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Is it Turbo Lag?



 
 
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  #1  
Old July 8th 04, 07:09 PM
Nige
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"Len S." > wrote in message
...
> I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now.

If
> I start off spirited, the car moves our alright, then at around 3k rpms it
> snaps me back into the seat, and I have to back off before I shift. I

am
> guessing this is what is known as turbo lag. It's kind of an awkward
> sensation.
> Is that typical of these 1.8 T engines? I am wondering if it needs to

be
> checked out. Thanks in advance.
> - Len
>
>


No mate, turbo lag is where you plant your foot & nothing happens for a
second or two then whhoooshhhh! It's mot as bigger problem now as on old
Saab's etc. What your are experiencing is some kind of overrun for emissions
or some other bloody annoying crap reason!!

My wife's A4 Cab does the same thing & I hate it for that reason only.


Ads
  #2  
Old July 8th 04, 09:41 PM
Byron
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Sounds exactly like turbo lag to me. Some manufacturers get around it
by adding a small turbo (in addition to the regular big one) that spins
up quickly despite the slower exhaust velocity at lower rpm. Audi on
their 2.7T uses two of the same size, but that engine has enough
displacement to provide decent torque even at low rpm. And with each
turbo filling just one bank of 3 cylinders, each one can be small enough
to compress air at lower rpm while being big enough to compress air at
the redline. Engine design is full of compromises.

When you say you 'start of spirited' I'm guessing you use some clutch
slip to get and then keep the engine near 3000 rpm - until the clutch
fully engages and you floor the throttle. If you don't, that's one way
to increase the exhaust velocity enough so the smallish motor doesn't
spend much time fighting to breathe well. You'll typically get the best
acceleration numbers this way. It's also an excellent way to decrease
the life of your clutch if done poorly.
  #3  
Old July 9th 04, 12:02 AM
Cam Newton
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On Thu, 8 Jul 2004 19:44:21 -0400, "Len S." >
wrote:

>I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now. If
>I start off spirited, the car moves our alright, then at around 3k rpms it
>snaps me back into the seat, and I have to back off before I shift. I am
>guessing this is what is known as turbo lag. It's kind of an awkward
>sensation.
>Is that typical of these 1.8 T engines? I am wondering if it needs to be
>checked out. Thanks in advance.
> - Len
>
>


I have a 2004 1.8q and always drive in Tip mode. When I am in 2nd I
can feel a little 'bump' at around 2800 rpm or so and then I go to
3rd. I thought this was the lag.

What is happening in 2nd then as I go thru the bump?
  #4  
Old July 9th 04, 12:44 AM
Len S.
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Default Is it Turbo Lag?

I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now. If
I start off spirited, the car moves our alright, then at around 3k rpms it
snaps me back into the seat, and I have to back off before I shift. I am
guessing this is what is known as turbo lag. It's kind of an awkward
sensation.
Is that typical of these 1.8 T engines? I am wondering if it needs to be
checked out. Thanks in advance.
- Len


  #5  
Old July 9th 04, 12:57 AM
ZiggyPopp
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Len S. wrote:

> I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now. If
> I start off spirited, the car moves our alright, then at around 3k rpms it
> snaps me back into the seat, and I have to back off before I shift. I am
> guessing this is what is known as turbo lag. It's kind of an awkward
> sensation.
> Is that typical of these 1.8 T engines? I am wondering if it needs to be
> checked out. Thanks in advance.
> - Len
>
>

Your turbo charger doesn't kick in until around 3K rpm.

  #6  
Old July 9th 04, 01:11 AM
Hairy One Kenobi
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"Len S." > wrote in message
...
> I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now.

If
> I start off spirited, the car moves our alright, then at around 3k rpms it
> snaps me back into the seat, and I have to back off before I shift. I

am
> guessing this is what is known as turbo lag. It's kind of an awkward
> sensation.
> Is that typical of these 1.8 T engines? I am wondering if it needs to

be
> checked out. Thanks in advance.


"Turbo lag" is the bit that happens /before/ 3k rpm*

The "problem" you're experiencing is "Turbo smile" ;o)

--

Hairy One Kenobi

Disclaimer: the opinions expressed in this opinion do not necessarily
reflect the opinions of the highly-opinionated person expressing the opinion
in the first place. So there!

* Should finish at a lot lower than this - my chipped engine's "whoa!" point
is at about that.


  #7  
Old July 9th 04, 04:29 AM
Byron
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Default

Len S. wrote:
> I'm very judicious with my clutching. I'm not letting it slip like you
> suggest. I usually am off the pedal asap. The same takeoff happens in
> all the gears when the engine gets around 3000, but it is most prominent in
> 1st gear.


That's the way turbo lag will seem the worst, but when it spools up near
3k rpm, the 'turbo smile' feels the best because of the dramatic difference.

