I searched and have been looking at the fsm, however I am having a hard time conceptualizing this one. I am installing an electronic boost controller in my s5 tII. What is the consensus on the duty solenoid? Keep it or get rid of it? It seems redundant with an electronic controller.

If I do get rid of it, would the lines that went to the solenoid be an acceptable vacuum source for my boost gauge? From the diagram it looks like the lines that go to the solenoid enter from the turbo inlet duct and exit to be tee'd between the compressor and wastegate actuator.

I have removed the air pump, and I am doing a custom turbo inlet duct for my bnr stage 2 turbo, but plan on keeping the acv and reconnecting everything as it was so it will make it easy to put the pump back in later if necessary. I am running the stock ecu and exhaust for now, minus the cat, and a greddy fmic.

Am I missing anything here?

 

the factory solenoid IS a boost controller, so you should disconnect it from the turbo. if you're on the stock ecu though you might want to leave it electrically plugged in, no code that way.

 

There won't be a code if it's disconnected, at least in my S5. Just take the "T" out and run one to the contoller and the other to the diaphram.

 

Thanks guys. I will defiantly take out the duty solenoid, and it seems like the location where the solenoid used to be would be a fine place to tap into for a boost gauge because it should still have vacuum running through it.

 

I'm not sure what you mean by this. Like most OEM boost control systems the boost control solenoid comes off a T from the compressor housing and vents back to the turbo inlet duct:



None of the boost control plumbing sees manifold vacuum so that's hardly optimum for a boost gauge.

 

best bet is to pull boost gauage/controller source from the nipple below the BAC.

 

"Defiantly" has a very different meaning than "definitely" haha. Are you running ANY sort of fuel enrichment with this setup?

 

Ok got it, for a boost gauage/controller vacuum source tap into the nipple below the BAC so the controller can see manifold vacuum. Thanks, thats the advice I was looking for. I see what you mean. I guess that it should be obvious that you would want to measure vacuum from the manifold in hind sight, but this is my first time dealing with a turbo system so its still a bit overwhelming. Any thoughts on capping the duty solenoid line vs looping it? I assume it wont make a difference...

Nope no fuel enrichment yet, but I do have a pressure relief valve that I am planning on setting to around 8 psi so I shouldn't be running too much boost for the stock maps. I'll set my max boost to 8 on my controller too, just wanted to get it installed while I do everything else. And yes, I know the controller wont lower my minimum boost level. My turbo has a ported wastegate too. Also installing a wideband so I can monitor afr. Anyone know what kind of duty cycle the stock injectors run at? How much more can you safely push them?

I was going to install my haltech and tune it, but I lost my job so I am just finishing up the project as cheap as possible for the time being. Got 4 720 cc injectors and a walbro fuel pump waiting to go in, but I realized I should install a fuel pressure regulator and maybe ditch the pulsation dampener when I do my fuel mods. So until I can save up a bit no fuel system mods or tuning.

 

Ack I should really turn off correct as you type spell check.

 

to disconnect the factory valve, just bypass it from the turbo.

i'd also start tuning with the boost controller off, get that right and then start raising it.

walk before running....

factory boost on an S5 is about 8psi, so you're safe there.

 

Thanks, much appreciated. This is gradually starting to make sense.

 

You can unplug the factory solenoid without getting a code. I removed my rats nest (boost controller included). I replaced it with a manual boost controller, and I assume that an electronic boost controller works in the same manner.

That being said it should go between the nipple on the intercooler side as the vacuum source, and the out is to the wastegate. (see below)



+1 on hooking your boost guage to the vac nipple under the BAC with a T fitting and going to the pressure sensor.

 

Thanks, the diagram is very helpful. That really clears it up!

 

I'm getting ready to go the same route as you Lunchbox but I'm still not understanding exactly where I need to hook up the vac source for the manual boost controller I am using.

You say "nipple on the intercooler side" can you be more specific please? Just to make sure the other end needs to go between the wastegate actuator and the steel line on the front of my turbo? BTW I am running a s5 keg and externals in an 88 TII. Stock s4 electronics.