How is BOOST measured in the 2.0d engine??

[ELO]

Thats interesting... so a poor vacuum will lead to slow turbo activation and therefore slow boost hence underboost. I thought that because I was getting turbo boost that the vacuum lines must all be working ok, but if its not just a binary type situation, on or off, and the strength of vacuum also determines speed of turbo response then I need to find out how to test vacuum lines more thoroughly.

The routing of pipework in my engine is as follows



When inactive, the Y-shaped throttle body at the top of charge pipes 4 & 7 is open to flow from 7, and closed to flow from 4. The older system didn't have hose 4. Not sure what the point of 4 is?

Thanks... learning a lot from you

[alfadave11]

strength of vacuum is dependant of boost controller or more so activation

[ELO]

Here is the rolling road graph after



These values..



I thought that torque might have been a bit higher as the generic maps on this car usually produce 168bhp and 303 lb/ft

http://www.celtictuning.co.uk/servic...e-1#t3-content

[ELO]

Originally Posted by alfadave11

strength of vacuum is dependant of boost controller or more so activation

Sorry what does this mean??

[alfadave11]

boost controller limits vacuum ie strength as actuator has a spring that reacts against it

don't worry about torque being higher ..its smooth and be transmission friendly
so you know not to rev it past 3500

[ELO]

When under the car checking the vacuum hoses (just visually) I noticed that some, like the longer one going around to the turbo actuator was very soft and easy to compress. Hoses that are soft will collapse easily and fail to hold vacuums and kink easily. Maybe I should replace all vacuum hoses?...they are 10 years old!

[alfadave11]

hoses can feel squidgy when you squeeze them with fingers and thumb but do remember that atmospheric pressure acts on all sides of hose
yes not a bad idea if you gonna keep car but make sure you get correct bore size for a good seal

[ELO]

In the interests of finding out what is causing my underboost P0299 fault I've been looking at what might be causing a loss of Boost. With zero success, having checked and double checked all the positive pressure side of my turbo, and with the very kind advice of alphadave11 I'm now looking towards the control side of my turbo. I've ordered new vacuum hose and 3 Turbo Control Valves (TCV) to replace mine which could be 10 years old. These have a suggested lifespan of 4-5 years (even heard of them going annually!). My car has 3 because of the Y-shaped throttle body (which I still dont understand why this was installed when previous models had a single intake). My Haynes was pre-Y-shaped throttle body so only speaks of two TCV and describes the one on the left (as looking into engine bay from front) as an anti shudder valve. Here I have 2 TCVs not 1.

Following video has a useful explanation of how electronic boost controllers work, which is basically what these TCVs are....


https://www.youtube.com/watch?v=TpdUBe2YJxQ

[ELO]

Has anyone got access to a proper diagram, or would mind sketching a diagram of where all the vacuum hoses are meant to be connected properly to the 3 control valves in the Y-shaped throttle body version of the 2.0d??




It may well be that I'm getting low boost at low RPM because my Variable Geometry Turbo isn't being activated and staying in the closed vanes position, so boost is ok at higher engine RPMs but very poor at low RPM??

[alfadave11]

Originally Posted by V50 PSK

In the interests of finding out what is causing my underboost P0299 fault I've been looking at what might be causing a loss of Boost. With zero success, having checked and double checked all the positive pressure side of my turbo, and with the very kind advice of alphadave11 I'm now looking towards the control side of my turbo. I've ordered new vacuum hose and 3 Turbo Control Valves (TCV) to replace mine which could be 10 years old. These have a suggested lifespan of 4-5 years (even heard of them going annually!). My car has 3 because of the Y-shaped throttle body (which I still dont understand why this was installed when previous models had a single intake). My Haynes was pre-Y-shaped throttle body so only speaks of two TCV and describes the one on the left (as looking into engine bay from front) as an anti shudder valve. Here I have 2 TCVs not 1.

Following video has a useful explanation of how electronic boost controllers work, which is basically what these TCVs are....


https://www.youtube.com/watch?v=TpdUBe2YJxQ

just replace one hose at a time ...that video is no use or ornament to you
variable vane controls boost pressure by altering exhaust gas flow ..just think of it as a water wheel ...where your altering paddles pitch so your keeping wheel at a constant speed regardless of speed of water flow ...