So there you have it, a sneak peek at a motorsports turbo. Like other parts of the engine, parts need to be variable in geometry in order to maximize performance over the broadest operating range. Variable length intake runners, variable cam timing, variable cam lift, variable nozzle/geometry turbines, variable compression ratio, variable speed water pumps, and probably a few other variable things I’m missing on cars these days. With modern computing power, adding in some variable compressor side to gain performance is no big deal. Well, it does make the engine mapping that much more complicated! As with most things automotive, motorsports is used as the playground for proving out concepts that can make their way into production. Garrett used ball bearings first in motorsports turbos before they became available to the general public. They developed high temperature VNT with the Audi LMP program before that technology made it’s way onto vehicles you can buy like a Ford Powerstroke diesel and the VWs using the Garrett gasoline VNTs. So maybe one day, we’ll see variable geometry compressors on a turbo on a car you can buy in the future.
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I believe those vanes are like the IGV valves or 9th throttle as seen on the CART era Cosworth engines starting with the XD engine as I recall, could be wrong it was a long time ago. What they were for on those engines was to let the turbo spin in a vacuum on overrun so the shaft speed would stay higher and there would be less lag when the throttles were cracked again. They were also used to make the engine coming on the pipe less violent for more traction on corner exit.
I’m with you on that one. Its a combination the reworked TDI le mans turbo with a vacuum valve right after the restrictor. It’s used to save clutches, driveshafts, propshafts and the like. Its there to mittigate load on all parts, since they need to be running for 24 h, as well as spooling up the turbo faster, as it won’t slow down as much.
In a sence you could easily make something like this with a sliding plate valve or ballvalve and an actuator, with a simple switch that actuates on closed throttle.
The thin walls are actually used to minimise packaging constraints.
Glad to see I got beat to this… inlet vanes 100% remind me of the 80s vintage Renault DPV system. Cool to see stuff like that being used again.
I think the geometry of the valve pre swirls the air to help the compressor which a plate or ball valve won’t do. Plate valves tend to stick when there is decent vacuum on them too.
Plate valve won’t help swirl, but a ball valve can if you flow it accordingly. Some F1 teams use them as intake and exhaust valves as well.
There is one thing I’ve allways wondered though, but actually never tested: contra rotating impeller setup: One turbo rotates clockwise, with another one close behind it rotating counter clockwise. Should get efficienty up quite a lot, but packaging becomes a nightmare. Should get between 5% and 15% increase compaired to rotating them in the same direction.
BTW, anybody remembers the “Cyclone”? That piece of crap from the ’90?
If you have static blades in stages it’s like an axial flox compressor in turbines, super-efficient like in the 90% range.
Downwind it should be possible, but only if there is pressure involved. and at least 2 chambers: In other words: 2 turbo’s, and 2 static rows of blades. Or a very small unit like a mini turbine that houses al components into one. Axial compressors work in essence because of all the different chambers. Basicly a jet engine without igniting fuel.
There are 2 big problems with that though. That 90% is only in a very small range. And you don’t want to stall the air, is it’ll become unstable very quickly, wrecking the whole turbine. So you have to let it run on a steady speed and divert boost where you don’t need it.
The other problem is heat. You need a mighty fine intercooler to cool such a charge in the first place. or more likely several. Way beyond the packaging of a normal car.
Pre-swirl can help with compressor surge and efficiency. I found a quick study on it:
https://www.matec-conferences.org/articles/matecconf/pdf/2017/47/matecconf_bultrans2017_04002.pdf
It’s a updated version of this one
http://www.speedhunters.com/2012/08/the-monoturbo/
Maybe the 2nd actuator is for a VNT then… ha. Well, would have been cooler if it were variable vaned diffuser.
The Monoturbo isn’t a copy of the turbo in this article. It doesn’t have any variable inlet geometry on the compressor.
Also, I wonder how the new Dual-Boost Turbos fit in with this technology. It seems like turbo technology is getting really interesting. I honestly thought that we had seen the best turbos years ago. I have to admit that it is pretty exciting. I hope that someday it trixkles down to the consumer market. I would love to see what I could do with some of these puppies.
Here is the 2015 Merc F1 turbo inlet w/ guide vanes, hydraulic control from a Japanese race engine magazine I have. Motorsport turbos are the coolest.
https://www.instagram.com/p/BMy48gsgn6v/?utm_source=ig_web_options_share_sheet
Cool. Thanks for sharing.
Wow…. amazing that someone was able to snag a pic! Nice find.