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Old 29th April 2011, 17:11   #1
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Default Turbo Lag 101

Is it that delay you experience from the point where you step on the accelerator pedal to the point where the vehicle actually moves ?

The only turbo charged vehicles I've driven so far are:
Sumo Grande
Toyota Innova
Mahindra Scorpio

I've never felt anything in the Grande(though it's Turbocharged). Not much in the Scorpio either, at least not enough to be pestered by it/amused by it. The Innova is a different story though. When I left my foot on the pedal playing at 1000-2000 revs just to feel the lag it felt like something I've never experienced in a car before. So I'm guessing that delay could only be one thing- Turbo lag.

BTW is the Innova the only Turboed car in India with such lag? Like I said I've only driven 3 Turboed cars so perhaps my presumption that the Innova has the most lag is fallacious.

Hopefully some of you experts can shed some light!
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Old 29th April 2011, 17:53   #2
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Default Re: Turbo Lag 101

Quote:
Originally Posted by D33-PAC View Post

BTW is the Innova the only Turboed car in India with such lag? Like I said I've only driven 3 Turboed cars so perhaps my presumption that the Innova has the most lag is fallacious.

Hopefully some of you experts can shed some light!
Maybe because Innova is underpowered (105Bhp) among the 3 MUVs you mentioned. Whereas the other 2 are 120bhp engines.
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Old 29th April 2011, 18:03   #3
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Default Re: Turbo Lag 101

Quote:
Originally Posted by D33-PAC View Post
Is it that delay you experience from the point where you step on the accelerator pedal to the point where the vehicle actually moves
No, you got the definition of turbo lag wrong. The real definition is :

TThe time required to bring the turbo up to a speed where it can function effectively is called turbo lag. This is noticed as a hesitation in throttle response when coming off idle. This is symptomatic of the time taken for the exhaust system driving the turbine to come to high pressure and for the turbine rotor to overcome its rotational inertia and reach the speed necessary to supply boost pressure.

Basically what happens in turbo lag is that until you reach 2000 RPM, the car accelerates in a sluggish manner. After that, Zoooooooom!
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Old 29th April 2011, 18:04   #4
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Default Re: Turbo Lag 101

I've driven only 2 turbo diesel cars and all I can say is that, I admire people who can manage to drive them well.. I suppose it takes some amount of getting used to so that you can keep the car in the optimal power band.

(Driven the Swift Dzire VDi & Mahindra Xylo.)
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Old 29th April 2011, 18:15   #5
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Default Re: Turbo Lag 101

My Magnum has a noticeable turbolag. Newbies on the car either dont enjoy (shifting before the turbo range) or they cant control it. It takes some getting used to and becomes manageable. Especially in the city its takes some working with the gears.

But the good thing: after the lag comes the turbo kick pushing you into your seat
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Old 29th April 2011, 18:17   #6
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Default Re: Turbo Lag 101

Quote:
Originally Posted by Mustang.101 View Post

Basically what happens in turbo lag is that until you reach 2000 RPM, the car accelerates in a sluggish manner. After that, Zoooooooom!
But what I'm saying is that in 1st gear when the engine is turned on, at any range within the powerband the automobile should move forward at any amount of revolutions per minute except at idle.(As in naturally aspirated automobiles)

Similarily, shouldn't the same happen in a Turboed car? What I experienced in the Innova was that the car was not moving forward in gear even a few revs above idle.

Okay lets forget the definition of Turbo Lag for a while , I just want to know if what I experienced is Turbo Lag.
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Old 29th April 2011, 18:18   #7
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Default Re: Turbo Lag 101

Quote:
Originally Posted by D33-PAC View Post
Is it that delay you experience from the point where you step on the accelerator pedal to the point where the vehicle actually moves ?
No, Turbo lag is the delay taken for the turbo to kick in.

