G60 vacum system

[colsy 0]

Hi all,

A couple of questions:

1) When the throttle on the G60 is fully closed, in this instance changing gear - how does the G60 dispense the boost from charger/plumbing to keep the charger spinning and prevent blowing pipes.

2) When the throttle on the G60 is fully closed, in this instance changing gear - how does the G60 take air in to fuel the engine...without passing air when on boost? one way valve?

3) When the throttle on the G60 is fully closed, in this instance at idle - how does the G60 take air in to fuel the engine...without passing air when on boost? I expect the same answer as for question 2.

 

Below are a few engine diagrams, hopefully they will help people in explaining there answers with the part no's ect.

[Riley 0]

1/

It blows excess boost out of the bottom of the throttle body, back to the charger. This is called the boost return.

 

2/

Within the throttle body is a small hole before the butterfly, this channels to the other side of the butterfly passing the idle screw (Back of the throttle body) and hence air. Though this is minimal as when you change gear, the fuel cut off should kick in over 2/2.5k rpm.

 

3/

Same as above, but with no fuel cut off as the idle map is being used.

 

Very quick answer btw as im currently knee deep in paperwork!

[colsy 0]

Cheers for the answers, couple more questions :)

1.2 how does the throttle body know when it see's excess boost? Some kind of diaphram valve actuating a wastgate on the throttle body maybe, like a turbo wastegate?

2.2 when throttle closed, and charge on return, why does the charge not pass through this channel from one side of the throttle to the other? Is the wastegate I precieve much bigger port than this channel bore? I.e. The charge follows the path if least resistence?

Can you please quote sum part numbers so I know what I'm looking at.

Cheers!

Col.

[dirtytorque 0]

[MattWilde 10]

1.1, If you look at your first diagram and part 2a, that is the first part of your throttle body. The section that is encompassed by 2 is the second part which contains the butterfly that controls the air that enters the engine. Underneath all of that is a connector rod, part 3. This connects the inlet butterfly to the boost return butterfly. you can see this boost return butterfly housing above part 6a. With these 2 connected they both operate from the accelerator cable but they work in opposites to each other. When the inlet butterfly is open (eg WOT) then the boost return butterfly is closed and vice versa. So when you are changing gear the boost return butterfly is open allowing the boost that is being produced to vent back into the intake system.

 

2.2 The boost return vent is much bigger than the idle bypass hole so the majority of the air will pass through this, the remaining will pass into the engine to help continue idling. At idle, the charger won't be producing massive amounts of boost either, so it's not likely that the system will be under much pressure.

 

Hope that all helps!!!

[colsy 0]

Cheers Matt, wrapped that up lovley.