Hi there,
I have a question related to the turbo boost in Tdi engines.
For the first time since I have my Defender today I checked the turbo pressure of my VNT (TGV as it is known in Spanish) turbo.
The engine is an International Powerstroke 2.8L. It is installed in a year 2000 Defender 110 (former Td5). The engine has 130,000kms, it
has a moderately tweaked fuel pump (1.5 clockwise turns on the full power screw) , it runs well and has had no problems so far. I have
a small (same size as the original IC) uprated Allisport IC and new air hoses all around. I have an EGT gauge installed and with the current IP setup I have to control the throttle in order to keep the exhaust gas temperature below 700C.
The thing is that I have just found that my turbo is sending only 15 psi of air to the intake chamber (I am measuring the pressure
near the rear of the intake chamber or inatke manifold, don't know the exact name, where the 2.8 has a screw). According to the
International 2.8 L manual my turbo should deliver 1.2 bars of pressure (17.4 PSI), but apparently is is currently not achieving this
pressure.
When stepping hard on the throttle in fourth gear and going up a pretty significant slope, between 2500 and 3000 rpm (the conditions under
which I imagine that I should achieve full boost) I only get 15 constant PSI. Just after I step hard on the pedal it goes up to 16 or at
the best 17 psi but just for a fraction of a second (maybe for 1 sec?) and then it decreases to 15 PSI. I imagine that the 16 to 17 PSI
short peak in pressure must be the overboost stage that I have read about.
Given the description given above, do you agree that I should adjust (shorten) the screw in my VNT turbo in order to achieve the 17.4 psi
it should deliver? Or am I missing the point and the 17.4 psi (1.2 bars) that the engine's manual refers to is related to the overboost
pressure which I am almost achieving for a very short period of time? The manual states that 1.2 bars or 17.4 psi is actually the
"operation pressure" of the Garret GT 22 (56V) VNT turbo which I have.
My objective is to have the engine recieve the amount of air it is supposed to recieve (as from factory) or perhaps maybe a little bit more.
In this regard, any opinions as to Which would be the highest relatively safe operating pressure for my engine / turbo combination?
According to what I have read in this forum it appears that a maximum of 18 to 19 psi appears to be the consensus for the 300 Tdi engine.
What about the International 2.8 VNT turbo engine? The same should apply or slightly higher?
Perhaps Overlander and others have some experience to share related to the 2.8's turbo boost.
Thank you.
Regards,
Santiago
I have a question related to the turbo boost in Tdi engines.
For the first time since I have my Defender today I checked the turbo pressure of my VNT (TGV as it is known in Spanish) turbo.
The engine is an International Powerstroke 2.8L. It is installed in a year 2000 Defender 110 (former Td5). The engine has 130,000kms, it
has a moderately tweaked fuel pump (1.5 clockwise turns on the full power screw) , it runs well and has had no problems so far. I have
a small (same size as the original IC) uprated Allisport IC and new air hoses all around. I have an EGT gauge installed and with the current IP setup I have to control the throttle in order to keep the exhaust gas temperature below 700C.
The thing is that I have just found that my turbo is sending only 15 psi of air to the intake chamber (I am measuring the pressure
near the rear of the intake chamber or inatke manifold, don't know the exact name, where the 2.8 has a screw). According to the
International 2.8 L manual my turbo should deliver 1.2 bars of pressure (17.4 PSI), but apparently is is currently not achieving this
pressure.
When stepping hard on the throttle in fourth gear and going up a pretty significant slope, between 2500 and 3000 rpm (the conditions under
which I imagine that I should achieve full boost) I only get 15 constant PSI. Just after I step hard on the pedal it goes up to 16 or at
the best 17 psi but just for a fraction of a second (maybe for 1 sec?) and then it decreases to 15 PSI. I imagine that the 16 to 17 PSI
short peak in pressure must be the overboost stage that I have read about.
Given the description given above, do you agree that I should adjust (shorten) the screw in my VNT turbo in order to achieve the 17.4 psi
it should deliver? Or am I missing the point and the 17.4 psi (1.2 bars) that the engine's manual refers to is related to the overboost
pressure which I am almost achieving for a very short period of time? The manual states that 1.2 bars or 17.4 psi is actually the
"operation pressure" of the Garret GT 22 (56V) VNT turbo which I have.
My objective is to have the engine recieve the amount of air it is supposed to recieve (as from factory) or perhaps maybe a little bit more.
In this regard, any opinions as to Which would be the highest relatively safe operating pressure for my engine / turbo combination?
According to what I have read in this forum it appears that a maximum of 18 to 19 psi appears to be the consensus for the 300 Tdi engine.
What about the International 2.8 VNT turbo engine? The same should apply or slightly higher?
Perhaps Overlander and others have some experience to share related to the 2.8's turbo boost.
Thank you.
Regards,
Santiago