Usually at ~500 - 1500 the vehicle will have much lower response than higher up the rpm range. Nowadays VGT (Variable Geometric Turbo) helps reduce turbo lag and increase driveabiltiy. There are tons of info on the web regarding this topic. Please go through them. Or I would be happy to share what limited knowledge I have.
Quote:
Originally Posted by D33-PAC View Post
Sumo Grande
Toyota Innova
Mahindra Scorpio
The Scorpio came in many engine options. Which one are you talking about?. Does the Sumo Grande have the same 2.2vvt engine of the Safari?. Also, as for the Innova, I have found it to be a vehicle with minimal turbolag.
Quote:
Originally Posted by D33-PAC View Post
When I left my foot on the pedal playing at 1000-2000 revs just to feel the lag it felt like something I've never experienced in a car before. So I'm guessing that delay could only be one thing- Turbo lag.
Not sure what you are pointing to.
Quote:
Originally Posted by D33-PAC View Post
BTW is the Innova the only Turboed car in India with such lag? Like I said I've only driven 3 Turboed cars so perhaps my presumption that the Innova has the most lag is fallacious.
For some perfect examples of turbo lag, please take a test drive of the 1.3 MJD engine seen in the Swift, Vista and Punto. Also, the 2.0L engine in the Magnum.


EDIT:
Quote:
Originally Posted by D33-PAC View Post
... What I experienced in the Innova was that the car was not moving forward in gear even a few revs above idle.

Okay lets forget the definition of Turbo Lag for a while , I just want to know if what I experienced is Turbo Lag...

What you experienced is definitely not turbolag. Please tell your friend to get his clutch overhauled.

Last edited by dhanushs : 29th April 2011 at 18:21.
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Old 29th April 2011, 18:25   #8
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Default Re: Turbo Lag 101

Quote:
Originally Posted by D33-PAC View Post
Similarily, shouldn't the same happen in a Turboed car? What I experienced in the Innova was that the car was not moving forward in gear even a few revs above idle.

Okay lets forget the definition of Turbo Lag for a while , I just want to know if what I experienced is Turbo Lag.
The Innova should have moved forward. I have not driven an innova yet but i have also never heard anybody stating this problem.

In my car, Even if you do not press the accelerator pedal and just release the clutch pedal slowly, the car starts to move forward. I own a fusion TDCi.

What you experienced is probably not turbo lag but something else but i do not know what. Probably some kind of clutch adjustments are required.
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Old 29th April 2011, 18:38   #9
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Default Re: Turbo Lag 101

Quote:
Originally Posted by D33-PAC View Post
But what I'm saying is that in 1st gear when the engine is turned on, at any range within the powerband the automobile should move forward at any amount of revolutions per minute except at idle.(As in naturally aspirated automobiles)

Similarily, shouldn't the same happen in a Turboed car? What I experienced in the Innova was that the car was not moving forward in gear even a few revs above idle.

Okay lets forget the definition of Turbo Lag for a while , I just want to know if what I experienced is Turbo Lag.
As engine rpm rises, the Turbocharger starts to spin faster and only after the turbocharger attains a certain rpm (this is not the engine rpm but the turbocharger rpm) it causes a sudden surge in torque.

In simpler words: If you are around 1200 rpm in a certain gear and you floor the accelerator, you will feel sluggish response till, say, 2000 rpm (different for different engines) and then the car will sprint. The power delivery will not be linear but there will be a sudden rush. This delay in response is the time the turbo takes to attain a certain rpm, after which it has an effect on the torque. This is called Turbo lag.

I am not able to understand what you actually felt. But, turbolag is usually not noticeable in 1st gear because of the gear ratio. It is most prominent in 2nd and 3rd gears.

Last edited by benzinblut : 29th April 2011 at 18:40.
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Old 29th April 2011, 18:47   #10
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Default Re: Turbo Lag 101

I used to ride my sister's Kinetic Honda years ago and I noticed something similar to turbo-lag in that.

When starting from idle, the scooter would inevitable feel sluggish (at full throttle, engine screaming) till the speed hit roughly 5-10kmph, and at 10kmph the power would suddenly rush in and throttle had to be reduced to gain some control.

My guess is that it was the torque converter playing games at low wheel-rpm, and once the speed increased some sort of clutch mechanism took over (or the torque converter efficiency improved.) Any comments?
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Old 29th April 2011, 18:48   #11
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Default Re: Turbo Lag 101

Quote:
Originally Posted by benzinblut View Post
As engine rpm rises, the Turbocharger starts to spin faster and only after the turbocharger attains a certain rpm (this is not the engine rpm but the turbocharger rpm) it causes a sudden surge in torque.