The fact you feel the same effect in each gear confirms it is turbo lag
and therefore nothing to worry about unless it changes as the miles go by.

The lag of the 1.8T actually isn't nearly as bad as early turbo cars
from the 1980s. Those engines had _nothing_ below a certain rpm, but
once it kicked in the rush was often violent and had somewhat
unpredictable effects on handling, especially if you were exiting a turn
where smoothness was key to good lap times.

Enjoy.
  #8  
Old July 10th 04, 01:55 AM
Len S.
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I'm very judicious with my clutching. I'm not letting it slip like you
suggest. I usually am off the pedal asap. The same takeoff happens in
all the gears when the engine gets around 3000, but it is most prominent in
1st gear.

"Byron" > wrote in message
news:ZjiHc.1579$6B.1265@fed1read06...
> Sounds exactly like turbo lag to me. Some manufacturers get around it
> by adding a small turbo (in addition to the regular big one) that spins
> up quickly despite the slower exhaust velocity at lower rpm. Audi on
> their 2.7T uses two of the same size, but that engine has enough
> displacement to provide decent torque even at low rpm. And with each
> turbo filling just one bank of 3 cylinders, each one can be small enough
> to compress air at lower rpm while being big enough to compress air at
> the redline. Engine design is full of compromises.
>
> When you say you 'start of spirited' I'm guessing you use some clutch
> slip to get and then keep the engine near 3000 rpm - until the clutch
> fully engages and you floor the throttle. If you don't, that's one way
> to increase the exhaust velocity enough so the smallish motor doesn't
> spend much time fighting to breathe well. You'll typically get the best
> acceleration numbers this way. It's also an excellent way to decrease
> the life of your clutch if done poorly.



  #9  
Old July 10th 04, 02:00 AM
Len S.
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Default

Well then, I guess having a happy turbo is not such a terrible thing, eh?
Turbo smile ... hmmm. So it's not a problem, it's a feature?

"Hairy One Kenobi" ]> wrote in message
...
> "Len S." > wrote in message
> ...
> > I have been enjoying my 02 A4 Avant 1.8T 5 spd for about six weeks now.

> If
> > I start off spirited, the car moves our alright, then at around 3k rpms

it
> > snaps me back into the seat, and I have to back off before I shift. I

> am
> > guessing this is what is known as turbo lag. It's kind of an awkward
> > sensation.
> > Is that typical of these 1.8 T engines? I am wondering if it needs

to
> be
> > checked out. Thanks in advance.

>
> "Turbo lag" is the bit that happens /before/ 3k rpm*
>
> The "problem" you're experiencing is "Turbo smile" ;o)
>
> --
>
> Hairy One Kenobi
>
> Disclaimer: the opinions expressed in this opinion do not necessarily
> reflect the opinions of the highly-opinionated person expressing the

opinion
> in the first place. So there!
>
> * Should finish at a lot lower than this - my chipped engine's "whoa!"

point
> is at about that.
>
>



  #10  
Old July 10th 04, 11:48 AM
Cesar Borgia
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Bear in mind that -- unlike a torquey, beefy V8 such as the one found
in the '04 S4 -- the smallish, 1.8T engine works best above 1950RPM,
at which point the turbo is fully spooled up. Also, if you had a
larger engine previously (mine was a 3.0L V6) you may be alarmed that
optimal cruising happens at what you might consider high RPM's. I
typically downshift at 2.5K, and upshift around 4.5K, and cruise on
the highway at well above 3K. I still get 28mpg.

When I first got my '02 A4 I was alarmed because I was used to
shifting much lower, and cruising much lower. These days it's just
another way to enjoy the pleasant exhaust note.

--Cesar


On Sat, 10 Jul 2004 18:12:01 -0400, "Len S." >
wrote:

>Thanks for the information.
> - Len
>
>"Byron" > wrote in message
>newsioHc.1627$6B.623@fed1read06...
>> Len S. wrote:
>> > I'm very judicious with my clutching. I'm not letting it slip like you
>> > suggest. I usually am off the pedal asap. The same takeoff happens in
>> > all the gears when the engine gets around 3000, but it is most prominent

>in
>> > 1st gear.

>>
>> That's the way turbo lag will seem the worst, but when it spools up near
>> 3k rpm, the 'turbo smile' feels the best because of the dramatic

>difference.
>>
>> The fact you feel the same effect in each gear confirms it is turbo lag
>> and therefore nothing to worry about unless it changes as the miles go by.
>>
>> The lag of the 1.8T actually isn't nearly as bad as early turbo cars
>> from the 1980s. Those engines had _nothing_ below a certain rpm, but
>> once it kicked in the rush was often violent and had somewhat
>> unpredictable effects on handling, especially if you were exiting a turn
>> where smoothness was key to good lap times.
>>
>> Enjoy.

>


=
= Cesar Borgia
=
 




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