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Discussion Starter · #1 ·
Hey guys is it possible to adjust or upgrade the stock wastegate on my 08 Passat 2.0T k03 turbo?
Looking for more boost ?
What about a external boost controller?
Thanks
 

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2007 B6 Passat 2.0T, 1994 E36 M3 3.0L, 2004 Silverado Z71 5.3L
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It is possible to adjust the wastegate with more preload but it is not advised for the purposes of making more boost (besides the boost control system with the N75/wastegate actuator would make that difficult to achieve anyway). Adjustments are generally done to put more preload on an aging wastegate/actuator system that will start to open more easily and thus to combat losing boost not to add boost.

How much boost are you making? Typically a stage 2 tune will request 21-22PSI peak boost and that is all you should aim to make on your K03. Past 22PSI on a K03 you're hardly going to make anymore power. At that point you're milking that turbo for all it is worth and pushing it well outside of its efficiency range which means its basically going to be a glorified hair dryer blowing hot air. This will increase your IATs and your ECU will intelligently pull a bit of timing so you'll actually lose power, if anything, and you'll shorten the turbos life.

If you're not stage 2 already then go stage 2 if you want more boost. If you're already at stage 2 and you're not satisfied it is time for a bigger turbo, you're tapped out. If you are interested in talking about going that direction I have plenty of info to share on that end of things too.
 

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Discussion Starter · #3 ·
thanks for reply.
Im stock Map at the moment. trying to figure out which Stage 1 to go maybe a stage 2. I already have installed
Intake kit by HPS
3in Down pipe
Updated DV with atmospheric release
KW coil overs
which tuner would you recommend?
I only have 80,000 miles on the car stock Clutch
 

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2007 B6 Passat 2.0T, 1994 E36 M3 3.0L, 2004 Silverado Z71 5.3L
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1,818 Posts
thanks for reply.
Im stock Map at the moment. trying to figure out which Stage 1 to go maybe a stage 2. I already have installed
If you have the 3" DP you may as well go stage 2, however, the difference between stage 1 and stage 2 could be the difference between your stock clutch surviving or not surviving so bear that in mind. It is impossible to predict; there are way too many factors that go into that likelihood. It is possible it will hold up to stage 2 for a few years and it is also possible it won't even hold up to stage 1 for a year. It depends on its current condition and other things that you just won't know until you know. But bottom-line: if you are looking to make good power out of the car you'll need to upgrade eventually. It's actually not the clutch disc friction material itself that is not up to the task, it is the weak pressure plate that does not provide enough clamping force for the disc so that is yet another factor in whether your clutch will get burnt up or not. If you pressure plate and slave cylinder/throwout bearing unit are still strong then you should be fine for awhile; if they aren't, your clutch is gonna be toast if you launch or load it up with high gear-low RPM throttle. If you want just about every bit of info you need to consider clutch options then checkout my build thread (link in sig) or ask away.


Updated DV with atmospheric release
If you are interested in maximum performance then get rid of this. A DV that has atmospheric release isn't really a DV (DVs recirculate boost). Blow-off valves (BoV) have atmospheric release. While they are an outrageously popular mod to do they are actually not a performance part; they are a noise-maker and nothing more. I will help you understand why:

In most cases they act slower than electronic diverter valves but, more importantly, the ECU expects an electronic diverter valve for calculations it makes. The stock rev D diverter valve can hold the boost of a stage 1-2 tune and even sometimes stage 3 just fine. As long as it is operating/sealing properly. Folks often go from a Rev D OEM DV to a aftermarket DV/BoV and see that they are able to hold more boost but unless it is on a K04 or BT application which sees well over 22PSI then the only reason for this is that the stock Rev D DV they had was not sealing properly and needed replace. If they had replaced it with another new stock Rev D unit they would have seen the same results as with the aftermarket piece. Even in many cases on the K04/BT cars the stock Rev D DV holds the boost fine. It does for mine and it does for many companies high-performance race cars (APR uses the stock Rev D on their race cars making far more power than even my BT Passat).

If for some reason you want to upgrade anyway, replace it with a GFB to retain ECU control over the valve but to be stronger than stock. The reason you want to maintain the ECU electronic pulse-width modulation control over a DV unit (stock or GFB only) is because when the throttle valve closes and the motor is in overrun (translation: when you let off the throttle at WOT/high revs) back pressure develops in the turbo housing which reduces speed of the turbine and increases turbo lag for when you get back on the throttle. To combat this, the DV is opened by an electrical actuator which allows the air to blow back to the intake side to the turbine and maintain turbine speed. Then when the throttle valve reopens (when you hit the go pedal) the DV closes. These behaviors COMPLETELY rely on the pulse-width modulation (PMW) electrical signal from the ECU to operate correctly and that ONLY happens with the stock DV or the GFB DV+… so moral of the story is when you get a BOV with atmospheric release or even an analogue DV that doesn’t retain the connection to the ECU, you are robbing yourself of that design and performance/turbo spool advantage with the regular DV or GFB.


