I have been reading Maximum Boost and the VATN turbos really intrigued me. I will quote a little from the book describing how wonderful these things are, but first, if you don't know how these work, here's a link to a diagram.

"The VATN is a whole new deal. The vanes of the VATN pivot to present varying ares to the discharge stream, changing the exhaust gas velocity as it enters the turbine, permitting the speed of the turbine to vary. The merit of the VATN lies in several areas: it acts like a small A/R when asked to do so, a large A/R when required, and it produces a smooth transition through all points between the two extremes. The VATN can create such a huge A/R that turbine speed over the entire range of operation can be controlled by varying the A/R alone. Thus, the VATN becomes its own boost controller, and no wastegate is required. When no wastegate is present, all exhaust gas energy is available to power the compressor, and "waste" becomes a thing of the past. Turbine performance can take on whole new dimensions. Since turbine speed is always controlled by the VATNs, the A/R ratio is always the largest possible for the boost pressure at that instant. If the A/R were smaller, turbine speed would rise, creating more boost, which would raise the turbine speed, which would raise boost again. This situation will always keep exhaust gas back pressure at its lowest for any given boost pressure. This creates the wonderful condition of the exhaust back pressure being less than the boost pressure. When this "crossover" occurs, power production takes on new dimensions. This condition is generally not feasible with conventional turbos without the turbine's being so large that it becomes unresponsive at low speeds."

I have read on a few lists that someone with a VATN equipped Miata was able to produce half of their maximum boost at 1000 rpm, with full boost kicking in around 2,200 rpm. Is no one with a 4G63 running this kind of setup? I know that the VATN turbos are a little cost prohibitive right now, but I believe that aerocharger sells kits for around $3,500 (not for our cars though). That's not rediculously expensive, considering the remarkable piece of tech you are getting. This definitely seems like the turbo of the future.

 

Are you dyslexic?

 

garreett vatn turboraed me em

doesnt even make sense when it's reversed.

 

Too mucho

 

variable area turbine nozzle..... old news

the only real challenge is timing the vanes. some just hook it up to a vacuum canister, so at low vaccum the vanes produce the smallest possible a/r. promoting quick spool up, and under boost they open up, producing a larger a/r

 

I was reading about all that new stuff on some site not long ago, although I've seen this stuff quite a while back. The particular site mentioned unusual sequential setups (big-time desiel motors) and such. Its not exactly the smoking gun, but its one hell of a bullet. You still have the weight of the wheels/shaft, although ceramic is being used for them now. You also have the size of the wheels; all this can do is help reduce backpressure and speed spool time & response. Until they make inertial-dampening devices, turbos will always have some lag.

Regardless, I'd run one if I had the cash & the right car to use it in.