RKX 1.8T 2.7T Precision machined Diverter Valve SILVER Compatible With VW & Audi MK4, B6, B5, C5 1998-2005

I bought this for a 2003 Passat (B5.5) 1.8T to replace OEM valve. The only upgrade I have is GIAC software upgrade for 91 oct. Prior to installation I was spiking at 22psi and trailing down from there. I was told I should replace the OEM due to eventual and inevitable failure. After research this looked like as a good a replacement as other top-brand models. I first installed it as is recommended from RKX, which is the opposite from the OEM. I put in the red spring with the two washers. I found that boost ran very similarly to the OEM valve - would spike to 22 psi then trail off quickly from there. Though that was odd. So decided to try turning the valve to the OEM orientation (with stem/side port to the intercooler and the piston/end port to the air intake). I must make known, however, that when turning the valve to OEM orientation I discovered that the vacuum line had come loose from when I had first installed this valve. I'm not sure when it came loose, but I believe that it was only just prior to the changing the orientation of the valve. I say this for two reasons: 1) The car was able to make boost to 22 psi before trailing off, and I don't think the car would be able to make this amount of boost with a vacuum line open; and 2) the car was acting funny just prior to me getting it on the lift - wouldn't really boost up, etc. So, after all that, the car now holds boost at 22 psi for noticeably longer than from when the valve was oriented per RKX's recommendations. To me this makes sense, because the valve will ONLY open when vacuum is created. If the piston side of the valve is to the intercooler, then it can open when boost exceeds spring pressure. The argument could be made that I needed to put in a higher rate spring and leave the orientation per factory recommendations, but I chose to just turn it and see if that helped and worked. And it did.UPDATE 10-7-2017: Still spiking around 21-22 psi and holds well. Highly recommend this product.

I was pleasantly surprised by the quality of this part. The machining was top notch, the mating parts fit together smoothly, and the finish appears to be high quality. It installed easily enough, although there is limited space to work on my B6 Audi A4.I was careful to install this valve backwards is indicated in the instructions. I took the car for a test drive after installation. The car seemed to pull slightly harder at higher RPM, which ndicated a better internal seal that the stock valve. I cut open my old vallve to see if it was defective, but didn't notice any tears in the diaphragm. This indicates to me that the valve holds boost slightly better than the stock valve, even at low boost levels. I consider this a worthwhile, even necessary, upgrade for anyone considering increasing the performance of their VW/Audi cars by increasing boost on the 1.8T engines.

I got this DV yesterday, I love Amazon's new international shipping options. The valve itself looks well made. But the springs look ages old, with the paint cracking everywhere, horrible paint quality from what I can tell. Just by looking at the springs I would have thought it was a used product. However the valve itself and the rest of the packaging is decent. Feedback for the manufacturer: spend a bit more on a decent paintjob for the springs, it sucks.Anyway I used a wire brush and cleaned out the cracking paint on the springs I was going to use and have just installed this on my 1.8t Audi S3. I blew on the tubes to make sure it was sealed before I did anything to this, and had a tiny bit of air circulating through there. So right off the bat I was expecting this to suck. However, I just drove my car 60 miles and I am surprised to say it is fairly good so far. Just slightly louder than my Bosch OEM valve, with a nicer "ptzzzzz" noise when off the throttle (you don't buy this for the noise anyway). No CEL lights for now, and the car has not decreased performance. I would say it feels like it pulls harder but that may just be my wishful thinking getting in the way.Keep your OEM valve at hand if it is still working just in case. I will see what happens with this product, if it fails quickly then I guess I can just trash it since its so cheap, and if it works like it is doing right now I would say it's an absolute bargain. I guess I'll update this review depending on what happens.Also, the o rings provided are garbage. Like, serious garbage, they don't even fit.

First day update: Just installed this nice little valve. It appears to be good quality and comes with helpful directions. For anyone wondering about removal of the ear clamps on your stock DV, use a screw driver, pliers, or side cutters to manipulate and destroy the nasty contraptions. The supplied hose clamps seem to be good quality.Upon first drive, paired with my new N75 valve, the car is crisp and responsive. It feels like power delivery is more linear, but it's a subtle difference. After all, my car is stock except for the upgraded N75 valve. This valve will become more important for anyone wanting to upgrade their tune or go to higher boost. Replace your tired factory DV (it is a mechanical/wear item after all)!

Fantastic part in general, not just for the price! The only complaint for me is the top seal was just slightly undersized, I had to gently stretch it to avoid tearing it. I also removed the side port and loctited it on just for peace of mind. Part works perfect, I installed it "backwards" according to the manufacturer's directions so the boost pressure enters the side port, I don't like the sound it makes with the boost entering the bottom. Getting great results at 22 psi+ using only the blue spring. I wish they made more things for me to buy!!! It's rare to find a product actually sold for about what it should cost.

Part functions, as it should and arrived on time. O-ring for top does not fit well into area machined. Do not over tighten or it will displace and pinch and great a boost/vacuum leak. Piston has a finish that is cast instead of polished or smooth. Both issues resolvable with awareness and a little elbow grease. I would order again. Cheaper than a Forge DV rebuild kit!

Good quality, working good. Vacuum line they supply is a little loose fitting. I just bought some new vacuum line.