Boost pressure from turbo out let it intake manifold

Liam bird · Dec 10, 2019

Hi just been reading about we’re you take boost pressure for IP and found this ?

“mine, having done the intercooler and FiP pin and max fuel screw mods this matched the pressure and saw a jump from 0.9bar at manifold (std wastegate setup) to 1.3 bar at manifold, taking wastegate feed from inlet, under full boost. it was quicker off the mark and used less fuel.

The second part is the FiP pin which moves down under pressure.

The greater the pressure the further the pin moves down and then the higher the fuel delivery.

In standard this pressure feed comes from the same pipe as the wastegate pipe (its T'd in)

If you leave this feed here it means the FiP diaphragm will move down as the turbo instantly produces pressure.

If you moved this feed to the inlet manifold it would produce pressure and move the pin down still but the pressure would be less compared to the pressure at the original 'T' piece, due to losses in the pipework (from tubo to intercooler)

So to give the vehicle more low down you need to make the FiP pin move down asap, so therefore keep the FiP feed direct off the turbo”

This goes opposite to what I have been lead to belive and my 300tdi is taking pressure from the back of inlet manifold ?
So it’s turbo actuator to intake manifold to IP via a T in boost gauge.
OR
turbo actuator to outlet of turbo to IP via boost gauge .

from your findings what’s the best way cheers .

neilly · Dec 10, 2019

Liam bird said:
Hi just been reading about we’re you take boost pressure for IP and found this ?

mine, having done the intercooler and FiP pin and max fuel screw mods this matched the pressure and saw a jump from 0.9bar at manifold (std wastegate setup) to 1.3 bar at manifold, taking wastegate feed from inlet, under full boost. it was quicker off the mark and used less fuel.

The second part is the FiP pin which moves down under pressure.

The greater the pressure the further the pin moves down and then the higher the fuel delivery.

In standard this pressure feed comes from the same pipe as the wastegate pipe (its T'd in)

If you leave this feed here it means the FiP diaphragm will move down as the turbo instantly produces pressure.

If you moved this feed to the inlet manifold it would produce pressure and move the pin down still but the pressure would be less compared to the pressure at the original 'T' piece, due to losses in the pipework (from tubo to intercooler)

So to give the vehicle more low down you need to make the FiP pin move down asap, so therefore keep the FiP feed direct off the turbo.

This goes opposite to what I have been lead to belive and my 300tdi is taking pressure from the back of inlet manifold ?
So it’s turbo actuator to intake manifold to IP via a T in boost gauge.
OR
turbo actuator to outlet of turbo to IP via boost gauge .

from your findings what’s the best way cheers .

I have a hybrid turbo, pinned , ringed, tuned pump and a thicker IC, plus a twin inlet manifold. I run 27~28PSi .

I have 2 turbo gauges fitted, one on the line from the turbo to the wastegate and one on the inlet manifold.
I see a maximium delta between both of approx 1~ 1.5PSI, if that, and yes I have swapped the gauges to make sure one does not read low. The turbo to wastegate line one measures the higher of the two, there is no difference in the ramp up of pressure between the two.

Cheers

Liam bird · Dec 10, 2019

neilly said:
I have a hybrid turbo, pinned , ringed, tuned pump and a thicker IC, plus a twin inlet manifold. I run 27~28PSi .

I have 2 turbo gauges fitted, one on the line from the turbo to the wastegate and one on the inlet manifold.
I see a maximium delta between both of approx 1~ 1.5PSI, if that, and yes I have swapped the gauges to make sure one does not read low. The turbo to wastegate line one measures the higher of the two, there is no difference in the ramp up of pressure between the two.

Cheers

Thanks for quick reply,
so there pretty much the same give and take , am a right to think for quicker fuelling in low down take off it would be best to switch back to turbo .

neilly · Dec 10, 2019

Liam bird said:
Thanks for quick reply,
so there pretty much the same give and take , am a right to think for quicker filing in low down take off it would be best to switch back to turbo .

I left mine on the turbo / wastegate pipe, as it is where it was designed to be. Also LR use this point to set up and check the turbo pressure.
I fitted 2 gauges too:

a) check the pipework is all OK and I am not losing any pressure in the pipes or IC due to a hole.
b) check to see how much loss I actually got, in real terms it is sweet FA.
c) because I was bored.
I see on quite a few FB pages people stating the turbo gauge should be on the inlet and the FIP should takes its input from there, But I really do not think it makes any real world difference from what I have seen.

Cheers

EeEk · Dec 10, 2019

On my last 300tdi I had similar mods...blocked the wee wastgate pipe at the turbo and plumbed it to the rear of the inlet manifold. Had a boost gauge connected on to the pipe that supplies boost pressure to the top of the pump. a couple of inches back from the pump....the gauge didnt show any loss of boost pressure...but then again there was hardly any extra pipe it was just plumbed differently.

Liam bird · Dec 10, 2019

neilly said:
I left mine on the turbo / wastegate pipe, as it is where it was designed to be. Also LR use this point to set up and check the turbo pressure.
I fitted 2 gauges too:

a) check the pipework is all OK and I am not losing any pressure in the pipes or IC due to a hole.
b) check to see how much loss I actually got, in real terms it is sweet FA.
c) because I was bored.
I see on quite a few FB pages people stating the turbo gauge should be on the inlet and the FIP should takes its input from there, But I really do not think it makes any real world difference from what I have seen.

Cheers

ok thanks for clearing that up going to check and clean IC out and check for leaks in the whole system , then change and tidy up all pipe work and vacuum piping and see how she goes .

neilly · Dec 10, 2019

Liam bird said:
ok thanks for clearing that up going to check and clean IC out and check for leaks in the whole system , then change and tidy up all pipe work and vacuum piping and see how she goes .

