Boost Gauge Installed - Photos and Question

I posted this topic over at another LR Forum, but since i live in the colonies, the other yanks couldn't help me with tdi questions! see below.

Per my signature. I have a '95 disco 200tdi. I just installed a VDO boost gauge ($30/amazon) low on the center console, and drilled/tapped into the intake manifold.
So far, i really like it. I'm waiting for my green light bulb covers so i can wire up the light on the gauge to match the rest of the vehicle.

It looks like i'm only getting a max of 10 psi. That is flooring it at about 3,800 rpm.

From what i've read, 15 psi is ideal, and what most people get. But most people seem to Tee into the rubber hose at the turbo/wastegate rather than drill/tap the intake. I wanted to know the boost at the engine, feeling it is more accurate, and more useful if i change up intercoolers in the future, etc. to see what change it is making.

Any thoughts? Does the intake pipe and intercooler reduce boost pressure as much as 5 psi?

cheers.

https://plus.google.com/photos/11766...28147162510193

No idea but I do know my 300 tdi is boosting to 22psi at the turbo

Quick google, standard is 0.8 bar at the turbo which is 11.6psi so 10psi at the inlet isn't bad

My 300 boosts 13 to 14psi at the top intercooler pipe on full throttle at any revs above 1500 ish.
Cruises about 6psi or less at 50mph on flat motorway

Maybe i should fiddle with the waste-gate actuator arm and see about getting a little more pressure.

Your readings at the top inter-cooler pipe should be the same as at the intake manifold. I may give the fuel pump a little turn as well.

I live in flat coastal Texas, but plan to hit up some serious mountains in Colorado this summer, so i'd like to tweak everything now, then get some miles under it's belt to make sure i don't screw up anything....

Boultman said:

Maybe i should fiddle with the waste-gate actuator arm and see about getting a little more pressure.

Your readings at the top inter-cooler pipe should be the same as at the intake manifold. I may give the fuel pump a little turn as well.

I live in flat coastal Texas, but plan to hit up some serious mountains in Colorado this summer, so i'd like to tweak everything now, then get some miles under it's belt to make sure i don't screw up anything....

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Good idea, if it is under fueled you will not get the boost, my boost went up on part throttle after I had given it a little more fuel.

I used the branch that goes to the disconnected EGR and connected a pipe to that with a reducer to feed the boost gauge.

You shouldn't need to alter the waste gate, correct fueling with provide the boost , yours may have been leaned off for emissions

I don't think there is an EGR on the 200s. Maybe I'm wrong. Mine doesn't.
The rover has been in Texas since the conversion (originally v8 auto. Only option in the states) and Tx doesn't have emissions on diesels. Thank goodness.
I also many to add an exhaust temp gauge eventually. Do you guys see any issue with running this thing at 75 mph for hours on end in the 100 degree F heat of the desert? I will be cruising through west Texas in July where the speed limit is 85 mph.

Boultman said:

I don't think there is an EGR on the 200s. Maybe I'm wrong. Mine doesn't.
The rover has been in Texas since the conversion (originally v8 auto. Only option in the states) and Tx doesn't have emissions on diesels. Thank goodness.
I also many to add an exhaust temp gauge eventually. Do you guys see any issue with running this thing at 75 mph for hours on end in the 100 degree F heat of the desert? I will be cruising through west Texas in July where the speed limit is 85 mph.

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I ran mine for hours at a time across Europe at speeds up to 85mph, granted it wasnt 100 degrees (it was Northern Europe) and mine is a 300tdi but as long as you keep an eye on the temp gauge then all should be well, after all i heard the 200tdi is better equipped in the cooling stakes than the 300, something about rad flow directions and the like i believe.

landowner said:

You shouldn't need to alter the waste gate, correct fueling with provide the boost , yours may have been leaned off for emissions

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Please explain how increasing the fuelling ups the boost pressure?

They are compeltely seperate things

IIRC the actuator has an adjustable arm so i would adjust it a turn at a time and see what changes you get, if you up the boost though make sure you adjust the fuelling as more boost on its own wont do much.

Generally you might see a 1psi drop in pressure from the turbo to the manifold depending on the condition of the pipes and the size of the intercooler.

You should take it off the turbo for a more accurate reading, the intake is wider and therefore your Reduce in pressure what with valves opening and closing its a turbo gauge not for a manifold gauge.

please correct me if i am wrong
but i thought to test the boost pressure
you had to be accelerating up an incline???
as i say i could be totaly wrong
regards
mike

Is it a rally car or a disco?

wiltshire landyman said:

Is it a rally car or a disco?

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I got a virtuel boost gauge , its called black smoke and lack of power

I added it so i can adjust boost and fuel a little a time and objectively see the increases in boost, if any. You don't need to be on an incline, but it has to be under load. I.e. driving to show boost. I know i could search some and find out, but do you guys have a rule-of-thumb ratio between actuator arm rotations and fuel pump adjustment screw rotations to keep things balanced? For example. turning the actuator arm two rotation and turning the fuel pump screw a 1/4 turn.... So i should only expect a 1 psi differential between the turbo and the manifold? I always read that it is a more accurate reading at the manifold, not the turbo. So you can see what pressure is entering the engine. Also, you can see any changes that occur if piping and/or intercoolers are changed??

turbo will boost as soon as you rev it ,vehicle stood is fine ,tdi isnt anywhere near a tuned engine just shorten the waste gate rod as much as possible (with arm removed from waste gate as diaphragm can be broken )

fireblade7 said:

please correct me if i am wrong
but i thought to test the boost pressure
you had to be accelerating up an incline???
as i say i could be totaly wrong
regards
mike

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Vehicle under load. Thing is most all US diesel vehicle have a boost gauge and EGT gauge as standard issue works very well so you don't over boost or fry your turbo. When you start maxing pressure and turbo temp you can back off the right foot a bit and not fook things up.

Mine will boost upto 30 psi before it goes into the red zone of 40psi and damage at 45psi

well, i get overboost situations with my seized wastegate valve being closed, and the edc ecu cuts the fuel off momentarily. this only happens when decking the throttle up steep inclines, so I think that's how it should be tested!

jamesmartin said:

turbo will boost as soon as you rev it ,vehicle stood is fine ,tdi isnt anywhere near a tuned engine just shorten the waste gate rod as much as possible (with arm removed from waste gate as diaphragm can be broken )

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Can you open that out with a bit more detail please ??

Boultman said:

I always read that it is a more accurate reading at the manifold, not the turbo. So you can see what pressure is entering the engine. Also, you can see any changes that occur if piping and/or intercoolers are changed??

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Taking a reading from the turbo will show you how much its putting out and taking it from the manifold will show you whats going into the engine. Both have the pros and cons.

Measure at the turbo and you wont know if you have a leak and only half of the pressure is getting to the manifold. Measure at the manifold and you might see a nice 14psi but you could have a leak and the turbo is working its tits off to try and maintain it.

A bigger intercooler can see a boost increase of 2-3psi although thats me coming from a petrol tuning background and not a diesel one

Boultman said:

https://plus.google.com/photos/11766...28147162510193

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Linky = not

tombardier said:

well, i get overboost situations with my seized wastegate valve being closed, and the edc ecu cuts the fuel off momentarily. this only happens when decking the throttle up steep inclines, so I think that's how it should be tested!

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you will but vast majority of 300 tdis and all 200 tdis arent edc so extra boost isnt going to have that effect just more power