Turbo Lag Proven

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

  1. hasslemoff

    hasslemoff Premium

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    People basically have two views on turbo lag, one is when the engine is below the boost threshold and the other is when the engine is in the threshold.
    The video on the OP shows the engine below the boost threshold which inturn produces less acceleration which is interperated as turbo lag by some.

    Prime example on Top gear (google it if you have not seen it) they did what they called a turbo lag test with a EVO, notice it was started at 30 mph, high gear and low revs well below the boost threshold of the EVO this will off course hinder the accelaration of the EVO as its well below the Threshold, a common miss interperation of turbo lag.
    That test was to show that the car is not that good for day to day running as the turbo is so large.


    Turbo lag:
    A measure of the delay between when a turbocharged engine’s throttle is opened, and a “significant portion” of the maximum boost pressure is available.

    Basically its measured when you hit full throttle when then engine is at the right revs for the turbo to work.

    Boost threshold:
    Turbo lag should not be confused with boost threshold, which for simplicity’s sake we’ll say is the engine RPM above which the turbo is capable of producing a “significant portion” of its maximum boost pressure. For example, stamping the throttle open at 1500RPM and having to wait until 3000RPM for boost is not so much lag as it is a function of the engine and turbo system’s boost threshold. Once the engine is operating above the boost threshold however, then the delay when the throttle is opened can be assumed to be turbo lag.

    Again basically to measure turbo lag the engine needs to be above the boost threashold, when the engine is in the threshold apply full throttle and if it does not respond straight away that is lag.


    There will always be a delay in acceleration when the accelerator is applied in cars with large turbos ( newer cars not so much now) when you are below the the threshold as they are not made to be driven around at low revs they are made to be driven in threshold, EVO's are a great example you have to keep them revs high or you will not get full use out of the car.


    I've not tested lag in GT5 so I couldnt tell you if there is or there isnt but the way to test it is to apply full throttle when the engine revs are after the boost threshold and see if there is a delay.
     
  2. LERK84

    LERK84

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  3. Morgoth_666

    Morgoth_666

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    That is actually a great demonstration of what many people consider to be turbo lag. From the moment he says "we're both in top gear and both going 30 miles per hour" you know they are showing the difference in power output between when the engine is not able to use the turbo effectively and when it can, not the responsiveness of the turbo unit itself.

    hasslemoff's post basically sums up the point of disagreement. The issue is that there are two different uses of the term "turbo lag" propogated in various places on the web as well as in the GTP community.


    Some define turbo lag as the sharply peaked power curve common in turbo engines which makes them very sluggish outside of the powerband. This means that it takes a very long time for the turbo to reach maximum pressure when accelerating from outside of the powerband. All engines obviously have this behavior to some extent, it takes my NA Camaro a long time to get from 15mph to 25mph in third gear but it accelerates much faster once you get there. No one would call this "NA lag," of course. The effect tends to be greatly accentuated by the addition of turbos because of the way they work(and don't). If NA cars in GT5 had a "horsepower gauge" however you would see a similar result to what you see in the Turbo gauge, with little power being produced at no throttle then instantly bulding to a certain level once throttle is applied and then slowly building to peak power output.


    Others define turbo lag as the time delay between the time the throttle is opened and the time that the turbo unit spins up to reach it's maximum pressure at that RPM level. Since the turbo is powered by the exhaust flow, the response will be always slightly more delayed than with an NA engine. "No turbo lag" just means "imperceptibly small lag." When the engine RPM is in the turbo's proper operating range (which is what I've always understood "boost threshold" is about), there will likely be somewhat less delay but the most noticeable difference is in the amount of boost produced as it begins to build rapidly towards it's maximum boost after that point. There will always be more lapse in time between the application of throttle and the engine reacting in a turbo engine than in an NA engine(though the amount can vary widely based on the turbo's design), and as far as I have observed, this does not occur in GT5 or is at an imperceptibly low level. The oft-exampled Option Stream Z produces exactly as much power as it should at all RPM levels the instant you hit the gas.


