356.png
     
    Last edited: May 23, 2019
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  13. bil coz

    bil coz

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    That is interesting information but it's not what I was referring too.

    I know how to calculate speed from rpms, gears and tires diameter. But again this is not relevant.

    My observation is that for the exact same gear ratio, you will attain a higher top speed in the last gear because the RPMs are allowed to go higher.

    Mr Praiano I have great respect for you, and I know you will be able to try this out quickly:
    Do 2 tunes with AE86 with identical final drive at 4.000 (or any other value that you like)
    In tune number 1, set the 5th at 1.000 (or any other value that you like)
    In tune number 2, set the 4th at that same value.
    Tune number 1 will show higher speed in 5th than tune number 2 in 4th.
    Take both tunes to the track and you will confirm that. Because highest gear is allowed to go to higher RPMs.
     
  14. praiano63

    praiano63 Premium

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    Yes this is another point , you're right , the last gear RPM limiter at least with this car , no time to test others , is around 200 RPM under the others gears.
    Why ??? I don't have any idea !
     
  15. bil coz

    bil coz

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    I guess you mean 200 RPM higher?

    It's all the cars, and it's by design. Just look at the gear graphs on the right side when you adjust the gears. The last gear always goes higher, some cars not much, some other cars a whole lot like the F1 car. And it's been like this since long before GT Sport.

    Also before GT Sport we didn't have the top speeds displayed for each gear so it was less obvious.
    But now if you look at any car, with any tune, and do this
    1st gear ratio X 1st gear top speed
    2nd gear ratio X 2nd gear top speed
    etc...
    you find always the same number, which is normal.

    but when you do
    last gear ratio X last gear top speed
    you find a higher number than the other gears always. Meaning top RPM is higher here.

    It is not a bug and it's beneficial when drifting for example, because you will be able to reach a higher wheel spin/speed without having to use a looser ratio. Also because power seems to drop until the point that the engine RPMs stop rising naturally.

    I just want to know if this is a common behavior with real world engines/transmissions.
     
  16. daan

    daan Moderator

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  17. bil coz

    bil coz

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    No, it might have been further tweaked but the feature I'm talking about is there since at least GT6 and almost certainly earlier than this.
    Can nobody be bothered to just look at and read a graph?

    Just look at these stills from YouTube videos.

    1st one from Forza Horizon
    2nd one from GT6

    Compare the last gear depiction and please take the time to understand what I'm talking about.
     
  18. snowgt

    snowgt

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    I think I understand what you mean. The max speed given in the graph for each gear except the highest one refers to the max speed at the red line, while for the last gear it shows the max speed at rev limiter. At least, I think it does.

    To add to that, the rev limiter in highest gear has been “smoothed”, so you can’t bounce off of it anymore, as people have already pointed out above. I’m not sure how exactly it’s implemented, or if you can reach higher revs than in other gears though.
     
  19. bil coz

    bil coz

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    Thank you for understanding what I mean. I'm pretty sure it was common English and the others could have to if they had actually read and not jumped to their keyboard to teach me basic mathematics.
    But I still disagree with you, max speed for each gear is simply the max gear that you're supposed to reach at max RPM in that gear, and max RPM is higher in the last gear. And basic maths show that before even testing it on the track. And actually working EYES show that too if anybody looks at the graph.

    I think I'm gonna have to do a video.
     
    Last edited: May 24, 2019
  20. praiano63

    praiano63 Premium

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    Not at all. This is exactly what happen with any custom gearbox. The modification they did in the last update don't allow you to reach the RPM limiter in last gear.
    Your RPM in the last gear will stabilize around 200 RPM under the RPM limiter. This for any car in the game with a custom gearbox .
     
  21. bil coz

    bil coz

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    I actually saw that using the incar view and looking at the RPM counter, but in reality it goes higher because the speed attained is greater.
    Here is a demonstration with a Z33, which is one of the cars for which it is less pronounced, could have chosen a more spectacular one, but anyway..

    Testing the same gear ratio in 5th then in 6th. (Also it's not shown in the video but just before that I tested with 5.0 final drive and the car did bounce off the limiter in the last gear at like 80kph..)


    maybe tomorrow I'll pick a car that really shows a big difference like the 86 and make a vid.
     
