Garret T03/04 slow spool up [Archive] - SaabCentral Forums

: Garret T03/04 slow spool up


cubase
17th July 2002, 04:15 AM
I have just installed a hybrid T03/04 turbo
with an intercooler located on the front.
The problem is slow spool up, which is
much slower than with the old Garret T03
and original cooler. What could be wrong?
I have heard that this hybrid should spool
about up as fast as the original. The new
cooler is not _that_ big and the piping is
quite short, so they should not create any
problems.

The car is 900T16 Aero -89 with 3" pipe and
1.0bar pressure. The air intake is still
original.

-Pekka

Fan-TC
17th July 2002, 09:14 AM
have u checked ignition timing??
um, inlet pipes too large diameter cause slow air velocity (when without boost) and incorrect cylinder filling, could be this....

Maybe what you heard is wrong...
is it a roller/ball bearing core???
hmm, overfuelling if u got any fueling mods.

What intercooler core did you use?
Tube fin or bar plate?
is it high flow?
could be APC playing up....

I am out...

cubase
17th July 2002, 10:00 AM
> have u checked ignition timing??

Not yet, since I don't know how to check
that myself, and I don't want to pay for
that yet if the problem is somewhere else.
Could it cause so big difference in spool
up?

> um, inlet pipes too large diameter cause
> slow air velocity (when without boost)
> and incorrect cylinder filling, could be
> this....

They are about the same size as in the
original. I think the total volume of
the piping and cooler is about the same
size as it used to be.

> Maybe what you heard is wrong...

Two other guys with the same turbo
has about as quick spool up as with the
T03, so it shouldn't be so slow as I have.
T04 parts were almost new, from the same
turbo and correctly balanced.

> is it a roller/ball bearing core???
> hmm, overfuelling if u got any fueling
> mods.

No fuelling mods. I don't know about the
bearings.

> What intercooler core did you use?
> Tube fin or bar plate?
> is it high flow?

It's front installed high flow cooler,
tube fin type with the size 40cm x 50cm
i.e. 16" x 20".

> could be APC playing up....

I tried with the wastegate pipe
disconnected -> no change, so it
should not be APC either.

-Pekka

Alex
17th July 2002, 01:21 PM
If by lag you mean the boost threshold of the turbo (point at which it starts to make boost), then a T3/T4 hybrid will come in much later than the original T3. Escort Cosworths used this type of turbo and are famed for producing nothing below 3500rpm.

Janne Selinummi
18th July 2002, 12:01 AM
Pekka, have you checked that your wastegate works properly? A defect wastegate (or actuator for that matter) can cause problems of the kind you described.

I hope you can get it right soon!

cubase
18th July 2002, 01:23 AM
> If by lag you mean the boost threshold of
> the turbo (point at which it starts to
> make boost),

I think the threshold is about the same,
which is a good thing! But the boost rises
quite slow after the base boost level
...even with high rpms.

>Pekka, have you checked that your
>wastegate works properly? A defect
>wastegate (or actuator for that matter)
>can cause problems of the kind you
>described.

Actually, I just though the same this
morning when I saw that the boost
stops rising near the base boost level
with the fifth gear, when the old turbo
went to the red immediately. It really
seems that the wastegate begins to open
near the base boost level even with APC
disconnected. But how can I check that
without a miniature video cam? :smile:

-Pekka