VATN?

[broncr]

I got through most of Maximum Boost yesterday. It answered a lot of my questions on practical turbocharging.

One topic that was of particular interest was the Variable Area Turbine Nozzle, Variable A/R Turbine Housings and Twin Scroll Turbine Housings. Can anyone post a source for more info on price (comparison) & availability?

The concept seems to be the answer for selecting a turbo that will function better "down low" AND "up high". I imagine it doesn't come without a price (not just $$$).


Thanks

broncr

 

[Anonymous]

It's a great concept but difficult to work. They came in later 80's turbo dodge cars, but they had a habbit of coking up. There are some newer ones on the market that the newer powerstroke uses, but I don't have any specific year info.


-=Whittey=-

 

[Anonymous]

The PS uses (some) a variable geometery Garrett GT37R with pretty good results. Saab, Volvo, Scania, etc all actively use them on production models.

Corky is a big fan of the Aerocharger and VN types; most of his mid and high-end kits use them exclusively. They work great, but they most certainly come at a price. But 650whp is never cheap, is it?

The twin scroll housings have been around for a while, and do help keep exhaust gas velocity high in two regions of the turbine wheel, but like anything else, they are a bandaid vice a perfect fix. However- most production stuff uses TS, with the non-divided housings being more for fixed-speed powerplants and the like (race aps, too- they really don't care about spool up at 3000 rpm).

My next OHC is going turbo- I think there's more power to be had, more reliably. BOOST IS GOOD!

 

[Anonymous]

I work at International and the new 365 (Ford P/S) creates a nice 14 lbs of boost right when you hit the throttle. i think a max of 25 psi boost is what they use. But....they dont perform very well if you do not have enough exhaust back pressure. The exhaust back pressure is about equal to the amount of intake pressure (except at idle). The engine runs better with an even airflow (intake and exhaust) through the engine. It moves through the engine at one velocity...respectively. I think it may have something to do with achieving a high boost pressure at a low RPM. The variable vains needs the back pressure to spin the wheel when they are actuated to create intake pressure.

They work Very well..at 200 horse and about 700-750 ft lbs i believe in the International trucks...they really get movin..sound like a jet rolling into the shop...The garret they sue is computer controlled too though..so it would take a little work to make it work with something its not designed to cooperate with. unless you put the whole engine and computer in your truck!...a little spendy

 

[Anonymous]

Just a few things..

Why are twinscoll turbos a bandaid fix? like, if half of the engine's exhaust gas is working on half of a turbo's scroll at any given moment, it should produce a more even event on the centrepoint of the turbine, thereby making the compressor wheel act more evenly..

and with the Powerstroke needing backpressure as high (or exceeding) the intake manifolding pressure, I dont quite see how that would work, except for Ford wanting exhaust pressure high to help the catalysis of unwanted exhaust byproducts.. Either that, or its a syphon effect, but that'd be more of a exhaust pipe sizing issue...

 

[Anonymous]

Band-aid meaning that it helps alot, but doesn't cure everything.

Bad choice of words, maybe?

I'm not so keen on the 'needs backpressure' deal either; if so, then why is one of the most popular mods a larger exhaust?

 

[Anonymous]

Is the most popular mod on the 2004 6.0L powestroke a larger exhaust?...or on the older powerstroke? Different turbo perhaps? totally dierent engine?....i wish i could explain...but it was explained to me and it made perfectly clear sense when i heard it..but i can remember exactly how it effects it...maybe i should open my mouth when i have my crap together...hehe.....ill be back with an explanation....i dont give up that easily....thanks guys

( really...thank you very much...ill see what i can come up with)