    This is why two people can watch the video of that Supra and one sees lag displayed over several seconds, while another sees only a brief moment of less than a second of lag.

    I'm sure I'm wrong about a lot of things in my understanding of the mechanics, but the point is that the issue that causes so much disagreement is not that people aren't seeing the same things happening in GT5 but rather that they are not attributing the same terms to describe the things that are(and aren't) happening.
     
    Last edited: Aug 10, 2013
  4. Exorcet

    Exorcet Premium

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  5. MrWednesday

    MrWednesday

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    You've got the basic behavior right. The issues that lead to this delay:


    • Rotational inertia of the turbo---with the rotating assembly spinning at over 100,000 RPM, it can take a significant amount of energy to get the rotating assembly up to speed. This can be mitigated by having less weight farther away from the axis of rotation, either because the wheels are smaller in diameter or because they use lighter materials at the tips.
    • Time lag between the compressor and the turbine---how much time it takes increased boost at the compressor to lead to increased flow through the turbine (which is then immediately reflected at the compressor wheel).
     
  6. Wankelhead

    Wankelhead

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    Here`s a video from a graduated mechanical engineer.
    I hope this helps.

     
  7. Lock2Lock

    Lock2Lock Premium

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    No that's where you are wrong. Throttle does not matter in figuring out turbo lag. I even did a break down of your video of the HPA R32.

    In that video it shows turbo lag. You obviously have no clue what Turbo Lag actually is.

    Once again even in your own video of the HPA.
    At four seconds in you will see the turbo gauge go up then stop. Right after that, you will see it start slowly building boost/spooling up. This is what Boost Threshold is.

    At eight seconds into the video, you will see the turbo gauge stop: which indicates the turbo has stopped spooling. This means the turbo is at the point of "Peak Boost".

    The time it takes for the turbo to start building boost (which is Boost Threshold) and reach max boost (which is Peak Boost) is Turbo Lag.

    You showed this in your own video. Full throttle or half throttle doesn't matter, we are showing Turbo Lag.
     
    Last edited: Aug 10, 2013
  8. Tornado

    Tornado

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    It's very easy to win an argument when you just repeatedly write off everyone who disagrees with you as just not knowing what they are talking about (without actually countering what they are saying), huh?


    :lol:
     
    Last edited: Aug 10, 2013
  9. Lock2Lock

    Lock2Lock Premium

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    Throttle does not matter. It really doesn't :lol:.

    I even broke down his video with the HPA at full throttle, proving that throttle doesn't matter in showing Turbo Lag.
    So you pointing out that I said it doesn't matter and trying to act like a smart:censored: by saying ":lol:" is only making yourself look stupid.
     
  10. Tornado

    Tornado

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    Throttle is literally all that has to do with turbo lag, because turbo lag is a measurement of throttle response.

    You did watch the video Wankelhead just posted, yes? You clearly didn't when I posted it earlier, but maybe him embedding it allowed you to do so.
     
  11. Lock2Lock

    Lock2Lock Premium

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    Once again.
    ======

    Fixed that for you.
     
  12. Tornado

    Tornado

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    And repeating yourself verbatim without even attempting to respond to the evidence posted to refute your statements is... making you look... smart?



    Here. I'll even post it a third time:



    Explain why that video is wrong in its explanation.
     
  13. Lock2Lock

    Lock2Lock Premium

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    I fully understand that video. In fact I believe I have posted it before.

    Since you want to post it.
    The HPA is a perfect example of that video. It even shows on the turbo gauge which is the amazing part of your miss understanding of Turbo Lag.

    No I am repeating myself because there is no other way to word it. Funniest part is that I actually proved it with Exorcet's own video.
     