In simpler words: If you are around 1200 rpm in a certain gear and you floor the accelerator, you will feel sluggish response till, say, 2000 rpm (different for different engines) and then the car will sprint. The power delivery will not be linear but there will be a sudden rush. This delay in response is the time the turbo takes to attain a certain rpm, after which it has an effect on the torque. This is called Turbo lag.
most prominent in 2nd and 3rd gears.
Quote:
Originally Posted by Mustang.101 View Post
The Innova should have moved forward. I have not driven an innova yet but i have also never heard anybody stating this problem.

In my car, Even if you do not press the accelerator pedal and just release the clutch pedal slowly, the car starts to move forward. I own a fusion TDCi.

What you experienced is probably not turbo lag but something else but i do not know what. Probably some kind of clutch adjustments are required.


Thank you! That made a lot of sense.

This is what I felt in first gear in the Innova:
When I stepped on the accelerator (I was feathering the accelerator), the car initially went nowhere even though I was well above idle. There was a sense of motionlessness, and I could tell the engine was well above idle because I could hear the engine note change from idle. I have never experienced this in any other car I've driven.


@Mustang.101, I understand what you're saying Sir , the clutch should grab and slowly the torque should be transmitted from the crankshaft to the wheels. But this doesn't really apply to my scenario as I was not coming off the clutch after a shift, so it's not possible that the clutch was still engaged(that explains the motionlessness and the change in engine note)

But like you said, it could probably be a problem with the car.

Last edited by D33-PAC : 29th April 2011 at 18:57. Reason: To elaborate
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Old 29th April 2011, 18:50   #12
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Default Re: Turbo Lag 101

By the way,

are there any recommendations , tips ... for new drivers (like me) who learned to drive on petrol vehicles but will be driving diesels now?

If there is a thread on that please send me the link.
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Old 29th April 2011, 18:58   #13
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Default Re: Turbo Lag 101

Quote:
Originally Posted by vina View Post
When starting from idle, the scooter would inevitable feel sluggish (at full throttle, engine screaming) till the speed hit roughly 5-10kmph, and at 10kmph the power would suddenly rush in and throttle had to be reduced to gain some control.
Well that is the rubberband effect on the CVT gearbox that the kinetic had. In the kinetic you can feel the engine rpm rising but the scooter doesnt' move as fast as the engine is. The CVT takes some time to come into effect. Most of the kinetic riders i know startoff with full throttle and reduce it only after the speed that they want is attained. So this is a general observation and a common complain.
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Old 29th April 2011, 19:01   #14
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Default Re: Turbo Lag 101

Quote:
Originally Posted by benzinblut View Post
As engine rpm rises, the Turbocharger starts to spin faster and only after the turbocharger attains a certain rpm (this is not the engine rpm but the turbocharger rpm) it causes a sudden surge in torque.
A slight change is there. The turbocharger does not spin until a certain rpm.

ie, it takes the engine revs to reach a certain rpm where the exhaust pressure is powerful enough to start turning the turbo. The rpm where the turbo kicks in, minus, the idle rpm can be termed as turbo lag.

EDIT:
Quote:
Originally Posted by vina View Post
are there any recommendations , tips ... for new drivers (like me) who learned to drive on petrol vehicles but will be driving diesels now?
Turbo lag affects city drivebility the most. Try to keep the engine on boil if you need immediate throttle response.

Also, whist drving some powerful turbo diesels like the magnum, I would advise you to NOT floor the pedal on tight overtaking in cities. When the turbo kicks in you will be surprised by huge wave of torque, which is quite difficult to control for newbees.

On the highway, do not rev above the power band.

You're gonna miss revving till the rev limiter, but then you are gonna gain the 'turbo kick'. Both are fun in their very own ways.

Last edited by dhanushs : 29th April 2011 at 19:09.
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Old 29th April 2011, 19:15   #15
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Default Re: Turbo Lag 101

Quote:
Originally Posted by vina View Post
By the way,

are there any recommendations , tips ... for new drivers (like me) who learned to drive on petrol vehicles but will be driving diesels now?

If there is a thread on that please send me the link.
Always idle your turbo charged diesel for about 30 seconds before moving and stopping. Not doing so will cause damage to the turbo charger.
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