WRX Clutch problem, caused by turbo boost?

[Paul]

My 2002 WRX at 42,000 miles is in need of a new clutch and flywheel which
was really scored and burned up. My mechanic tells me that this was caused
by a broken connector on the turbo boost control hose, which allowed the
turbo pressure to go way above the safe pressure, and produce too much h.p.
for the stock clutch to cope with. Before someone tells me it sounds like a
fairy story made up by a greedy mechanic who needs work, it is in line with
certain symptoms I experienced during the preceding few weeks - on
accelerating after a short (4mile) warm up first thing in the morning in
cold weather (52F) the rev counter would shoot up to 7K and then quickly
drop back to around half that even though the car was physically
accelerating in a normal manner (i.e., not consistent with a quick boost in
revs). After about 15 miles everything felt normal. I tried stopping the car
and putting it into 2nd gear with the handbrake firmly applied and let the
clutch out, and the car stalled as indeed it should. Also flooring the gas
pedal while on the move did not cause the clutch to slip either. The other
day I was traveling on a level freeway at about 80 in 5th when I slowed to
about 60 and then accelerated again and the car felt like it was in neutral.
Right, the clutch had burned out within an instant! The day before this, the
car felt a lot more lively than usual. I thought this was due to the cold
weather and maybe the gas had improved in quality. In retrospect that would
be consistent with extra over the limit turbo boost.
My type of driving should not have burned out the clutch as I take off
gently and only accelerate after the clutch is fully engaged. 90% of my
driving is on a freeway mostly in 5th gear.
My love affair with Subaru is about to come to an end - at 38,000 I had to
have the high-pressure a/c hose replaced due to a bad fitting at a cost of
around $350. Even though the car was less than 30 months old, it was not
covered under warranty. The actual mileage should not have affected it, the
part was defective. My other car is now 14 years old and the paint looks
practically new with but a fraction of the rock chips that I have on the
WRX. A great shame as the WRX is in a class of it's own when it comes to
steering feel, front seats, luggage capacity, (at least with the wagon
version), and gas mileage versus performance. Has anyone else experienced
the type of problem I have described?

 

[mike]

It doesn't sound completely unreasonable.
Firstly the clutch slippage is most likely to occur whilst accelerating in
5th gear as this when the engine is applying the most torque to the clutch
for a long period of time and is the most obvious when the clutch is
slipping.
As for over boosting that too is a possibility.
If the connection to your waste gate or controller is damaged it could
result in over boosting .If there was a small air leak waste gate could stay
open for longer & provide more boost. If the connection was broken then you
would definitely get over-boosting. The waste gate wouldn't open at all and
you get uncontrolled boost. In this case you would probably get the engine
cutting out to prevent damage - you would definitely notice that. it would
feel the same as hitting the rev-limiter. That why I think its a good idear
to have a boost gauge in your car.
If you let you clutch slip at full boost for what ever reason there could be
100kW+ heat being transferred to you clutch plate & that will pretty much
fry anything quickly.