V6 T5/Multivan

[Tornado T5]

Just wanted some feedback from anyone that owns a V6 T5/Multi. I have a friend that wants to try the newest technology Liquid Injection (LI) LPG (not vapour injection) system on a V6 T5 however he would like some real world average fuel useage for his "spreadsheet" before he makes a final purchase. I'm also interested because LPG is now 1/3 the price of diesel in Melb and if the claimed economy difference between LI lpg and petrol is between 5-10% then the figures even allowing for the conversion and initial purchase price of a V6 VW need more serious analysis.

I actually raised the question with my dealer after the oil cooler replacement if VW were looking at LPG more seriously now that the pricing gap is enormous. I know that the engine warranty is voided atm if you convert to LPG however if sales drop off due to diesel pricing they can't sit back forever.

In my own case, the ease of towing with my tdi would keep me away from a petrol/lpg unit unless the fuel use increase under heavy loads was less dramatic then what I experienced in my previous pet/lpg T4. It's also becoming more difficult to recoup increased cost with customers.

[shogun2]

I don't know the answer to the petrol/lpg question. However, I also have a similar question over the diesel/lpg system of http://www.dieselgasaustralia.com.au/

Cheers,

[gregozedobe]

I did a bit of reading on the diesel/gas conversions (ie not just the sales gumph on their web site).

It seems the only real advantage for most vehicles is the price difference between diesel and LPG.

You can only use about 1/3 LPG to 2/3 diesel though, and you have to factor in that you don't go as far on a litre of LPG as you can on a litre of diesel, so the maximum possible cost savings aren't quite as great as you might hope.

Their web site didn't mention any conversions on VW PD diesels when I looked. I wondered how well the LPG fuel injection would be integrated with the standard VW ECU.

[Seano]

Their web site didn't mention any conversions on VW PD diesels when I looked. I wondered how well the LPG fuel injection would be integrated with the standard VW ECU.

It doesn't. Having seen one of these conversions (not in a VW) I could see how it works.....kind of. Basically, the conversion doesn't touch or even talk to the ECU. It does rely on input from some of the engine sensors though.

Essentially, the gas is inserted into the air intake prior to the turbo (in the T4, I suspect a custom collar would have to be inserted on the intake line between the airbox and the engine).......the LPG brain then uses the engine data to decide how much LPG is injected into the system.

The vehicle ECU doesn't realise that there's LPG in there and it is not re-mapped to suit. The LPG brain is tuned to suit the ECU.....

[gregozedobe]

Hmmmm, then depending on how comprehensive the VW ECU's programming is, it could get confused at how much power and heat is being produced on such a low accelerator setting (because the LPG side is doing an extra 1/3 of the work). And if anything goes wrong the factory limp mode will only control the diesel side of things, not the LPG.

Oh well, if anyone does install one, please let us know how it goes.

[Tornado T5]

Sorry if I wasn't clear however my friend wants to convert a PETROL T5 V6 to LPG dual fuel using the latest Liquid injection LPG system and was after some real world V6 economy numbers.

[Tornado T5]

I don't know the answer to the petrol/lpg question. However, I also have a similar question over the diesel/lpg system of http://www.dieselgasaustralia.com.au/

Cheers,
This is a vapour injection system however the newer (and considered better system) is Liquid injection which if tuned on a dedicated LPG car will actually produce more power then the original petrol engine.

[gregozedobe]

Sorry if I wasn't clear however my friend wants to convert a PETROL T5 V6 to LPG dual fuel using the latest Liquid injection LPG system and was after some real world V6 economy numbers.

My apologies, I was responding to Shogun2's (hijacking) mention of diesel/gas conversions.

I think the petrol V6s are quite rare in T5s, in fact I think I've only ever seen one (that I've noticed the little V6 badge on anyway).

And what he/she actually needs are real world V6 petrol consumption figures AND V6 LPG gas consumption figures, otherwise they will be relying on general or marketing figures for their evaluation.

Maybe you could ask the same question on the brickyard (UK) site as there seems to be more T5 owners there (but again nearly all TDI engines, not petrols) site address is - http://www.brick-yard.co.uk/forum/default.asp

[shogun2]

Sorry, didn't mean to hijack the thread. I was responding to the last paragraph of Tornado T5's post.

[Tornado T5]

Thanks to all. No probs Shogun2, in fact one of my suppliers deliver drivers wants me to visit a company in Pakenham Vic, which has converted a couple of Hilux diesels to LPG/Diesel and the owners are absolutely rapped in the results.

[shogun2]

OK, means that it may require a bit more investigation here in Adelaide. I'm interested in anything that can make the fuel cheaper (and the Kw and torque increase can only be good). I also want to understand what the downside is (and I know there is always a down side).

[gregozedobe]

I also want to understand what the downside is (and I know there is always a down side).

I appears not everyone had a happy experience with diesel/Gas
http://www.brick-yard.co.uk/forum/forum_posts.asp?TID=29122