VGT/VNT Questions

Rahulk76 · 13th August 2007, 12:37

Hi

I was wondering, what the VGT/VNT is and came across this website on their workings.

How does Variable Turbine Geometry work?

All i understood was that it increases low end power and low speed drivability.

Now what comes to mind is that,

A) Does it harm the engine than the common TC.
B) Does it increases the fuelefficiency
C) Does it increases the power
&
D) Can it be retrofitted into the cars which already have a turbocharger ?

Rahul

Thnks

Rahulk76 · 14th August 2007, 16:14

Mod Gurus....Are u here

porsche_fan · 14th August 2007, 19:32

To answer your questions -

A) Does it harm the engine than the common TC. - That would be w.r.t a wastegated TC - No.
B) Does it increases the fuel efficiency - Yes. It gives the engine higher air flow all over the operating range thus requiring less fuel to achieve the same torque. It actually directly impacts the Brake Specific Fuel Consumption or BSFC - Power produced per unit quantity of fuel, which directly effects the fuel consumption of the engine. However, the overall fuel effciency of the vehicle may depend on other parameters, but is usually improved too.
C) Does it increases the power - Yes - More air means more efficient combustion of the fuel injected and hence increases the power output.
&
D) Can it be retrofitted into the cars which already have a turbocharger ? No - VNT turbochargers, being controlled by the engine ECU, are pre- programmed at the OE and then sold. To change from a WG to an VNT would need a complete ECU re-mapping and compatability to ensure efficient performance.

13th August 2007, 12:37	#1
Rahulk76 Senior - BHPian Join Date: Sep 2005 Location: India Posts: 1,149 Thanked: 235 Times	VGT/VNT Questions Hi I was wondering, what the VGT/VNT is and came across this website on their workings. How does Variable Turbine Geometry work? All i understood was that it increases low end power and low speed drivability. Now what comes to mind is that, A) Does it harm the engine than the common TC. B) Does it increases the fuelefficiency C) Does it increases the power & D) Can it be retrofitted into the cars which already have a turbocharger ? Rahul Thnks
	() Thanks

14th August 2007, 16:14	#2
Rahulk76 Senior - BHPian Join Date: Sep 2005 Location: India Posts: 1,149 Thanked: 235 Times	Mod Gurus....Are u here
	() Thanks

14th August 2007, 19:32	#3
porsche_fan BHPian Join Date: Mar 2005 Location: Epinal,France Posts: 83 Thanked: 8 Times	To answer your questions - A) Does it harm the engine than the common TC. - That would be w.r.t a wastegated TC - No. B) Does it increases the fuel efficiency - Yes. It gives the engine higher air flow all over the operating range thus requiring less fuel to achieve the same torque. It actually directly impacts the Brake Specific Fuel Consumption or BSFC - Power produced per unit quantity of fuel, which directly effects the fuel consumption of the engine. However, the overall fuel effciency of the vehicle may depend on other parameters, but is usually improved too. C) Does it increases the power - Yes - More air means more efficient combustion of the fuel injected and hence increases the power output. & D) Can it be retrofitted into the cars which already have a turbocharger ? No - VNT turbochargers, being controlled by the engine ECU, are pre- programmed at the OE and then sold. To change from a WG to an VNT would need a complete ECU re-mapping and compatability to ensure efficient performance.
	() Thanks