  14. MSTER232

    MSTER232

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    Some people just like to keep arguments going for as long as possible. Turbo lag is in GT5 and it's obviously been proven countlessly amount of times. If you do not believe it, then take the same Option Z, put your foot down from a standing start without revving your engine. You'd have to be extremely ignorant not to see the turbo lag from about 2-4 rpm.

    Do the same thing again in a stock 350z and the turbo lag (if fitted with a turbo, you can fit some 350z with either supercharger or turbo), is still there but very minute in contrast.
     
  15. Lock2Lock

    Lock2Lock Premium

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    Dude, I could even take a Stock R34 Skyline (which has a very steady power band and is not "peaky"). Then put a Stage 5 Turbo on the car and buy one without it. If it showed the same type of thing as the Option Stream Z or HPA R32 ect, they still would find some lame excuse to why it isn't turbo lag.

    Quite amusing to say the least.
     
  16. MSTER232

    MSTER232

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    Wait, there's a stage 5 turbo in GT5? That must have inconceivable amounts of turbo lag...! Your tacho has to be in the redline area before your car even does anything :lol::tup: .
     
  17. C53A 4G63T

    C53A 4G63T

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    What real world knowledge are you applying to this? Do you have any experience building real life cars, or are you just a theory slinger? It's not an open/shut case unless you actually know about the things we are dealing with. Like the size of the turbo, the size of the engine, air flow dynamics of the head, intake manifold and exhaust manifold, compressor maps and such. A lot more needs to be taken into consideration then just, "When I hit the gas it doesn't make whistle noises till later."
     
  18. Tornado

    Tornado

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    Thanks for that contribution. We're well aware of the behavior that the Option exhibits in that range. Most of us are also aware that that isn't turbo lag, however.


    You clearly don't if you're claiming that turbo lag has nothing to do with throttle (especially when "POOR THROTTLE RESPONSE" is written in big red letters on the board behind him); and that video is pretty plainly at odds with your previous posts in this thread.

    It clearly is not since the information provided in the video is not represented in the HPA video; most obvious at 0:11, 0:13, 0:31 and 0:33.


    You proved that the same behavior that is not turbo lag is present in the video in the OP as the behavior in Excorcet's post that is also not turbo lag.

    If I showed the same type of thing as the Option Stream Z or HPA R32 with a Peugoet 905, Chapparal 2J and Spoon Civic Type R or some other extremely peaky normally aspirated car, people would call that turbo lag. And they have.
     
  19. MrWednesday

    MrWednesday

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    I gave L2L an opportunity to demonstrate that he has the faintest inkling whereof he speaks, and so far, he has declined to take advantage. At this point, it appears to be willful ignorance.
     
  20. Lock2Lock

    Lock2Lock Premium

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    So what you have said previously is "The Option Stream Z has a peaky powerband that's why it acts that way."

    So let's think about this for a second.

    To say if I put a Stage 5 Turbo on a R34 (which doesn't have a peaky powerband), and it creates the same type of increase of power, it is Turbo Lag. I can do that.

    I can also turbo a N/A car with the very same turbo. So how much you want to bet that it will do the same thing I am talking about now.

    I bet you will still continue to say the same thing.

    So what you have said previously is "The Option Stream Z has a peaky powerband that's why it acts that way."

    So let's think about this for a second.

    To say if I put a Stage 5 Turbo on a R34 (which doesn't have a peaky powerband), and it creates the same type of increase of power, it is Turbo Lag. I can do that.

    I can also turbo a N/A car with the very same turbo. So how much you want to bet that it will do the same thing I am talking about now.

    I bet you will still continue to say the same thing.

    What tell you if I have driven/worked on a real life car with a turbo?

    For the record I have driven a few, but not with a huge turbo like the Option Stream Z or any type that has a turbo that will cause turbo lag. Like your very own car.

