Ok so i just installed my buschur deluxe fmic, lower and upper ic piping and added the Forge replacement bypass valve on my IX. So i already understand the boost drop because of the bigger piping and fmic, but did i maybe do something wrong with the lines to the bypass valve? It seems that when i punch it, the bypass opens up very early, and i put in the stiffest spring. Does this have something to do with the controller valve that it was originally connected to? Sorry i don't remember the name of that valve, but hopefully someone can answer this for me. TIA

 

the forge bypass valve should be referenced off of the intake manifold with a vacuum line. this is what "opens" the valve allowing the air from the UICP to recirculate back into the intake before the turbo.

sorry i am a bit confused by your question... anyway i guess a refresher on the parts might allow you to word it better.

what controls the boost level is the wastegate. the wastegate is also a valve, but in the exhaust stream. it controls how much exhaust goes into the hotside of the turbo. a closed wastegate means all the exhaust gas goes through the hotside, and boost will jump really high. an always open wastegate means youbuild very little boost and it will lag really bad.

the wastegate is controlled with some form of boost controller (be it electronic, manual, or the stock cycling valve). the manual boost controller usually has 2 vacuum lines running to it. one goes to the wastegate, the other goes to the compressor on the turbo, or else the intake manifold.

now where was it you think the problem was? and what exactly is happening?

 

If you installed the Diverter Valve correctly, it shouldn't be "opening early", especially with the stiffest spring. You may have a boost leak. Can you hear air escaping? And thats why you think the DV is opening early? You should do a boost leak test if you haven't yet.

And the controller valve I think you are referring to is the Boost Controller.

 

yea sorry about the confusion....i guess this is what i get from coming from Audi's. Well on my A4 before i changed out to a manual boost controller, there was a valve call the N75 valve. It helped control boost thru the ecu and that is what it seems to be like for the evo as well, i'm just not sure what they call it. But the issue is that it seems to open early, or sounds like its opening early and i'm just trying to find out why. I guess i should really just get the car tuned first and work from there. Let me know if i gave good enough info to help me troubleshoot this issue. Like i sad before i'm sure i lost a bit of power due to the upgrades and not increasing the boost, but i'm just making sure this is not hurting the motor.

 

oh forgot to mention....another reason i'm worried is because on the original intake arm to the turbo inlet, there was a nipple on that arm and now on the new intake pipe there is none, so my question is where does the hose go to now?

 

do a boost leak test +1

 

yes, just like the audi, the evo has a ECU controlled valve which regulates the boost. it is located under the air filter on out cars. it has two vacuum lines going to it if it is in use. there are many names for it (i come from the porsche 944 turbo where it was the "Cycling valve", but you'll also see boost control solonoid, boost regulator, wastegate controller, etc etc, etc..) for starters, you wont be able to hear this valve over your exhaust. it is just venting a vacuum line back into the intake which over the sound of the motor will be impossible to hear. you are likely leaking something elsewhere.

and yes, the stock cycling valve does actually let the boost "Fade" off at higher rpms and a tune can correct some of that (it is an adjustable parameter in ECUflash). a EBC or MBC can also correct it.

 

Well you really need to do a leak test (if you search you can find how to make one). How much boost are you loosing? As for the lines off the intake, one goes to the valve cover, and I can't remember where the other one goes (it may go to the stock boost controller). Both of mine are pluged.

 

Sweet thanks for the info guys. I hope its just the normal pressure drop due to the new fmic. But for sure i'll try out a leak test to make sure.

 

How much is the drop? And did you put the intake on at the same time?