Along with the various cam designs (overlap differences), the "location" of the gauge tap will also alter not only the overall boost number, but also the sensitivity of the needle movement. Everyone tapping from different locations is like measuring green apples to red. Still apples...just different.

As another did, I also tapped off of the "down tube", after the intercooler, (don't know the actual name of the cast tube). The trapezoidal block (machine stop) on the casting is a perfect place if not taking the front of the car apart to get at the intake manifold. Grind the casting flat, about .040" above the main surface. Make a diaper to catch chips. Drill - tap for an 1/8" pipe thread. Tap it deep enough so that minimal air is disturbed inside the tube when the fitting is installed. Install a 90 degree fitting, install the nylon tube fitting into that...connect to the gauge.
That tube or the intake manifold itself is the best/most accurate place to tap off of.

Also, for this discussion, the more exhaust system back pressure, the higher the intake pressure will read. More freer flowing exhaust systems, will show slightly lower intake system pressures. Kinda falls right behind the way the cam effects system pressures.

So again, comparing intake systems (blower boost) pressures, one car to another...just doesn't work. Most everyone's combinations are...different..!

Mike

 

 

it's because your blower is dead

 

could be? I thought that was normal for a factory jcw setup, but I'm not worried about it, no abnormal noise and no wear noticeable when I changed the oil

 

13.5psi is normal anywhere near sea level. You can do the calcs for altitude

 

I might have got my cars mixed up, no boost gauge on it to tell now

 

I was finally able to read boost this afternoon as I got a quality OBD bluetooth dongle and used the Torque app.

I'll be putting in an analog boost gauge in the near future though.

My max reading was 15.8psi.

2006 JCW with stock pulley, 2% WMW crank pulley, Detroit Tuned bpv

Would be curious to hear people vacuum readings also.
At idle mine fluctuates between 19.0 - 19.6 inHg

 

So...bluetooth and torque app, the highest I normally have is just over 12. When I went "down the hill" to sea level, I was close to 14; unfortunatly i wasnt logging so i dont know what it actually was.

2004- 200 JCW
mods-back of airbox cutout
Cravenspeed lightweight 0% pully
VGS mod

114k on the clock

 

I think anything at or over one BAR (14.7 psi) or if you are a pilot you recognize it as (29.92 inches) is great..

For more usable pressure I'm a +1 for hoses and clamps.

Motor On!