LPG on SIII SWB

[JBorges]

I’m considering install LPG on my S3 88”.

In all the pictures I see the tank (cylinder shape) is on rear tub in spare wheel place. I don’t like this solution (space problem) and I’m thinking install the tank (wheel/toroidal shape) under the rear tub between the chassis.

Anyone have this installation type? If is possible post some pictures...

Thanks

[mickeyw]

I’m considering install LPG on my S3 88”.

In all the pictures I see the tank (cylinder shape) is on rear tub in spare wheel place. I don’t like this solution (space problem) and I’m thinking install the tank (wheel/toroidal shape) under the rear tub between the chassis.

Anyone have this installation type? If is possible post some pictures...

Thanks

Hi,

I spent a long time contemplating this problem myself before I converted my Ninety to LPG.

One thing to consider is that if you like to take your Landy off road, having a tank underneath is not a great idea anyway.

There is very little useable space under an 88" without a fair bit of alteration.

I considered using the space where the exhaust silencer is, but decided that it wasn't possible to fit a big enough tank there to be worthwhile. There's not much room behind the rear axle. Also you have to modify the exhaust system, (move the silencer somewhere else,) and having a non-standard system is a pain when you need to replace exhaust parts.

I also looked at fitting a tank under the seat box, opposite side to the petrol tank. Again, getting a big enough tank there was the problem.

I thought about a small tank each side, and relocating the petrol tank. Now you're looking at a lot more work, and then there's the extra cost of buying two tanks.

In the end I conceded that the only solution for me was to put the tank inside.

I fitted a single 80 litre tank behind the seats. It's a close fit between the wheel arches and does not stick up about the bulkhead. I think it's possible to get a 90 litre tank that's the same length, just a bigger diameter.

For me the options were not ideal, but at least it made running a V8 vaguely affordable. I have lost around 40% of the floor space, but this has not proven too much of a problem.

I chose not to build a box around the tank as it leaves more room to stack stuff on top (soft stuff of course).

I am sorry to not be able to offer more positive suggestions, but I hope my thoughts will be useful for you.

Michael

[JBorges]

Thanks!

[aimbones]

Like mickeyw I found the area under the load area would only allow a smallish 40L tank however unlike mickeyw I couldn't live with reducing the load area so fitted 2 tanks one under the load floor and the second under the seat box, opposite side to the petrol tank giving me 80L nominal capacity. I haven't found any real reduction in ground clearance and have yet to ground either tank despite using the landy offroad when ever possible. My only regret was not initially wiring the two tank cut offs separately.

[West4x4]

Like mickeyw I found the area under the load area would only allow a smallish 40L tank however unlike mickeyw I couldn't live with reducing the load area so fitted 2 tanks one under the load floor and the second under the seat box, opposite side to the petrol tank giving me 80L nominal capacity. I haven't found any real reduction in ground clearance and have yet to ground either tank despite using the landy offroad when ever possible. My only regret was not initially wiring the two tank cut offs separately.

Would ike to see this. GF is thinking of LPG on her series 3 bing a SWB CSW we really dont want a tank taking up valuble room inside

[aimbones]

I'll try to take some pics this weekend as long as it's not tipping it down

[sotal]

Can you really justify LPG any more?

LPG costs around 55-60p / litre versus petrol being 99.9p (at the moment)

An average decent conversion kit returns 70% of the mpg of the car running on petrol, a more primitive system on an old engine is likely to return more like 50-60% max.

so if the normal petrol engine series does 25mpg the series on LPG will do 12-15mpg. So a 100 miles on petrol at 99.9p will cost £18.20, the same 100 miles on LPG will cost between £16.67 (55p / 15mpg) and £22.75 (60p / 12mpg).

But then you have the cost of the install, and the cost/hassle of insurance.

As an absolute best case example if you bought a decent kit (more expense) for the series and managed to achieve 17.5mpg on LPG and you were able to buy it at the cheaper end of the scale at 55ppl. Then 100 miles would only cost £14.29.

If you then took a worst case for petrol and assume the current low price doesn't last and it goes back up to 109.9ppl then it would cost £20 to do the same 100 miles.

Therefore the saving per 100 miles would be approx £5 (don't forget this is an absolute max saving).

How many miles do you do a year? For every 1000 miles you do you will save £50. So for every £1000 cost of installing the LPG kit you need to do 20,000 miles just to break even.

On the best figure from the more realistic figures you save £1.50 / 100 miles which is £15/1000 miles. So for every £1000 cost of installing the LPG kit you need to do nearly 70,000 miles. So if the LPG kit cost £1500, you're going to have to do 100,000 miles just to get anywhere near breaking even.

I must admit I've never installed LPG and all my figures on the percentage returns are based from other people comments I have read, but I've never found anything to disagree with them. If anyone can prove otherwise please do. I was put of even the thought of LPG by doing the maths. It would be useful to see some backed up data to show the mpg of a series running on LPG

[Fatboy]

I've converted two V8 90's and fitted a 35l tank under each seat. A 10 gal fuel tank was made to go under the rear floor and the battery moved into another location. The LPG tanks can actually be located quite high up above the chassis rails and I've fitted rock slider sills to aide in side protection.

I would have thought a similar arrangment would potentially be easier on a Series wagon because you don't have the rear trailing arm brackets to contend with.

[edwardatherton]

so if the normal petrol engine series does 25mpg

[mickeyw]

so if the normal petrol engine series does 25mpg the series on LPG will do 12-15mpg. So a 100 miles on petrol at 99.9p will cost £18.20, the same 100 miles on LPG will cost between £16.67 (55p / 15mpg) and £22.75 (60p / 12mpg).

But then you have the cost of the install, and the cost/hassle of insurance.

25mpg? Are you going downhill with the engine off? That's more like 2.25 diesel economy! I used to drive one of those too.

My old 2.25P never managed more than 20mpg on a long run. I had an overdrive and road tyres at the time to achieve this. Normal mpg was more like 17-18.

As a comparison the V8 90 I currently have has been gased for 7 years now. MPG on petrol was about 14-18 depending a type of trip. LPG running manages 13ish for normal running around. I did record 18 on a run behind a 2.5 diesel 90 once. Note this is with big BFG M/Ts.

It is true that LPG is not as economic as petrol. I reckon I save around 30% costs on average, not quite the 50% that is often banded around by the LPG converters.

I converted both my vehicles myself, the kits cost £750 for the V8 90 and a bit more for the RRC as I fitted twin tanks. I only do about 8000 miles a year but I plan to keep my motors for a long time, so I say LPG is definitely worthwhile.

As for insurance, I have never had any problems with that either. The 90 is with the NFU at no extra premium. I have been completely honest with them about the conversion. It was a self installed system, so they asked that it was inspected by an approved installer. No problems there.

My RRC with LPG was insured through Firebond, again no problems getting cover.

Michael

[rtbarton]

My old 2.25P never managed more than 20mpg on a long run. I had an overdrive and road tyres at the time to achieve this. Normal mpg was more like 17-18.

I got 24.9 on a long run SIII SWB, petrol, no overdrive but 750 x 16 radials and FWH fitted. I was driving to the vac gauge and the journey took 25% longer than normal!