    Also whether I have other not is irrelevant. Reason being. In that Turbo Lag Fun! thread, there is a person in that very thread that commented in there by the name of Blksupratt. He has been a mechanic for some over 15 years plus. He has owned and worked on many turbocharged cars. They still acted like his experience in turbocharged cars meant nothing, so what would my experience mean? Nothing.

    So before you think I am ignoring you, I am actually ignoring things that are irrelevant for this discussion.
     
    Last edited: Aug 11, 2013
  21. Tornado

    Tornado

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    I don't know what a Stage 5 turbo is. If you're referring to something gotten from hacking the game, I'd think it would be pretty self-evident that the results after doing that wouldn't be the same as if you were doing something within the normal parameters. There's precedent for that exact thing too. For example, if you give cars 40,000 horsepower in GT5 through hacking, they will start showing off what could be most closely described as massive torque steer at all speeds even though in the regular game they do nothing of the sort.

    I'd scarcely believe it.

    And those cars would be?
     
  22. Lock2Lock

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    No I don't like unrealistic BS cars like that, neither will I use them.

    The Stage 4 and 5 Turbo is actually yes, a hidden part in GT5. Which can be applied to certain cars within GT5. Most of these parts are actually already in the game but most like the hidden tires are applied to certain cars by default.

    Basically my reason for mentioning this, is that you keep saying GT5 doesn't really model the turbo, but only the powerband. So if I was to take a N/A car or a car with a none peaky powerband, and put one of these turbos on the car. By what you are saying this will actually prove your statements false.

    Because you constantly say, "Oh it is just a peaky powerband". Well if that's the case adding a bigger turbo like in the example I gave earlier, will have no effect on the way the car acts right?

    No I don't like unrealistic BS cars like that, neither will I use them.

    The Stage 4 and 5 Turbo is actually yes, a hidden part in GT5. Which can be applied to certain cars within GT5. Most of these parts are actually already in the game but most like the hidden tires are applied to certain cars by default.

    Basically my reason for mentioning this, is that you keep saying GT5 doesn't really model the turbo, but only the powerband. So if I was to take a N/A car or a car with a none peaky powerband, and put one of these turbos on the car. By what you are saying this will actually prove your statements false.

    Because you constantly say, "Oh it is just a peaky powerband". Well if that's the case adding a bigger turbo like in the example I gave earlier, will have no effect on the way the car acts right?

    Like I said before my personal experience means nothing.

    If you must know, I haven't worked on these cars. Which means absolutely nothing to this discussion.

    I have driven a few different types of Lancer Evolutions. Those that I have driven are long gone. The reason I will not show pictures of them is because of what they were used for. I used to do a lot of illegal stuff, which I will not talk about because it is in the past. We used the cars for this type of situations. Like i said illegal.

    I honestly do not care what you want to say about it, but I will not discuss this anymore. For one it is illegal, and two it is in the past. I cannot contact anyone for pictures, because most of them are dead now, and the cars are long gone, lately I do not associate with anyone from that. I think you can respect that. If not, well then I guess we will have to leave it as "no experience". I would rather say that then go on and on about what I used to do. You can give me that much respect not to push that topic.
     
    Last edited: Aug 11, 2013
  23. Tornado

    Tornado

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    I can already test the same thing with cars and parameters in the game. Any one of the air-cooled Volkswagens have almost diesel-like performance attributes. As a result, any one of the three regular turbochargers will completely shift the power curve to whatever RPM range it "takes effect" in; and practically double the engine power in any place where that is occurring.



    It doesn't model the effects of the turbo, but that doesn't mean that applying the different turbocharger types will have no effect on the way the car drives at all. Go back to one of the air cooled VW examples. A low RPM turbo will make only the first 2000 RPM be useable, to the extent that the car is literally undriveable with an automatic transmission (or by the AI). A mid-RPM turbo will make the middle 2000 RPM have all of the power (but still not very good for an automatic, but much easier to gear properly). The high-RPM turbo will shift all of the torque up high, but at the expense of lower actual output and an even narrower powerband than the other two.

