Comments by "Mikko Rantalainen" (@MikkoRantalainen) on "" video.

Direct injection engine wouldn't have any carbon buildup with EGR. And the only reason to use EGR is because manufacturer wants to cheap out on DEF/AdBlue.
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2:55 WOW! I thought VAG TDI engines with lots of EGR activity and sulfide rich Diesel fuel had bad build-up but this looks even worse. The "after" image around 14:00 looks quite a bit different indeed.
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5:00 You should have mentioned where the carbon comes from. It's from EGR valve that circulates exhaust gas to the intake manifold. Without EGR the only thing moving in the intake manifold would be fresh air from the air filter and that wouldn't cause any carbon build-up, obviously. The EGR system is there to reduce nitrous oxide pollution and if you were to disable that system, the engine would last much longer but the pollution would increase, hence that's not allowed. However, with the TSI engine design, I fail to understand how EGR system could work even in best case in long term. Is this engine type going to suffer from carbon build-up failures in all cases? The interesting part is could you avoid this build-up if you used the revive product during e.g. every oil change. It doesn't seem to remove all build-up but does seem to have some effect and if you were to prevent the huge build-up in the first place, the build-up will grow slower because the air will flow more smoothly. After there's quite some build-up, it will clog even further pretty fast because of high turbulence due build-up in the intake.
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