What is the REAL stock boost of RB20DET? 7, 10, 12??

[s13_240_rb20]

There are too many different answers on the internet. Will someone please clarify and explain why every person has a different answer?

--TJ

***btw, My gauge is "tee'd" in inbetween the intate arm and the nipple on the back of the intake manifold, and I have always gotten 7 lbs tops. Also, my engine is out of a 1993 Skyline GTS-T. I also don't know my my engine came with a HKS bov installed (as seen in my signatute pic) and I have no idea what my wastegate even looks like to try to see if it is stock...lol

[l0nestar]

As you have been told multiple times, stock WGA pressure is ~ 10 PSI ( 0.68 bar).
It's in the FSM.

[s13_240_rb20]

As you have been told multiple times, stock WGA pressure is ~ 10 PSI ( 0.68 bar).
It's in the FSM.

but no one has explained to me why my gauge says 7psi. Can you help me with that one? My engine appears all stock except I can't figure out why it was imported with a HKS bov...

--TJ

[RustspecS13]

I a really common swap is an RB25 turbo. Like I said before it has a 7psi boost pressure.

Or you have a boost leak. Or your gauge in not accurate. Or your gauge is hooked up wrong. Try giving it its own source directly on the intake manifold.

Try blocking off your extra BOV and see if the stock one works, and doesn't leak.

PS stock boost is 10psi.

~Alex

[l0nestar]

The 25 WGA is 7 psi, the 20 is 10 psi.
A common budget upgrade is a 25 turbo with a 20 actuator.

[s13_240_rb20]

I a really common swap is an RB25 turbo. Like I said before it has a 7psi boost pressure.

Or you have a boost leak. Or your gauge in not accurate. Or your gauge is hooked up wrong. Try giving it its own source directly on the intake manifold.

Try blocking off your extra BOV and see if the stock one works, and doesn't leak.

PS stock boost is 10psi.

~Alex

My gauge seems quite accurate according to conditions and sounds. it sits evenly at -2 VAC at idle, and boost readings seem appropriate to the throttle-given and the subsequent "air-sounds".

On the intake arm, right beside the coupler to the throttlebody, there is a 3/4inch air line run to the AAC on the back of the intake manifold. A smaller air line comes off this 3/4inch line and goes to the back of the intake manifold (near the AAC adjustment screw). My gauge is "tee'd" in on this small line. Page EN-15 of my FSM calls this the "air regulator" line, and it comes off of the "aac" line....I am flipping through my FSM but don't see any page that says where the gauge hooks in at.

I do not see another location to put my gauge that isn't being used (the fpr nipple). Is there a location on the RB20DET that isn't being used that I just don't see? Got a pic of where you hook up yours?

Is there a way to see if I have the RB25 turbo without taking off the heatshield? I am afraid the old bolts will just break.

I have just blocked off the lines going to the HKS bov. Revving the throttlebody has a very slight delay in throttle response but then it still revs strong after that and air pressure is built and released (somewhere else) accordingly with the revving. I will take it out on a drive now and see what psi I can get with the HKS bov blocked off.

Be back soon.

[s13_240_rb20]

Yep. With the HKS hoses blocked off, I still top out at 7psi and it stops pulling around the top rpms....2nd will get up to redline but it takes forever and third tops out around 5200 rpms.

--TJ

[themadscientist]

As you have been told multiple times, stock WGA pressure is ~ 10 PSI ( 0.68 bar).
It's in the FSM.

but no one has explained to me why my gauge says 7psi. Can you help me with that one? My engine appears all stock except I can't figure out why it was imported with a HKS bov...

--TJ

Because your turbo is old as hell and that's all it pushes. It has been splained. It was imported with an HKS bov because at some point in its life someone installed one.

I've owned close to a dozen GTS-Ts with RB20s and the manual-stated and actual boost of good condition stock turbos IS .7 ish, about 10 lbs.