    The issue is that a turbocharger that changes the torque curve of an engine with such a low compression ratio that much would have dramatic hesitation in throttle response when you were in the area of highest boost; yet in GT5 there is no such thing. The turbocharger literally doubles the engine horsepower in three different places, yet no such change in throttle response occurs; not even for the turbo type where the game specifically warns that it will happen.




    If you've actually driven turbocharged cars, it means quite a bit because it shows that you actually have a practical understanding of the driving characteristics of them.

    I've driven 3 of note, one of which (1980-something Thunderbird Turbo Coupe) had pronounced turbo lag and a relatively high boost threshold (and thus peak torque RPM) with a narrow powerband; another of which (1989 Dodge Shadow ES Turbo) had pronounced turbo lag but a very low boost threshold that was low enough (and had enough torque at a really low RPM as a result) that you could drive it around in 5th gear all the time and have a nice flat torque curve to play with; and one (2000 Volkswagejn Golf GTi 1.8T) that produced most of it's power practically just off of idle and other than the numerous times where it simply wasn't running properly (which was more often than not, I'm sorry to say for the college student owner) there was fairly little lag to speak of.

    I'm not trying to drag some admission of illegal activity out of you. I'm merely posing a question. When you drove them, in the proper gear in the proper RPM range, when you applied the throttle, did you instantly have power? Or was it more like what is described here, from a car with largely an identical drivetrain.
     
  24. Lock2Lock

    Lock2Lock Premium

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    Well, maybe that's the case on that car.
    Doesn't mean they are all like that.

    What I am explaining and you can use the "Turbo Lag Explained" video to confirm this. I am going to compare that video with the HPA video.

    Basically by doing the full throttle application what it is showing the lack of full power till Peak Boost aka Max Boost. Which when the Turbo starts to spool up to get to Peak Boost is Boost Threshold. The in between the point of the turbo actually starting to build positive pressure (which is anything past positive pressure), to where is reaches Peak Boost is Turbo Lag.

    Which in the HPA video.

    You see him go full throttle. Within around that time you see (even on the turbo gauge itself it go up to a certain place and stop). This is NOT where the Turbo Lag is.
    After that you start to see the gauge start rising (which means it is building positive pressure aka spooling). The point where the turbo actually starts to build boost aka spool up, is Boost Threshold. Which in that particular point in the video is 4 seconds in.

    Now, for the next 4 seconds you will see the turbo spooling up till it stops again which indicates Peak Boost aka Max Boost (at about 8 seconds in the video). Those 4 seconds where the turbo is spooling up to reach Peak Boost is where the Turbo Lag is.

    =====================
    What I was showing in my video is the following.
    The only reason I did this with a steady 3/4th throttle was to show it on the gauge. Basically I am taking 3/4th throttle and putting it as full throttle.
    Hints the reason I said I agree that the gauges on most cars is incorrect (Also is the reason I didn't move the throttle from that position. Technically the 0 pounds of boost should be straight up or half way on the gauge. Anything before that point is Vacuum and anything after is positive pressure aka boost. Which I agree they didn't model this correctly.
    So if you picture 3/4th throttle on that video full throttle and watch the gauge, I will break down the video.

    On the first roll on the video anything before 20 seconds doesn't matter.

    Pause the video at 20 seconds in.
    Alright, right after the 20-22 second mark you will see the turbo gauge start going up which indicates the turbo is spooling aka Boost Threshold.

    Press play on the video again and pause it between 26-27 seconds.
    Alright, at this point of the video you can see the turbo gauge has stopped climbing. This means the turbo is at "Peak Boost" aka Max Boost.

    Now, if you put the video back to 20-22 seconds again and watch the gauge again till 26-27 seconds, you will see the turbo go from Boost Threshold to Peak Boost. The time between is where the Turbo Lag is.

