Help needed with K04 issues.........
Member
Joined: Oct 2000
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Re: Here's my take on this...
How long does it take you to get to 19psi? Where do you have the boost gauge Tee'd into? Try another boost gauge too.
Log your throttle angle, if it is not closing, which I dont know how it would... you must really have a big leak, or your wastegate is opening. A matter of fact it almost seems like a wastegate issue.
You know what psi spring is in the wastegate? You running a boost controller or N75 valve? If your wastegate sspring is 5psi maybe for some reason your wastegate is opening?
Cause with a boost leak that big I bet it may trake a little longer then normal to get to 19psi and I thibnk you would realize this.
So obviously you can feel a power difference when the boost goes from 19 psi to 5?
Log your throttle angle, if it is not closing, which I dont know how it would... you must really have a big leak, or your wastegate is opening. A matter of fact it almost seems like a wastegate issue.
You know what psi spring is in the wastegate? You running a boost controller or N75 valve? If your wastegate sspring is 5psi maybe for some reason your wastegate is opening?
Cause with a boost leak that big I bet it may trake a little longer then normal to get to 19psi and I thibnk you would realize this.
So obviously you can feel a power difference when the boost goes from 19 psi to 5?
Thread Starter
Junior Member
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some answers.....
I hit 17psi at around 2700-2800rpm and 19psi at around 4000rpm. I have the gauge spliced into the vac line at the front of the intake manifold leading to the bpv. I've had this gauge before the K04 so I don't think it's a problem.
My throttle angle looks fine except it only opens up to 78° max and I've seen logs by others where it opens up to 85°. I don't recall if it's closing or not. I'll have to check my laptop and see.
The wastegate is set to whatever AWE sets them to, so I have no idea what it is. I'm running the stock N75.
Yes, the power loss at 5500rpm is very noticable. It runs strong then all of a sudden boost drops to 5psi. Sometimes it holds up to 6000 to 6200, but power always drops after that. These past few days I've been reluctant to take it past 5k much due to what usually happens after.
Gas mileage is also down 3mpg, but that's probably mostly due to the 5bar fpr.
My throttle angle looks fine except it only opens up to 78° max and I've seen logs by others where it opens up to 85°. I don't recall if it's closing or not. I'll have to check my laptop and see.
The wastegate is set to whatever AWE sets them to, so I have no idea what it is. I'm running the stock N75.
Yes, the power loss at 5500rpm is very noticable. It runs strong then all of a sudden boost drops to 5psi. Sometimes it holds up to 6000 to 6200, but power always drops after that. These past few days I've been reluctant to take it past 5k much due to what usually happens after.
Gas mileage is also down 3mpg, but that's probably mostly due to the 5bar fpr.
AudiWorld Super User
Joined: Aug 2001
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try a throttle body adaptation w/ the VAG. I get 87.7 degrees at WOT on my non-dbw
my friends S4 used to behave the same way, would run fine after being reset and then go into limp mode, a new MAF fixed it for him, but it sounds like your MAF readings are good. could try swapping a new one in just to see.
AudiWorld Senior Member
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I had the exact same problem. Im running Oct setup with 22 psi....
I would spike to 25 then hold steady at 5 psi(limp mode)did every logical test we could think of only to find that a tuner that I had gone to before K04`s were installed put a darn Race n75 valve causing boost spikes.I replasced it with stock valve and I have no more problems.
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Member
Joined: Oct 2000
Posts: 3,201
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Re: I say throw a manula boost controller in for testing...
to bypass the N75 valve and see if it boosts faster without the delay.
Seems like
Huge boost leak
N75 or boost control issue
Wastegate issue.
G-Luck, sorry in hurry :-)
Seems like
Huge boost leak
N75 or boost control issue
Wastegate issue.
G-Luck, sorry in hurry :-)
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