Darklands

@ Sterling

You need a gastank because you start on gasoline.The respirator needs warm coolant.so you drive with cold engine 3-4 km on gasoline.Adding an fuelcell for gasoline at the rear under the floor require a lot of wielding.
In germany you need a TÜV safetyinspection .A lot of trouble.

Here´s a link to prins:http://www.prinsautogas.com/view_att...PG_English.pdf

Tony

I think more vehichles in the US should be ran this way...commercial trucks...busses(which are getting more common)..trains. Generally the larger vehicles that already have the capacity to store the extra volume of fuel needed.

So..where is the 928 barbeque attachement. Run a T fitting off the back and you can power your grill and campsotve!

tryng to get a grasp on the milage...
360km with 80L? is that correct?

Hilton

LPG tanks have a max fill of 80% - Darklands' fill is 63L so he's getting around 17L/100km which is about 14mpg.

Roy928tt

It's an 80 litre tank, maximum fill 63 litres, so that will be 360 km divided by 63 liters equals 5.71 km/l 100 km divided by 5.71 equals 17.5 litres/100km, the relief comes from the price difference between LPG and petrol. In Australia LPG is half the price of standard petrol ! It's around 13.5 miles per US gallon.

Roy928tt

HaHaHa Xlot what are we doing on here at this time of day?

Darklands

Here in Germany we drive 928 fast! ;-)My milage is perhaps low,but driving 928 must be fun!Gasoline cost here 1,18€ l,LPG 0,64€.So do the math.

15l gasoline/100km =17,7 €

or 17.5 l LPG/100 km =11,2 €

17,7-11,2=6,5€/100km

The installation of the LPG system was 3000 €.I drive 40000 km/year with my S3.

3000/6,5 =~46500 km =breakeven

It´s a nice way to reduce cost for cars with big engines then you drive a lot miles/year and your country has very high taxes on gasoline.

Last year gas cost 1,55€ and LPG 0,72€.

Roy928tt

It is very much the same story here in Australia, but here the government, in an attempt to prove it's green credentials, gives a $2000 cash back for gas conversions. Which was enough to pay for my simple conversion !

My gas conversion inspector wanted me to go with a more modern system, but a '79 doesnt have a crank trigger or oxygen sensor or any of those other things that EFI systems have that modern gas systems tap into.So I was happy to use 1979 technology for my car.

Hilton

I have a 2 year old and a 3 month old - sleep times aren't totally up to me

At least it was after 6am here.. you're in the earlier time zone!

belgiumbarry

hahhhaha... Tony, this is in fact the case in Belgium.... Propane or butane, sold in bottles for coocking etc.. are more expensive than LPG.. so people let them bottles refill at gas stations with the LPG ! ... which is "forbitten" by law ( safety reasons ? ) , as gastations may only fill fixed installations in cars, not loose bottles... but yeah...

Roy928tt

please find the 2nd part of this story, Twin turbocharged LPG powered 928,

zefke

Hello 928 LPG drivers,

Since the LPG is indeed burning hotter and stressing the valves and seats more (specially the outlet valves), I was wondering how things are going with your engines on LPG.

Very curious what your experience is!

Porsche greetings
Paul

Roy928tt

Hi Paul

Yeh it is true that LPG should be hard on valves and seats, I have not seen any evidence yet that I have any issues, however, I have done very few kilometers ie. less than 10 000 with the LPG fitted.

I don't expect problems however, as the alloy Porsche cylinder head is fitted with very durable valves and seats.

I had a LPG turbocharged Mini years ago and it ate a set of valve guides in 500 kilometers! Admittedly it was a very stressed engine, over 25 psi boost!

Cheers Roy

zefke

Hello Roy,

Thanks for the info. 10.000km is indeed not much to tell if it is OK or not!

I drove a '75 350SE merc on LPG after the first 5000km the valve clearance on the exhausts was gone. Later it became better, but after 10.000km you absolutely had to adjust the clearance on the exhausts or you would get some tremendous Back-fires.

Did you check the claearance on the valves of the 928?

Porsche greetings
Paul

Lizard928

Paul,
All 928s are hydraulic lifter cars. So this tolerance would automatically be taken up.

zefke

Colin,

I agree, but the hydraulics can take only a certain amount of wear. If it gets to much you will have to bring the system back to the basic setup.

At least that's how it works with my 1981 380SE merc with hydraulic lifters. They have as special measurement tool that fits on the valve stem. With this tool you can see wether your basic setup is still good. If it is not you can get different sizes of "push-rods" to compensate the wear and bring the system back to its basic setup. I believe on petrol you have to check this every 60.000 km. On LPG you probable want to check it more often.

Does it work the same way with Porsche? If haven't gotten into this matter that deep with my 928 (YET)...

Porsche greetings
Paul