Here's a link to installation instructions if anyone is curious. This company is offering kits for 4-6 and 8 cylinder engines.
I asked him about California regulations and he said.. " this is for off road use only "

I guess just like the HID bulbs and all the rest of the aftermarket parts for sale.
Even a K&N filter is "for off road use only"

http://www.dudadiesel.com/files/propane/propanemanual.pdf


Here's a nice Video of an install on a Porsche Cayenne in UK
http://www.youtube.com/watch?v=ifDtBhP65O8

Looks pretty clean.

The more i read about it the more i want it. People associate the LPG conversions to the old single point systems that would feed one line to the intake manifold next to the MAF sensor.
Those systems were primitive and there was nothing electronic in them. A lot of backfires, smells and 'accidents'.

Current systems have an injector for each cylinder that uses manifold pressure to calculate load, oxygen sensor to calculate the unused oxygen, engine and LPG temperature and an ECU that does all the adjustments.
Funny that i read European forums and find lots of positive feedback about it and the few negative comments are usually left by US people.
The current systems auto calibrate the flow of gas and burn very clean. They allow custom mapping and are easy enough to be adjusted by owners using a laptop.
The other times i see negative comments is from people trying to install LPG on 1.8 4 cylinder cars/ Now that's something that will need a lot of time to recover the investment.

I see people commenting.. "well you aren't driving 100 miles a day in a 5.0 engine"
I do. 100 miles commute to work with the V8. And i LOVE my car. Don't want a Prius. I ride a bike normally but the season will soon be over and don't feel like paying gas stations that much.

The systems perform constant auto testing and will alert you in case of a leak. Premium Gas is 4.4 in California and i can bet money that it will never be cheaper. 2.10$ for LPG
Even if i loose 20% of my engine Horse Power i'm fine with cruising the CL500 @ 260hp

The Propane tanks fit nicely in the spare wheel compartment and i would throw away the spare either way (that's what AAA membership is)
Lots of EU companies will ship to US. And the price you pay for the Front Kit alone in the US can get you a Full kit with a nice tank from EU.

All the shuttle companies, buses and fleet vehicles use LPG in the US. I don't think they do it for the sake of environment. Why wouldn't we do the same. I understand if you have a 4 banger honda, it wouldn't make sense. But on a big V8 or V12 it would be worth it.
Mercedes, Honda, Volvo, Mitsubishi all make LPG cars. And i really doubt you will see the Mercedes stamp on LPG components. They will have a BRC or other big LPG manufacturers label on them.

What am i missing ? Is this another brain wash ?

One thing I would look at the need for when doing a CNG conversion is hardened valve seals.

I work for a truck equipment manufacturer and one of our large fleet customers recently wanted to convert part of their fleet to CNG bi-fuel service trucks.

They decided to go with 2012 Ford F-350s, SRW, 137" WB, 6.2L V8 Gasoline.

When their fleet advisers were discussing the process of the conversion, they said that to extend the life of the engine, they would be pulling the heads off the V8s and installing hardened valve seals. I vaguely remember him explaining that a standard valve seat engine would last 100,000 to 120,000 miles and that an engine with hardened valve seals would last up to 250,000 miles.

Just thought this may be helpful for people who are seriously looking into a conversion.

__________________
2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)