turbo boost question - 300tdi

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nicks90
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turbo boost question - 300tdi

Postby nicks90 » Thu Jan 18, 2007 11:16 am

Hi folks,

came across an interesting suggestion on another forum a few days ago.
it suggested that you lose boost pressure from the turbo to the inlet valves due to restrictions and friction in the intercooler, pipes and due to bends in the pipes.
Soooo, my question is how much boost does get lost through the standard i/c and pipework on a 300tdi defender?

the turbo wastegate measures and controls the boost and is measured at the actual output of the turbo via a little pipe,
if the i/c etc loses 1 or 2 psi, is it worth taking the little wastegate pipe off the turbo and placing it on the intake manifold so that you get the full 18psi boost at the valves? Would it make much difference?
There is a little blanked off valve type "nubbin" on the intake that could be used, but before i start messing about - is it really worth it?




cheers
Nick


[sarcastic v8 owners need not reply 8) )
Bugger!
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Bobcat
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Postby Bobcat » Fri Jan 19, 2007 10:41 pm

If you havnt already done so, get a set of silicone hoses and stainless pipes.You will notice a difference,although not great.
I do know someone who ran a 300 at 30psi boost.It went like a rocket but not for long though. :cry:
You can turn the turbo up a bit without doing damage.My 200 has been running at 17psi for at least 70,000 miles mostly towing without problems.Standard boost is 13/14psi. :twisted:
Mark, Amanda & the mud monsters!!

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davew
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Postby davew » Sat Jan 20, 2007 11:16 am

Every time an inlet valve opens you will lose pressure at the manifold for the time it is open (the recovery time being effected by flow restrictions). My guess is that this is why someone measuring the boost at the manifold would see a 2 psi drop and they are wrongly interpreting that as a loss of pressure through the intercooler. What you need to measure is the pressure at the time the valve starts to open (when it will be at it's maximum pressure) rather than taking an average pressure over one cycle which will give a lower reading. Not easy to do as you'd need a very fast acting pressure sensor with it's output being digitally recorded - a "normal" mechanical boost gauge will have damping in it that produces an average.

I suspect there is a very good reason why the pressure is controlled at the turbo rather than the manifold. Think what would happen as, over time, the i/c gets more and more blocked by "gunge" restricting flow and decreasing the average boost. Having your pressure monitored at the manifold means that as the average boost pressure drops at the manifold the pressure at the turbo is increased to compensate... until the point at which the pressure at the turbo side gets so high that something goes bang !

I'd go with Mark - increase the pressure at the turbo but keep it regulated at the turbo. (Or fit a V8, obviously :twisted:)

nicks90
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Postby nicks90 » Tue Jan 23, 2007 9:56 am

never thought of it that way - makes sense though.

will look into getting some silicon hoses for it, supposedly calibra turbo hoses are all silicon as standard and the same width as LR ones, and there are plenty of them around the scrappies. Might have to have a rummage.
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dave willard
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Postby dave willard » Wed Jan 24, 2007 11:56 am

I am having the some thoughts on the 300 turbo boost

1
Do you need an accurate gauge, the cheapo compessor gauge may not be accurate enough, if fitted to the inlet manifold I would be temped to fit it & leave it in
2
It is difficult to get at the waste gate adjustment rod unlike 200tdi I have had my turbo recondiioned by Garret agent who stated that the boost pressure should be set on a test rig & only checked when on engine The setting entails taking mechanical movement measurrements as well as pressure
3
If you look on ebay using "300 TDI" search you will find an adjustable pressure regulator which regulates the pressure to the waste gate actuator connected by putting it in the actuator feed pipe, effectivley dropping the pressure to the actuator which means it will not operate until a higher pressure is reached.
This can be fitted inside the landie so in conjunction with a gauge you can set the boost as you drive for different conditions This costs about £25 (buy it now)available from uk & US suppliers
I am thinking of trying this using it with an accurate gauge You can easily remove it so return to std settings

