Boost leak?

[drifter17a]

I had an old prosport which have used for years and i bought a greddy as controller but that soon became redundant as tuner used the link g4 boost solonoid so ecu is controlling it

 

i have paid for both so decided to keep both and what i have noticed is prosport reads 18 psi and greddy 15.5 so a difference of 2.5 psi

 

there is a vacume pipe after throttle body connected to both gauges and also blow off valve ( two tees)

 

could the tee be causing pressure drop?

 

Greddy used to read 17psi until below

my greddy controller was inside the hood with prosport sender but i relocated the controller to inside the car and run a vacume pipe through fw to it. Since then it is reading around 2 psi less

 

no leaks on inside hose to the greddy controller as when i blow ( no where close to boost level) but it is not leaking

thoughts?

 

also have bought a water injection which needs a boost source so planning to tee off the hose inside and connect it to it so in essense i will have 4 devices( two gauge, bov and water injector) running off that single vacumme

 

 

[Slap]

You can buy 12v boost switches cheap as on ebay and wire em to a relay. You can usualy adjust the switch to suite the psi you want, im sure you will figure how.

 

If the gauges are using the same source they should see the same.

A dedicated inlet source from the plenum is best so that the bov and tevs else ya got dont mess with it but ya can still use it if needed.

The extra length in the extended line may be absorbing some pressure before the gauge try a more solid line maybe. I cant see the tee interfering with the pressure reading much, if we were talking flow then yes.

Test it on a shorter line or in a parrelell setup out of the car if ya get me and you can.

The gauge may be dieing but doubtfull unless it was droped or something.

 

Good luck!

 

 

[Slap]

Oh and as i said in the other thread pvc can and usualy will cause a boost leak but probably not the issue here.

[GTSBoy]

Yuh, so long as there is no flow, there is no such thing as "pressure drop" in a pneumatic system.  There may be a slight delay in transmitting a pressure change from one end to the other (of a long hose) because you do have to blow a little bit of air into the hose to increase the pressure, but the speed of sound is like 1000km/h, so the delay is imperceptible.

I have a ProSport boost gauge and it routinely reads differently to the boost display on my Profec, both connected to the same source.  10+ year old pressure transducers cannot be expected to be 100% perfect.

If you are worried, borrow a high quality, recently calibrated manometer from someone and do a check/calibration of what you have so you know which one is closer to correct.  Keep in mind that the error of any pressure instrument can change from the low end of the range to the high end, especially if the error is some sort of zero-offset like my Pro-Sport has (it sits lower than zero with the power on but engine off).

 

Edited April 1, 2019 by GTSBoy

[GTSBoy]

3 hours ago, Slap said:

said in the other thread pvc can and usualy will cause a boost leak

PCV, just for the sake of correctness.  I read your post wondering why anyone would use PVC plastic in their intake tract on the pressure side, then I realised what you were talking about.  PVC<>PCV.

[Slap]

...my terminology is sometimes sickening. Sorry.