  22. snowgt

    snowgt

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    Have you been able to confirm the same thing at higher speeds? At 130km/h in this car, the rev limiter naturally sets in pretty roughly. Usually, this results in an intermittent power loss, and therefore you lose speed. At this speed the power sets in again very quickly, so it bounces off the limiter in rapid succession. Maybe that's why you can't go as fast as in top gear where it lets you rev close to the limiter. Maybe you can test it at a higher speed, where you don't go into the limiter quite as forcefully?

    I also can't confirm what you said in an earlier post, that you can rev higher in top gear. You can see exactly where the rev limiter is in the graph. For the Z33, it's at 7.700 rpm. I can see you bouncing off 7.700 in the video in 5th, and go very close to 7.700 in 6th, but certainly not over. I also tested this on the 911(991) where you have the same thing at 9.000 rpm.
     
  23. bil coz

    bil coz

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    I have confirmed this on any car, and like I said, the Z33 is one of the car where it's not apparent much. (I just had to use that very low top speed because I was busy having fun drifting that track and I just thought let's do a quick vid about this other thing and wanted to reach top speed early on this tiny straight lol)
    (135/132)x7700=7875
    so it's just 175 RPM more in the last gear (and it will not show on the RPM counter like I said in my latest post, which will actually make it look like it doesn't even reach the normal limit, but when you see the speed counter rising and the RPM counter sitting still, you know something funny is going on)
    But for some other cars it can be much more of a difference, like 8500 instead of 8000 or even more.


    Just pick any car and go to the gearbox settings
    you will see something like
    1st 3.000 100kph
    2nd 2.000 150kph
    3rd 1.500 200kph
    4th 1.200 250kph
    5th 1.000 315kph

    now for each line you do this
    3 x 100 is 300
    2 x 150 is 300
    1.5 x 200 is 300
    1.2 x 250 is 300
    ....
    1x315 is not 300?

    EVERY car. and like I already said countless times, it's shown graphically, all the gears lines stop at the same RPM except the last one that goes past the line.
    all the cars, since at least GT6.

    The only point of this thread is to get an answer to this question: is this bollocks or are all cars made that way?
     
    Last edited: May 24, 2019
  24. PerformLAB1

    PerformLAB1

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    I know what he is on about, however I do not know the answer to why either. Take a look at this graph, and you will see that the final "gear" goes above the 6500RPM limiter...


    Shelby Cobra for anyone curious that wants to confirm it.
     
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  25. snowgt

    snowgt

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    Ah, I see. In THAT graph the 6,500 rpm are where the red line is, but you can rev up to the rev limiter at 7,000 rpm in the Cobra, which you can see in the power/torque graph.

    So, naturally, the gear-graph shows you the lines for all gears only up to the red line, because it is assumed that you will change up a gear at that point. With the top gear you have no other choice than to keep revving higher, so the line is drawn longer past the red line, because theoretically (i.e. if the engine still has enough power there) you can still accelerate there past the red line.
     
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  26. PerformLAB1

    PerformLAB1

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    I would be inclined to agree, however, when you try it, it won't go past 6500 rpm in any gear but the last one when you are actually driving it...
     
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  27. bil coz

    bil coz

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    Wrong sorry is it that hard to pick ANY car and try out?
     
  28. sumbrownkid

    sumbrownkid

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    Yes, with that attitude of yours. You want help, fine. But I have no idea why you to be so aggressive about it.
     
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  29. bil coz

    bil coz

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    I think anybody will sound aggressive when they're made to repeat the same thing 10 times and met with constant rebutal by others who haven't bothered to try.
    So yeah, it's unfortunate if that makes me sound like that cause I'm not. I'm only waiting for a valid take on the subject.
     
  30. snowgt

    snowgt

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    I just tried that and can not confirm. The Cobra revs to 7000 rpm in any gear except top gear, where it does exactly what praiano described above (it stays about 200rpm below the limiter). This behaviour is a bit car specific, it seems.

    I also found that the speeds given in the transmission settings mostly do not align with actual maximum speeds in the respective gears. I don't know, if they are supposed to be speeds at red line or limiter, but I found them to be neither. It's odd, but I never really look at those when I'm adapting the gearbox.

    What I can safely say is, that not one car I looked at revved past the rev limiter in top gear. It is a false conclusion to say "the car is going faster than I think it should, so therefore it revs higher." The rev counter says it doesn't rev higher and also the pitch of the engine says it doesn't.
     
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