Turbo Lag Proven

Discussion in 'Gran Turismo 5' started by Lock2Lock, Aug 9, 2013.

  1. Lock2Lock

    Lock2Lock Premium

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    Since some people still deny the existence of Turbo Lag in Gran Turismo 5, I want to show that it does in fact have this implemented in the game.

    One of the problems as a few other members (including myself) have said before, the turbo gauge itself is not always accurate in the game. But this doesn't mean there isn't turbo lag in the game.

    ======================
    Here's a easy test to prove its existence in GT5.


    This video is to demonstrate the existence of Turbo Lag in Gran Turismo 5.
    To demonstrate this I took a stock Option Stream Z on Special Stage Route X, to give the best conditions to display my evidence.

    I start off at around 3,000RPM before holding the throttle at 3/4 application causing the RPM to climb steadily. As the RPM rises the turbo will begin spooling; once the RPM reaches roughly 4,000 RPM the engine is producing sufficient exhaust flow to build up boost, otherwise known as the "Boost Threshold".
    From this point forth you can see the boost increasing in small increments, this is known as "Turbo Lag" - the time between Boost Threshold being met and the turbo charger reaching "Peak Boost".

    In this instance the Boost Gauge is able to show the correct values for a period of time due to the lower throttle input, this leads me to believe that Exorcet is indeed correct about the Boost Gauge which I have said from the beginning - upon reaching what the Gauge reads as "Peak Boost" you can both hear and feel the turbo continuing to spool.

    I find this to be conclusive evidence that Turbo Lag is indeed present in Gran Turismo 5, despite the misleading gauges.
     
    Klitlika and Parnelli Bone like this.
  2. YN89

    YN89

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    lol
     
  3. Akmuq

    Akmuq

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    Very insightful and constructive response.
     
  4. GTP_CargoRatt

    GTP_CargoRatt

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    Nice demonstration. Keep up the good work. Your efforts are appreciated. :tup:
     
  5. Lock2Lock

    Lock2Lock Premium

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    Don't worry about it man, I tend to overlook posts like that.
    I appreciate it.
     
  6. Streeto

    Streeto

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    You tell 'em locky boy.
     
  7. Tornado

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    And how is this video any different from the videos and claims posted in this thread (most of them in relation to that specific car, even) that didn't prove it was there? Because I'm still just seeing a car with an obnoxiously high boost threshold being started at a really low RPM far below the glut of the torque curve and being forced to push through it anyway (this time with less throttle applied); and that being called turbo lag again.
     
  8. MrWednesday

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    I don't think this is a good description of turbo lag, or at least, of what I would think of as turbo lag. What I would think of as turbo lag is the delay between application of throttle and the boost the turbo is capable of at that throttle level and RPM---the time it takes the turbo to spool up from idle to the ~100k RPM (give or take 20 to 50k) operating speed. What you are describing is more like the basic performance curve of the turbo, the interaction between the amount of exhaust gas passing through the turbine wheel, the power recovered from it, and the amount of compression delivered on the other side.

    I'd conclude that you're measuring something, but I don't think it's necessarily turbo lag. Or rather, I think your example is really only one side of the equation, the non-lag side of it. If you want the lag side, start out coasting at 4,000 RPM and apply 3/4 throttle, how long does it take for the engine response to match the response you saw when you had steady 3/4 throttle up from 3,000 RPM? Turbo lag is inherently an unsteady-throttle phenomenon.

    (Wikipedia agrees with my interpretation: http://en.wikipedia.org/wiki/Turbocharger#Turbo_lag )
     
    Last edited: Aug 10, 2013
  9. Lock2Lock

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    The throttle does not matter. Turbo Lag is Turbo Lag doesn't matter what throttle it is at. What I am doing (which is explained in the OP), is showing the Boost Gauge actually showing the turbo's activity. That's why the throttle is where it is. Like I said, that discussion of the throttle position is 100% irrelevant in trying to disprove Turbo Lag in GT5.

