question about this hose/line?

[anumeric]

Sorry if this is a dumb question but I had no luck searching. This line was already cut when I got the motor. But where does this line attach to, what is it, do I need it, and if not can i just cap it.

Thanks in advance.

[f s t caz]

mine's plugged into the inlet intake pipe, right around the pcv hose connector right above the ribbed section

[tattman77]

It is just a vac line. I disconnected it from both ends on mine. It connects in to one of the four lines between the 3rd and 4th runners on the intake manifold.

[dattodude]

Here comes the answer :-)

It's the vaccuum line that the ECU controlled boost solenoid bleeds pressure off from the vaccum line from between the turbo and the wastegate actuator. There is a metal t-piece it connects to above the turbo.

Factory Boost control? I hear you asking...

Yes, the ECU uses the 02 sensor and ping sensor to detect high octane fuel, it then switches to use a second fuel/ignition map to suit, and raises the boost by 2-3psi by fluttering a solenoid bleed valve to raise the boost.

Now you know. I don't believe the SR20DET has this feature.

Chris

[capwred]

^^^^ i do believe you are correct.lol

[anumeric]

thanks for the help guys, hopefully it wont be too much longer until my swap is finished.

[niscort]

Here comes the answer :-)

It's the vaccuum line that the ECU controlled boost solenoid bleeds pressure off from the vaccum line from between the turbo and the wastegate actuator. There is a metal t-piece it connects to above the turbo.

Chris

Very close, but not quite exact. Between the metal t piece and the intake connection after the afm the above happens, meaning the line is basically a waste line, where the bled off pressure from boost solenoid returns to the intake system. The line running behind the rear of the head is also a waste line returning bled pressure from the secondary intake butterfly control solenoid back into the intake system. It basically allows everything to be a closed metered system.

[sideways danny]

you're all close but it's not a boost solenoid. it's a hot start solenoid that fits inline to the FPR vacuum. it's to help prevent flooding the engine when starting it from hot. it's a useless piece of kit which should never be fitted as it makes the car run lean for 3 minutes from start-up

[biosehnsucht]

you're still only partially correct

On autos its for hot start FPR crap, but its also T'd over at the other end for the stock butterfly control. For manuals its only for butterfly control.

basicaly its a filtered, metered, but unboosted source of air for whatever the designers wanted iit for (butterfly control system, and on autos, fpr hot start crap)

See.

[niscort]

The hot start is a Euro thing when it uses the same solenoid as the boost control on the JDM version on the turbo side.

Even with the Auto version the line is still a return of air passed through the solenoids, which returns into the intake on the JDM versions.

[Ca_Silvia]

So can it can be blocked off or should it be ran to flow air back in to the intake pipe?

[niscort]

If you block it, the solenoids will be unable to vent/bleed any pressure rendering them useless. You can remove it and let them vent/bleed to atmosphere, just make sure you block the hole from the intake.