940turbo and lpg

Because there's more to the internet than hits alone, Valerio M wrote: Don't know where in the world you are (Italy?) but I've cross posted this to uk.rec.cars.fuel.lpg where people can be pretty helpful.

"Stewart Hargrave" ha scritto nel messaggio news: snipped-for-privacy@4ax.com...

nice way to say "hey buddy, you're off topic here!!!" btw, yes i'm in italy :)) anyway that 940 is just wonderful... i fell in love as soon as i saw it. i wish i could fix this fuel issue, 'cause otherwise i couldn't afford such a car :)

thanks for your help!! bye ____________________________ V a l e r i o M e r a n i

I read this article recently:

Graeme

Didn't mean to imply you were off topic - there are a few in the Volvo group that run on LPG, me included. But I thought some LPG specialist knowledge might be useful too.

I'm no turbo expert, but I didn't think there were any technical problems involved with such a conversion - whether anybody supplies a kit for your particular setup is another matter. But the chap I got my kit from, in the UK, had plenty to say about some turbos he'd converted.

's OK. Good luck.

Try asking Megasquirt

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs

"Valerio M" ha scritto nel messaggio news:WBHBb.186365$ snipped-for-privacy@news2.tin.it...

if someone cares to know: today i've talked to a lpg kit installer and he told me (only after asking me about the kW of the engine) that there are no problems with the volvo 940 2.0turbo, although seems like it's not recommended using lpg during city drive (while it works ok in motorway rides). he said the conversion'll cost me around 2000euros.

bye, ____________________________ V a l e r i o M e r a n i

What's the downside of using it for city driving? For whatever reason LPG vehicles are *very* rare here, I think I've seen two or three in my entire life aside from old school busses. Sounds like they have some fascinating advantages though.

"James Sweet" ha scritto nel messaggio news:ij2Cb.364693$ao4.1227250@attbi_s51...

well i don't really have a clue on the downsides, but will investigate further :)) the thing is very simple, here in europe gas is expensive (in a word, italian government pays much of its expeses thru gas taxes, cigarettes and alcohol), and i guess you'd switch to lpg too, if you paid roughly $1,20 for about 1/4 of a gallon :)) well i'm assuming you live in the us. Anyway as far as i know, all lpg does is cut the fuel costs, while you give up around 12-15% of your engine power.

bye, ____________________________ V a l e r i o M e r a n i

In a properly set up installation you will lose a few % in power, but

In theory it should be possible to make an engine run on LPG much more efficiently than it does on petrol, but in practice this is not really acheived. Remember that you are converting an engine designed to run on petrol, so there will be some compromises - in particular there is no real chance of exploiting LPG's much higher octane rating.

Other benefits include cleaner exhaust gases, particularly on pre-cat cars, less contamination of the oil, and less engine wear. On a Volvo, there is less in-car noise, too, because the underfloor fuel pumps can be turned off.

I'd want to investigate the comment that town driving is best not done on LPG. I can't think of any obvious reasons why this should be the case. This is where some of the advantages of LPG are particulary evident - fuel consumption is relatively high under these conditions, so is engine wear.

Here in the UK the latest news is that the tax break given to LPG is to be phased out over the next three years. But I console myself with the thought that one reason I converted was so that I made less environmental impact.

Okay, I'll now step in and disagree with both of you. :-)

I spent my apprenticeship as a mechanic installing LPG on vehicles. Most of them were _straight_ LPG on V8s.

If the installation is dual fuel, particularly on a injected engine, then a small power drop is to be expected. This is very much a case of the fuel injection being fairly efficient to start with.

In *stark* contrast, changing a carburetted engine to straight LPG can achieve in the order of 15% _more_ power than on petrol!

Liquid injection of LPG will _always_ beat petrol for both economy and power, but doesn't appear to be commercially available.

Generally, LPG has a higher octane rating and will be able to have more boost without detonation. If the engine is set up for LPG, the turbo system should actually respond _better_ to LPG than a normally aspirated engine.

I read recently that the butane content of fuel in Italy and Greece is much higher than in northern europe, and hence the octane rating is lower...

The energy content, by mass: premium petrol (gasoline) 43.5MJ/kg, average mixture of LPG 46.1MJ/kg.

Yes, there is, actually. Dual timing curve controllers, different wastegate settings for the two fuels, cold air induction...

Or, as in my case, removed completely. Of course, the 350 chev makes much nicer noises than the V6 did. :-)

The only thing that I've seen with some european convertors is that they can freeze if you haven't warmed it up sufficiently from a cold start and you plant it... Other than that, I don't know why this suggestion would have been made.