    Which is once again explained perfectly in the OP. That's how a turbo works and that is what Turbo Lag is. It can't get any simpler than that.

    Honestly, if you still deny it after that explanation in the OP, it is you not understanding how a turbo works or what turbo lag is.

    What is happening is turbo lag. You can't deny it, it is clear as day in the video.


    No.

    Turbo Lag is the time it takes for the turbo to spool from "Boost Threshold" to "Peak Boost". That's it. Plain and simple. That is what happened in the video.
     
  10. MrWednesday

    MrWednesday

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    See my Wikipedia reference (which I added while you were composing your response). You're measuring steady-throttle response, but turbo lag is an unsteady-throttle behavior.

    I'm not saying you aren't measuring something real, but it's not turbo lag. It's just the way that the turbocharger's performance curve influences the power curve of the engine.
     
  11. Lock2Lock

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    Throttle does not matter :lol:. It has nothing to do with Turbo Lag to be honest. The only reason I did this test with 3/4th throttle was to show that the gauge was showing the turbo spooling up. Keeping that same throttle actually proves my point even more.

    As many have said before, "the guage doesn't work correctly at full throttle on some cars", which I agree with. So this is showing the turbo spooling up. Which is Turbo Lag.
    Don't trust everything you read on Wikipedia :lol:.

    Turbo Lag- is the time it takes the turbo to spool up from "Boost Threshold" to "Peak Boost". That's what turbo lag actually is. Check your facts again.
     
  12. UrieHusky

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    Turbo lag by definition is the time between "Boost Threshold" and "Peak Boost" there are no ifs ands or buts about it.
    If you have a different definition of turbo lag, good for you - however it doesn't change what the definition is.

    The video is clearly depicting all three stages of the Turbo spooling up, having the low throttle is irrelevant - all it's doing in this case is allowing for the spooling to be visible despite the woefully inaccurate gauges.

    Power curve isn't going to effect the boost gauge =/ why exactly is that being brought up? the gauge is simply showing the pressure - the pressure is caused by exhaust gas spinning the turbines; the more throttle, the more exhaust gas, the faster the turbine spools.

    The time it takes for that pressure to build up once the spooling begins is Turbo Lag which you can see in the video.
     
  13. Tornado

    Tornado

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    No. What is happening is you're saying an engine having a peaky torque curve with even throttle being applied as the car revs is the same thing as the game featuring turbo lag. Again, this thread seems like nothing more than a pretext for you to repeat your statements from the other thread free from the scrutiny that posting in that thread would cause.


    That's not actually a rebuttal. Considering your fundamental misunderstanding of the concept and your general behavior in the thread I linked to, I'm pretty far away from accepting that Wikipedia's explanation of the concept (which several people explained as being the case in that other thread, and is parroted around the web, broken down on a technical level in the latter two links) is wrong just because you said it is.

    Which is exactly what Mr. Wednesday said:
    Meaning after the engine spins past boost threshold, the amount of time it takes to reach peak boost on application of the throttle.


    And is something that the test in the OP doesn't actually measure any more than these did:

     
  14. UrieHusky

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    Except due to the lower throttle input we can actually see the boost building, almost like in slow motion.

    This leads me to believe that the gauges are incorrect, however the actual lag is still present.

    I absolutely believe that it's the gauges that are incorrect, however turbo lag is certainly present - if it wasn't surely the turbo would simply raise with the throttle input? clearly the turbo is raising pressure from the exhaust rotating the turbine and nothing else, what exactly would you call that if not turbo lag?

    I should make it clear that I'm not making any kind of attacks here, I just find this to be rather conclusive evidence that the gauges are the system at fault here, not a lack of "lag"..
     
  15. MrWednesday

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    The more boost, the more power*. The two are inextricably linked. The power curve comes into it because it controls how quickly the car accelerates, hence how quickly RPMs increase, hence how quickly you move on the performance curve of the turbo and get more boost (until you hit the pressure where the wastegate actuates).


