Ok, can somebody please tell me the advantages and disadvantages of turbo?

Positives, smaller engine needed, higher power output when turbo kicks in. When turbo kicks in, fuel consumption goes up. Without turbo, fuel consumption is much better.

Disadvantages: lag in turbo power boost, since it is run from the exhaust gasses (there are mechanisms to make this somewhat better). Mechanical complexity, it's another piece of equipment. Car will need more frequent oil changes, but that's only good maintenance anyway. (not more frequent than 3000 miles). Turbo has a limited lifetime, and will eventually require replacement. (yet another thing to break).

They're not. Mercedes has them, Subaru has had them, Volkswagen (I think) might have had them. Mitsubishi, Ford, Mazda have had them (Ford Probe GT, 1989 to about 1993 or so, GT model). Mitsubishi Eclipse, mostly any GX, I think.

Saab is the only manufacturer that makes the turbo standard on all models, iirc.

Two varieties, depending on how much boost (additional air pressure) you have. LPT and HPT. LPT generally (2000 9-5, for example) does not have a turbo pressure gauge. engine is a 2.3t (small t), HPT has more boost, higher horsepower, and is a 2.3 T.

Higher boost generally means more engine power.

(note: had an 89 probe GT, loved the car. Had mitsubishi 98 eclipse without turbo... was really dead.) Father had 200D (diesel, turbo) Mercedes... had very bad turbo lag, (dead to 2500 rpm, then zoom after it), have 2000 9-5... much nicer.

Harvey

For normal driving, fuel consumption with turbo is better. This is because the engine is more efficient and more torque is available at low RPM. If you use the extra performance, then yes you have to pay for it.

No noticeable lag in LPT, (light pressure turbos). These are designed to take advantage of the turbo for improved driveability at low RPM. Turbos last well (> 100,000 miles) if treated with a minimum of care.

The VW 1.8T engine goes into VW, Audi, Skoda and Seat. Rover also have a 1.8T which replaces their 2.5V6 and has identical performance, but with lower fuel consumption and emissions. Vauxhall (of course Saab's cousin). Mercedes use a different system (Kompressor) to get positive displacement. Most car diesels from all manufacturers use turbos.

Was! Saab now also have non-turbos: 9-3 1.8i and 9-2 2.5L

See above.

Yes - you get more power (and the correspondingly higher fuel consumption) when you're getting heavy on the "loud pedal", but when you're driving normally you continue to have the fuel efficiency of the small engine.

The recent generation of turbo that Saab uses has a "low mass" configuration so it spins up much more quickly than the turbos of the 1970's, but it's still noticable. I'm not sure it's _bad_, just that it's noticable.

I'm not sure I agree with this statement. The turbos are robust; it's not a normal wear item that you have to plan to replace or anything. My '88

900 Turbo still had (has?) the original turbo in it, when I traded it in at 247,000 miles, and the only "unusual" thing I did was use synthetic oil throughout my ownership of the car. Hearing about a turbo failure in a saab isn't by any means a common thing, going by this group's history and so on.

Also, turbos are widely used in the diesel trucking industry, for pretty much the same reasons - better fuel efficiency and power. Dave Hinz

Turbos have come and gone in other cars, usually billed as a performance item. They haven't been all that reliable for other manufacturers. Saab, on the other hand, has been using turbos forever and has it figured out. I've got a 1995 9000 LPT. With the turbo, I've got the economy of a 4-cylinder with the power of an 8. I traded in a Lincoln Mark VIII for the Saab and don't feel I lost anything at all on power, except in the 90mph+ range -- a range I don't visit much. My "around town" gas mileage in the Saab is 26-27 mpg, 31-32 for straight highway driving. The Saab runs well on mid-level and even regular, while the Lincoln required premium and only got 14 mpg around town, 24 highway. I test drove a regular turbo and the LPT when I bought the car. The power curve on the LPT is the most useful. Most important, the turbos are fun to drive!

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design, print design, photography

Thanks to all who answered my question on turbo. Feel a lot better about that now!

Now two follow up questions:

What is the quality of Saab, the newer generations in particular.

I am interested in the 9-3, convertible so another questions would be what is the consensus on Saab convertibles?

Just for comparison, I have a Mustang convertible right now and it is working ok but it took most of the 36k warranty to get all the quirks out of it.

Thanks again for taking time to respond to my questions!

