Diesel Blend Getting Common?

[Bailes1992]

I joined this forum over 2 years ago looking for information about LPG fumigation on diesel engines. It was rare in the UK, a few installs about in Australia and America but still a dark art over here. Most installs were basic using 1 injector and an ECU mapped on Boost and RPM alone. I was looking at it mainly for more power, the savings would have been a nice bonus.
Unfortunately I waited another 12 months before deciding to go for it and get it fitted which ultimately was a big mistake. That 12 months I was doing nearly 200miles a day, if I wasn't so worried about damaging my engine then it would have paid for itself in that 12 months alone.
When I did look into getting it booked in somewhere the boiler in the house went pop and the money I had to one side for the LPG install went on replacing our ancient Baxi with a Combi which turned out to be a blessing in disguise. 6 months later I ended up having to sell the car after I found out it had a new clutch at 5,000miles by a Ford dealer who cross threaded 3 of the bolts holding the flywheel onto the crank.

So here we are in October 2015 and the last 3 months I've noticed something very strange. I'm seeing a fair few lorries and large vans that have been converted to CNG/LPG.

Yesterday I saw two lorries with Prins logos on the front doors and 3 trucks with 'Dual Fuel' on them.
I've also noticed Volvo are building trucks which can run on 95% CNG!

Also every time I have a search about it I'm finding more and more companies offering it. Most systems seem to be fully sequential substitution based which use a mix of sensors including EGT and Knock sensors to reduce the amount of diesel injected and replace it with LPG, some offering upto 50% substitution rates at low loads.

Is anyone on here doing many installs on diesel engine vehicles? What sort of savings are they actually achieving?

I'll certainly be going for it as soon as my Focus is out of warranty. Until then I will be keeping a close eye on things as it does seem to be getting very popular, certainly on HGVs.
Question is do I go for a system which adds LPG as an additional fuel (15-20%) giving me some smaller savings but improved power or a more modern LPG substitution system. 2 and a half years to decide I guess.

[rossko]

The economics don't scale well to smaller vehicles. The complex systems cost as much as a "full conversion" for a petrol engine, but with smaller savings in the 10% league. So demand is limited.

I know Mint were selling a van-scale system a while back, we considered trialling it on a works van but decided it wasn't worth it even for us, we could see no sales potential in our area (rural, i.e. the target van market would be tradesman doing higher mileages than their city brethren).

Diesel/petrol/LPG debates are complicated by ever changing trends in city toll/exclusion schemes. Diesel cars seem to be becoming the demon just now.

[Bailes1992]

I agree about the economics not making much sense.
The system I would like for mine comes from a company called CRD performance. They use their own control module to mimic a petrol ECU so you can use any LPG system along with it.
I think a Liquid LPG injection system which would help to cool the charge temperatures would go down a treat.
However I would be doing it for the performance and emissions benefits rather than for the economy. My car currently costs me 10p a mile to run. A 10% saving would be 1p per mile. That means a £2000 install would take 200k to pay for itself! However look at it as a performance modification and it's not too bad.

I'm unsure what the MINT guys were using, I know I tried to get some information out of them but they really didn't want to know and certainly were not interested in doing the installation on my Mondeo. Sounded like they had one or two go bang.

It'll be interesting to see what the more advanced substitution systems are gaining in terms of savings. If they are averaging a 40% substitution ratio then maybe it would make much more sense economically. Again today I saw a handful of HGV's with dual fuel systems fitted, they must work.

[LPGC]

There are a few LPG systems available off the shelf for diesels and these generally include an EGT sensor to install in the exhaust - they reduce or completely turn off LPG injection if exhaust temp gets too high. These come as a complete kit for install on common rail diesels, no need to buy another LPG ECU...

There are two main issues with LPG on diesels, the EGT and star fire, dosing with too much LPG can cause both. To me, so far it seems the off the shelf systems will be safer for most installers - They come with injectors / reducer and recommendations on nozzle size and pressure for different engines...

£2k for an LPG blend system, for most vehicles, seems a high price. Wouldn't be too surprised if the same firm were asking a similar price to convert a petrol vehicle yet good installers on this forum convert petrol vehicles for just over half that price and off the shelf diesel systems are not much more expensive / there isn't much difference in the amount of work needed to convert a petrol or diesel.

For most cars, including your Mondeo, I would charge more like £1200, this would be fitting an off the shelf system with EGT protection and using manufacturer recommend dosage...

Simon