Your Definition Of Turbo Lag

[Bazza-NZ]

If someone asked you to define: Turbo Lag

What would you say...

I've heard many different version of what turbo lag is, so for once and all i want to get everyone else opinion

(And prove a mate wrong at the same time) ;D

[Shale]

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

When I put my foot down in the Impreza, foot down = sh!t happening. With turbos, unless you're at high RPM, there's a build-up. Do not want. Guess that's why I'm being stupid and doing a monster N/A build...because no turbo is small enough and lagless enough to give me perfect lack of turbo lag...

But I'm guessing you're talking in relative, not absolute ;D

[wildturkey]

to me it means........the amount of delay between the time you put ur foot down...... and when the turbo starts to kick in..........and when it reaches full boost

[aim]

 wildturkey said:

to me it means........the amount of delay between the time you put ur foot down...... and when the turbo starts to kick in..........and when it reaches full boost

This.

[Bazza-NZ]

Interesting.... no wounder you guys complain about the lag

What is Turbo Lag?

Turbo lag is the time delay of boost response after the throttle is opened when operating above the boost threshold engine speed. Turbo lag is determined by many factors, including turbo size relative to engine size, the state of tuning of the engine, the inertia of the turbo's rotating group, turbine efficiency, intake plumbing losses, exhaust backpressure, etc.

What is Boost Threshold?

Boost threshold is the engine speed at which there is sufficient exhaust gas flow to generate positive manifold pressure, or boost.

[wildturkey]

 Bazza-NZ said:

Interesting.... no wounder you guys complain about the lag

What is Turbo Lag?

Turbo lag is the time delay of boost response after the throttle is opened when operating above the boost threshold engine speed. Turbo lag is determined by many factors, including turbo size relative to engine size, the state of tuning of the engine, the inertia of the turbo's rotating group, turbine efficiency, intake plumbing losses, exhaust backpressure, etc.

What is Boost Threshold?

Boost threshold is the engine speed at which there is sufficient exhaust gas flow to generate positive manifold pressure, or boost.

remember that definition when u install ur fmic ;D I expect word for word full recital.........

[Bazza-NZ]

 wildturkey']

[quote name='Bazza-NZ said:

Interesting.... no wounder you guys complain about the lag

i]What is Turbo Lag?[/i]

Turbo lag is the time delay of boost response after the throttle is opened when operating above the boost threshold engine speed. Turbo lag is determined by many factors, including turbo size relative to engine size, the state of tuning of the engine, the inertia of the turbo's rotating group, turbine efficiency, intake plumbing losses, exhaust backpressure, etc.

What is Boost Threshold?

Boost threshold is the engine speed at which there is sufficient exhaust gas flow to generate positive manifold pressure, or boost.

remember that definition when u install ur fmic ;D I expect word for word full recital.........

I'm not worried about a little bit of lag, hence why the FMIC kit is even going on the car in the first place... if i was concerned with turbo lag i would have keep the water to air on. I'm hoping the benefits of the external wastegate combined with the GFB Atomic boost controller are going to offset some of the lag

In fact the WAIC will still remain on the car for a little while longer yet :

[Stoffa]

Lag as I understand it is the time ot takes to go from full boost in one gear to full boost in the next gear. i.e if you nail it and change gears as quick as you can, a car with alot of lag will take longer to get back on full boost.

I was told its not the time it takes your entire intercooler system to pressurise when you first make your car come on boost.

[zarnah]

 Shale said:

When I put my foot down in the Impreza, foot down = sh!t happening. With turbos, unless you're at high RPM, there's a build-up. Do not want.

yea but even in our turbocharged subarus shale, foot down still= sh!t happening, and then later on up the rev range= a whole lot of sh!t happening, and hand out window waving goodbye to N/A subaru......

[aim]

 Stoffa said:

Lag as I understand it is the time ot takes to go from full boost in one gear to full boost in the next gear. i.e if you nail it and change gears as quick as you can, a car with alot of lag will take longer to get back on full boost.

I was told its not the time it takes your entire intercooler system to pressurise when you first make your car come on boost.

So a tiptronic car has less turbo lag than a manual car with the same engine? Transmission shouldn't be factored in to 'turbo lag' and the lag should be comparable between cars with paddle shifters or a manual box.

[Bazza-NZ]

 aim']

Lag as I understand it is the time ot takes to go from full boost in one gear to full boost in the next gear. i.e if you nail it and change gears as quick as you can, a car with alot of lag will take longer to get back on full boost.

I was told its not the time it takes your entire intercooler system to pressurise when you first make your car come on boost.

So a tiptronic car has less turbo lag than a manual car with the same engine? Transmission shouldn't be factored in to 'turbo lag' and the lag should be comparable between cars with paddle shifters or a manual box.