    That's all I was doing. I am not trying to create a loophole or anything, I am simply showing it in a way that will help better understand what is going on.




    To be perfectly honest, when I drove them I didn't really attention to it. If I didn't feel like I was getting a lot of power, I would simply shift down to a gear that would raise the RPMs high enough to spool the turbo back up to the point which it was past Boost Threshold but not at Peak Boost. However, this wasn't always the case. But no, if I say left the car in a higher gear and I was cruising down the highway at a low RPM, and then went full throttle, no I would not have full power at that point in time.
    I get what you are saying about those cars, and yes, it was the same point as what that guy is stating about his car. That's about the same thing would happen if I did that in one of those EVOs

    I also thank you for not pushing at that subject.


    Isn't that the same exact thing that I am showing in the my video (given the circumstances I said in this post above)?
    And what that guy in that thread is describing is exactly what I have been saying this whole time Tornado. At least what I have been trying to describe.

    Boost Threshold- Where the turbo starts building boost or positive pressure
    Peak Boost or- When the turbo reaches Max Boost or stops spooling up.
    Turbo Lag- The point between Boost Threshold and Peak Boost.
     
    Last edited: Aug 11, 2013
  25. extreme car

    extreme car

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    People who deny there is no turbo lag in gt5 has obviously never driven a fwd car with high rpm turbo and a low grip tyre in gt5. It's very obvious there is a power delay when you apply full throttle with these cars at any rpm and after the turbo spools the front wheel just loses grip, that's why it's better to use mid rpm turbos on these cars because of their responsiveness.
     
  26. Bopop4

    Bopop4

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    You install a turbo on the R34 and it doesn't just add a high rpm turbo, it also changes many engine parameters to optimize it for high rpm running.

    You ride a peaky 2-stroke an it's going to do the exact same thing as in the Option Z video, no power until high rpm, and then it just takes off.
     
  27. Team THRT Drift

    Team THRT Drift

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    *sigh* Trolls will be trolls. I love how people still argue about this.
     
  28. Gravitron

    Gravitron Moderator

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    I don't.

    Let's keep the arguments to a minimum guys. And the walls of text as well. Refer back to hasslemoff's post for sanity.
     
    Last edited: Aug 11, 2013
  29. 4everdelayed

    4everdelayed

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    No no no no no no no no no and no.

    It doesn't show turbo lag. It just shows how the engine is. If it can only output 90hp at 3000rpm and has 1000hp at 8000rpm, then that's the way it is and accelerating from 3000rpm all the way to 8000rpm is no measure of turbo lag. Turbo lag would be the time needed for the engine to output 90hp at 3000rpm when you're at 3000rpm and off the throttle and then smash the throttle. That's it. NA engines will do that much quicker than turbocharged engines because of turbo lag. Is that really that hard to understand? If it is, download a few books from here www.libgen.org (and I know I'll probably get banned for this but **** it).
     
  30. Ridox2JZGTE

    Ridox2JZGTE

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    I can make custom turbo in GT5, single or twin system, or even twincharger, less boost, more boost, ( less or more lag/response ) more low end torque, more top end torque, or all out high rpm top hp type :) I have F40 LM replica that uses twin turbo high rpm, but it emphasizes on mid rpm torque, also 787B engined Rx7 with lower boost, lower rpm range, less lag high rpm turbo, resulting 660+HP, much lower than original setup on 787B car, anyone interested to try how different the same engine perform with different spec turbos, it's on share :D

    Supercharger also have variety of type in GT5, some operate at higher boost, some on low boost as well as rpm ranges.

    Currently building 400HP Gr. A replica, it will perform like the real life - turbo wise ( high rpm kit ), peaky but minimum lag on lower rpm :D It has better traction than the stock car on CS tire.

    @L2L : Add me on your other account ASAP, I would like to send a car with custom spec turbo that you will love to drive :D
     
    Last edited: Aug 11, 2013