Boost Return removed - what to do with the ISV

[markmcie 0]

Hi all,

 

Take a look at the pic of my engine bay below. Is it a good idea to have the ISV re-routed back into the boost tube to the TB ? This is how the boost tubes were setup when I bought them ? Is there any benifit to haveing the ISV breathing to the atmosphere ?

 

The car runs fine like this and idles perfect.

 

[gibber 0]

They way it is routed at in your picture prevents your isv from venting off boost if you ecu detects your engine pinking. But it does allow you to run more boost at the risk!

[markmcie 0]

Is there not a knock sensor on the G60 that prevents pinking ?

[gibber 0]

From what I know, it prevents pinking by venting the boost!

[Timo. 0]

Hi all,

 

Take a look at the pic of my engine bay below. Is it a good idea to have the ISV re-routed back into the boost tube to the TB ? This is how the boost tubes were setup when I bought them ?

 

edit. cos i is silly :)

 

T.

[Timo. 0]

And yes the g60 has a knock sensor.

[gibber 0]

Timo. if you look it has been re-routed into the inlet boost pipe, not the boost return pipe.

[Timo. 0]

Ah, so it has. Whoops :(

 

Thats basically done to stop the ISV venting the boost.

 

T.

[h100vw 0]

Q. What is detonation?

A. Detonation or "knocking" is uncontrolled combustion with a very steep rise in pressure. It is caused by spontaneous ignition of the fuel mixture, which has not yet been reached by the ignition spark. As the high-pressure waves hit the walls of the combustion chamber, their impact produces a metallic knocking sound. Failure to recognize and deal with knocking will inevitably lead to serious engine damage.

Q. What is pre-ignition?

A. Pre-ignition is an uncontrolled ignition process in which the temperatures in the combustion chamber can rise to such an extent as to cause serious damage to the engine and the spark plug. Full-throttle operation can generate localized hot spots and cause pre-ignition at the following locations:

 

* At the tip of the spark plug’s insulator nose

* On the exhaust valve

* On the protruding sections of the head gasket

* On loose deposits (ash and carbon residue)

 

 

Pre-ignition of the air/fuel mixture can cause severe damage to an engine and this is one reason why the heat range of a spark plug is so important.

 

 

Detonation is pretty similar to the operation of a diesel engine. The pressure in the cylinder causes the mixture to ignite before the spark sets it off. It can be reduced by lowering inlet temps(water injection/intercooler) or reducing boost(ISV venting). Diesel engines are designed to take the extra stress of the combustion process.

 

Gavin

[markmcie 0]

You really think it could be that serious that I could damage the engine ? I've had the car for over a year now and never heard it pink even under full load.

[stevemac 0]

The G60 ECU automatically retards the ignition when it senses "pinking".

 

AFAIK - it does this for an individual cylinder, or for all 4 cylinders as neccessary.

 

I doubt that preventing it from bleeding boost (if indeed it does when the engine "pinks") would be a problem, once the ignition has been retarded.