Turbo Boost Gauge Fitment

Yes I thought that some time later I dunno Jon
Regards the gauge reading ,mine reads about 10 psi on vac .....now then .....some gauges are calibrated in Hg which is about double ie 20 .

http://www.lds-vacuum.com/conversion.html

You have me there, but i thought that it would blow off the excess pressure and in my case re-circ it back to the intake (as opposed to venting to atmosphere) this all happens before the throttle body to prevent Turbo "stall" I think that the diaphragm maybe controlled by my non-existent vacuum from the top of the DV.

I am of course probably completely wrong being a non mechanically minded musician- so please forgive my ignorance!!!

Yep mine is in Hg so 16 is a little under.....

You have me there, but i thought that it would blow off the excess pressure and in my case re-circ it back to the intake (as opposed to venting to atmosphere) this all happens before the throttle body

It does not matter wher the excess pressure is vented to, it will have no effect on the engin, but what does matter is that the dump valve actuating pipe is plumbed in after the throttle body, where vacuum exists on overun, Lee, pse confirm, so I can have my ovalteen and go and lay in a darkened room

The blow-off must also suck to work innit.
Now ,you go and lie down deary ......Do you know where you are

That of course is true, merely that the valve is also set to blow off at a certain pressure to prevent turbo stall as well as being actuated by the manifold vacuum pressure, it's a two way system of actuation. I think we're in total agreement John it's just that my car for whatever reason does not seem to have vacuum at the DV actuator pipe, although it will show positive pressure...

Enjoy your Bovril/Ovalteen

[quote="clee"]The blow-off must also suck to work innit.
quote]

You have woken me up again Not quite sure what you are saying there there Lee. If you mean the dump valve (blow off) must have vacuum (suck) to make it work, thats what I am saying "innit"

Then were all agreed, yay!!!!

That of course is true, merely that the valve is also set to blow off at a certain pressure to prevent turbo stall as well as being actuated by the manifold vacuum pressure, it's a two way system of actuation. I think we're in total agreement John it's just that my car for whatever reason does not seem to have vacuum at the DV actuator pipe, although it will show positive pressure...

Just for clarification the valve will blow off at a certain vacuum, not pressure.
I cannot see where the two way system of actuation comes from, I believe it is vacuum only.
If you are plumbed into the manifold after the throttle actuator, There will be vacuum on overun
There are other spots on the inlet system where you will find a pressure reading, but no vacuum, which will not necesserally be the actual boost reading. I still have this nagging feeling that your boost gauge is plumbed into the wrong spot. I could be wrong, but everything you say is indicitave of this.
Am I right in saying that Lee has seen your installation, and has confirmed you are plumbed into the right spot?

The problem is that you can't see which pipe's going where due to the cladding. My DV was removed by DG during the instillation of the chargecooler. When fitting the boost gauge i found the blanked off hose (right colour/size) and assumed it was the DV hose - however no vacuum.

So today i swapped it over for the one going to the MAP sensor and although i now had a vacuum reading the car was v smoky and ran terribly! So i have now returned the hoses to the original way round and plumbed in the gauge to the MAP sensor to get a reading.

When i return from Croix i will investigate further, take off the cladding and report back....

assumed it was the DV hose - however no vacuum.


and plumbed in the gauge to the MAP sensor to get a reading.

Your first quote has at last comfirmed my "nagging feeling", but the second quote shows that you have found a point where the actual boost can be displayed, AND the vacuum will be displayed on over run.
You have cracked it

Yes your right, however the DV is still plumbed in to the other hose so if it wasn't reading a vacuum then there isn't one making the DV work.... what to do next? Well I guess I start by undress the spaghetti that's there now and see what leads where.

Just to check from the manifold there should be two hoses one to the DV and one to the MAP sensor. Then from the v6 plenum to the ?
Cheers

Jon

Yes your right, however the DV is still plumbed in to the other hose so if it wasn't reading a vacuum then there isn't one making the DV work.... what to do next? Well I guess I start by undress the spaghetti that's there now and see what leads where.

Just to check from the manifold there should be two hoses one to the DV and one to the MAP sensor. Then from the v6 plenum to the ?
Cheers

Jon

Morning Jon

Yes that thought struck me last night, but I refrained from mentioning it then, as I could see us going on all night , and my Ovalteen was getting cold
I am glad I did`nt mention it then, as it appears that you understand the system now a bit better, and you have worked it out for yourself, which must be a good thing
When you are at Croix, it might be worth having a look at another Turbo, and follow the actuator pipe from the DV to where it connects to the manifold, if it can be seen under all the bits and pieces

John

YOUR GOING TO LOVE THIS!!!

My session finished a little early so i thought i'd get home and have a look at what was going where whilst it was still light, pulled a few hoses about and discovered the following:

The DV had been plumbed in to the V6 plenum all along which had been blanked off after the turbo/chargecooler fit so god knows how long that had been like that!

The DV outlet on the manifold was plumbed into the MAP sensor.

The V6 plenum was plugged into the thingy next to the coil (round).

How the hell was it still running?!!!

I've now plumbed the DV in properly with the boost gauge T'd off it and fitted the V6 to the "Thingy (round)"

The Map sensor is now also wired in properly.

Just out of interest does it matter which outlet the MAP sensor and the DV come out of on the manifold?

Started her up and you could tell the ECU was having fun trying to get to grips with all the new feeds, after a short time though an easy idle ensued.

Took it for a spin in rush hour traffic and it seems that for the first time i can use all the throttle pedal travel to control things rather than all the sensitivity being at the top of the pedal travel. Not sure about anything else cause the traffic was so bad but she idles well and the vacuum pressure is still 16Hg so there's a leak or two still somewhere.

So there we are mystery solved, thanks for all your help.

Cheers

Jon

PS strange how no one noticed before.....

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