Think about it again - Transmission isn't a factor at all

Stoffa is talking about the time after you change gear to get back to full boost, not the speed of the change - which i think you have confused it with

HOWEVER Auto do tend to have less lag overall because the auto transmission Subaru run a smaller turbo (in most cases - not all)

Smaller turbos have less lag as they require lest exhaust gases to get them spooling.. etc

Small Turbo = Quick Spool but Lack Top end power

Larger Turbo = Laggier but great top end power

[quote name=' Turbo FAQ Paper I was Reading to Prove a Mate Wrong said:

If my turbocharged car has an automatic transmission, should I still fit a blow-off valve?

Yes, all the benefits of a blow-off valve can still be enjoyed, even if your car is automatic. Getting on and off the gas pedal

has the same effect on turbo lag regardless of the transmission type.

[wildturkey]

 Bazza-NZ']

[quote name='Bazza-NZ said:

Interesting.... no wounder you guys complain about the lag

i]What is Turbo Lag?[/i]

Turbo lag is the time delay of boost response after the throttle is opened when operating above the boost threshold engine speed. Turbo lag is determined by many factors, including turbo size relative to engine size, the state of tuning of the engine, the inertia of the turbo's rotating group, turbine efficiency, intake plumbing losses, exhaust backpressure, etc.

What is Boost Threshold?

Boost threshold is the engine speed at which there is sufficient exhaust gas flow to generate positive manifold pressure, or boost.

remember that definition when u install ur fmic ;D I expect word for word full recital.........

I'm not worried about a little bit of lag, hence why the FMIC kit is even going on the car in the first place... if i was concerned with turbo lag i would have keep the water to air on. I'm hoping the benefits of the external wastegate combined with the GFB Atomic boost controller are going to offset some of the lag

In fact the WAIC will still remain on the car for a little while longer yet :

yeah i wouldn't be too concerned about lag......far too much is made of it and it can be controlled thru your setup and dialled out further thru the tune......

[Joker]

yea it is cos an Auto is never "off throttle"

not entirely sure how that works... maybe an overactive BOV

[zarnah]

haha yea if anything, I kinda like a bit of Lag, makes your car feel really grunty when all that power finally hits in one big whack! lol

[Bazza-NZ]

 zarnah said:

haha yea if anything, I kinda like a bit of Lag, makes your car feel really grunty when all that power finally hits in one big whack! lol

Amen to that, Love that feeling when it just starts pulling ;D

[Treecrusher]

Yip, nothing better than a great big whack of power half way through the rev range. Think thats the main thing that make twin turbos so boring, no thumping great lump of power at ~4000 rpm

[BC5RA]

 Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

When I put my foot down in the Impreza, foot down = sh!t happening. With turbos, unless you're at high RPM, there's a build-up. Do not want. Guess that's why I'm being stupid and doing a monster N/A build...because no turbo is small enough and lagless enough to give me perfect lack of turbo lag...

But I'm guessing you're talking in relative, not absolute ;D

I'm not sure you qualify to be posting in this thread.

[Treecrusher]

 Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

When I put my foot down in the Impreza, foot down = sh!t happening. With turbos, unless you're at high RPM, there's a build-up. Do not want. Guess that's why I'm being stupid and doing a monster N/A build...because no turbo is small enough and lagless enough to give me perfect lack of turbo lag...

But I'm guessing you're talking in relative, not absolute ;D

If you are so concerned about turbo lag, just don't get of the gas.

[Drunkenmonkey]

 Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

this turbo doesn't have "lag", i just drove it from auckland up 16 and every time i went to pass someone it was on full boost almost instantly. yes i was in third at about 3500 - 4000 rpm but as soon as i put my foot down it was on full boost pretty much instant, in fact it seemed quicker than my gen1 with vf10. which i think could be because of the vf39 being a newer turbo.

[Guest boostin]

 JoKer said:

yea it is cos an Auto is never "off throttle"

not entirely sure how that works... maybe an overactive BOV

When my wagon was still auto it had a HKS SSQ on it, and it definitely had the psshh, but only when you eventually backed off the gas. Otherwise there was nothing on gear changes.

Our auto WRX has a pod on it, and we can hear the factory BOV working in the same way.

[Treecrusher]

 Drunkenmonkey']

[quote name='Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

/quote]

this turbo doesn't have "lag", i just drove it from auckland up 16 and every time i went to pass someone it was on full boost almost instantly. yes i was in third at about 3500 - 4000 rpm but as soon as i put my foot down it was on full boost pretty much instant, in fact it seemed quicker than my gen1 with vf10. which i think could be because of the vf39 being a newer turbo.

I think once you are up at that rev range you won't get any lag as such because the turbo is already spooled.

An example of lag as I understand it is: if you take off quietly in first change into second at low revs then put your foot flat. the laggy bit is your engine bogging down due to the restriction caused by the turbo while it isn't helping performance. With a smaller turbo that bogging down period will be shorter than it would be with a bigger turbo/longer piping etc.

