beware VW turbo repair scham

"Not more so than a hybrid car. Turbo doesn't make extra energy, but
if
you think there's no potential energy in exhaust gasses, well, you are
wrong."

JS> That's not a valid comparison. Anyway, yes a turbo will increase
the power output by compressing the air. But that power increase is
not free as you stated, it does come at some cost in milage, just as
there is a milage cost from a belt driven supercharger. It takes some
energy to spin either kind of compressor. There is no arguing a
turbocharger when running results in a net increase in power - one can
feel it in seat pants.

A turbo allows an otherwise small modestly powered engine to operate
with a wider range of power output. That is what I think truck and car
owners are looking for. Most of the time we are not really using an
intake compressor (turbo or super), it just provides more of a power
reserve that a comparably sized normally aspirated engine does.

One has to be careful in matching compressor enhanced engines to useage
though. Strapping a turbo or super charger to a small engine and
expecting it to perform at near maximum output can dramatically shorten
engine life. At least one of the big motor home manufacturers found
this out in the early 1980's then they took a small turbocharged diesel
motor and put it in a medium sized motorhome. Those little engines
were running close to full output on all but the flats and they were
dying after 40,000 miles and their warranty claims went through the
roof.

If you don't think that turbos exact some impact on milage just look at
the instant mpg readout available on many turbocharged cars. It
plummets when you hit the gas, much faster than on the same standard
aspirated car. I've tried it on a Volvo S80 in T6 and 2.9 and a Volvo
V70 in 2.5T and 2.5 engine configurations.

Magnulus wrote:
> "John S." > wrote in message
> oups.com...
> > JS> Did you buy it new in 2002 or did you buy it used. A diesel
> > powered car may car get better fuel milage but the cost to properly
> > maintain a diesel can be more than on a comparable gas engine car.
> > They usually take more oil, require more frequent oil changes, have
> > more expensive filters. Glow plugs and injectors require maintenance.
>
> This is simply not true. The VW TDI's are some of the cheapest cars to
> own for total cost of ownership. Maintance for the cars is not that bad.
> You only have to change the oil every 10,000 miles, it uses about 4 1/2
> liters of oil, and the oil filter costs 7 dollars. The power steering fluid
> will last about 100,000 miles, the auto/manual transmission fluid will last
> 50k-100k miles, and the coolant also is rated at 100k miles. The secret is
> that the car uses only high quality fluids- synthetic, diesel-rated oil only
> (CF or better), synthetic transmission fluid, and an exact specification for
> the coolant and PS fluid. Using petroleum motor oil will lead to a cooked
> turbo and sticking cylinder ring.
>
> The only major $$$ a person might have to do is have the exhaust gas
> recirculator valve cleaned every 100,00 miles or so, which can cost about
> 400-500 dollars at a dealership. Go to a non-dealer and it will cost much
> less, and you can also do it yourself if you are mechanicly inclined.

Don't forget the possibility of replacing the MAF sensor, and the
once/40k timing belt changes.

No matter what, this car is not a Toyota gas-powered car, and it will
require as much money to keep on the road, when you include all the
maintenance.

A TDI car is a choice, but it's not going to be a significant cost
savings, even if you keep the car until it's completely depreciated.
Now, at that time, you'll probably get more in resale than for a Toyota
car of the same vintage, but only because there's a diesel fan out
there with a certain idea of value in his/her mind. That's why a
diesel Passat wagon that's 10 years old can fetch $10-12k for a good
example right now. (And less, if you shop around.)

That's a lot of money for a 10 year old diesel four-banger, and not
really in line with its true value.

Maybe in 10 years your slushbox TDI will fetch 50% of that, but I
wouldn't count on it.

E.P.

>>> So, even though you can get more *power* from a turbocharged engine,
> it's
>> less efficient at typical alititudes. For example, the Subaru
>> Outback 2.5L 4 cyl loses 3-5mpg when you strap a turbo on it.
>
> Diesel don't lose any fuel economy from having a turbo, in fact they
> gain fuel economy from the turbo.

Simply posting an incorrect statement does not make it so. Go back and read
what I said.

> You lose some power to a
> restrictive exhaust, but you gain it back through the turbocharger,
> and then some.

.... at a huse expense of fuel economy.

> Most big trucks and busses have turbos. Fuel economy is the name
> of the game for these kinds of vehicles- a trucking company can spend
> almost as much money on fuel as labor costs. If turbos lead to worse
> fuel economy, they wouldn't use them.

Turbos lead to a higher power to weight ratio, not better economy.

"fbloogyudsr" > wrote in message
...
> This is an absolutely crap statement. Take any engine and put it in a
> vehicle
> and measure it's fuel economy. Then add a turbo. The economy *will* go
> down: you never get something (more power) for nothing: 2nd law of
thermo-
> dynamics at work.

You are wrong. I know what the second law of thermodynamics is but the
fact is there is alot of waste energy in an engine that can be reclaimed. A
diesel engine is only about 40-50 percent efficient, and the average gas
engine is less than 25 percent efficient. There is lots of room to reclaim
thermal efficiency, and a turbo is one way of doing this.

Using your logic, a hybrid car could never work, because it gets its
energy from somewhere besides burning more fuel.

> No. You get more *power* out of a smaller engine.

which still equals improved fuel economy. Jesus, don't you GET it? You
cannot downscale a buss or truck engine beyond a certain HP before it just
won't work. The turbo allows it to use a smaller engine than it otherwise
could, which results in less fuel consumption.

