Kit_Chris

Diesel engine technology has been using variable geometry turbos for a few years now, has anyone looked at the possibility of using one of these on the 951 as a potential solution for lag on highly modified high output engines ?

Regards,
Chris

OriginalSterm

aerocharger makes a kit for the boxster i believe. it uses variable geometry to reduce lag.

emwporsche

I believe they were used on chryslers and had several problems with longevity.
(I assume your talking about a cold side that opens up at higher boost)

Laust Pedersen

Here is a reference to pictures of a variable vane turbo (Garrett VNT25, used by Chrysler).

Some years ago I attended a seminar by Garrett, where they stated that variable vane turbos were not recommended to for gasoline engines, but were OK for Diesel engines, something to do with the moveable vanes getting stuck by the exhaust deposits from a gasoline engine.

What happened to Aerocharger’s website? Are they out of business?

Porsche-O-Phile

That just sounds like a very expensive problem waiting to happen. Cool, yes - but a financial time bomb I'd suspect. Simple solutions are usually better.

azmi951

There a two types from my understanding

A Variable Nozzle-moving parts on stationary parts.

Variable Vane-moving parts on moving parts=problematic

Correct if wrong, as I'm not positive.

J Chen

The only Variable Nozzle that I know was
builded by Nissan some years ago.
The really interesting one would be a turbo
that's powered by oil pressure. It was design
by an ex Garrett engineer. Don't know what
happen to him & the design. Can you imagine,
you can place the turbo anywhere as long as
theres space to mount it. Say goodbye to
crossover, down pipe, wastgate. On top of that
no LAG.

dmoffitt

i thought the new mitsu evo had something like this?

Waterguy

My trucker brother just ordered a Kenworth tractor unit with a Detroit Diesel Series 60 515 hp diesel engine. The brochure shows a picture of the Variable Geometry Turbo (VGT), which is a variable-vane type turbocharger made by Garrett. The specs say it is capable of 1 bar boost at idle(!). The power curve for the 14 L diesel engine is a dead-flat 1650 ft-lbs of torque from 1200 to 1500 rpm, rolling off to 1500 ft-lbs at the horsepower peak of 1800 rpm. He expects to get about 33% more torque than his old-technology Caterpillar engine while using about 25% less fuel.

My understanding of the issue is that variable geometry is more practical on diesel engines because the exhaust temperatures run about 500 F cooler than on gasoline engines.

dmoffitt

holy torque batman.

84black944

Aerocharger is not to far from me here in buffalo. The place that makes the turbos in batavia NY, but im not sure if its still in business. I went to go there a while back but got discouraged when i realized after a couple of hours of driving i didnt know how to get to the street it was on and got discouraged and turned around. Those turbos are interesting, they wont give you the top end like a normal turbo but the low end will be significantly increased. From what i hear it doesnt give you the feel of the turbo kicking in which is so addicting but rather it supposedly feels like a larger engine instead.

Edman951

On the new 6.0L Ford turbo Diesel.
The turbo is a GT37 with variable turbine wheel,
To regulat boost it uses the variable wheel to make it into a smaller turbo at low rpm and big turbo at high rpm.
I had one a few month back. (got it stolen) And it work OK.
But the truck still had some lag.
The diference from open to closed was so big.
That i unpluged the vane controller once. And i could barelly get 5 psi at the top end. Maybe 10psi on the highway.
Factory it runs 24psi. And in the winter i had it up to 35psi.

dmoffitt

i'm pretty sure aerocharger was bought / absorbed by one of the larger mfgrs.

DIESEL-ONLY

You are talking about an engine that has a 2100rpm redline so 1200-1500 is in the middle of it's rpm range.

PorscheDoc

Lol, way to resurrect a post from 2004.