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Turbo= almost free power? Posted by REM in Seattle [Email] (#4) [Profile/Gallery] (more from REM in Seattle) on Wed, 18 Jun 2003 11:37:50 In Reply to: Re: Turbo= free power. (or otherwise wasted power anyhow), Dean, Wed, 18 Jun 2003 10:33:44 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Ffrom 'How Things Work' article on turbos (see lowbars post in this thread);
"Turbochargers allow an engine to burn more fuel and air by packing more into the existing cylinders. The typical boost provided by a turbocharger is 6 to 8 pounds per square inch (psi). Since normal atmospheric pressure is 14.7 psi at sea level, you can see that you are getting about 50 percent more air into the engine. Therefore, you would expect to get 50 percent more power. It's not perfectly efficient, so you might get a 30- to 40-percent improvement instead."
"One cause of the inefficiency comes from the fact that the power to spin the turbine is not free. Having a turbine in the exhaust flow increases the restriction in the exhaust. This means that on the exhaust stroke, the engine has to push against a higher back-pressure. This subtracts a little bit of power from the cylinders that are firing at the same time."
So the turbo does have some power robbing influence, but less power robbing than say a supercharger. So turbo = almost free power? :^)
Rob Mustard (aka. REM in Seattle)
1984 Saab 900T, 3 door, 5-sp; 242,000 miles RIP
1991 Alfa Romeo Spider, convertible, 5-sp; 91,000 miles
1998 Saab 900SET, 5 door, automatic; 58,000 miles
posted by 208.49.241...
_______________________________________ REM in Seattle Current: 2013 Volvo XC60 R-Design, Rebel Blue, 3.0L 6-cyl turbo, Automatic 2024 MINI Cooper S Convertible, 2.0L 4-cyl turbo, 6-speed manual Former: 2005 Saab 9-3 Aero Convertible, Steel Gray metallic, 2.0L 4-cyl turbo, 5-speed 1998 Saab 900SET 5-door, Silver, 2.0L 4-cyl turbo, Automatic 1991 Alfa Romeo Spider convertible, Alfa Red, 2.0L 4-cyl, 5-speed 1984 Saab 900T 3-door, Red, 2.0L 4-cyl turbo, 5-speed
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