how can you tell if a 1.8T has sludge buildup?

[Tyson Varosyan]

>From what I know of these cars, this cannot happen. I have not seen the
inside of the intercooler on this car, but on my 3000GT it would be
impossible for anything much bigger than a 1 cubic millimeter to get from
the turbo to the intercooler. Intercoolers have tiny aluminum baffles inside
designed to make as much surface contact area with the passing air. As a
result, an "exploding turbo" would deposit 99% of it's material in the
intercooler. That being said, I have experienced turbo failure on my 3000GT
a few times.

First time around, the rear turbo busted the oil seal at around 180k - a
pretty common issue at that mileage. Oil went everywhere and as a result
there was enough shaft play for the compressor wheel to hit the housing
instantly snapping the shaft and sending the wheel up against the compressor
housing hole. This is about as bad of a turbo crash as you will get. After
my examination, I could not find any evidence of any part of the turbo to
have broken off and gone down the intake tract.

Later that year, I had installed a race motor with a set of brand new
turbos, crank, piston, rods, etc. The shop that did the short block screwed
up and as a result the thrust bearings fell out of the motor almost
immediately. Without the bearing, there was nothing holding the crank in
place and the classic crank walk occurred where the new $1200 forged,
hardened, nitrated crank ate into the side of the cast iron block. The crank
won the battle but by the time everything was over, there was enough metal
shavings floating around the oil system to choke any moving component. The
$2,200 turbos, both of them, were the first to take the hit. Rear tubo
bearing got clogged up and seized, luckily without casing much of a fuss.
The front turbo however, must have taken it's fatal doze of metal shavings
while at high RPM and snapped the shaft. Again, flying compressor wheel went
eating into the housing but again, nothing in the way of material went down
the intake tract.

The only piece that I would ever be worried about coming off from the turbo,
would be the little nut that is on the shaft holding the compressor wheel -
but there is no way that thing would fit through the intercooler.

I have heard a few times when people break their pistons or bust a rod,
cylinder's bits and pieces making it down the exhaust system and trashing
the turbo's turbine wheel. I have never once heard of a turbo sending parts
flying down into the engine - and even if it could, I think virtually
anything dangerous would find itself stuck in the intercooler which could
then be shaken clean upon removal.

Tyson Varosyan
Technical Manager, Uptime Technical Solutions LLC.
tyson at up-times.com
www.up-times.com
206-715-TECH (8324)

UpTime/OnTime/AnyTime

-----Original Message-----
From: quattro-bounces at audifans.com
[mailto:quattro-bounces at audifans.com]On Behalf Of Kent McLean
Sent: Sunday, December 26, 2004 7:39 AM
To: quattro at audifans.com
Subject: Re: how can you tell if a 1.8T has sludge buildup?


Josh <docwyte at comcast.net> wrote:
> If the stock turbo goes, you can buy low mileage used ones for
> $250 and swap it out yourself in an afternoon.

Provided no metal bits of the old turbo worked their way
through the intake and into the cylinders.

Kent
'94 100 S Avant
'89 200 TQ, "Bad Puppy" has a new home


_______________________________________________
quattro mailing list
quattro at audifans.com
http://www.audifans.com/mailman/listinfo/quattro