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Quick EBC Questions

Hi folks, i just pick up a Greddy Profec for my R32 GTR, and I have 2 quick EBC questions.

1) What is a good source for boost pressure (going to Profec's control solenoid)?  

The manual is showing to use a source between turbos and intercooler.  As far as I know there is no existing nipple between turbos and intercooler, but there is one on the underside of intake plenum, which is between intercooler and throttle body.  Is this where most of you tap in?  Or do you drill and tap a new nipple between turbos and intercooler?

2) Is it okay to unplug and bypass factory boost solenoid, and will it throw any code or affect engine operation?

Thanks in advance!

 

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1) Anywhere UPSTREAM of the throttle.  Ideally off the compressor cover, then the next best is hot side intercooler pipe.  I was going to say "NEVER from the plenum"...but then remembered that this is a GTR, the plenum IS upstream of the throttles, and that that is where the factory boost solenoid sources the signal from.

2) Yup.  ECU doesn't know whether it's connected or not.

I like running cold side for pressure source because it gives you better boost control (if you have pressure drops across the intercooler) however you tend to get a bit of spiking, which isn't the end of the world.

Yeah from what I read, there are some exceptions but most people utilize the existing nipple under the plenum.  So a follow up question on connecting the Profec control solenoid to wastegate actuators.

Is it better to run new hoses to wastegate actuators?  Or can I utilize the factory metal tube since it T's off to both actuators?

 

RB26VacuumDiagram.rev3.JPG

 

If I use factory metal tube, then I can mount the Profec control solenoid close to plenum and essentially T off the factory (green) hose.  I image factory metal tube would flow air better although travel path is longer.

If running new hoses to wastegate actuators is the better way to go, then mounting the Profec control solenoid closer to wastegate actuators would be better, correct?

There's no air flow.  Well there is a little, but the flow is from the boost signal source, through the solenoid and out to atmosphere.  That's why it's called a bleeder valve (when it is manual anyway, but the function is exactly the same).

The line from the boost controller to the wastegate actuator is just a pneumatic control line.  Pressure rises and falls.  A little air flows in to raise the pressure, or flows out to lower the pressure, but it doesn't actually "flow" through the pipe.

I am not sure EBC solenoid works the same way as a MBC bleeder, but either way I often read that shortening the lines as much as possible would reduce boost spike.

So I guess it's fine to place the Profec control solenoid at driver side and just utilize factory metal tubes.  I think that makes a cleaner installation than placing solenoid at passenger side and running new vacuum hoses.  

6 hours ago, TXSquirrel said:

I am not sure EBC solenoid works the same way as a MBC bleeder, but either way I often read that shortening the lines as much as possible would reduce boost spike.

 

They work EXACTLY the same way.  They are just a controlled leak that reduces the size of the pneumatic signal that reaches the actuator.  The only difference is that the EBC can offer changeable control through being able to run the solenoid differently under different circumstances.  The manual bleeder's behaviour is essentially fixed.

When i bought my car it came with a profec 2 mounted on the factory solenoid position, looking like it is using the same hoses! My mechanic told me it was wrong, however i elected to leave it as it seems to work fine, no spiking, off, high, low all perfect. can anyone shed light into why it would be better hooked up the 'proper' way

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