LB7: Drive Pressure Gauge Going Crazy

[bullfrogjohnson]

We just put a DP guage in 02bigstrokins truck this past weekend for his new twins. We have set the guage up like everyone else does theirs but when the motor gets in higher rpm the needle goes crazy. The needle will follow boost up until about 30 psi then the needle goes nuts. We have swapped guages and nothing changed. It did this with the stock turbo and also does this with the twins.

Any ideas?

 

[LarryJewell]

adjust the vanes more open as you progress in the upper rpm range, the stock tune has really high drive pressure in it, you need to adjust both the max vane and target vane tables.

 

[sweetdiesel]

adjust the vanes more open as you progress in the upper rpm range, the stock tune has really high drive pressure in it, you need to adjust both the max vane and target vane tables.

How do you adjust them on a lb7 ......with a pipe wrench?


Maybe the line to the gauge is leaking? or plugging up with soot and then releasing?

maybe try using the DP gauge as the turbo gauge and see if its doing the same thing.

 

[LarryJewell]

How do you adjust them on a lb7 ......with a pipe wrench?


Maybe the line to the gauge is leaking? or plugging up with soot and then releasing?

maybe try using the DP gauge as the turbo gauge and see if its doing the same thing.

I just assumed it was a lly or lbz, guess you caught me with my pants down

 

[RENODMAX]

Did you run the line in a coil before the gauge?

 

[SmokeShow]

they also make little soot catchers/filters to put in there before the gauge.

Is it an electrical gauge or mechanical?

 

[sweetdiesel]

Kinda off topic ....But mine has frozon before from a lil condensation. I now have it facing upwards off the exhaust manifold so it will drain moisture.

I also only use about 8" of 3/8" tubing and the rest is hose, fwiw

 

[LarryJewell]

Mines a 4' section of brake line looped and hooked to a 6" braided line then the gauge sensor.

 

[DuramaxPowered]

Mines a 4' section of brake line looped and hooked to a 6" braided line then the gauge sensor.

Are you using an electrical sensor? If so, what type?

 

[sweetdiesel]

Are you using an electrical sensor? If so, what type?

Pretty much any type of electric boost gauge or air press.

Get atleast a 100 psi gauge

 

[bullfrogjohnson]

Mechanical guage with 3' of copper tubing with about another 6' of nylon line running to a trippin mount

 

[JOHNBOY]

Any chance it is reading correctly and your see what is happening because the air flow is overwelming the small IHI turbine and wastegate. Maybe time for an external gate.

 

[bullfrogjohnson]

The twins have an external gate, Its Tim Jackson old MPI kit off his dually. The watsegate setup is rediculously hard to get tuned

 

[LarryJewell]

Are you using an electrical sensor? If so, what type?

its a full sweep 100 psi autometer electric fuel pressure gauge

 

[Fingers]

I think what he is talking about is the needle twitching like crazy. You will get that if you have the tap lined up with one of the exhaust ports. Either move the tap to reduce the pulsing, or add some more line between the tap and the gauge to dampen the pulses.

 

[dmaxvaz]

the twins have an external gate, its tim jackson old mpi kit off his dually. The watsegate setup is rediculously hard to get tuned

i just left my stock wastegate alone and it works fine. My guage was doing this when i had the banks big head wastegate.