Stock boost control functionality

[Kaldek]

Hi folks, I'm still new to the VR4 and so I wanted to ask some questions that don't appear to be answered anywhere else.

Stock boost control
It looks like the stock car just uses mechanical boost control (i.e. wastegate spring) to control the boost. There is no electronic boost controller in the stock ECU (unlike, say, my XR6 turbo), and the ECU has no view of the boost pressure, just the airflow. Correct?

Boost cut/Fuel Cut
Given there isn't (I assume) an electronic boost controller, the boost cut is a function of the ECU airflow tables. Once you head too far "outside the box" - so to speak - the ECU cuts ignition. Correct?

 

[fieldy107]

ECU does control boost via a solenoid. Waste pressure is about 6-7 psi I think and ECU usually set at around 9-10 psi. If you get the ECU tuned you can remove boost cut and run up to around 18 psi depending on supporting mods.

 

[Kaldek]

Great, good to know. Second question - where is the stock solenoid located? The car currently has an Apexi AVC-R fitted and I've disabled all the boost maps in it, so to my mind that means I need to have the stock boost controller connected otherwise boost will be a tad sluggish, right?

 

[Kaldek]

OK I think I found the solenoid and Boost sensor. About three inches below the throttle body, and slightly towards the front of the motor. Looks like two separate devices, connected in a daisy chain.

Seems like the boost solenoid has no vac hoses heading to it, but the boost sensor does - probably to stop it throwing a code.

 

[VOLK]

Two solenoids in that spot, front is ebc, rear is fpr. Boost cut is load and duration dependant. This might shed some light on the situation, I've posted a vac diagram in here. http://www.ozvr4.com/threads/how-to-fit-a-3-port-boost-control-solenoid.12042/

 

[Guest]

English version of same diagram, also with notes for plumbing in an EBC.

Plus my own simplified diagram for fitting an EBC. The pressure source for "to boost controller" is Tee'd into the hose just behind the throttle body on this diagram, but many people opt to take it from the rear centre of the plenum instead.. same thing, but you can hide your handiwork easier on the front hose

 

[Kaldek]

Right so I need to get cracking because the FPR isn't connected to the fuel solenoid and I've gone back to stock regulator.

 

[Kaldek]

OK so the fuel regulator solenoid just forces enrichment when cold. Car is going in for roadworthy tomorrow and pulling all the plumbing apart is not in my schedule today! Went to the AVC-R, set it to 8.5psi boost and 50% duty cycle, stuffed all the kit back up into the dash out of sight.

I warmed up the engine and too the car for a quick spin around the block. Even on 8.5psi this thing pulls HARD. Waaaaay quicker than my BF XR6 turbo.

 

[VOLK]

Bumps rail pressure for cold and warm start.

 

[Kaldek]

Bumps rail pressure for cold and warm start.

Indeed? Must admit it's not something I'm used to seeing. Does the Magna do it?

 

[VOLK]

Not sure, never got into 6G stuff much or Magnas at all. Check the vac line to the fpr on your TL?

 

[Kaldek]

I must admit, this is the weirdest engine start enrichment method I've seen in a while. Most stuff I'm familiar with is just based on a combination of IAT and ECT data.

 

[VOLK]

Think it's used as an analogue adder of sorts, keep IDC around mid-range but add enrichment. Piqued my interest a while back, turns out fpr vac solenoids are fairly common.

 

[Kaldek]

Think it's used as an analogue adder of sorts, keep IDC around mid-range but add enrichment. Piqued my interest a while back, turns out fpr vac solenoids are fairly common.

I'll probably find both the Magna and the XR6 do it. Have never had to dig into the Ford since I bought it; she's been super reliable. Aside from the constantly warping from rotors, anyway.

 

[VOLK]

Ever since the BA they've high/hot spotted rotors like they're going out of fashion. Barra Turbo is top notch, the car it's in, not so much.

That being said, I'd own an F6 Typhoon, they're mental.

 

[Keheetit]

Old post but didint want to make new topic, anyone know can you remove fuel pressure solenoid and original wastegate solenoid from wiring or does it give fault code?

 

[mezje]

Old post but didint want to make new topic, anyone know can you remove fuel pressure solenoid and original wastegate solenoid from wiring or does it give fault code?

I am fairly confident it won't. I have neither.

 

[themuss]

English version of same diagram, also with notes for plumbing in an EBC.

View attachment 22528

Plus my own simplified diagram for fitting an EBC. The pressure source for "to boost controller" is Tee'd into the hose just behind the throttle body on this diagram, but many people opt to take it from the rear centre of the plenum instead.. same thing, but you can hide your handiwork easier on the front hose

View attachment 22529

Makes no sense wouldnt that be changing the fpr solenoid vac not the boost?