Re: Turbos and superchargers

Thread View: net.auto.tech

4 messages

[T] Back to Threads [V] Tree View [G] Group Articles

4 total messages Started by Mike Moroney Sun, 26 Jan 1986 05:43

#627

Author: Mike Moroney
Date: Sun, 26 Jan 1986 05:43

35 lines
1781 bytes

Turbochargers and superchargers do the same thing, they compress air to force
more air/fuel mixture into the cylinders to get more power.  The basic
difference in automotive language is where the devices get their power. 
Turbochargers get their power from a turbine in the exhaust system, powered by
exhaust pressure.  Superchargers (often called "blowers" by racing types) are
belt-driven, like the alternator, water pump, etc.

Advantages to Turbochargers:

1) Use "free" power (exhaust power)
2) Physically smaller, since the device uses higher RPM's (as much as 100K)

Disadvantages:

1) Turbo "lag" between the time you step on it and the turbo kicks in
2) Non-linear function of throttle position and power (many people with turbo's
   love this, though)
3) Potentially unreliable, because of the high temperature from exhaust + high
   RPM's (they are pretty good now, however)
4) Not too useful at low RPM's


Supercharger advantages:

1) Linear power response, like a bigger motor
2) No turbo "lag"

Disadvantages:

1) Uses motor power
2) Can be large (racers often have them sticking through the hood)

-Mike Moroney
..decvax!decwrl!rhea!jon!moroney

Re: Turbos and superchargers

#659

Author: William Svirsky
Date: Mon, 27 Jan 1986 17:54

16 lines
1179 bytes

In article <715@decwrl.DEC.COM> moroney@jon.DEC (Mike Moroney) writes:
>
>Advantages to Turbochargers:
>
>1) Use "free" power (exhaust power)
>2) Physically smaller, since the device uses higher RPM's (as much as 100K)

One more advantage is that because the turbo doesn't "kick in" at
lower RPM's, you can drive the car for economy, by shifting
early, or drive it for speed, by shifting late.
-- 
Bill Svirsky
Citicorp/TTI
3100 Ocean Park Blvd.
Santa Monica, CA 90405 Work phone: 213-450-9111 x2597
{philabs,randvax,trwrb,vortex}!ttidca!ttidcb!svirsky

Re: Re: Re: Turbos and superchargers

#663

Author: Larry Lippman
Date: Sun, 02 Feb 1986 04:42

29 lines
2319 bytes

> Turbochargers and superchargers do the same thing, they compress air to force
> more air/fuel mixture into the cylinders to get more power.  The basic
> difference in automotive language is where the devices get their power. 
> Turbochargers get their power from a turbine in the exhaust system, powered by
> exhaust pressure.  Superchargers (often called "blowers" by racing types) are
> belt-driven, like the alternator, water pump, etc.
> 
> Advantages to Turbochargers:
> 
> 1) Use "free" power (exhaust power)
> ...

	Nothing is "free" in this world...  The turbine motor which powers an
exhaust-driven turbocharger gets its power from the exhaust gases by paying
the price of increasing exhaust backpressure, thereby increasing engine load
and decreasing engine efficiency.  There is not a great deal of power (when
compared to total engine output) expended to run the turbine motor, but it
could be as much as several BMEHP at high rpm's.  The resulting power gain from
the turbocharger action more than justifies the power required to drive the
turbine motor.  The same thing is also true of a direct-coupled Roots-type
supercharger; the engine power required to operate this blower is more than
justified by the increased power gain.

==>  Larry Lippman @ Recognition Research Corp., Clarence, New York        <==
==>  UUCP    {decvax|dual|rocksanne|rocksvax|watmath}!sunybcs!kitty!larry  <==
==>  VOICE   716/741-9185                {rice|shell}!baylor!/             <==
==>  FAX     716/741-9635 {G1, G2, G3 modes}    duke!ethos!/               <==
==>                                               seismo!/                 <==
==>  "Have you hugged your cat today?"           ihnp4!/                   <==

Re: Re: Re: Turbos and superchargers

#669

Author: Jan Vandenbrande
Date: Mon, 03 Feb 1986 18:16

12 lines
1285 bytes

Refering to the loss of power due to the increase in exhaust pressure by
adding a turbo charger on your car. 
I believe that you have to look where you try to get the energy from.
As much as I remember my thermodynamics class (oh what a nightmare) it isn't
so much the pressure of the exhaust gasses as it is the combination of
pressure and the TEMPERATURE difference between what you have after it leaves
the engine and what you have outside. Hot exhaust gasses still have alot
of energy in them, which usually goes to waste. Turbo chargers try to use
some of this energy to press more air/fuel stuff in you combustion chambers.
Correct me if I am wrong.
Jan
.

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads