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Discussion Starter #1
What is the max boost you can get out of the K04? I've got the 7163 off and everything back to stock but I never ran an actual boost gauge prior to the EFR. DIC says 23psi as it always did but my mechanical boost gauge never sees more than 20psi. This is on an E54 tune.
 

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I haven't done the research myself, but from what I hear the K04 was really designed to be happy in the 15-18psi range, and anything over ~23-24 on the LNF and you'll want to go with the bigger turbo both to increase efficiency and save your ring lands.

While I'm sure it has a few left, you're playing a game of high-risk low-reward going for any more.
 
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What is the max boost you can get out of the K04? I've got the 7163 off and everything back to stock but I never ran an actual boost gauge prior to the EFR. DIC says 23psi as it always did but my mechanical boost gauge never sees more than 20psi. This is on an E54 tune.
Are you trying for more boost, or just confused that your mechanical gauge doesn't match the DIC reading?
 

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With a stock car, stock IC, and stock cat, a K04 on our cars can do 24 or 25 before it becomes a heat pump, but it'll do more. With an IC and HFC, I've been told that the K04 can do 28 or 29 safely. It's been said they can go as high as 30 but it's not recommended for daily use at that much pressure. I'm assuming you are looking for "max" numbers....
 

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Discussion Starter #5
I'm not asking for modding recommendations just trying to determine if I have the stock K04 performing correctly. It feels sluggish but that may just be from losing 150hp after pulling the EFR7163 and direct port meth. Ghost makes it seem like I have a boost leak though.
 

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Wasn't trying to imply that at all. It depends how your car was tuned. My numbers of course are from mine at out 500 feet above sea level. And this is what I've learned over time. Your car might only like 22psi before the turbo starts acting like a heat pump and giving knock. It might take 26psi...it varies.
 

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I'm not asking for modding recommendations just trying to determine if I have the stock K04 performing correctly. It feels sluggish but that may just be from losing 150hp after pulling the EFR7163 and direct port meth. Ghost makes it seem like I have a boost leak though.
I am assuming you have the stock 2-bar MAP sensors fitted.

23 psi of boost is 37 psi absolute, or 2.5 bar, and the limit of the stock 2-bar MAP sensors. The DIC can't display any more than 23 psi because that is all the range they have, and would explain why that was the reading you saw with the larger turbo.

The discrepancy between your mechanical gauge and the MAP sensor is either a calibration issue with the mechanical gauge, or a damaged MAP sensor from being over-pressurized. the MAP sensor should be able to withstand 2x its maximum reading, so that option is unlikely unless you were running 60 psi of boost.
 

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Discussion Starter #8
I'm asking what it should be able to physically produce at 100% WGDC on a stock setup. More than 20psi?

Stage 1 sensors.
 

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Discussion Starter #9
This is merely a troubleshooting exercise to determine if everything is working correctly.
 

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I'm asking what it should be able to physically produce at 100% WGDC on a stock setup. More than 20psi?

Stage 1 sensors.
Max boost for an un-tuned engine was advertised as 16 psi. The basic tunes were supposed to increase that to the range of 20 psi, or a bit more.
 

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Recently Performance Autowerks tuned my car. Stock Turbo. Upgraded Werks IC. 3 bar map sensor added. It shows 24 psi boost on the factory Gage when accelerating. Dave specifically said he tuned for 93 octane and no knock etc. It is actually a bit conservative. If that info helps.
 

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We purchased a 2007 GXP in San Antonio, and during test drive could only get 15 PSI boost... trailered it to 8,000 Ft elevation in Colorado and with no change other than elevation "suddenly" got about 21 PSI boost (due to the thinner air at elevation). I then installed High Flow Cat, and max boost pressure dropped with "stock tune" to about 17 PSI... then added Trifecta Tune (& when tune on/Cruise Control off) I can achieve up to 24 PSI boost.
The mix of components, the elevation above sea level and what type of software tune a vehcile has can all affect what you might achieve in boost pressure readings
 

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I've seen 23-24 on the DIC. if it went higher I didn't see it. By then I was paying more attention to the road. At 140+ mph, that's a tad over 200 feet per second. doesn't take long for bad things to happen.
 

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My dash was reading a higher boost number than my HPTuner datalog. Per Dave at PAW, I preloading the waste gate actuator an 1/8". Now the numbers seem to match up.
 
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