Mat's BX Blog

Post by **mat_fenwick** » Wed Jan 12, 2011 10:11 am

At least you didn't have to go out into the street and close the stopcock...

Got the gas kit yesterday and it is considerably more advanced than the old one - rather than having to create a separate map for the LPG fuelling it intercepts the signal from the petrol injectors (thereby using the vehicles original map) and adapts that for the injector timing needed for LPG, altering it based on ambient/gas pressures and gas temperature. It also means the revs will be raised when things like the A/C compressor kicks in (the old system was slightly prone to stalling). Injectors can be batch or sequentially fired - so when switching fuels it will (should?) do it seamlessly. Rather than simply taking signals from one lambda sensor and adjusting the fuelling based one one bank the new ECU takes signals from both lambdas, and also can communicate with the original ECU via the OBD socket!

I was chatting to the kit supplier after I'd decided to buy it and he was saying they don't usually supply DIY but the number of installers (his customers!) that he'd trust with his vehicles he could count on one hand…

I told him of my experiences and he said "It wasn't Hardys was it?" These were the second lot I went to and it turned out he'd had Simon Hardy on the phone bragging how he'd had a customer in (me) and how he'd probably end up charging £300 for diagnostic time and no guarantee of fixing the problem - and then he'd end up fitting a kit if unsuccessful. Glad we didn't take it there in the end then.

As he said, this sort of thing ruins the reputation of the whole LPG industry.

electrokid · Post by **electrokid** » Wed Jan 12, 2011 10:51 am

Now that does sound as though it's properly engineered

and that the guy knows what he's doing in detail - it's so pleasant to be dealing with people like that - as for the other guy - what a drongo - I'm always amazed that some people think they can make a living on the back of bullshit !

At least you didn't have to go out into the street and close the stopcock...

scarecrow · Post by **scarecrow** » Wed Jan 12, 2011 10:53 am

Excellent business model - contempt for your customers! I hope he fails miserably. I distrust garages as much as I distrust estate agents and councillors and politicians and tv repair men and plumbers and builders and teachers and the police and doctors and bankers and all types of bull terriers and alsations and big dogs in general and supermarkets and energy companies and sport and pop and the rich...

rayfenwick · Post by **rayfenwick** » Wed Jan 12, 2011 11:30 am

electrokid wrote: ...I don't wear pyjamas ... So up into the loft...It was then I realised I'd completed the job without having to put any clothes on

I'm guessing your loft is boarded out then Brian? In Dec I did the wiring for a friend's new loft conversion and rewired the upstairs ring main below it. I got rockwool everywhere - the damn stuff is horrible to work with. I'd asked for it to be cleared before I went in there, but somehow that didn't happen...

It's definitely not a job I'd want to do naked

Post by **mat_fenwick** » Wed Jan 12, 2011 12:00 pm

Ouch! Getting that up your....don't even go there!

electrokid wrote:it's so pleasant to be dealing with people like that

And unexpected in today's world it seems. I sent him an email at half nine last night about some of the wiring (I suspect our Disco is too early to have the standard OBD protocol) and had a reply within half an hour!

electrokid wrote:Now that does sound as though it's properly engineered

Yes - things seem to have come a long way in 8 years. Another interesting feature is that if you have a high performance car (the kit is 'only' rated to around 400bhp) or notice any power loss due to the slightly lower calorific value of LPG you can allow supplementary injection with the petrol injectors under certain conditions to compensate.

scarecrow wrote:I distrust garages

It takes a good while to find one you can trust - I did when I lived in Gloucester but have yet to get to the same level of confidence with the ones around here although there is one that's getting there.

electrokid · Post by **electrokid** » Thu Jan 13, 2011 10:22 am

I'm guessing your loft is boarded out then Brian?

in the old house - yes - there was an electronics lab up there

and I had removed the glass wool insulation because that's nasty stuff too. Current house is done too but that's just a storage area - I've used vermiculite insulation around the edges which is damned expensive (which is why it's only around the edges

) but not nearly so nasty as the alternatives - produces an inert dust if kicked about but otherwise stays where it is. Best to seal insulation in polybags really.

contempt for your customers!

Finding the right tradesmen does seem to be fraught with difficulties. I used one particular garage for some 3 decades - Field Brothers in Woking - totally trustworthy etc, then when I started driving BXs THEY suggested I took it to Andy's Autos

and that was spot-on advice. I've discovered that they always do that - if they are faced with an unusual problem they will recommend taking it to someone they know who has better in-depth experience of the marque. Top marks there

And unexpected in today's world it seems. I sent him an email at half nine last night about some of the wiring (I suspect our Disco is too early to have the standard OBD protocol) and had a reply within half an hour!

