such a great forum

Very well said, I wouldn't like to tot up how much this site has saved me in simple fixes, just like the one you mention.

If you fancy it there is a meet at Tatten Park on the 7th September, currently Tony & myself are attending, there is thread open with the details.

Zitat von wayneblackwell1000;50840

Very well said, I wouldn't like to tot up how much this site has saved me in simple fixes, just like the one you mention.

I agree, being a bit out of the mainstream I have found the site very helpful, especially when it comes to thoughts of modifications..... As a result of what I have read on these pages I am about to change the diff to a 3.64 with LSD, and while fitting a new set of Bilstien's also fit the rear reinforcing plates and front camber plates, all as a result of the experiences of others I would not have be aware of without this site.

Well done all the contributors.

Alan

No worries

Zitat von Wildatheart;50828

I absolutely adore my 8-er, and I feel great about running it as a daily driver (especially since converting it to LPG).

I have been looking at various LPG systems for a while now with a view to getting one installed when the funds are available.
I would be very grateful if you could provide some information about your LPG system;

What did it cost?
What type system is it?
How long did it take to install?
Where is the tank located and what capacity?
Where is the filler located?
Is the performance as good using LPG?
Have you noticed any adverse affects using LPG?

Many thanks.

BUT.... 1800 pounds even at todays silly prices will buy you around 350 gallons of fuel, which under motorway driving will get you upto 8500 miles, maybe more @ 75mph.

LPG is roughly half the price, so you would need to drive 17000 miles before you break even on the project, and that assumes there are NO technical glitches of the LPG install, requiring costly maintenance.

I've driven about that in three years ownership.

For me at least it doesnt make economic sense to convert, unless you intend to drive 25000 miles a year for the next few years. That coupled with adding further complexity to an already (at times) troublesome and ageing motor car scares me somewhat.

LPG from factory YES
LPG conversion on a e31.... ?? Discuss

The last time I was up at JAYMIC in Cromer they had an E9 3.0 csl that they had converted to LPG for a South American owner that used to come over and use it to tour in Europe. I believe they have significant experience with LPG and of course BMW's. I suggest you talk to them.

My own experience here with LPG was pretty good running it in a Toyota mini coach. The drawbacks? The size of the tank if you don't want to remove the petrol option, the more limited availablility and most importantly the reduced range between fills.

You can buy a lot of petrol for 1,800 and personally I would not do an 8.

Thanks for the info, a few more questions if you dont mind;

Do you have a guage for the LPG?
How many miles on a full tank of LPG?
What happens when the LPG is empty?
Where is the changeover switch located?
Do you get cheaper road tax?

I had a brief experience with LPG about 3 years ago - I had an E32 7er with LPG for about 6 months until the engine threw a wobbler on the motorway about 100 miles from home. Power suddenly disappeared and running very lumpy, managed to limp back at 40mph top speed. The garage found 3 rocker arms had actually broken and said it was likely something to do to the LPG as they had never come across such a problem before. Due to the overall value of the car I ended up getting rid as it was and replacing it with an E38 7er.

I too, get depressed when filling up at ~£100 a pop. I only do about 8k miles pa but would most likely do a lot more if the cost per mile was cheaper.

However, if Im not using the 8er, Im using the 7er which has the same engine and fuel consumption. I do about 12k miles pa in the 7er so really could do with getting both of them done - 2 x £1800 = ouch !!

I am contemplating sticking it all on a 0% card for a year or two, that way the pain is much less and the overall cost shouldnt be too much difference until its all paid off.

The only thing that bothers me is what the government might do regarding the tax on LPG. A few years ago, diesel was half the price and there was a boom in diesel car manufacturing and sales. A lot of people enjoyed a lower cost of motoring for a brief spell until the government realised how much tax they were losing from petrol sales and hiked up the tax on diesel to compensate.

Whats to stop them doing the same with LPG?

Zitat von rob840;51188

I had a brief experience with LPG about 3 years ago - I had an E32 7er with LPG for about 6 months until the engine threw a wobbler on the motorway about 100 miles from home. Power suddenly disappeared and running very lumpy, managed to limp back at 40mph top speed. The garage found 3 rocker arms had actually broken and said it was likely something to do to the LPG as they had never come across such a problem before. Due to the overall value of the car I ended up getting rid as it was and replacing it with an E38 7er.

This sounds like a typical response from a mechanic who doesn't have a clue why the failure occurred, so the non-standard part gets the blame. You should have asked him in what way the different fuelling system could affect the rocker arms, I'm sure an equally nonsensical answer would have been forthcoming.

The main potential issue I'm aware of due to running on propane are valve seat recession due to higher burn temperatures -- never heard of it happening on a BMW, since the valve seats are hard enough to handle the extra heat for hundreds of thousands of miles. This is a common problem on Zetec engined Fords, and some Japanese cars, and is similar to what happens when you run an engine designed for leaded petrol on unleaded. Most unleaded engines are fine on propane, it's just the few that are barely hard enough for unleaded petrol (i.e. some Ford, Honda, Toyota, ...) that are problematic.

You can also get problems if the system is poorly mapped, allowing it to run lean, in exactly the same way that a poorly mapped petrol car causes problems. This should never happen in practice, and I've never heard of it happening. Certainly you don't get the issue of pre-ignition with a lean propane mixture that you do with petrol (which has killed many Japanese import turbo cars mapped to run on 100+ RON fuel), as the octane of propane is much higher (around 110), so it's really just high combustion temperatures to worry about.

Without knowing anything about the engine, my best guess is the rockers were probably damaged by an oil starvation issue. On the M70 V12, the banjo bolts on the top end oil sprayer bars are known for working loose. On the M60 V8 the oil pump bolts are known for working loose. I expect your mechanic had never heard of these issues either, so it's easier to blame the modifications than actually investigate.

Interesting that a smaller-chain molecule such as Propane (LPG) has a higher Octane rating than Octane itself, when generally, it's the longer chain molecules that have higher Octane ratings.

Interesting article about LPG and gasoline here:

http://www.thepanamanews.com/p…/issue_21/science_01.html

Found this out of interest, to quell the doubters:

http://cars.uk.msn.com/greenmo…spx?cp-documentid=6760122