If you are playing with the fuel / turbo / etc, then make sure to fit a EGT gauge. They can get hot , too hot real quick.

Cheers

Liam bird · Dec 10, 2019

EeEk said:
On my last 300tdi I had similar mods...blocked the wee wastgate pipe at the turbo and plumbed it to the rear of the inlet manifold. Had a boost gauge connected on to the pipe that supplies boost pressure to the top of the pump. a couple of inches back from the pump....the gauge didnt show any loss of boost pressure...but then again there was hardly any extra pipe it was just plumbed differently.

that’s how mine is now , just reading that post I posted on hear made me question things .

Liam bird · Dec 10, 2019

neilly said:
If you are playing with the fuel / turbo / etc, then make sure to fit a EGT gauge. They can get hot , too hot real quick.

Cheers

I have one coming in the post thanks . Just seems gutless pulling away. I have a uprated boost pin in but won’t change settings till I can read egt temps

neilly · Dec 10, 2019

Liam bird said:
I have one coming in the post thanks . Just seems gutless pulling away. I have a uprated boost pin in but won’t change settings till I can read egt temps

Did you adjust the top smoke screw , it is the one under the cap on top of the pump, this adjusts the fueling before the turbo starts working.

There are a few good vids on youtube showing an ozzy adjusting his FIP.

Cheers

Liam bird · Dec 10, 2019

neilly said:
Did you adjust the top smoke screw , it is the one under the cap on top of the pump, this adjusts the fueling before the turbo starts working.

There are a few good vids on youtube showing an ozzy adjusting his FIP.

Cheers

Not yet. I have a few jobs to finish first going to change engine oil , diff oil and transfer box oil . Grease the prop-shaft UJ’s and have a new battery to fit as well as changing or adding to the grounds and battery cables to starter and actuator . Tricky these p38’s with voltage and battery drain.
I will get round to posting my figures from the electrical guide once all complete

Liam bird · Dec 10, 2019

Liam bird said:
Not yet. I have a few jobs to finish first going to change engine oil , diff oil and transfer box oil . Grease the prop-shaft UJ’s and have a new battery to fit as well as changing or adding to the grounds and battery cables to starter and actuator . Tricky these p38’s with voltage and battery drain.
I will get round to posting my figures from the electrical guide once all complete

then onto the IP tweaking . Hopefully she be good to go

neilly · Dec 10, 2019

Liam bird said:
Not yet. I have a few jobs to finish first going to change engine oil , diff oil and transfer box oil . Grease the prop-shaft UJ’s and have a new battery to fit as well as changing or adding to the grounds and battery cables to starter and actuator . Tricky these p38’s with voltage and battery drain.
I will get round to posting my figures from the electrical guide once all complete

A 300tdi in a P38?

Cheers

Liam bird · Dec 10, 2019

neilly said:
A 300tdi in a P38?

Cheers

Bought it this way it’s not to bad to be fair

Liam bird · Dec 15, 2019

neilly said:
A 300tdi in a P38?

Cheers

just me again matey just wanting to clear a few things up . I have changed all oils and ready to pipe up the vacuumed boost pipes , as mine is all ready from the intake plenum and there is no noticeable difference from either turbo or plenum I am going to stick with the plenum .

So this is right yeh ?
Actuator running up to inlet plenum, from plenum straight to the injection pump with a T put in that pipe running to boost gauge.

ok if that’s the right set up I have 2 ways I can do this.
I have 2 tapped inlets into the plenum intake, one at the back we’re most ppl use and one directly in the side between the 2 split intakes see attached picture

Could I join these 2 inlets and send them down to the actuator as one pipe then off to Injection fuel pump for a better overall reading with boost gauge T in.

Or am I better to use the middle side inlet for boots the to fuel injection pump and actuator leavening the boost gauge out this set up .

And run the boost gauge on its own from the rear inlet .
Cheers Liam

neilly · Dec 15, 2019

Liam bird said:
vacuumed boost pipes

Hi, they are not vacuum boost pipes as they have positive pressure.

Liam bird said:
Could I join these 2 inlets and send them down to the actuator as one pipe then off to Injection fuel pump for a better overall reading with boost gauge T in.

No point in joining the pipes together from the inlet manifold.

Liam bird said:
Or am I better to use the middle side inlet for boots the to fuel injection pump and actuator leavening the boost gauge out this set up .

Yes, use one for the turbo actuator , take the turbo gauge from this one. at least you will know the pressure going to the actuator.

Take the other outlet from the inlet manifold to the FIP.

Cheers

Liam bird · Dec 15, 2019

neilly said:
Hi, they are not vacuum boost pipes as they have positive pressure.

No point in joining the pipes together from the inlet manifold.

Yes, use one for the turbo actuator , take the turbo gauge from this one. at least you will know the pressure going to the actuator.

Take the other outlet from the inlet manifold to the FIP.

Cheers

thanks neilly will sort this tomorrow . And true al drop the vacuum name ha .

Liam bird · Dec 15, 2019

Liam bird said:
thanks neilly will sort this tomorrow . And true al drop the vacuum name ha .

3.2 I’d fuel line will be good for this ?

neilly · Dec 15, 2019

Liam bird said:
3.2 I’d fuel line will be good for this ?

I cannot remember the size, but I used reinforced fuel line from Halfords.

Thanks

Liam bird · Dec 15, 2019

neilly said:
I cannot remember the size, but I used reinforced fuel line from Halfords.

Thanks

Cheers fella

Boost pressure from turbo out let it intake manifold

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