Definition of "lag" and "spool up"

[repo]

Please post here how You personally define lag and spool up.

I am sure we will never find uniformity to the terms, but let's see what seems to be the trend.

[dest]

For me personally, lag is the time between flooring the pedal and it coming onto full boost.
Spool up is the time between the turbo starting to spin and getting to full speed.
No doubt everyone will have their own different ones!

[Rusty]

Lag / Spool - The time taken from the application of WOT to the attainment of full turbo boost.

There is also the RPM after which the engine is capable of producing full boost. In the real world this varies for each gear and load condition, not sure on what to call this, sometimes it's referred to as the above terms, perhaps 'boost threshold' is a better term.

[GazzaG60]

interesting this repo. certainly a different topic starter, i like.

dest said it well but lag for me is either what dest said combined with the brain contemplating do i drop it to second or do i let that car pull a car or 2.

spool would be time between the time between the start of coming on boost to hitting the desired level. not very long really.

for example short shifting brings a spool time whereas dumping at 2k and waiting brings lag

[Jamo]

Lag = From applying throttle ( typically WOT ) the time taken for noticeable acceleration of the car forward in relation to the production of turbo boost and gear used.
Spool = The time taken for a turbo to reach a desired boost level typically measured against engine RPM

[S2central.net]

I'm with Jamo's definition here - I definitely see lag and spool as different things.

[kritis17]

LAG: is a few steps before heaven.

SPOOL: is how fast you are going up these steps!!!

[dest]

Jamo seemed to say the same as me, but worded better

[Jamo]

Jamo seemed to say the same as me, but worded better

Rare I know

[lind4hl]

+1 for Jamo!

[dest]

Of course this is an extreme example, but demonstrates it well!

http://www.youtube.com/watch?v=2cvFl7IQKe4

[Bram]

I think Jamo describes it how I see it as well.

And this is how Scooby drivers define anti-lag:

http://www.youtube.com/watch?v=hqEvl0bF9dA&feature=related

pffffffff........

[terrybullwon]

Two of the same?
I would say its the time taken for the exhaust gases driving the turbine to come to a higher enough pressure to drive the turbine to overcome its rotational inerta and reach the speed necessary to supply +/boost. So the lag or the "spool" you wait for is the turbine to reach a effective velocity.

[aronmatic2]

lag: bad thing
medicine: small turbo, als

spool: good thing, if fast
medicine: small turbo, turned exhaust cam

sorry, i am pigman.

[A80Avant]

blablabla...

everyone who cares about lag really needs to know what is the earliest rpm the full boost is achieved. Terminology is for those who just want to sound important. Euphism if you may...