Weird idea, feel free to make fun of me.

[Captainlvsac]

Would unplugging my 3 port ECBS limit me to wastegate pressure? Would this throw a code or be otherwise bad for my engine?

 

I am in the final stages of getting my car together for a tune, and I am trying to drive it around like a camry until I get it on the Dyno. After installing the catless upipe and perrin downpipe, the thing has become much harder to keep out of boost. The VF52 builds around 2300 rpm, so I am constantly modulating the throttle to keep the boost as low as I can.

 

Today, it went into limp mode (Probably false knock from the extremely loud and annoying exhaust rattle) and it was so much easier to drive. It runs just like a healthy NA car.

 

So it got me thinking, how great would it be to be able to switch it into limp mode on demand. It doesn't have to be limp mode either, just limiting it to waste-gate pressure would probably do the same thing, right?

 

I could add a interrupt switch to the ECBS circuit, this would be the closest I'll ever get to the Mad-Max Blower on a switch.

[Cincy05LGT]

Removed

 

Reason: terrible advice

[utc_pyro]

Unplug the vacuum hose to the wastegate actuator, and cap off the line. Now you're on oem mechanical spring pressure. That's the least amount of boost you can run.

 

 

Dude. No. You just told him to blow his motor. This does the exact OPPSITE of that! It makes as much boost as the turbo will spool to without pressure pushing the wastegate open. We could bypass the EBCS but capping anything on a 3-port will lead to uncontrolled boost.

 

 

OP: your idea will work, but if IAM got so low to turn off boost control you really shouldn’t be driving the thing. If you want to force low IAM mode, start the car then connect the green programming connectors. You need to start it first, but as long as they are connected after that it forces IAM to 0. You can use this as a ghetto map switch as you described if your tuner sets it up properly.

[Cincy05LGT]

Apparently I need to reevaluate my understanding of how our boost control works...

[Captainlvsac]

 

 

OP: your idea will work, but if IAM got so low to turn off boost control you really shouldn’t be driving the thing. If you want to force low IAM mode, start the car then connect the green programming connectors. You need to start it first, but as long as they are connected after that it forces IAM to 0. You can use this as a ghetto map switch as you described if your tuner sets it up properly.

 

I'd rather just force 0 wastegate duty. Then I'd be able to do it on the fly. This is essentially what SI drive does, right? It just lowers the wastegate duty?

 

I read that SI drive doesn't switch any maps, just limits boost.

[Cincy05LGT]

Testing my newfound understanding after reading Cobb's technical piece on Subaru boost control... Would connecting the WG actuator directly to the compressor housing effectively limit boost to spring pressure? What would need to be done with the vacuum hose coming from the ebcs?

[utc_pyro]

I'd rather just force 0 wastegate duty. Then I'd be able to do it on the fly. This is essentially what SI drive does, right? It just lowers the wastegate duty?

 

I read that SI drive doesn't switch any maps, just limits boost.

 

SI drive just switches requested torque tables, but those cars do boost control based on requested torque so you can can set your tables up in such a way that it just switches boost levels. ‘05-‘06 does it based on throttle position, so it’s not as flexible.

 

The green connector method of dropping IAM also zeros WGDC. You can wire a switch/button to the green connectors to make it easily accessible.

 

You could also put a switch inline to just disconnect the EBCS, but you’ll ether have to switch to a dummy load or change the tune to not pop CEL’s.

 

Testing my newfound understanding after reading Cobb's technical piece on Subaru boost control... Would connecting the WG actuator directly to the compressor housing effectively limit boost to spring pressure? What would need to be done with the vacuum like coming from the ebcs?

 

Yep, that’s how you do it. You can just leave the EBCS hoses dangeling, the amount of air they’d leek into the inlet when the ECU request WGDC is negllable.

 

I think this is what you were trying to say in the first place, but the way you described would have lead to a bad day. I actually had this happen when a vacuum tee melted. The tune was extreamly conservative so it didn’t end up damaging anything, but hitting boost cut at part throttle was kind of scary.