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      06-28-2008, 10:29 PM   #76
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Drives: '13 S4, '15 Q7
Join Date: Feb 2007
Location: Woodstock, GA

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Originally Posted by NeoE46 View Post
Well, I looked and looked and diagramed the system and watched the install video over and over. No matter how many times I did, the rear turbo wastgate ended up cponnected directly to the vaccum accumulator. I asked a question but was rebuffed by fan boys. The majority opinion was that both accumulators were hooked up through the front solenoid to keep duty cycle times the same. I don't deny that the rear accumulator has a path to the front solenoid, however, it is on the wrong freakin side and has a direct path to the wastegate. I decided to wait. Not a week later, the forum was awash with people with ticking and whiring noises from the.....drumroll......rear turbo wastegate. What did the majority of these people share in common??........Vishnu.
Actually, this is an incorrect assessment. The solenoid bypass (which is no longer required with V2 and V3) was to fool the DME into using a higher duty cycle which allowed increased boost as well as better control. The downside is that with only one solenoid in the loop, things respond more slowly.

As for the affects of one or both solenoids being used. The solenoids are in parallel to both turbos. One is not controlling one turbo, etc. There is a single vacuum accumulator per solenoid but after the solenoids, there is a single line which later gets Tee'd to each wastegate actuator.

To sum up, bypassing one solenoid does not affect a single turbo, it affects both. But now that is irrelevant as V2 and V3 do not require a solenoid bypass.