Thread: 75 SIII LPG conversion, pics added

In a recent post I was asked to put up some pics of my LPG conversion that I just had done on my series 3 LWB so here they are.

Placement of the tank in the back of the car. Tank is 85 litres water which is about 72 litres of gas.

LPG gauge nicely tucked in so as to be as unobtrusive as possible. Perfect fit in the hole designed for the trip meter reset knob. Currently that resides where the choke would go under the steering column but is hard to turn so will be moved elsewhere as soon as a good spot is found. I wanted the install to not stand out too much or ruin the original look where possible but still be practical.

Is it an auxilliary petrol filler on the passenger side, or.....

...a concealed fill point for the LPG. I used an old aux fuel filler which I picked up for nothing, cut it down and modified it to fit a standard panel filler with abs surround, machined down to fit in the space (good old electric drill in the vice using wood chisels to machine it down - hah - who needs a lathe!), cut the hole and fitted into place in time for the install - all they had to do was hook it up!

For those who like facts and figures, all up cost was $2260 but I'll get $1500 back from Julia once the claim goes through. Another 2 days and the rebate drops to $1250. I supplied the tank ($60 on ebay 3/4 full of gas) which saves a few hundred off installation. So $760 net cost to me. Also went with the flexi lines rather than copper, these lines can be reused if they are removed, copper is single use only. Plus it's better for off road use. Costs a little extra but worth it I figure. If I ever want to relocate things or change tanks there's no need to shell out another $200 for copper lines.

Everything the guys did was done beautifully, the even went to the trouble of using rivets rather than self tappers to mount clips and small brackets so it all matched the rest of the car. The only casualty was the washer bottle which was bang smack where the converter had to go. If I can't find a spot to fit it I'll leave it off (I believe they were an optional extra anyway as not all S3 vehicles seem to have them) or I'll go for a bag type that goes flat against the side like a lot of Euro cars have.

Originally Posted by pfillery

I think that may be the problem, the cable is just that bit too short to properly reach the old choke hole, can't quite get a good grip on it to turn it, hopefully it should be right to go below the gauge or some similar spot. My original thoughts were the same as yours to redrill it below the gas gauge (I put the gauge there because the hole was exactly right and it was visible easilly and looked like it belonged there, didn't want to do some dodgy retrofit elsewhere that looked bad) but with daylight well and truly running out on sunday and the car needed Monday, it was time to put it back and worry about it another day. I'll see how it goes for length and may take you up on your generous offer if required. I'm fairly certain my washer pump and tubes have a one way valve, it always started as soon as I pushed the button but generally missed most of the windscreen because the flow was minimal and the jets mounted on the bonnet rather than the firewall, on the plus side my firewall is ok after missing out on years of internal water leakage. Quid pro quo!

I'm intrigued about your water injection system - what does this entail? Is it a vaccum operated one or a pump type?

The water inj system I use was sourced as a NOS (new old stock) item.

It's an Edelbrock Varajection system, and was seemingly a popular choice back in the 80's. Word is, Edelbrock stopped selling them after people tried applying them in ways which caused their engines to be damaged.

The system uses vacuum and coil/tacho pulses to function.

Pretty simple to hook up really.

Only problem I found, was that the 1x gallon bottle/tank is insufficient, and you have to stop and refill the bottle every 130-150klm, which is ok(ish) at the start, but soon becomes annoying.

I use a single shooter jet (kit has a double shooter too, but that one seems to be a bit too large to be practical), positioned above/central to the primary venturi. (I use a blueprinted 34 ADM Weber mechanical secondary carb)

Not sure what you're looking to do, so can't advise you much, other than to suggest you look at cooling your combustion chambers in other ways first. Look first at the ignition and spark plugs.

You can drop the combustion chamber temps by as much as 150-200 odd degrees just with ignition/plugs, so I'd be starting there.

I use reverse osmosis filtered water in mine, and initially mixed it 50/50 by volume with methanol, just to give it a bit more kick, but after a while I dropped the methanol and just went with the water.

*When I was mucking around with all that, I was focused on extending the poor fuel economy/range.

There are ways to have degrees of success in that area, but you have to keep an eye on your A/F ratio (air to fuel), as there are quite some ill conceived misconceptions going around as to which way to go there, and most people are of the belief that it's beneficial to run an engine far "leaner" than the standard 14.65:1 ratio.

Their notions are quite simply wrong.

I think I know where they got those ideas from, but I'll not say anything about that here, other than suggest that you need to go in exactly the opposite direction if you want to see some serious efficiency improvements.