Modern WRC anti-lag

[navmangt]

Evening all,

I was watching a youtube video of VW's ill fated 2017 wrc car testing and noticed its anti-lag system seemed very sophisticated. No pops or bangs, a slight whistle from the turbo off throttle now and again, then constant turbo speed until back on throttle:

https://www.youtube.com/watch?v=eUZptH4hDFw

Are the modern cars running a similar setup to the prodrive 'rocket'?

[Krikkit]

They had a few different maps for the strength of the ALS, some later tests had it ramped up to a much more aggressive setting: https://www.youtube.com/watch?v=P25IvqnBGlg

I believe (although I await correction) that most modern systems include an element of using the EGR to allow air bypass. i.e. When the throttle is closed an EGR valve is opened to allow the charge air from the compressor or hot-side intercooler to the exhaust turbine, keeping everything spun up for when the throttle is reopened.

Edited by Krikkit on Tuesday 6th March 21:52

[navmangt]

Correct me if I'm wrong but this is the bypass valve anti lag system, where fresh air is bypassed post compressor into the manifold pre turbine and ignited (due to the heat of the exhaust) with fuel rich flow coming from the cylinder?

I can understand if this is used in the older polo you linked, where incomplete combustion causes the pops and bangs but has this system become so efficient in using the fuel that it causes mostly complete combustion pre turbine without using a intermediate system like the can combuster 'rocket' device?

[User name]

Or are they running hybrid turbos?