Date: Sun, 25 Jan 2004 12:27:05 +0000 From: Johannes H Andersen <johsnopsamfitter.com> Subject: Re: Ok, can somebody please tell me the advantages and disadvantages of turbo?
Harvey White wrote: > > On Sun, 25 Jan 2004 05:18:39 GMT, Peter <garbagenopsamsafe.com> wrote: > > >hi, > > > >I just started looking at Saabs and the 9-3 inparticular but with so > >few cars around using a turbo and my complete lack of experience with > >turbos I need some information. > > > >What is the positives with turbo and are there any drawbacks? > > 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. 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. > 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). 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. > >Since Saab seems to be the only manufacturer with turbos, the question > >is why? > > 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. 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. > Saab is the only manufacturer that makes the turbo standard on all > models, iirc. Was! Saab now also have non-turbos: 9-3 1.8i and 9-2 2.5L > 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. See above.