slate blue

For the guys running LPG and others who might want to some day, make sure you are using the correct oil and changing it more often. A standard oil, one that is good for petrol is no good at all. The minimum is a diesal oil but Penrite make a gas oil and that is what I am using now. You do need a thicker oil, I would suggest using a 20w/60 which Penrite sell. They are a great company and strong on the info front.

The 928 has very tough valves and seats, you don't have to worry about that aspect. The valves are faced with Stellite and the seats are made from stellite. I never face 928 valves for this reason. If there is a problem which I haven't had yet I would replace them.

We have a current model Holden Caprice, it has the 6.0 LS2 engine and runs on gas, that system is stunning. More power, around 5% without tuning, upto 10% more power with tuning/remapping. Economy is awesome along with driveability. It is a JTG system from Holland and I must admit was not cheap but after rebate and a year of driving we are square. The system costs $5250 gross, it is a liquid injection system.

Basically 3 types of systems, the manifold system, used a lot by taxis, the direct injection system, in our case there would be 8 gas injectors and then the liquid injection system. Can handle around 550 hp as fitted to the Caprice, then you would need bigger injectors. You will start to hear more about this system in the future.

In the Caprice, Sydney Melbourne return and drive around the City etc for the week cost $150 AUD That was with 4 people in the car, fully loaded running the air, range was 675 kms on gas onlone. More cars here should run gas, less petrol imports and less pollution.

Greg

zefke

Hello Greg,

Thanks for the inputs.

Happy to hear that something is tough on the 928, after all the electric issues I began to doubt a little..

I'm not sure about the oil story though, normally LPG burns much cleaner than petrol and you get no dilution of the oil and much less carbon residu. Your oil and oil filter stay much cleaner and as far as I know the normally used oil will do perfect on LPG.

As for LPG systems, as far as I know there are only 2 actual manufacturers worldwide of indirect injected liquid LPG systems. One is Vialle in the Netherlands with their LPi system and one is Icom in Italy with their JTG system. In Australia there is also a company holding some patent on a system, but I don't believe they actually sells systems.

Porsche Greetings
Paul

slate blue

Hi Paul, I thought my system was Dutch but evidently it must be Italian. It is a JTG system. So the oil, it has nothing to do with dilution. It has to do with the oil becoming acidic through the mixing of combustion by products into the oil. The level wont change like with petrol getting into the oil like it did with carburetors. It can get so acidic on gas that it can eat away the white metal in the bearings. Do some research, however I will give you my personal garantee that I am correct on this issue. Diesal does the same but to a much lesser extent.

Greg

zefke

Hello Greg,

I'm still not convinced on the oil story. Where did you get the information?

Over here LPG consists of 40% Butane and 60% Propane in wintertime and vise-versa in summertime. It is an absolutely clean fuel with a straigt RON of about 100 to 110 depending on the mixture (no additives here!!). There are almost no sulferic residu's like in some petrol and diesel fuels. It is the cleanest fuel for your car you can get over here..

I know that some countries have some propylene and propyn inside the LPG, which will give you some sludge in your vaporiser due to polymere transformation. You don't have this problem if you use an injection system though. But for your oil to become acidic you would have to have sulfer or something in your LPG and as far as I know that's not the case. At least not over here in Europe, maybe it is an issue in Australia ? I'm not sure.

Porsche Greetings

Paul

slate blue

Hi Paul it comes from the oil engineers at Penrite.


"Older LPG fuelled cars and light commercial vehicles will respond well to this higher viscosity oil. Contains carefully chosen additives to minimise nitration and prolong bearing life. Ideal for older fleets of mixed fuelled light vehicles including turbocharged. Good for four stroke motorcycles too.
SAE 20W-60, API CG-4/SL, ACEA A3/B4, HN 2314, MB 229.1"

Product info tech sheet.

http://www.penriteoil.com.au/pis_pdf...JAN%202010.pdf

Do some searching on the topic, some people have lost their bearings.
Greg