-Peter

Agreed, they are, but I was speaking in an absolute sense. Older cars needed more frequent oil changes with "turbo" oil (SF or SG rated for the probe, for instance). I always changed mine more frequently, and tried to let the turbo cool after a run. I also tried not so drive with my foot in the turbo. What "broke" on it is that the seal to the engine is going, so that's a problem.

I've seen reports of some turbos going bad in Saabs, but I'm not sure which models, and which model years.

yep, no data there, though. I can speak about the cars above, probe, eclipse, vw (no turbo), and mercedes diesel.

Harvey

I don't think anyone can produce any statistics that show that turbos have some designed-in reliability issue. Engineering book in hand, there's no reason why they should. The "more moving parts" does not hold water when keeping in mind turbos are actually very simple mechanical devices, and that the altrnative is a V6 or V8 with *far* more moving parts subjected to far more mechanical stress than turbos, which merely spool in very predictable fashion. Cylinder heads and valves are subjected to far higher temperatures and pressure, just as an example.

Turbo engines are extensively used in aviation, which is not known to take on design and reliability risks. Almost every propeller plane uses a turbo engine. The reasons point at the basic key advantage: more power, less weight. The only disadvantage of a turbo in an automotive application is the famous lag, but it's been engineered down to a minimum these days. The other one is the engine noise when the engine is pushed, but typically one wants some noise when flooring the throttle. On the other hand, in cruise mode many turbo engines are eerily quiet (the Saab's is). The noise is a bit more agricultural than a Beemer's I6 under load. Other V6 engines do not compare as favorably, in my opinion.

...pablo

And with the addition of one part and swapping another, you would blow by the Mark VIII! LPT to FPT conversion on the 9k is a painless project I have done twice. I prefer the LPT as a used car because they were not beat upon as much.

As the the original poster's question. The performance/economy issues have all been covered. A turbo is not a negative but a plus. The 9^3 has modern engine management and hardware which minimize the 'lag' that people talk about and with periodic oil changes (3-4k) the turbo should last 200kmi or more. With synthetic, it should last much longer than that. If the maintenance is neglected on it, though, your guess is as good as mine as to longevity.

I have 130kmi and 115kmi on 2 of them now and a friend has one with

275kmi on the original turbo.

KeithG

LauraK wrote:

nph wrote: :: Thanks to all who answered my question on turbo. Feel a lot better :: about that now! :: :: Now two follow up questions: :: :: What is the quality of Saab, the newer generations in particular. :: :: I am interested in the 9-3, convertible so another questions would :: be what is the consensus on Saab convertibles?

The quality of the Saab cars has improved a great deal up through the 90's. Today the Saab's are VERY reliable. A recent study here in Scandinavia shows that Saab ownrs in generel are very pleased with their cars and the service they get. I believe Saab was in the top 4.

Cheers!

Saab is one of the better cars. In general I split the quality into three parts: Engineering, manufacturing and service.

You can have cars that have fine engineering, but the manufacturing quality is patchy. I found that was the case with a Ford Fiesta (My first new car in 1978) It required a new gearbox under warranty, and the read window frames had some strange sticky gooey to fill in gaps (presumably quality control :)

Then I had the Fiat Croma (sister car to the 9000). Again nice engineering design, but the interior plastic panels warped and the car squeaked a lot. The servicing was poor, I often have to visit the FIAT garage several times to fix a problem.

My 10 year old Saab 9000 is much better of course, I'm impressed by the attention to detail, it is a joy to open the bonnet on this car.

However, as they say: Past results does not guarantee future performance... In particular, there is now a new requirement that all manufacturers are required to recycle their cars when eventually disposed of. This has led to the use of cheaper plastics materials e.g. the new 2004 VW Golf. It may be OK, but you may loose the quality feel inside the car.

So shop around in showrooms, read magazines, consumer reports etc.

Thanks for the info. Can you please post a link to that survey in Scandinavia? (I speak Swedish so it is ok if it is not English)

Dallas (Texas) weather just screams out for a convertible!

Thanks

Peter

Peter wrote: :: Thanks for the info. :: Can you please post a link to that survey in Scandinavia? :: (I speak Swedish so it is ok if it is not English)

Here you go Peter:

:: Dallas (Texas) weather just screams out for a convertible!

Well, I'm not a bit jealous - with 5 cm. of snow and freezing temp's here..... :(

Cheers!