The LPG-powered Focus ST already had „LPG-proof“ valve seats, but cylinder compression was declining since they were changed (they were adjusted to -Spinal Tap like- „11“ on all five cylinders).
As these engines are turbocharged, the old school „Flashlube Valve Saver“ would not be of much use – it relies on the vacuum in the intake of naturally aspirated engines (if I am not totally wrong it was invented to serve lead substitute zu oldtimer engines long before LPG became popular). Something with a pump needed to be installed.
The homepage http://www.valve-protector.de/ still exists, so I think you can still buy this system. It also was small enough to fit beside the lateral engine (yes, the tuning circle of this model is „subprime“). Good thing the LPG system was a liquid injection one – otherwise the evaporator would also have been in there…
In the end there was only one place to put the additive tank. And the intake manifold startet on the other side (mounting instructions recommended looking for the throttle valve and putting the injector just behind).
I had to ask a few guys, before I dared to drill into (plastic part of) the inlet manifold, but everything went well. The internal screw thread was formed and the injector put in place, after I was sure that the tube could be guided there properly.
With the Kit you need software and a USB <=> EIA-232 bridge. It is a cable with audio jack connector, the 3.3V version from FTDI. Then you can configure how the injection should be done (in my case relative to the engine speed provided the best throughput). Using too much additive will get you an unnecessarily dirty air intake, using too little will not protect your exhaust valves.
As we already had one child by then it took me only four days to install and configure everything during not being on a trip, but still on holidays. 😉
(Original Post: http://www.metalforum-owl.de/viewtopic.php?f=21&t=138&start=80#p28840, Aug. 20th 2010)