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View Full Version : RB25 swap... What is this?


Turb0wned
07-01-2013, 06:41 PM
Doing my RB25 swap into my S14 just waiting on a few more parts.

First what are these two things in the pictures?
Do I need them? If I don't do I cap the vacuum lines?

fliprayzin240sx
07-01-2013, 07:05 PM
I dont have it on mine so it couldnt be important. Where was it located?

Turb0wned
07-01-2013, 07:07 PM
I dont have it on mine so it couldnt be important. Where was it located?

First pic is by the turbo. Second is coming from a vacuum source from the back of the intake manifold.

Sileighty_85
07-01-2013, 07:26 PM
Left pics is stock boost controller, Right pic is Stock Boost sensor for the Cluster boost gauge.

Turb0wned
07-01-2013, 07:31 PM
So what should I do with the vacuum lines if I disconnect them? Where would be the proper place to run them?

I'm guessing the one on the right I can just run that vacuum from the back of the intake manifold to my boost gauge. But the other one? Their is some kind of vacuum source for it on the turbo side...

Sileighty_85
07-01-2013, 07:33 PM
Thats up to you, Your turbo needs a vac/pressure for the WG so if you dont run a line to the turbo WG it will over boost and grenade.

Search around and see what other ppl did.

Turb0wned
07-01-2013, 07:41 PM
Thats up to you, Your turbo needs a vac/pressure for the WG so if you dont run a line to the turbo WG it will over boost and grenade.

Search around and see what other ppl did.

Ok that factory boost controller... One vacuum line went to a nipple that is connecting to the factory intake, the other I'm guessing went to the waste gate and I see a tee in that line so it probably went to a vacuum source correct? If I get rid of that, the intake pipe can get capped and the wastegate can go to a vacuum source of my choice...

feito
07-01-2013, 07:50 PM
the boost solenoid gives u an extra 3 (?)psi at higher rpm's under load instead of the 5 the stock wg holds. The other one's for boost/vac sensor for the skyline's instrument cluster. You dont need either, but getting rid of the solenoid may confuse the ecu which is programmed to to work with both boost levels at a given rpm.

BadgerWorks
07-01-2013, 07:58 PM
that is correct sir. i dont know a single person that uses the factory boost solenoid.. just make sure the wg has a dedicated source unless running a boost controller of course. the factory boost solenoid brings you up to 10psi iirc. you could run a aftermarket controller, keep it at 7psi or run an rb20 wg. 20 gate is 10psi

Turb0wned
07-01-2013, 08:21 PM
the boost solenoid gives u an extra 3 (?)psi at higher rpm's under load instead of the 5 the stock wg holds. The other one's for boost/vac sensor for the skyline's instrument cluster. You dont need either, but getting rid of the solenoid may confuse the ecu which is programmed to to work with both boost levels at a given rpm.

I keep reading people saying so many different things... Some people say without it 7psi some say 5 psi. I read someone else say the manual rb25det will be at 7psi and the auto will be at 5.5 psi without it....

So I will not be about to up the boost with that waste gate even with a boost controller?

Turb0wned
07-01-2013, 08:23 PM
that is correct sir. i dont know a single person that uses the factory boost solenoid.. just make sure the wg has a dedicated source unless running a boost controller of course. the factory boost solenoid brings you up to 10psi iirc. you could run a aftermarket controller, keep it at 7psi or run an rb20 wg. 20 gate is 10psi

So the waste gate going to the intake manifold tee'd to the boost gauge will work properly?

BadgerWorks
07-01-2013, 08:27 PM
no. the boost controller is put inline with the wg line

BadgerWorks
07-01-2013, 08:27 PM
and the stock wg is def. 7.

Kingtal0n
07-01-2013, 08:37 PM
and the stock wg is def. 7.

If the RB25 is from a Laurel (not sure on spelling) then the oem wastegate is set to 3psi. just sayin'

Turb0wned
07-02-2013, 07:46 AM
What coolant temp sensor do I run? S14 like the SR20?

What gauge temp sensor?

OutToWinPAHC
07-02-2013, 08:00 AM
I have this on my r33 its not a boost solenoid, just what wakes vac/boost and turns it to a digital signal for the cluster to read.

Turb0wned
07-02-2013, 09:29 AM
What about this mess of tubes here... Can this stuff be deleted?

supersayianjim
07-02-2013, 11:50 AM
no, not if your running the stock turbo/maf setup.