Turbo Vacuum Line Question

[cmanreinhart]

Alright so im coming to the end of my Xr project. And one of the things I have left to do is what I think are some Turbo Vacuum Lines? If anyone could point me in the right direction to where these go that would be great! And thanks in advance!

[Esteban]

Top pic: this is for cruise control. Can delete of cruise is removed.
Bottom pic, left: goes to factory Boost control solenoid.
Bottom poc, right: hard to tell from pic, is it on the large fitting that also goes to the valve cover breather? If so, mine was always blocked off.

[xrattiracer]

both of the bottom two go to the bcs. connect them together with a piece of hose to always have "high" boost.

[cmanreinhart]

Thank for the reply guys!
- So for the top picture I guess I can just plug it off sine I don't intend on using cruise control.
- Then for the bottom two I dont belive i have a boost solenoid... Would this be because my car was an Automatic before I switched it to a mannual? Do automatic cars not have boost solenoids?

[John Brennan]

They have them, but it was widely conjectured that they were disabled in the auto cars. If so, that seems silly, because they could simply have gone off wastegate spec for their 10 PSI.

[Ed Lijewski]

My two '88 autos had the OEM boost control solenoid.

YMMV

[cmanreinhart]

They have them, but it was widely conjectured that they were disabled in the auto cars. If so, that seems silly, because they could simply have gone off wastegate spec forr their 10 PSI.

My two '88 autos had the OEM boost control solenoid.

YMMV

Hmmmmmmmm, thats weird I never even remember pulling one of when I painted my engine bay... I did pick up a Mannual ECU how hard would it be to wire one in? And is there a way I can bypass system for a quick start up?

[Ed Lijewski]

They're mounted between the air box and strut tower-~2"Hx1" with two hose ports and a two wire connector. Tge wire harness may still be on your car...somewhere along the inner fender or lower toward the frame rail in the engine bay.

Google "Gillis boost control valve" re installing a manual one.

YMMV

[John Brennan]

All the auto cars had them; I had one new off the showroom floor in '88. If you look above, you'll see you can connect the two outlets at the turbo and get boost-- at least 10 PSI, perhaps more, if the orifices are sized rightly.

One thing the BCS may have done on the auto cars is delay the 10 PSI until certain RPM and other requirements were met to the PK1's satisfaction-- no other reason to have one, unless it was Ford's way of saying, "You can't handle the boost!"-- even just 10 PSI. It may be that Ford wasn't risking Mom and Pop having wheelspin/oversteer out of a corner, in combination with protecting the engine from possible harm from allowing even the 10 PSI if the EEC wasn't happy with things... who knows?

[Ed Lijewski]

It's very likely Ford via the PK1 was focused on sustaining the auto C3's reliability, i.e., Avoiding full boost 1-2 upshot if not also the higher rpm 2-3 shift.

Merkur Encyclopedia:
Wastegate

"Modifications: The EEC-IV uses the BCS (boost control solenoid) to limit boost to 10 psi under 4000 RPM. Adding an adjustment to the wastegate controller is fairly easy by disconnecting the vacuum lines from the BCS and connecting them will allow full boost at any RPM. Some vehicles need a small orifice to replace the BCS to limit maximum boost. A simple orifice is a metal tube with a crimp in it easily done with diagonal cutters.
The full boost limit is set by the orifice size ratio in the brass fitting in the compressor housing. This fitting has orifices that function as pressure dividers and control absolute boost levels. Drilling out the bypass orifice will increase maximum boost."

YMMV

[Jimroberts]

Hello Jimmy here new to ur site but have owned xr4s since 1995 wrecked my xr4 3 years ago have intercooler disconnected I think have criss cross vacuum lines I am really disappointed with myself