Even with a massive turbo with huge lag, like a turbo drag car (I am guessing), if you keep the revs high dump the clutch and flat shift you won't experience lag.

Top gear had a good example of turbo lag by dragging an evo 9? vs a volvo estate or something like that. they had both cars at ~50km/hr in 5th gear, both put their foot flat and over a quarter mile the volvo easily won. Even though the evo was double over head cam, high performance and light weight at low revs the turbo hindered performance so much it was beaten by a piece of sh!t. Of course if th evo changed gears and upped the revs it would have been a different story. (or had been a subaru ;D)

[Guest boostin]

 Treecrusher']

[quote name='Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

/quote]

this turbo doesn't have "lag", i just drove it from auckland up 16 and every time i went to pass someone it was on full boost almost instantly. yes i was in third at about 3500 - 4000 rpm but as soon as i put my foot down it was on full boost pretty much instant, in fact it seemed quicker than my gen1 with vf10. which i think could be because of the vf39 being a newer turbo.

I think once you are up at that rev range you won't get any lag as such because the turbo is already spooled.

An example of lag as I understand it is: if you take off quietly in first change into second at low revs then put your foot flat. the laggy bit is your engine bogging down due to the restriction caused by the turbo while it isn't helping performance. With a smaller turbo that bogging down period will be shorter than it would be with a bigger turbo/longer piping etc.

Even with a massive turbo with huge lag, like a turbo drag car (I am guessing), if you keep the revs high dump the clutch and flat shift you won't experience lag.

Top gear had a good example of turbo lag by dragging an evo 9? vs a volvo estate or something like that. they had both cars at ~50km/hr in 5th gear, both put their foot flat and over a quarter mile the volvo easily won. Even though the evo was double over head cam, high performance and light weight at low revs the turbo hindered performance so much it was beaten by a piece of sh!t. Of course if th evo changed gears and upped the revs it would have been a different story. (or had been a subaru ;D)

That and the Volvo will be high compression and low boost, and the Evo will be low compression high boost.

[Drunkenmonkey]

 Treecrusher']

[quote name='Shale said:

Having a turbo is turbo lag for me. Even a VF10 can annoy me and the TD04 on my Legacy leaves me reminded of the existence of turbo lag. And don't get me started on a certain VF39... only one way to drive that car and that's over 4000rpm

/quote]

this turbo doesn't have "lag", i just drove it from auckland up 16 and every time i went to pass someone it was on full boost almost instantly. yes i was in third at about 3500 - 4000 rpm but as soon as i put my foot down it was on full boost pretty much instant, in fact it seemed quicker than my gen1 with vf10. which i think could be because of the vf39 being a newer turbo.

I think once you are up at that rev range you won't get any lag as such because the turbo is already spooled.

An example of lag as I understand it is: if you take off quietly in first change into second at low revs then put your foot flat. the laggy bit is your engine bogging down due to the restriction caused by the turbo while it isn't helping performance. With a smaller turbo that bogging down period will be shorter than it would be with a bigger turbo/longer piping etc.

Even with a massive turbo with huge lag, like a turbo drag car (I am guessing), if you keep the revs high dump the clutch and flat shift you won't experience lag.

Top gear had a good example of turbo lag by dragging an evo 9? vs a volvo estate or something like that. they had both cars at ~50km/hr in 5th gear, both put their foot flat and over a quarter mile the volvo easily won. Even though the evo was double over head cam, high performance and light weight at low revs the turbo hindered performance so much it was beaten by a piece of sh!t. Of course if th evo changed gears and upped the revs it would have been a different story. (or had been a subaru ;D)

wouldnt that be turbo "thresh hold" your talking about not lag?

[Treecrusher]

 Drunkenmonkey said:

wouldnt that be turbo "thresh hold" your talking about not lag?

Thats why I said as I understand it. Could be wrong on the technical terminologies but that is what I have always considered turbo lag to be.

[Treecrusher]

so looks like I am completely wrong :-[

url=http://=http://forums.nasioc.com/forums/showthread.php?threadid=197405]http://forums.nasioc.com/forums/showthread.php?threadid=197405]=http://forums.nasioc.com/forums/showthread.php?threadid=197405]http://forums.nasioc.com/forums/showthread.php?threadid=197405[/url]

 nasioc said:

I'll skip the bull*****.

Boost Threshold: The time it takes for the turbo to start producing boost RPM wise.

I.E. my car begins to make boost at 1500 RPMs, that is the Boost Threshold.

Lag: The time it takes for the turbo to respond to throttle inputs, and create boost.

I.E. at 4k, I hit the gas, boost gradually builds after a moment, that's turbo Lag.

Fact: Most modern turbocharged cars do NOT suffer from noticable Turbo Lag.

Myth: Cars that are sluggish low in the RPMs, (I.E. the WRX) suffer from Turbo Lag.

Fact: The car hasn't reached it's boost threshold yet.