TJ
SuperDork
10/4/10 11:25 p.m.
Aerocharger
What's the story with these things. Anyone actually use them? Other than the cost what else is wrong with them. They claim to need no wastegate and don't use engine oil for lubrication, and due to the variable vane setup build boost faster then conventional turbos.
Why does their website mostly discuss ATVs and snowmobiles (snow machines for Sarah Palin fans)? Seems like spending $2500 for a turbo for an ATV is silly.
Just looking to see if anyone has experience with or opinions of them.
Thanks,
T.J.
Taiden
Reader
10/4/10 11:27 p.m.
These are neat. In for more info. My first thought was you were asking us about electric superchargers.
I remember reading about those in Maximum Boost. I didn't know they were still around.
They were in use on a Miatas for a little while, and I tried one on a then-new Ford Focus circa 2001. Aerodyne was the company that was making / distributing them.
It worked pretty well, but not WAY better than a properly sized turbo and a good tune IMHO. At least on the Focus. They used a sealed oiling system with a proprietary lubricant on the turbo bearings, so installation was 1 step easier.
For my money, I'd stick with the reliability of a turbine wheel with no moving parts. Variable vanes make a lot of sense on paper, but not in my engine bay. YMMV.
RossD
Dork
10/5/10 9:21 a.m.
Who makes the variable vane turbos in the high end turbo cars? (IIRC Porsche has variable vane turbos, right?)
RossD wrote:
Who makes the variable vane turbos in the high end turbo cars? (IIRC Porsche has variable vane turbos, right?)
I think those are still KKK units.
Holset VNT is similar/the same, i believe.
Even MORE nifty, is that there's aftermarket controllers for the Holset units.
The Porsche KKK unit is similar to the Aerodyne unit, working at the periphery with smaller vanes:
Holset VGTs are very similar as well:
SVTF
Reader
10/5/10 10:26 a.m.
The Garrett VNT25 used on the Shelby Dodge's had variable vanes. Many new diesel turbos have variable vanes, some actuated with hydraulics using engine oil (Garrett).
TJ
SuperDork
10/5/10 10:44 a.m.
unevolved wrote:
I remember reading about those in Maximum Boost. I didn't know they were still around.
That's where I read about them, then googled and was surprised to see that they still exist.
Starting the late 90's (I think) the TDI had the VNT turbos. I know my 2001 has one. Seems to work well, though they say it's best to ensure you keep using them (IE: run the car hard occasionally) to ensure they don't start sticking.
I'm ok with that.
Raze
Dork
10/5/10 11:28 a.m.
unevolved wrote:
Holset VGTs are very similar as well:
You've misquoted here, pivoting vanes is how Garrett does it, that's not how the Holset VGTs do it. They have a slider section around the turbine which varies the turbine housing size, the vanes do not move as in the video you've shown. See here for more info on how a Holset VGT works: http://www.diyefi.org/forum/viewtopic.php?f=15&t=199&sid=24d8625657ba9471699eafe8fc0ceee4
Vigo
HalfDork
10/5/10 11:29 a.m.
Ive got a working variable-vane (VNT) turbo sitting in my turbo pile at home.. it came off a $400 parts car (1990 dodge daytona shelby vnt).
It's not new in any way. It's a decent idea, but it does add complexity and moving parts (a wastegate might be moving parts but its not gonna carbon up and stop working).
Also, i know it was found on the dodges (first oem app of VNT) that once you decrease the backpressure from the exhaust system it throws the factory controls off hardcore and the vane system cant compensate enough/fast enough to prevent wild boost spikes.
unevolved wrote:
Holset VGTs are very similar as well:
No they are not.
Holset VGT's use a sliding nozzle ring and not pivoting vanes.
The pivoting vanes are better from a flow/ theory perspective and the sliding ring works better in a HD truck application. I can explain more if you want.
Raze wrote:
unevolved wrote:
Holset VGTs are very similar as well:
You've misquoted here, pivoting vanes is how Garrett does it, that's not how the Holset VGTs do it. They have a slider section around the turbine which varies the turbine housing size, the vanes do not move as in the video you've shown. See here for more info on how a Holset VGT works: http://www.diyefi.org/forum/viewtopic.php?f=15&t=199&sid=24d8625657ba9471699eafe8fc0ceee4
also know how you can tell its not a holset.. 6 point cast nut on the turbine wheel. Holset uses 12 pointers.
The Aerochargers used on Miatas were highly unreliable. Ridiculously so. Even freshly rebuilt units had a high DOA ratio. Corky Bell hung on to one on his personal car for years as customer cars grenaded around the world, but I think even he has admitted defeat by this point.
From my understanding, they're now found on some Powerstroke diesels and apparently Porsche has figured out how to make it work. IIRC, the 2008 (?) Porsche turbo was the first mass-produced gasoline application of a variable geometry turbo.
Oooh OK that makes sense. I thought Holsets were different, but when I saw that I assumed I was wrong and modified my post. And yeah, I'd love to learn more about them.
Shaun
Reader
10/5/10 11:38 p.m.
I was less than convinced by their argument on their website that water and motor oil cooled and motor oil lubricated turbos are somehow un-reliable. there are literally million of said turbos out there that are 10+ years old with 100k plus on them working just fine.
they also argue that motor oil is the wrong stuff for turbo bearings. that is simply not true, engineers have had a handle on specifying the right bearings for that application for a long long time as well.
cool design and all. more parts, and way more money from where I am sitting, which is the cheap seats.
unevolved wrote:
Oooh OK that makes sense. I thought Holsets were different, but when I saw that I assumed I was wrong and modified my post. And yeah, I'd love to learn more about them.
The Holsets are cool as hell if you've got the room for them. If you've ever held one in your hands, they're friggin' ENORMOUS, and weigh every bit of 60lbs or more.
The neat thing is that you can go from so small that they work as an engine brake, to so large it'll make a Supra blush.
There are two people running them on 1st gen MX6s right now.
You can get them for dirt cheap on Ebay if you find the right supplier. They had an issue with getting clogged with soot, and most places will just replace rather than clean. You can get them from sellers that will literally have dozens of them for under $100 apiece. Buy two. One will definitely be good after some time with a toothbrush.
kb58
Reader
10/6/10 10:49 a.m.
I got all excited about them via the Max Boost book, too, for about a day. Researching it showed that, as Keith notes, all the extra moving parts makes them so unreliable they're not worth it. I can see them working on a Diesel though, since the exhaust temperature is so much lower than a gas engine.
It's not a surprise Aerocharger tries to insult turbos... but while their points may have been true at one time, after water cooling was added, it transformed turbos overnight into a very reliable component.