    * More boost -> more mass of air going into the engine at the same RPM -> more fuel going into the engine at the same RPM -> more power


    Edit: Adding a response to your second post to avoid a double-post.

    :confused: Wait, what's wrong with the gauges? You're seeing the boost do what it ought to do, which is build more slowly at part-throttle (less air allowed into the engine providing less exhaust to drive the turbine). There'd be a problem with the gauges if they weren't showing that behavior.

    What you're referring to as the "lag" in this case is boost varying with engine RPM. I guess it could be perceived as a lag, because functionally it leads to a delay in getting maximum power, but this is also directly reflected in the power curve of the engine and it occurs at constant throttle. The delay in this case is due to the combination of the compressor performance map and the speed and power the turbine can develop at a given RPM and load, but it's not primarily affected by things like the inertia of the rotating assembly of the turbocharger.

    There's another kind of turbo lag that can arise, though. Suppose the engine is already at 5,000 RPM, and normally at 5,000 RPM and WOT you would get 15 psi of boost. But we're just coasting with the engine at idle. Now I mash the throttle. The delay in building boost between when I mash the throttle and when I get full boost is what I and Wikipedia are referring to as turbo lag. I would expect the inertia of the rotating assembly of the turbocharger to play a large role in this lag.
     
    Last edited: Aug 10, 2013
  16. UrieHusky

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    The higher the RPM the more frequent the detonations meaning faster flowing exhaust gas which means a faster turbo spool - which again we see later on in the video as the gauge shows the boost picking up speed.

    I'm not sure what your argument is? there isn't any turbo lag because the RPMs raise quicker because you're in the torque band which is raised by the turbo?
     
  17. C53A 4G63T

    C53A 4G63T

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    This shows nothing more than the engine power curve. As you are doing it with 3/4 throttle which will limit it to less than it's capacity, but in the game it shows full boost which would not be possible in real life. Boost builds with engine load, so it's going to be different than at full throttle. The boost gauge is a very simple display that just moves with how much RPM's you have and taking into consideration the % of throttle, in the game. There is no thought to lag, just set points due to a power curve. You are making this out to be more complicated than it really is.
     
  18. Tornado

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    The only reason you're seeing that is because he's rolling into the near vertical climb in horsepower that happens on that car around 5500 RPM, which in real life is where the turbo on the real car started taking effect but in the game isn't emulated beyond engine sounds and the boost gauge. It's so slow because he's doing it at 3/4ths throttle, but I have no doubt if you attempted the same thing with a similarly peaky NA car, you'd see very similar behavior.


    It does. Drive any turbo car in GT5 in a way that it stays above the boost threshold when you let off the throttle. When you go to WOT after letting off it, the throttle response is instantaneous (not what the boost gauge says, and not what happens when you roll into the boost threshold. The throttle response itself), exactly as it is if you were driving a car that was normally aspirated.


    That, the efficiency of the fuel/air mixture (including the intercooler), and the efficiency of the piping.
     
  19. MrWednesday

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    Not exactly. Maybe, maybe not. It means the turbo can extract more power from the exhaust gas; depending on the compressor map and the engine performance, that might mean that there's excess power to spool the turbo more (maybe increasing boost, maybe just making the air hotter), or it might just mean that you're just keeping up with the air demand by the engine and the rotating assembly stays at the same speed.

    Turbos are complicated in practice, and even when you have a lot of details on their performance, you still usually lack for some of the details. Compressor maps aren't that hard to come by, but turbine characteristics are a lot more difficult.

    (If you want to get into the gory details, Borg-Warner has a great page here: http://www.turbodriven.com/en/performanceturbos/matchbot.aspx )

    My argument is that a constant-throttle test doesn't (can't, by its nature) show the second kind of lag that I discussed in my previous post, since that is inherently a response to changes in throttle input.

    What you see in the constant-throttle test is something that is real and should happen, and it would indicate a major flaw in PD's modeling of a turbocharger if it didn't. However, it's not the only thing that they need to get right. In real life, with a slow-spooling (laggy) turbo, you need to drive differently to take minimize the lag and take maximum advantage of the turbo.
     
