Turbo Tech Question
09-02-2003, 12:24 AM
#1
Addict
Rennlist Member
Rennlist Member
Thread Starter
Join Date: Mar 2003
Location: Alberta
Posts: 670
Likes: 0
Received 0 Likes
on
0 Posts
Turbo Tech Question
I've been reading "Forced Induction Performance Tuning" by A. Graham Bell. In Chapter 8, which discusses 'Turbo anti-lag strategy', some of the technologies to reduce lag included: ball bearing turbos, ceramic turbines and most significantly the implementation of "Variable Nozzle Technology" (VNT).
Apparently Garrett make a multi-vane type VNT turbo. The vanes close at low RPM's (when exhaust flow is low) to provide a small nozzle size so as to maximize turbine wheel acceleration and speed. The vanes then progressively open as exhaust flow increases to minimize back pressure, control boost pressure, improve fuel economy and increase horse power. In effect, it works as a small A/R turbine at low speeds and like a big turbo with a larger A/R turbine housing at high speed.The book claims that boost response times of Multi-Vane VNT turbos are dramatically reduced when compared to ordinary turbos of similar size. Ordinary turbos take 70% to 90% longer to produce the same boost pressure.
This technology, although not new, seems to provide all the benefits of both large and small turbos. Has any one had experience with VNT turbos or know if Garrett is planning to make an after-market application for the 996TT?
Mike
Apparently Garrett make a multi-vane type VNT turbo. The vanes close at low RPM's (when exhaust flow is low) to provide a small nozzle size so as to maximize turbine wheel acceleration and speed. The vanes then progressively open as exhaust flow increases to minimize back pressure, control boost pressure, improve fuel economy and increase horse power. In effect, it works as a small A/R turbine at low speeds and like a big turbo with a larger A/R turbine housing at high speed.The book claims that boost response times of Multi-Vane VNT turbos are dramatically reduced when compared to ordinary turbos of similar size. Ordinary turbos take 70% to 90% longer to produce the same boost pressure.
This technology, although not new, seems to provide all the benefits of both large and small turbos. Has any one had experience with VNT turbos or know if Garrett is planning to make an after-market application for the 996TT?
Mike
