Turbo Lag.

  • Thread starter KVelocity
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KVelocity

KVelocity

85
Canada
Canada
Is it finally time PD implements this? I mean if Gran Turismo is the real driving simulator it claims to be wouldn't it be only right to implement this?
 
The lag is pretty negligible, but that might just be because the turbines are meant to be sensibly sized (hence the relatively meagre power outputs). The game does model the dead-spots, i.e. the steady-state boost (hence torque) profile is well represented, as evident in the differences between the low mid and high rpm kits' "power bands". But there is no real (transient) lag to speak of. I've noticed that when Jeremy Clarkson talks about "turbo lag", he doesn't make a distinction between the two effects i.e. "power-band" and actual lag (time it takes to reach that power).

Modeling transient lag properly would make different turbo configs more meaningful, e.g. twin vs. single etc.
 
I'm all for turbo lag, in terms of it being modeled. What would be great is if the engine tuning were broken down into more categories and certain modifications helped reduce lag slightly. For example, a displacement increase or higher compression would help in this regard.

Selecting twin vs single turbo setups would be nice as well. Maybe there are some big power cars that are a bit of a handful. A touch of lag could actually help make them just a bit more drivable, especially around corners, basically behaving like another form of traction control.
 
they gave a few cars "turbo" lag but it doesnt work like actual turbos do the few cars that do lag gradually spool up they just accelerate slowly if they have small displacement and big hp number where IRL a supra that has a huge turbo and makes 1000+hp will lag badly up until a certian rpm point and then pretty much within a second go from lagging to full spool.But yes they should definitively do a better job of making cars with forced induction more realistic.forza does a decent job of this a supra with twins will for example make 780rwhp at 6400rpm and a supra with a big single will make 900 at 7600 rpm or whatever.Id definitional like to see more realistic power number tho,also realistic performance.A 1200hp supra is not very uncommon now days and a 1200hp supra would be extremely fast in a straight line with tires that put the power down but also a 1200 hp supra would have ridiculous lag trying to race on a track that has a decent amount of turns and would be slower lap time then a 600-700rwhp supra with a turbo that spools faster.They should also add the ability to turbo v8's its more common on modern v8's to have a turbo then SC.And now days alot of the big hp supercharged v8s are using prochargers.I understand they do this so that the v8s arent womping on the 4cys and 6 every race but they should balance it out where that a gtr-r35 with 700hp/evo with 700awhp should beat a turbo 2012 camaro with 1000+hp on a track without many straight stretches.Also on a track like the ring without many sharp turns a 1000hp+ 99 camaro ss would run off on a 500hp lotus that handles like a dream.

http://www.youtube.com/watch?v=rmNy-ajRV0U
 
greedygenius
they gave a few cars "turbo" lag but it doesnt work like actual turbos do the few cars that do lag gradually spool up they just accelerate slowly if they have small displacement and big hp number where IRL a supra that has a huge turbo and makes 1000+hp will lag badly up until a certian rpm point and then pretty much within a second go from lagging to full spool.But yes they should definitively do a better job of making cars with forced induction more realistic.forza does a decent job of this a supra with twins will for example make 780rwhp at 6400rpm and a supra with a big single will make 900 at 7600 rpm or whatever.Id definitional like to see more realistic power number tho,also realistic performance.A 1200hp supra is not very uncommon now days and a 1200hp supra would be extremely fast in a straight line with tires that put the power down but also a 1200 hp supra would have ridiculous lag trying to race on a track that has a decent amount of turns and would be slower lap time then a 600-700rwhp supra with a turbo that spools faster.They should also add the ability to turbo v8's its more common on modern v8's to have a turbo then SC.And now days alot of the big hp supercharged v8s are using prochargers.I understand they do this so that the v8s arent womping on the 4cys and 6 every race but they should balance it out where that a gtr-r35 with 700hp/evo with 700awhp should beat a turbo 2012 camaro with 1000+hp on a track without many straight stretches.Also on a track like the ring without many sharp turns a 1000hp+ 99 camaro ss would run off on a 500hp lotus that handles like a dream.

http://www.youtube.com/watch?v=rmNy-ajRV0U
Click to expand...
Drive an Option Stream Z

Btw, the cars in GT5 have way less power than the examples you just brought. If you think a, geez I don't like this example, 700hp supra should have the same turbo lag as a 1200hp one when this was only realised trough boost, then you're completely mistaken.