which tuner would you recommend?
This is a highly contentious subject because it gets into the realm of the oft-debated "shelf vs. custom tune" area. I will give you my advice which is coming from personal experience in both camps (shelf tuning AND custom tuning/setups). Also, as a professional software engineer and avid researcher when it comes to my car build, you better believe I've delved into every bit of minutiae that these companies would discuss about the tuning parameters, variables, tables, maps, and the software itself. Obviously they aren't gonna tell me any of their trade secrets but the point is that, just by the nature of my profession, I have more insight into the end-user differences that are achieved by shelf tuning vs. custom tuning... and they really aren't that significant. It boils down to this: if you don’t plan to go with a setup that more or less needs custom tuning (e.g. non-standard hardware) then just stick to a shelf tune.

But I'm not a fan of making claims without backing them up so here is what you need to know. Reality is that shelf tunes are just as good as your average custom tune AS LONG AS they are paired with the standard hardware they are intended for. See everyone has this notion that getting a custom tune when they are stage 1, stage 2, or basic bolt-on K04, is better than a shelf tune because it is more tailored to their car... it really isn't. Those shelf tunes from the big tuners are tailored to that hardware they are intended for already; they are, in effect, a custom tune in-and-of themselves for that specific basic bolt-on hardware. The second you deviate from standard bolt-ons and add non-standard stuff like high performance intake manifold (do NOT unless you’re going BT), or water-meth injection, E85, etc. that goes out the window though. THEN, you want custom tuning because THEN you need a tune that can be tailored to your non-standard hardware to take full advantage of it. But that's only the case for a minority of enthusiasts/modders. In most cases, and in your case, you have basic standard hardware that the shelf tunes are written for. You will get little-to-nothing out of a "custom tune" at your stage. And the reason I threw "custom tune" in quotes is because most custom tuning companies do NOT actually give you a truly custom tune when you have basic bolt-on hardware because it would be a waste of their time; they already have a tune ready to go for that (just like the big "shelf" tuning companies). Why would they duplicate effort and tune specifically for each car when the stage 1/2/K04 cars with standard bolt-ons are nearly the same and any amount of custom tuning they do from one to the other is gonna net fairly minimal and possibly negligible difference in power from one bolt-on application to another. So for bolt-on stage 1 thru K04, shelf tune is totally fine and generally the only thing you’re going to get out of a custom tune at those levels is a bit more refined of a powerband and MAYBE a bit more power if your tuner really knows what they’re doing and if you pay for the time it takes to dial it in to that level. That’s best case scenario; worst case scenario is you’ll pay just for them to load a cookie-cutter file for your hardware (which will be at best as good as the heavily R&D’ed/refined shelf tunes) or they will do a more custom approach but it will take many retunes and more $$ to get it any better than a shelf tune that is already designed for, heavily R&Ded, and used by thousands of feedback-providing users for the same application. Rarely does a totally custom tune not require multiple retunes to be competitive, it’s just the nature of the game. Some people like that game, I like it, but not for a bolt-on stage 1, stage 2, or even K04 setup. Not worth the headache for minimal gain, at absolute best.

At the end of the day custom tuning is actually NOT all that much different than shelf tunes. They are all working with the same data, the same parameters, the same variables, the same tables, the same maps, etc. It's all the same process and the same techniques used to accomplish the same thing, the ONLY real tangible difference is that the custom tuners will adjust that stuff around your build and the shelf tune obviously does not. That is why I say that the ONLY reason to go custom tuned is if you have non-standard parts on your car that a shelf tune does NOT account for or take advantage of properly. This is why for stage 1, stage 2, and for K04, most "custom" tuners load a canned file anyway and it's no better than a shelf tune. It's basically the same thing because there is no significant variance to account for from car to car.

Hopefully that clears anything up on that subject for you and you see the merit of just going with a shelf tune from one of the big tuning companies for where you are at right now. As for whose to go with, that's up to you. Your budget and goals so weight your options and pick one. Look at what they're all offering/claiming and consider ease of access to support from the company because, while it is fairly rare to have issues with a shelf-tune, you're at their mercy if you do so having an affiliated Euro shop somewhat nearby is a big factor to consider. That can sway the decision of which companies tune to go with right there depending on your power goals. But understand that most of these tunes are going to be pretty similar because, at the end of the day, there is only so much you can get out of the K03 turbo. It is very peaky, peaks early, runs out of breath up top and there's only so much that tuning can do to flatten that powerband out and move it up the RPM range when the hardware itself dictates part of that behavior. So look at power claims, look at charts for powerband, and look at what Euro shops near you have which affiliations, that's my advice.
 
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