toddk911

WOW, where can I get one. Anyone here familiar with them??

I just got Maximum Boost book for my birthday and there is so much damn info in there. I was reading about the VATN turbos. Variable Area Turbine Nozzles. Sounds like a variable valve timing concept. At low revs the back pressure is more and boost builds very quick by the nozzles (fins?) being closed, and as boost and revs build, they open and release that back pressure to allow more flow.

Kind of like a K 26 being able to start with #6 hotside for fast spool up, then switch to #8 as boost and revs build.

The book has chart of boost build times for standard turbo and a VATN turbo. A standard turbo shows 2 psi by 1 second of lag and the VATN shows 8 psi with 1 second of lag.

How much do they cost?????????

Two other tid bits I found are that for every 3 octane points yo can add 2 psi and for every 15 degree drop in intake temps you can ad 1psi more of boost. Wish I lived up north This touches on the post of everyone noticing a big difference in performance with all things the same, except the outside temps.

There is actually a quote from a racer saying that on turbo race cars he can feel a performance difference when the sun comes from behind a cloud.

Jeff Lamb

Check out http://www.aerocharger.com. They produce a variable vane turbo that was tested on Boxster that was recently featured in Excellence magazine. I have no idea what these things cost, however, they do represent a very interesting technology.

Jeff

Ski

They are in use in aircraft at the moment,,not sure if other applications are applied,,maybe semi trucks? I think Dodge or Chrysler tried them on one of the smaller cars prior to the Shelbys but can't remember which.

nine-44

Ok, I've been looking into them for a little while, the poibilities are crazy!!!!!! The Aero charger won't be good enough, looked at it, too small and no oil or water cooling, not my choice! Garrett has the VNT which is designed for deisel apps, not sure if there would be any problems with the higher EGT on gas. I've talked to a local shop that has a very knowelegable guy there. Holset also has variable turbine housings too. This IS my future plan for my turbo, Garrett VNT. The shelby/Chrysler cars used a small VNT Garrett very successfully, it wa like a GT-17VNT, a T-3 is an upgrade. So, yeah they are small.

nine-44

I'd say that you would also need standalone engine management. Due to the VNT, you may idle at low boost, seriously! I'd love to be the first to do it succesfully on a 951, but due to my current cash situation, I'm afraid this will be another idea of mine that someone beats me to finishing.

toddk911

Yes, I have that Excellence issue of the turbo Boxster. Did not realize that was the turbo. He was only making about 350+ hp so I wasn't super impressed and did not look at the tubo closely. I will now.

I guess we could call the tuner company that did the boxster t oget specs and pricing on the VATN turbos. Or at least where they got thiers.

Dwayne Williams

Can you post the name of that tuner that did the Boxster? And was that a regular Boxster or the S? If it was an S that's a 100 hp jump from stock, which would turn the Boxster into quite a potent machine. If it was a "regular" Boxster that's a 130+ jump.

toddk911

I'll have to dig it out as it is packed. Wife and I just bought a house. I believe it was a Boxster S and was running about 8-10 psi. Thier initial claims was that about 400 hp and would hang with a GT 3. When they actualy drove it they said yes, much more potent than stock, but not up to GT 3 level. And only dynoed like 350-360 hp. But it was still a huge improvement. Actually says alot oabout the boxster motor as they were still running stock compresion with the 10 psi !!!