"John S." > wrote in message
oups.com...
> A turbo allows an otherwise small modestly powered engine to operate
> with a wider range of power output. That is what I think truck and car
> owners are looking for. Most of the time we are not really using an
> intake compressor (turbo or super), it just provides more of a power
> reserve that a comparably sized normally aspirated engine does.

This is completely bogus. My VW uses the turbo nearly all the time, I can
hear it with the windows rolled down during even mild acceleration.

> Those little engines
> were running close to full output on all but the flats and they were
> dying after 40,000 miles and their warranty claims went through the
> roof.

At 55-65 mph, the VW TDI engine is not even working that hard, maybe doing
between 1900-2200 RPM's.

Turbos on gas engines is totally different than a turbo on a diesel
engine. Turbo on gas engine is for performance mostly, on diesel engine it
is for power and fuel economy. The gas engine will also take more tweaking
to withstand the pressure. A turbo is just a natural marriage for a diesel
engine, which is why nearly all diesels now days, outside of generators and
small engines, use them.

"Magnulus" > wrote
> "fbloogyudsr" > wrote
>> This is an absolutely crap statement. Take any engine and put it in a
>> vehicle
>> and measure it's fuel economy. Then add a turbo. The economy *will* go
>> down: you never get something (more power) for nothing: 2nd law of
> thermo-
>> dynamics at work.
>
> You are wrong. I know what the second law of thermodynamics is but the
> fact is there is alot of waste energy in an engine that can be reclaimed.
> A
> diesel engine is only about 40-50 percent efficient, and the average gas
> engine is less than 25 percent efficient. There is lots of room to
> reclaim
> thermal efficiency, and a turbo is one way of doing this.

No. A diesel engine is about 30% thermal efficiency. A gas engine is
about 25%. Coal-fired (or gas/whatever) are around 40%. What you
neglect to consider is that the *COMBUSTION* temperature of a
diesel engine, whether turbo-charged or not, is the same - and that
is what drives efficiency, not how much fuel-air mixture you run through
the engine. By that logic, a turbo-charged gas engine is more efficient
than a (non-turbo-charged) diesel: clearly not the case.

> Using your logic, a hybrid car could never work, because it gets its
> energy from somewhere besides burning more fuel.

The hybrid uses a *SMALLER* engine (inherently more fuel efficient)
and regenerative braking to recover momentum/energy. Not the
same thing at all.

>> No. You get more *power* out of a smaller engine.
>
> which still equals improved fuel economy. Jesus, don't you GET it? You
> cannot downscale a buss or truck engine beyond a certain HP before it just
> won't work. The turbo allows it to use a smaller engine than it otherwise
> could, which results in less fuel consumption.

No. *YOU* don't get it. I remember my thermodynamics classes
from college - you evidently never took any.

Floyd

> wrote in message
ups.com...
> Don't forget the possibility of replacing the MAF sensor, and the
> once/40k timing belt changes.

The newer MAF sensors don't wear out as much. The timing belt is not
unique to VW diesels, lots of other cars have belts that must be changed.

>
> No matter what, this car is not a Toyota gas-powered car, and it will
> require as much money to keep on the road, when you include all the
> maintenance.

Maybe, but personally I think Toyotas are not as good. VW has better
crash ratings, better features as standard. And it just looks nicer.
Corollas look a bit cheap in comparison. And some people like hatchbacks
and wagons.

> Maybe in 10 years your slushbox TDI will fetch 50% of that, but I
> wouldn't count on it.

I would could on it. In ten years gas will probably be over 3 dollars per
gallon. A "slushbox" Jetta TDI is going to be alot more attractive than a
Ford Explorer.

"fbloogyudsr" > wrote
> "Magnulus" > wrote

Since you don't seem to want to believe me, go to
http://www.answers.com/topic/turbocharger and read the
wikepedia article. Notice it talks about "increased power",
but never mentions efficiency (other than the fact that
the turbo actually *reduces* efficiency). Perhaps
you're confused by the term "volumetric efficiency"
and "thermal efficiency". The latter is what mpg is about.

Floyd

"Turbo on gas engine is for performance mostly, on diesel engine it
is for power and fuel economy."

JS> And just what is the diference between performance and power...

" This is completely bogus. My VW uses the turbo nearly all the time,
I can
hear it with the windows rolled down during even mild acceleration. "

Well of course it is spinning - that is by definition the way turbos
work. Cruising down the highway it is having virtually no impact on
the engine. It is under acceleration that the value of a turbo can be
seen. Otherwise you could remove it and probably improve milage by 2-3
mpg.

"fbloogyudsr" > wrote in message
...
> Since you don't seem to want to believe me, go to
> http://www.answers.com/topic/turbocharger and read the
> wikepedia article. Notice it talks about "increased power",
> but never mentions efficiency (other than the fact that
> the turbo actually *reduces* efficiency).

Increased power can equal increased efficiency. The two are not mutually
exclusive. If you find a way to make an engine that burns less fuel but
delivers enough power for the application, then that engine is the more
efficient.

Turbos do save fuel for diesel applications in cars and trucks. They
allow use of a smaller engine with more horespower and less fuel
consumption. It jus so happens though that modern VW turbodiesels have a
little higher fuel consumption than older VW diesels from the 70's, despite
the horsepower. But then the engines also deliver almost twice the power,
and the cars weigh about 50-75 percent more than old VW Rabbits/Golfs. Some
of those older diesels took over 20 second to reach 60 miles per hour, today
it's more like 10-11 seconds; no different than any other economy car.