It is happening in Australia over 5 years, starting in 2008.

"Stewart Hargrave" ha scritto nel messaggio news: snipped-for-privacy@4ax.com...

answering to both Stewart and athol :) me neither. i think he ment the problem was related specifically to the 940 turbo engine (which btw is a 114kW engine, seemingly not the B230fk??). He sounded a bit prophetic and didn't give much explanation. since my knowlege on engines is very low, all i did was lurk thru the net in search of more info. in fact, the majority of articles i read were not so convincing about lpg and turbo engines. there seems to be always a problem with it. most of the problems are engine backfires that could damage sensors (well, besides engines, my technical english isn't also good :)). Everyone seems to agree that gpl engines do not perform so good if they're more than 150-160kW (which is a lot of power though).

We got one more tile in the puzzle: today another lpg installer refused to do the job. he said it'll most likely cause troubles and he wasn't going to bare any responsability... there must be areason for it i suppose!! i'm not giving up, but wouldn't want to end up trashing an engine like that :(

cheers, ____________________________ V a l e r i o M e r a n i

This was my Maserati that i had converted ,car is since sold but i have kept the Romano Lpg kit & tank if anyone is interested.

If you would l;ike to know a bit more about turbo engined cars and Lpg just drop me a line , the car before the Maserati was a 3.6 Twin Turbo Jaguar that i also had converted to Lpg but this was on an open loop system useing a R90/E vaporiser & a modified Mixer,its generally a good idea to have a flashlube kit fitted for the valves as the turbo's cause a lot more heat etc etc.

LPG can be more prone to backfires in the induction tract. You must take precautions against this, because the inlet tract downstream of the mixer (LPG carburetter) will be filled with explosive mixture, unlike the petrol system, where the injectors are very close to the inlet valves. The problem is usually cause by poor ignition components

- LPG makes it more difficult for a spark to cross, so it may try to fine a route back via another path. If it tracks to another plug lead, this can result in igniting the mixture in the manifold.

Make sure all the high tension components (plugs, leads, distributor cap, rotor arm, even coil) are in first class condition, and renew them if in doubt. Also make sure that the mixer has a blowback arrestor - this is a flap that closes to control the explosion and prevent it damaging fragile stuff upstream.

I thought Italy was the centre of the universe as far as LPG equipment goes, so I suppose there must be a fair bit of knowledge about it there.

Yes but...

I was exploring this a little on the .lpg group a couple of weeks ago. It's a shame that the pressure which LPG is contained at cannot be used to effect liquid injection - controlling it accurately would be the main problem. Main problems involved with LI seem to revolve around delivery and control of the fuel, and freezing injectors. But it does seem to be under developement - IIRC Canada is leading the way here.

Yep; with a turbo. Thus improving the volumetric efficiency.

I've heard this.

Something to do with how it behaves in its liquid form in different climates, I think.

Yes, by mass. But most people (in Europe, anyway) buy and measure their fuel consumption by volume. LPG is less dense than petrol, so miles per gallon is not as good.

I'm a bit sceptical about timing changes being utilised to exploit octane ratings. For sure you need to adjust the ignition timing because of the slower flame speed and different burning characteristics. This is not straightforward and is not easy to do throughout the power curve. But the higher octane can only be exploited by increasing the compression somehow. Wastegate settings and what-have-you can make a difference, but get nowhere near the potential of an octane rating around 110. Someone on the .lpg newsgroup was suggesting trying a diesel engine adapted with a spark ignition, running on pure LPG. I await to hear the resulting explosion.

One very important thing to consider is that the LPG mixer should be located _after_ the turbo (and intercooler, if fitted). The turbo is matched to the volume of _air_ to be pumped, and adding vapour fuel before the turbo will alter the volume of air/fuel mixture to be pumped by the turbo, shifting the operating conditions of the turbo to a different part of the turbo's characteristic "map". This can lead to "surge", insufficient boost and various other wierd problems.

The "Atmospheric reference" port of the convertor then needs to be connected to boost pressure immediately above the mixer - the convertor and mixer should see the same "reference" pressure. The closed-loop setup may affect this is some systems.

The only time that LPG should be used in a draw-through configuration is if the petrol system was that way to start with.

Some places are happy to limit the type of work they do because of potential problems with things they're not familiar with. I do the same in my work to some extent.

"athol" ha scritto nel messaggio news:bre7t2$2ba38$ snipped-for-privacy@ID-215292.news.uni-berlin.de...

sounds like you're pretty positive about the feasibility of it on a

bye, ____________________________ V a l e r i o M e r a n i

this system will work

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