RB25 vacuum / boost sensor

[NPux]

Hi everyone,

I found in the FSM for the RB25DET that one of the vacuums from the intake manifold has to connect to a boost sensor. Of course, my clip didn't come with any. I'd like to know where you guys connected that vacuum and what you did with it. I took a picture of it:



Also, do you have any suggestions of a good place on the piping to connect the vacuum to the wastegate?



Thank you very much.

[ninety1two40]

The vacuum line fitting that you circled goes to the brake booster. The smaller vacuum line fitting below the larger one went to the stock boost sensor (almost 100% positive on that)

[Darius]

Right on.

The two lines that are in the circle on the bottom pic are the lines that go to the boost solenoid. The one from the crankcase ventilation pipe will see vacuum and the main line that is circled is what is used to control the internal wastegate. I have the boost solenoid if you need it, $5 plus shipping.

[NPux]

Thanks a lot. Darius, I'm interested for the boost solenoid. Let me know how you want to do the transaction, I got Paypal. My email is [email protected]. Thanks.

[FriedEGs]

interesting.. can someone tell me where this boost sensor is located? the line off the intake manifold on my car is open..

Was this something mounted to the firewall that sends the signal to the ecu?

[BoostFab]

the first picture circled is for the brake booster;

the second picture; the wastegate actuator source is connect to the small metal hose that's next to the L inlet (if you want to bypass the stock boost-limiter; and run a boost controller). there's a pair, if you look at the L inlet that's over the motor; the other one goes to the carbon canister.

btw! the stock boost solenoid is for boost cut/limitter...if you plan on running more than stock boost, you dont need it.

[FriedEGs]

can anyone tell me where the stock boost sensor is located? and what it looks like?

[ninety1two40]

This is the only picture I have of the sensor right now:



The blue hose goes from the intake manifold to the sensor.

[l0nestar]

I would post a pic of it, but I lost my digi cam

[nizmo zilvia]

I dont think I have this boost sensor. What does it look like? And if not hooked up what does it cause?

[KATVERT]

This is l0nestar,

I realized I could use the cam on my phone and upload it from there. Excuse the quality of the pix -- Moto Razr :-\ HTH, enjoy.

[nizmo zilvia]

Yea I dont have that. I've been driving with out it. What does that do?

[Abdo]

yea, I'm not even using the stock boost solenoid.

[l0nestar]

And as both of you can see, mine is still attached as well.. *grin*

[wantsansr]

any exact location for this sensor i cant find it on my rb20. and i am experiencing what seems to be a miss at WOT but only in the high rpm range.

[Kansei240sx]

not having that thing wont cause a miss... The boost sensor is as good as garbage.

[rbsileighty]

I know this thread is kind of old... but found some useful/related info on this topic:

I'm trying to find a way to make my PFC Boost Control kit to work with my AP Engineering RB20 PFC... and I found this:

http://www.skylinesaustralia.c....html

Then looking around some more found this on the location:

http://www.gtr.co.uk/forum/upl....html

The pictures in this thread are better... but this is all good info

If I can finish my house sometime this winter… I'll let everyone know if it works (unless someone else has tried this already)
Modified by rbsileighty at 5:17 PM 2/15/2008

[RBSilvia]

sorry to bring back an old thread....

i also didn't get the factory boost solenoid with my motorset. what do you recommend using instead? I've got a bleeder type boost controller that i used on my last car, should i just use that? Or run no controller? (factory wastegate is set for 7psi correct?...that would be a little low)

please let me know what options i have without buying an expensive ebc

[s13point5]

i dont have the boost solenoid either. maybe that is what is causing my 10psi spike instead of holding the stock 7psi. i just have a vac house coming from my wastegate to the IM

[BoostFab]

if you don't have one just omit it. it's just a boost cut.

[Darius]

i dont have the boost solenoid either. maybe that is what is causing my 10psi spike instead of holding the stock 7psi. i just have a vac house coming from my wastegate to the IM

If you have a line from your wastegate to your IM, the only boost control you have is the "weight" of the spring to control it. If the turbo was bigger and the spring stiffer, you'd have a blown motor by now.

I'm surprised that this thread has gone so far as it has without someone catching this. The stock boost solenoid opens to allow the WG to see 7psi of boost instead of the 5 psi that it would otherwise see through the solenoid. With the boost solenoid connected but unplugged from the ECU, the most boost the engine will run will be 5psi. With it connected, the most the stock engine will run is 5 and stepping up to 7psi (not sure when though). With only the wastegate spring, it appears that you can only run 10 lbs (Thanks to s13point5 for that info ). With a boost controller, you can run anything that you set the controller for.

[Neejay]

I'm surprised that this thread has gone so far as it has without someone catching this. The stock boost solenoid opens to allow the WG to see 7psi of boost instead of the 5 psi that it would otherwise see through the solenoid. With the boost solenoid connected but unplugged from the ECU, the most boost the engine will run will be 5psi. With it connected, the most the stock engine will run is 5 and stepping up to 7psi (not sure when though). With only the wastegate spring, it appears that you can only run 10 lbs (Thanks to s13point5 for that info ). With a boost controller, you can run anything that you set the controller for.

I'm only running 5psi, but I do not have the boost solenoid. My wastegate/actuator's vacuum source is directly from the cold pipe nipple.

Anyone have any insight? With my research, this is the closest I've gotten to an answer.

[WhatsADSM]

I'm only running 5psi, but I do not have the boost solenoid. My wastegate/actuator's vacuum source is directly from the cold pipe nipple.

Anyone have any insight? With my research, this is the closest I've gotten to an answer.

Boost solenoid, are simply an electronic version of the mechanical boost controller (like the ball and spring type we are used to).

So the "boost sensor" that everyone is referring to in this thread is actually just a boost solenoid that allows the stock PCM to increase the boost a little bit more than the spring pressure of the wastegate solenoid.

So neejay in your case you have a 5 psi spring. If you add a boost controller (manual or automatic) in that vacuum line you can increase the boost pressure.

[Neejay]

Boost solenoid, are simply an electronic version of the mechanical boost controller (like the ball and spring type we are used to).

So the "boost sensor" that everyone is referring to in this thread is actually just a boost solenoid that allows the stock PCM to increase the boost a little bit more than the spring pressure of the wastegate solenoid.

So neejay in your case you have a 5 psi spring. If you add a boost controller (manual or automatic) in that vacuum line you can increase the boost pressure.

I really don't trust manual boost controllers. I'm currently looking for a RB20 actuator. I hate I wasted my dyno run on 5psi (231whp though). I now see why people always recommend a boost gauge with ANY turbo car.

[Neejay]

This brings about another question/inquiry: Without the boost solenoid, will the RB20 actuator still boost @ 10psi?

EDIT: r32's don't have a standard boost solenoid.
Modified by Neejay at 9:45 PM 3/4/2009

[CDub7]

I need some help please. . .

I am missing this vacuum hose i think it goes to the bov line and recirculates back in to the intake but im not 100% sure