It always depends on how extreme an engine is tuned, and the most in GT5 are still decent (of course is it already very high).
 
Who remembers GT1 and GT2? Now those games had turbo lag.

As for GT5, the Ferrari F40 does have turbo lag which adds to the appeal of old turbo charged beast.
 
greedygenius
they gave a few cars "turbo" lag but it doesnt work like actual turbos do the few cars that do lag gradually spool up they just accelerate slowly if they have small displacement and big hp number where IRL a supra that has a huge turbo and makes 1000+hp will lag badly up until a certian rpm point and then pretty much within a second go from lagging to full spool.But yes they should definitively do a better job of making cars with forced induction more realistic.forza does a decent job of this a supra with twins will for example make 780rwhp at 6400rpm and a supra with a big single will make 900 at 7600 rpm or whatever.Id definitional like to see more realistic power number tho,also realistic performance.A 1200hp supra is not very uncommon now days and a 1200hp supra would be extremely fast in a straight line with tires that put the power down but also a 1200 hp supra would have ridiculous lag trying to race on a track that has a decent amount of turns and would be slower lap time then a 600-700rwhp supra with a turbo that spools faster.They should also add the ability to turbo v8's its more common on modern v8's to have a turbo then SC.And now days alot of the big hp supercharged v8s are using prochargers.I understand they do this so that the v8s arent womping on the 4cys and 6 every race but they should balance it out where that a gtr-r35 with 700hp/evo with 700awhp should beat a turbo 2012 camaro with 1000+hp on a track without many straight stretches.Also on a track like the ring without many sharp turns a 1000hp+ 99 camaro ss would run off on a 500hp lotus that handles like a dream.

http://www.youtube.com/watch?v=rmNy-ajRV0U
Click to expand...

That's not lag, exactly. That's being at an operating point where the turbine isn't being pushed enough. You have to break a minimum pressure / throughput in order for a given turbine to "activate" and be able to drive the compressor and begin building boost. Once that starts to happen, you set off a chain reaction until friction slows things down / destroys everything or you crack open the wastegate to keep speeds under control. The time it takes to go from that initial state to the steady "on-boost" state is the lag.

For example, cruising at part throttle well in the "power band" will only be producing a small amount of boost, but if you suddenly open the throttle, the boost won't be there instantaneously. That chain reaction of exhaust pressure driving turbine, driving compressor, increasing cylinder pressure and hence exhaust pressure etc. needs to occur first. That is lag, the time it takes for the engine to get where it should be for the given inputs.

Driving the car off the turbine map (etc.), so to say, is not lag, in the same way that driving a very highly tuned NA engine off-cam is not lag. The engine just isn't making as much torque at that point, and never will no matter how long you wait.


That said, the lack of true lag in the game is, in my opinion, a combination of the relatively reserved turbo tuning in the game (low hp) and modern low-lag turbo-compressors. The power-band modeling is there, it's just not as extreme as it used to be (again, "sensible" tuning).
 
jimipitbull
modern turbos have variable geometry, minimal lag

the technology predates GT5
Click to expand...
VNTs are expensive, have a shorter lifetime, are more sensible, aren't that easy too handle, etc.

It is more the exception than standard to see a car with a VNT, and then it's usually a car with diesel engine. But yeah, they could include it, why not.
 
Vegard
Recommended reading:

Turbo lag vs boost threshold.
Click to expand...

Sweet and it may be technically correct, but it is already very common nowadays in, let's say, the urban language, to also use turbo lag in this certain context.
 
dr_slump
Sweet and it may be technically correct, but it is already very common nowadays in, let's say, the urban language, to also use turbo lag in this certain context.
Click to expand...

Except that that usage is confined mostly to people who don't know what they're talking about.
I doubt that in serious discussions about turbo specifications for a given application the people involved would say: "it lags like a pig until 4000 rpm"; instead: "it doesn't come on boost until 4000 rpm". Lag is a time delay, and the fact of the matter is that if you held rpm constant, boost would never build below the threshold rpm - you could say that's infinite lag, but it's hardly a useful quantification, much in the same way that holding the throttle shut technically leads to infinite lag.

In short, using "lag" in that context only implies you fail to grasp the underlying mechanisms, which is fine in and of itself, but that shouldn't make such usage acceptable or "official".
 