People who are interested in what they're doing and like to get on with it - salt of the Earth

you can allow supplementary injection with the petrol injectors under certain conditions to compensate.

Damn that's good - economy for the trip to Tesco's and performance when you want to rag it - somebody thought about that

Mike E (uk) · Post by **Mike E (uk)** » Sun Jan 16, 2011 6:54 pm

The system on my 406 is EGAS. ( On the bent one, not the replacement one yet.)

It works very well indeed, and sits on the back of the petrol injector signal like you describe.

I can't tell the difference between running on gas & petrol, except the lack of smells on LPG and the the lack of pain at the filling station.

Cars go faster on gas. No more power, but I can afford to put my foot down further.

Mike

scarecrow · Post by **scarecrow** » Mon Jan 17, 2011 10:43 am

Am I mad contemplating lpg for a 14?

electrokid · Post by **electrokid** » Mon Jan 17, 2011 11:16 am

Well ok my initial reaction was somewhere between

and

but then I had another think...

You need to do the math to see how much you'd save - first indication would be how many miles it would take to save the cost of conversion or break-even point so I did some very ball-park math using 30mpg, £1.40 per litre petrol, £0.70 per litre gas, and £600 conversion and the break-even came out to 5,700 miles which is not a lot - accurate pricings will make a difference of course.

My other initial reaction was - why... when you already have a diesel !

scarecrow · Post by **scarecrow** » Mon Jan 17, 2011 11:29 am

The tzd is 'getting on' whereas the 14 has only one tiny rust spot on an inner wing seam, has always been garaged, fsh too and only 70kmiles. I rarely use motorways, so the turbo on the tzd is superfluous most of the time, and the car is shitty-slow at low Revs with only small savings on fuel...

Post by **mat_fenwick** » Mon Jan 17, 2011 12:05 pm

Mike E wrote:The system on my 406 is EGAS.

Egas was one of the systems that I was looking at, I decided on OMVL in the end due to local importer, better spares availability (at least round here), and good reports on an LPG forum I visit. Am I right in thinking you're swapping it over yourself Mike?

scarecrow wrote:Am I mad contemplating lpg for a 14?

Other factors to consider are cheaper road tax for a 14, and less oil contamination running on LPG rather than petrol and lower emissions (it should pass the MOT test for catalyst equipped cars without one). On the downside you will need to factor in some petrol costs unless you are prepared for lots of cranking before firing, as LPG systems don't have any choke like your carb. If most of your driving is short trips that initial mile or so on petrol could be significant. Also, loss of boot space although I'd put the tank underneath on the BX for neatness and ease of installation. Prices for LPG are very high at the moment due to the demand for heating - hopefully they will come down again unless the filling stations realise they can get away with charging more...

Somewhere like Tinley Tech will do a kit for just over £500 but that doesn't include fitting and it'd be a few days work I would suggest.

scarecrow · Post by **scarecrow** » Mon Jan 17, 2011 2:02 pm

I suppose I should just get it running right on petrol first. Thanks for the tips though.

Post by **mat_fenwick** » Mon Jan 17, 2011 2:57 pm

Probably, especially if the existing problems are ignition rather than fuel related. It's harder for the spark to jump the gap in an LPG/air mixture than a petrol/air mixture so will exploit any weakness in the ignition system. Also bear in mind there would be a slight drop in performance and economy from the lower calorific value of the fuel and the fact (with a carb'ed car) you'd be putting a restriction (gas mixer ring) in the air inlet system.

Mike E (uk) · Post by **Mike E (uk)** » Mon Jan 17, 2011 10:59 pm

I agree with Mat, engine performance will be reduced on a non closed loop engine system with gas. An EFI engine is best option.

The lower calorific value means you need to burn more gas per mile than petrol. 15 to 20% more.

As Electrokid says, the break even point in months depends on your milage and mpg. If you break the car, you can keep the gas kit and put it on another car.
If you fit the kit yourself, that halves the up-front cost.

An engine must run A1 on petrol before it will run properly on gas.

Mike

electrokid · Post by **electrokid** » Mon Jan 17, 2011 11:59 pm

What is the price difference between petrol and LPG at the moment ?