4 I have found is a leak in the pipe going to the injector pump caused by the plastic pipe splitting. In theory the waste gate should compensate but made a difference when it was replaced. the leake was near the pump so perhaps the pressure to the boost mixture diaphram was low especially as the pipe has a small bore Note you could hear the leak which as expected sounded like a hiss when on load

Deve W

nicks90
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Postby nicks90 » Wed Jan 24, 2007 12:45 pm

If you look on ebay using "300 TDI" search you will find an adjustable pressure regulator which regulates the pressure to the waste gate actuator connected by putting it in the actuator feed pipe, effectivley dropping the pressure to the actuator which means it will not operate until a higher pressure is reached.
This can be fitted inside the landie so in conjunction with a gauge you can set the boost as you drive for different conditions This costs about £25 (buy it now)available from uk & US suppliers
I am thinking of trying this using it with an accurate gauge You can easily remove it so return to std settings


i have seen those before - but i would not fancy fitting one unless i had a very accurate exhaust gas temperature probe fitted into the exhaust manifold. the temptation to increase the pressure from the standard 18psi to 20+psi would be great, and unless you could keep a VERY accurate eye on these temps (possibly with warning lamp setup) your EGT could skyrocket and melt important bits.

I think i'll leave the boost alone for now and jsut look at improving flow with some silicone hoses.
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dave willard
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Postby dave willard » Wed Jan 24, 2007 1:29 pm

I have reached the same conclusion. you could remove the turbo & have it set up on test rig which with inspection fitting new seal costs about £120

On silicon pipes I still have the std ones which dont leak as there is no oil present on any joints ??
They all put oil thro the system from breather etc
Why should silicon improve things if not leaking? I dont know

Have you removed intercooler & cleaned it, I have, it didnt have much goo in it I soaked it in 100% engine degreaser for 24 hrs shaking it about every so often followed by flushing with hose, Important to dry it out to get rid of water I used fan heater

Other areas are
injection pump I had mine checked out by diesle specialist in wakefield 3 years ago they put it on test rig found low pressure to injectors due to broken spring in hi pressure pump
also the timing mey need resetting using two dial test gauges one to easily find tdc the outher to measure lift at the back of the pump at TDc easy to do I have the tools if you want to try it

If you want to compare the power by driving you can try mine which after rebuild etc should be as it should ( new head etc)problem is its auto so can ony compare on lock up above 48 mph let me know if you want to

Since my engine overheated due to the usual leak causing damage with no warning at all I now have a couple of probes measuring block temp incorporating a buzzer


Dave

nicks90
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Postby nicks90 » Thu Jan 25, 2007 12:05 pm

i have no problem with the amount of power it produces, certainly has a healthy amount of grunt with the egr blanked off and the exhaust boxes removed.
just always looking at freeing up a few more snorters from the engine without doing anything major. You know what landrover are like with diesels, always under-stress them just in case you dont have access to decent fuel while in the middle of africa!

but funds dont allow the fitting of a whacking big intercooler and major fuelling and turbo boost tweaks, so whittling away at little inefficiencies is all i can do for now.



as for silicone hoses, supposedly they free up a few horses and reduce turbo lag - as they dont balloon up under pressure and arent as porous.
Bugger!

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Bobcat
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Postby Bobcat » Thu Jan 25, 2007 4:09 pm

Nick unfortunatally youll want the stainless intercooler pipes as well as silicone hoses.They dont have the stupid kinks and sharp bends that the landy ones have.Thats what gives a better flow along with the silicone hoses which like you say dont balloon.
I think a ram air snorkel would help too.
Mark, Amanda & the mud monsters!!

TwoSheds
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Postby TwoSheds » Sat Jan 27, 2007 10:29 am

Bobcat wrote:I think a ram air snorkel would help too.

Interesting... I never thought that it would make much difference at Land Rover speeds. My home-made snorkel plan was to point the intake backwards to keep the rain out... Time for a re-think!
Has anybody tried it both ways? :lol:
Roger


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