Just come back from Sotico and observed the very clean exhausts on these WRC vehicles .
My exhaust is always sooty - Now I know it is recommended to run rich for safety reasons - especially when the raising boost or higher flow turbos but are we sacrificing performance by being too conservative with our fuel maps?

When running on leaded fuels you would also get a nice clean pipe like that.

Plus the engines are running a damn site hotter so the carbon buildup from the exhaust valves back is basically nill.

Dan