    Last edited: Aug 10, 2013
  20. Lock2Lock

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    Wrong again.
    The "peaky torque curve" you speak of is caused by the turbo. The car has a massive turbo which produces this effect.



    "scrutiny" :lol:? I actually did post this in that thread. I thought it would be better to make this thread so that thread wouldn't go further off topic. Plus it is a very old thread. So no I am not afraid of any so called "scrutiny", because once again both you and Exorcet are wrong.

    In fact the three videos I can actually explain what is happening.

    First. The HPA video.
    At 4 seconds into video, the turbo is at "Boost Threshold".
    At 8 seconds into the video, the turbo is at "Peak Boost"
    In between those 4 seconds that is where the Turbo Lag is.


    Now in the videos with the Option Stream Z and Suzuki Escudo There is practically no Turbo lag because the turbo is already at/reached "Peak Boost". So we can pretty much forget those two videos, they are not relevant in this.

    That's exactly what has happened in those videos. Since you want to bring up the past thread, I will too. I believe Exorcet had said "No turbo takes 4 seconds to spool to Peak Boost.", which that is 100% false all in itself.
    Don't believe me? Well here you go.
    This Supra Drag car has a 80mm Turbo like the Option Stream Z. Notice how long the turbo is taking to Spool to "Peak Boost", which once again is Turbo Lag.


    It actually wasn't meant to be a rebuttal. I was just stating that you guys are still wrong about what Turbo Lag is. I guess you will never understand what Turbo Lag is, your fault not mind. Keep thinking that you are right though.
    I am actually aware of how to determine Turbo Lag. Which is what I did. Your definition of Turbo Lag is wrong.



    ===================
    So once again, what I have shown is in fact Turbo Lag. The throttle position does not matter in this case. Stop mentioning the throttle position because that argument is invalid. Read the OP carefully again then watch the video again. You will see that where I have my throttle at shows the Turbo spooling up between "Boost Threshold" and "Peak Boost" which is Turbo Lag
     
    Last edited: Aug 10, 2013
  21. HuskyGT

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    Very nice demonstration:tup: I already noticed this before, but only in certain cars. An Example would be the Ferrari F40.

    What bothers me is that most cars have very little boot at high rpms, no matter which turbo you apply. In some cars it works, in some other it doesn't.
     
  22. Tornado

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    The peaky torque curve I speak of is caused by the car being programmed in the game to have a peaky torque curve. It's no different from GT3 in that regard, except now the turbo noise is tied to the engine itself rather than the "turbo" part ID.

    He didn't get to boost threshold until 8 seconds in the video. He merely applied the throttle at 4 seconds in.

    That's not what should have happened, so those videos are completely relevant.


    It took less then a second for the turbo to spool in that video. He did it thrice, after each upshift after the launch from the tree, at :53, :56 and :58.

    My definition of turbo lag is the one given by auto manufacturers when they explain what they did to minimize it. Ceramic turbo blades minimize how long it takes for the turbo to spin up at WOT because their inertia is so much lower. More efficient intercooler design decreases the amount of time the air spends being cooled before being pushed into the engine by the turbo. Less restrictive exhausts get the air to the turbo faster in the first place.


    Turbo lag is how long it takes the turbo to spool when WOT is applied. Period. End of. Done. Making another new thread and repeating all of the same incorrect arguments (this time around a slightly different video from one already posted) that you made in that thread shows that you still don't understand what the difference is between turbo lag (which means throttle response) and boost threshold (which means torque curves).
     
  23. Eric1512

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    I am leaning towards locks side on this. I do a lot of drifting and you can really feel lag in some cars. Rx8 for example.
     
  24. Lock2Lock

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    Here's your problem right here. You basically just said you have no clue what Turbo Lag is as a whole. According to what you just said "Boost Threshold" and "Peak Boost" are the same. Which they are not the same in any way.

