Manual Boost Controller

[CupraGTi]

Is this like, a huge secret that I shouldn't be spreading or something?

[CupraGTi]

And I don't see how it could be leaning out?? The n75 valve controls nothing but boost pressure... the Air Flow Meter is the sensor that controls air/fuel ratio... so the increased air being sucked in would be complimented with extra fuel...

I understand that timing isn't being played with, so I understand that I'm not getting the most outta the extra few PSI I've gained... but the butt dyno doesn't lie, theres extra power there.

I'm running 98 with octane booster. I am not getting any detonation.. and even if I was, does the 1.8t not have a knock sensor?

I need a front mount......

But the Manual Boost Controller CAN work on our motor.

[h100vw]

I can get 30 psi out of my polo if I want to. Not hard to do. But without the right software. It'll run lean and the chances of engine damage are high. So you haven't stumbled on anything new. Just don't be fooled by looking at only one aspect of getting more power from your engine.

[h100vw]

In my experience, engines feel strongest, just before they quit.
If you're intent on running it like it is. You should definitely be checking the afr.

[CupraGTi]

I hear what you're saying, but what makes a VW so much more fragile than a Subaru? with supporting mods you can raise boost on pretty much any standard computer trubo car. There is a limit to the Air/Fuel map true, but that's what the air flow meter is for... its to take control of the fuel... its not like I'm trying to pump 20psi through my motor... and I WOULDNT... but a couple extra psi should be taken care of by the engine management.

Putting a 3 inch exhaust, and new intake on the 1.8t naturally gave me another 2psi and took it from roughly 8psi to 10psi. The AFM would have taken that into account and given more fuel... All I am doing is fooling the n75, while letting the computer take care of the fuelling.

I will not post how I did this, as it seems to be a contentious issue.

Gav, when I get bigger Turbo, and need fuel upgrade I will definitely be talking to you about Custom Code.

[h100vw]

The agu will be ok to 300 hp give or take. But you have to have the afr in check. The agu doesn't see pressure, no map sensor. It just sees flow. I don't know the intricacies of the fuelling maps.but they control injectors duty cycle and how far outside the programmed limits you can go before the inevitable happens is anyone guess?
Std turbos can bend rods on an S3. The K03 is unlikely to do this, but what about detonation?

[CupraGTi]

knock sensor...???

[sambb]

I noticed you said you were using the turbosmart boost tee. Out of curiosity are you still running it with the internals intact ie. with the ball and spring fitted. When its used this way, it is a pressure relief and pressure regulator all in one. It will let no air through to your N75 at all until the signal air pressure is big enough to unseat the ball and spring, and only then will it start to flow choked down air to the N75. If this is how you are running it your boost ramp will be pretty aggressive as the N75 will be unable to pass any air to the actuator at all, and then suddenly will get a massive rush of it to try and deal with when the ball and spring cracks only 2-3psi off your max setting. Then when your boost tapers off higher in the rev range, the ball can actually reseat thus starving the N75 again. You'll see this as the boost gauge needle bouncing around at a really high frequency as the airbleed causes all kinds of osciallations. The ECU will be going crazy trying to correct for all this.
I'd suggest, and its recommended by turbosmart to do so, running it as an air bleed only, by removing the ball and spring. Then it is a pure pressure regulator only. It will be capable of passing air to the N75 continuosly and so the N75 will always have air pressure at its disposal, albeit with an upward shift in your peak boost. You should get less of an initial spike and a cleaner trail off. If you can't dial in a low enough peak boost (ie just the couple of extra psi you are after)you may have to play around with the inlet nipple sizes of the bleed. The inlet orifice on them is very small and sometimes the orifice becomes the prime flow limiter - your adjustments will do nothing. If you go to a nipple with an I.D just a smidge bigger (and I really mean just a little bit at a time) you'll get the required ballpark airflow back again and your ability to make adjustments to it too.
It can be a real sh%^t fight for just a couple of extra psi though. Doing it this way can really screw with things as you found out. When the ECU is checking with the MAF, MAP and O2 sensor and its changes to the N75 aren't getting the expected responses it can flip, even if it doesn't do anything drastic like. For instance my car is now running sweet on a 16-17psi peak compared to its previous 19psi peak because with the latter, even though the fuelling, timing etc looked ok at a glance the ECU was just permanently in compensation mode re the boost.

[CupraGTi]

Sam,

I have taken the spring out of the boost tee. The N75 is not in line with the MBC at all... its still plugged in, but is getting no reference, where the vacuum line ran in and out of the n75 valve, it now has a piece of vacuum line looping the nipples together. It is seeing nothing at all. The MBC is totally in control of boost. With the MBC wound all the way down, I got about 5psi, I gradually kept increasing the windage on the MBC until I got to 15psi which was where I was going into soft limp mode/fuel cut when the MBC was inline/series with the n75. With the MBC in-line/series with the n75, I could not control the amount of boost through the MBC and therefore it was hitting 16ish psi and cutting... with the n75 diverted, I am not going over this amount, but the MBC is controlling the boost.

I believe it is safe. but rocket scientist I am not.

[CupraGTi]

And I have no problem with part throttle... it isn't either on or off like you suggested, though I had read that elsewhere...

It is very drivable. I believe it is safe at 15psi. But I don't think it is making as much power as a computer which has been custom coded, or aftermarket tuned. It's not getting the same aggressive timing changes... all I'm doing is adding boost, and the computer is adjusting the fuel.