25 psi is out of the little ko3s effiecenty(sp?) range. when you get your chip, it will probably be 1 bar (15psi) or 1.3 bar (18psi) depending on chip. all you need is an upgraded dv and you will be fine. 710n dv from the 225 tt works great or a forge 007 if you can extend your budget. don't waste you money on getting n75 j or h valves, useless. a mbc costs have the price but is not needed. the stock n75 vavle works the best.

 

^^all correct except...

fixed

 

Wayyyyy wayyyyy wayyyy out of its efficiency range.

 

I was gonna pick up a race valve with my chip to get a few extra psi, not worth it?

 

https://www.audiforums.com/forum/sho...ght=mike+26psi

Its somewhat oversimplifying to quote a single psi #. But in that thread Mike states,

The OP was asking if 20 psi will damage the turbo which apparently is not the case if you are not abusing the car.

Ive run the N75J on two b5s and both of them push out an extra 2-3 psi and have a smoother curve which should be better for the turbo. I defintely can feel a difference over the stock N75. I wouldnt necessarliy go out and spend $100 on the valve, but if you can get one for cheap, you will likely see some improvement.

 

I've been boosting 20+psi daily for the last 5 years and 50k miles with no problems like many other people. It's more important to worry about sludge than anything else. The turbo gets boiling hot and really breaks down the oil that runs through it. You should worry more about reducing the chances of sludge blocking circulation to the turbo by doing premature or at least on time oil changes.
The stock N75 will get you to full boost quicker but the turbo will be exhausted by redline. The N75 "race" valve will provide a more gradual or smooth delivery of boost- nearly to redline. When it comes down to it though, you get to max boost more quickly with the stock valve. I've done all kinds of vag-com logging to know this.

 

Ive heard of the "race" valve or "H" version putting some cars into limp mode. Thats why I went with the "J" version. In my experience, the peak boost is consistently higher than the stock valve, and the boost builds up more gradually but holds for longer. It makes the car more fun to drive IMO.

 

Sure did and it still holds the quickest A4 1.8t K03 1/4 mile recored 8 years later. LOL

I even sold that stock K03 to another Socal A4 owner which put that turbo on his 97 and it is still running strong to this day.


Most of the chips now run up to 21psi on pump gas.


Come on guys, every turbo used is pushed past its effiency range. Thats how you make more power. The K03 will only hold high boost for a very short time so its not the max amount of air is going to be any higher by the time you reach high rpms, running higher boost gains you more tq down low and more mid range power.


What will damage a motor is bad tuning and making too much tq then the rods can handle.

 

LOL, but yet it was quick enough to spank stock S4's on the street so it couldn't have been a bad thing.

 

You must be 1/4 irish mike cause you have some luck running a stock k03 that long and not having it blow up on you. With my luck it would last a week Then again i don't have a custom tune.