Griffith500
Except that that usage is confined mostly to people who don't know what they're talking about.
I doubt that in serious discussions about turbo specifications for a given application the people involved would say: "it lags like a pig until 4000 rpm"; instead: "it doesn't come on boost until 4000 rpm". Lag is a time delay, and the fact of the matter is that if you held rpm constant, boost would never build below the threshold rpm - you could say that's infinite lag, but it's hardly a useful quantification, much in the same way that holding the throttle shut technically leads to infinite lag.

In short, using "lag" in that context only implies you fail to grasp the underlying mechanisms, which is fine in and of itself, but that shouldn't make such usage acceptable or "official".
Click to expand...
I see the difference, but don't mind if anybody uses the word lag for it, since estimated about 90% already do it anyway.

And btw, in german (my first language) I wouldn't use lag anyway, turbohole (you don't have to understand it) is much more common there.
 
dr_slump
I see the difference, but don't mind if anybody uses the word lag for it, since estimated about 90% already do it anyway.

And btw, in german (my first language) I wouldn't use lag anyway, turbohole (you don't have to understand it) is much more common there.
Click to expand...

I don't strictly mind either; however boost threshold is "modeled" in GT (by way of torque curves), but lag is largely negligible, so it sort of helps to distinguish the two.

By the way, I read "Turbohole" in German and thought it was a fun idiom (to "fetch" the turbo), but I realise you meant an actual "hole" (i.e. in the torque curve?) - is that much like you would describe poor carburettor tuning as creating "holes" or dead-spots?
So, is "Turboloch" (turbo hole) equivalent to "Verzögerung" (delay) in German, though? The last paragraph of this section of the German turbocharger Wikipedia article would suggest it's equivalent to the difference in the English: i.e. boost threshold = Turboloch and lag = Verzögerung. :)
 
Yes, I've driven the Option Stream Z, the Escudo, the F40, the old turbo Rally cars, and probably whatever else has a turbo and more than 200 hp.
 
The HPA R32 has turbo lag I think.

The turbo lag in general feels mitigated on most cars though. And with the way we drive when we race, turbo lag is basically nonexistent.
 
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If there is turbo lag in GT6, we should see Anti lag systems as well, but if you use one, your fuel should go down slightly quicker aswell.
 
Griffith500
I don't strictly mind either; however boost threshold is "modeled" in GT (by way of torque curves), but lag is largely negligible, so it sort of helps to distinguish the two.

By the way, I read "Turbohole" in German and thought it was a fun idiom (to "fetch" the turbo), but I realise you meant an actual "hole" (i.e. in the torque curve?) - is that much like you would describe poor carburettor tuning as creating "holes" or dead-spots?
So, is "Turboloch" (turbo hole) equivalent to "Verzögerung" (delay) in German, though? The last paragraph of this section of the German turbocharger Wikipedia article would suggest it's equivalent to the difference in the English: i.e. boost threshold = Turboloch and lag = Verzögerung. :)
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A loch is a hole, simply used because the power is that damn low as if it were (fallen) in a hole. The torque courve is in or has a hole (symbolic).
 
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A better solution for turbo is to cater for every power needs, make 3 base single/twin turbo upgrades - low, mid, and high.
Then give us the ability to set boost pressure within each kit level and overboost function. With every increase or decrease or pressure there will be consequences - more response or more lag and engine temp changes. Don't forget intercooler upgrades that affect turbo performance + cooling, and more detailed engine internals upgrade that will help turbocharging, ie : crankshaft, cam, bore/stroke increase, forged piston, and the ability to tune the ECU ( torque curve and peak power ). Prolonged high boost use on the road will heat up the engine and have detrimental effect, ambient temp will also be taken into account.

To add immersion, we should be able to install aftermarket boost gauge, rev meter and other assorted gauges for oil, water, volts, etc. These will be visible in the cockpit and can be positioned by the players.
 
dr_slump
A loch is a hole, simply used because the power is that damn low as if it were (fallen) in a hole. The torque courve is or has a hole (symbolic).
Click to expand...

Indeed, and thanks, but not to drag this out unnecessarily, I was trying to ascertain whether you use the same distinction between this "hole" (being below the boost threshold) and the true lag / delay in building boost above the boost threshold (i.e. in throttle transitions).

Purely because it seems GT accounts for boost threshold in the torque curves, but not for lag itself.
 

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