    Once again.
    Boost Threshold- The time where the turbo starts spooling or building boost
    Peak Boost- Is where the turbo is producing max boost.

    Your arguments are invalid because of your lack of understanding of how a turbo works.
     
  25. NinjaDesignz

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  26. SoullessApples

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    Obvious turbo lag is obvious. Why do you guys not believe it?
     
  27. MrWednesday

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    I'm curious: can you explain, in detail, what you get at the link that I posted to Borg-Warner's turbo selection page? Have you ever looked at a turbo compressor map before? Have you driven a turbocharged car in real life, not just in GT?

    (For the record, the turbocharged car that I've driven has a small, fast-spooling turbo, and it also makes boost at low RPMs and has a flat torque curve, so it has neither what you would characterize as "lag" nor real turbo lag.)
     
  28. Tornado

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    You just said that the Escudo and Option Stream Z shouldn't have lag after upshifting because they are at peak boost:
    That there should be instant throttle response when the RPM is high enough to achieve peak boost even after posting a video of a drag car where there wasn't in the exact same circumstances.


    So glass houses.


    I'm not saying that. I'm saying that the boost threshold is not reached immediately after you put the throttle on. For that R32, the boost threshold would be around 3500-4000 RPM, at which point the RPM rapidly rises from there (and in real life the turbo would dramatically increase in pressure at that point until getting to the peak). When you look at the dyno in the game, that is also where there is a massive increase in torque on the RPM range.



    For it to be what you are claiming (that booth threshold was met the instant the throttle was applied), the turbos (which are not sequential, like on the FD RX-7 or Mark IV Toyota Supra; but parallel like on the Ferrari F40 and designed for max power rather than driveability) would have to start taking effect at about 1300 RPM; which makes them amazingly efficient in picking up exhaust gasses considering their size, but so inefficient after that that they take 3000 more RPM to get going at the level needed to go full bore.
     
    Last edited: Aug 10, 2013
  29. Lock2Lock

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    Don't even try to pull the "You have to drive one to know" on me, it is completely irrelevant.

    Also the car you are speaking of has either little to no Turbo Lag.


    The video of the drag car was a example for Exorcet's statement from the other thread... "No turbo takes 4 seconds to reach "Peak Boost" (Peak Boost aka Max Boost). That is completely false. That's where that drag car video came into play. I was using that as example to show what all Exorcet has gotten wrong (No offense to him).

    Yes my statement still stands. Exorcet's videos of the Option Stream Z and Suzuki Escudo are irrelevant because they are not showing Turbo Lag in those two videos because they are past the point of "Peak Boost"

    Exactly what you just said above is Turbo Lag.

    However one thing that you have mistaken.
    On the R32 its "Boost Threshold" is actually at 2.000 RPM. Which at 2,000 RPM you can clearly see on the Turbo Gauge it is starting to spool after that point. When the RPMs are at 3,500 RPM you can see the turbo stop spooling, which is "Peak Boost" aka Max Boost.
    The time between 2,000RPM (Boost Threshold) and 3,500RPM (Peak Boost) is where the Turbo Lag is.
    Which once again....

    Turbo Lag- Is the time the turbo takes to go from Boost Threshold to Peak Boost.
    Boost Threshold is what your main problem in understanding is. You are confusing Boost Threshold with Peak Boost. You think they are the same thing, which they are not.

    This is where we are constantly butting heads man. I am not trying to insult you. I am trying to help you understand what you are getting mixed up.


    Never said that.
    I said Boost Threshold is when the turbo starts to build boost/start spooling. I am not even looking at the throttle meter on that video because like I said before, throttle position is irrelevant.
     
    Last edited: Aug 10, 2013
  30. MrWednesday

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    My remaining questions stand. (And it's certainly not completely irrelevant for you to have real life experience with a turbocharged car. It's not essential, but it does matter.)

    I did say this:

    So yes, I'm well aware of that.
     
    Last edited: Aug 10, 2013