Is it Turbo Lag?

On Thu, 08 Jul 2004 20:29:38 -0700, Byron > wrote:

>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

Probably also means he's changing up too early. Keep it on boost!!



andyt

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.

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
>
>

If you have had an 02 for only 6 weeks, this strongly implies that you
bought it used.

Could the previous owner possibly have installed an aftermarket 'chip'
for the ECU? That would certainly create more non-linear power delivery
curve than would stock tuning.

--
--------------------------------------------------------
Dave Lugo LC Unit #260 TINLC
Have you hugged your firewall today? No spam, thanks.
--------------------------------------------------------
Are you the police? . . . . No ma'am, we're sysadmins.

Well, I am definitely guilty of shifiting up at rpm's lower than you use
(usually around 3k) and downshift around1.8 to 2k. This car is so easy
to just go sailing way past the speed limit, so I guess I'm just being
careful, and in doing that, I am ending up shifting just before the real fun
starts. Are you sure the turbo is fully spooled that low (1950k)? I
figured the push I described in the beginning post was the point where the
turbo is fully spooled. Maybe it is just the point where the gate fully
closes and gives all the boost.
- Len

"Cesar Borgia" > wrote in message
...
> 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
> =

"Len S." > wrote in message
...
> Well, I am definitely guilty of shifiting up at rpm's lower than you use
> (usually around 3k) and downshift around1.8 to 2k. This car is so easy
> to just go sailing way past the speed limit, so I guess I'm just being
> careful, and in doing that, I am ending up shifting just before the real
fun
> starts. Are you sure the turbo is fully spooled that low (1950k)? I
> figured the push I described in the beginning post was the point where the
> turbo is fully spooled. Maybe it is just the point where the gate fully
> closes and gives all the boost.

<Much snippage>

http://tinyurl.com/33j42 shows a comparable power curve (IIRC, the TT225 has
a less peaky power curve than the 180, so the torque will be even lower) I'd
say that 3000rpm is basically just getting onto the torque curve (around
half of the rated power output of the engine..)

Quite a few rechips lower the point where the boost comes in (mine does the
opposite, which I prefer, in terms of engine response - it feels much more
like the 180 I originally test-drove. I know that this sounds odd, but a
sharper curve and higher peak power /feels/ sportier, if you're more used to
tuned normally-aspirated engines)

H1K

I have doubts that the car has been chipped. As far as I know, the car was
a lease return and was registered in Connecticut. Why would somebody mod
their car when it is not really theirs does not make sense.
A friend of mine has a 99 A4 and he says that his turbo kicks in at around
4k. I don't know if that even merits comparison.

I am thinking that it is just a matter of me getting acclimated to the cars
abilities and limits. It is after all just a 4 cylinder engine and it's an
avant (heavier than the sedan). To expect super performance is not
realistic. Expecting good performance is more like it. I still love the
car.

Thanks for all the responses. There's a bunch of good people in this ng.
I appreciate it.
- Len S.


"Hairy One Kenobi" ]> wrote in message
...
> "Len S." > wrote in message
> ...
> > Well, I am definitely guilty of shifiting up at rpm's lower than you use
> > (usually around 3k) and downshift around1.8 to 2k. This car is so
easy
> > to just go sailing way past the speed limit, so I guess I'm just being
> > careful, and in doing that, I am ending up shifting just before the real
> fun
> > starts. Are you sure the turbo is fully spooled that low (1950k)?
I
> > figured the push I described in the beginning post was the point where
the
> > turbo is fully spooled. Maybe it is just the point where the gate fully
> > closes and gives all the boost.
>
> <Much snippage>
>
> http://tinyurl.com/33j42 shows a comparable power curve (IIRC, the TT225
has
> a less peaky power curve than the 180, so the torque will be even lower)
I'd
> say that 3000rpm is basically just getting onto the torque curve (around
> half of the rated power output of the engine..)
>
> Quite a few rechips lower the point where the boost comes in (mine does
the
> opposite, which I prefer, in terms of engine response - it feels much more
> like the 180 I originally test-drove. I know that this sounds odd, but a
> sharper curve and higher peak power /feels/ sportier, if you're more used
to
> tuned normally-aspirated engines)
>
> H1K
>
>
>

Hi Len,

What you are experiencing is what's known as "boost onset". The turbo will
spool then begin to deliver a massive amount of air beginning a few RPMs
before making power. Turbo lag refers to how long after spooling to when
the engine really begins to make lots of power. It can occur at any RPM
point prior to loading (mashing the gas) the engine, including well above
the boost onset RPM.

What you feel is normal for a turbo car. It's the reason for "turbo smile"
and the "turbo smile" is why I will forever buy turbo cars.

-Guy
02 S4
02 WRX

"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
>
>