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[Lazydocker]

Finally got the mig back from the lpg installers shop.
Must admitt they did a great job.
So was wandering now about one thing.
Average consumption on the trip computer, do the rest of you have it (probably Tunnie could share some light since his is 2.2)?
Mine is showing consumption still although it is increased ( it probably should be when it is working on lpg)
I never tried to figure out how the trip computer works but I was surprised this works on lpg.
Oh by the way lpg is BRC sequent

actually your petrol ecu is still thinking the car is using petrol because lpg ecu uses petrol ecu signals to arrange its injection timing..  although not 1 to 1, still your lpg consumption is proportional to MID reading..

ehem..

Yep... You had covered it but I thought I'd give a more detailed description

 Anyway... No-one was listening to you

[cem_devecioglu]

Finally got the mig back from the lpg installers shop.
Must admitt they did a great job.
So was wandering now about one thing.
Average consumption on the trip computer, do the rest of you have it (probably Tunnie could share some light since his is 2.2)?
Mine is showing consumption still although it is increased ( it probably should be when it is working on lpg)
I never tried to figure out how the trip computer works but I was surprised this works on lpg.
Oh by the way lpg is BRC sequent

actually your petrol ecu is still thinking the car is using petrol because lpg ecu uses petrol ecu signals to arrange its injection timing..  although not 1 to 1, still your lpg consumption is proportional to MID reading..

ehem..

Yep... You had covered it but I thought I'd give a more detailed description

 Anyway... No-one was listening to you

as usual..  no problem

[Lazydocker]

Finally got the mig back from the lpg installers shop.
Must admitt they did a great job.
So was wandering now about one thing.
Average consumption on the trip computer, do the rest of you have it (probably Tunnie could share some light since his is 2.2)?
Mine is showing consumption still although it is increased ( it probably should be when it is working on lpg)
I never tried to figure out how the trip computer works but I was surprised this works on lpg.
Oh by the way lpg is BRC sequent

actually your petrol ecu is still thinking the car is using petrol because lpg ecu uses petrol ecu signals to arrange its injection timing..  although not 1 to 1, still your lpg consumption is proportional to MID reading..

ehem..

Yep... You had covered it but I thought I'd give a more detailed description

 Anyway... No-one was listening to you

as usual..  no problem

Pardon?

[zirk]

so in other words, the mid talks rubbish 

Guess it would be more accurate if LPG had same burn factor of petrol, the inaccuracy is that you need to chuck in more LPG to get the same amount of power from the burn.

I think Tunnie you should  base your comment's on a more personal experiences of your own Omega's rather than than an global indication of Omegas in general that you may read on the Forum, most of my posts are based on experience and are based on facts that I have encountered.

Maybe I'm repeating myself in saying my MID on lpg is spot on, may be I'm just lucky, or maybe you should take your lpg installation back back to the Installer and ask them them to re calibrate it properly.

Either way my MID does not read 'dangle berries's.

Chris

[mathewst]

One thing partially related to this.
A colleague of mine had an old Opel Kadett before (long before).
He was running it on lpg for a long time and never had any problems but one.
Fuel pump on his car went dead usually once a year.
Any problems with fuel pumps on migs that can be similar to this one with Kadett?

[Kevin Wood]

One thing partially related to this.
A colleague of mine had an old Opel Kadett before (long before).
He was running it on lpg for a long time and never had any problems but one.
Fuel pump on his car went dead usually once a year.
Any problems with fuel pumps on migs that can be similar to this one with Kadett?

There's no reason for LPG to affect the fuel pump, except if it's driven with very low fuel level in the tank, because the engine won't stop if the fuel pump sucks air.

Kevin

[mathewst]

Thanks for the info Kevin

[Lazydocker]

Maybe I'm repeating myself in saying my MID on lpg is spot on, may be I'm just lucky, or maybe you should take your lpg installation back back to the Installer and ask them them to re calibrate it properly.

Either way my MID does not read 'dangle berries's.

Chris

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

[tunnie]

Maybe I'm repeating myself in saying my MID on lpg is spot on, may be I'm just lucky, or maybe you should take your lpg installation back back to the Installer and ask them them to re calibrate it properly.

Either way my MID does not read 'dangle berries's.

Chris

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

 

[Kevin Wood]

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

It's just turned out that way due to a quirk of calibration, I think.

I'm sure it can't work by design. If nothing else, LPG is being injected as a vapour so you couldn't predict liquid consumption using injector duration in the same way that the MID does for petrol. It depends on the relative temperatures and pressures of the liquid and vapour as to how much liquid is flowing.

As I said.. Luck of the draw that the reading happens to coincide with LPG consumption for this particular setup.

I think every LPG car I've checked (from a quick check of the MID) it tends to read somewhere between petrol consumption and LPG consumption on gas, which is about what you'd expect. Engine load is slightly higher for a given output because the vapour injected displaces some air (hence petrol ECU is using slightly longer durations, hence MID reads lower MPG). Then there's an additional factor that LPG has a lower calorific value, which isn't accounted for at all.

By far the biggest unknown is probably the difference between individual system calibrations, though.

Kevin

[Lazydocker]

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

It's just turned out that way due to a quirk of calibration, I think.

I'm sure it can't work by design. If nothing else, LPG is being injected as a vapour so you couldn't predict liquid consumption using injector duration in the same way that the MID does for petrol. It depends on the relative temperatures and pressures of the liquid and vapour as to how much liquid is flowing.

As I said.. Luck of the draw that the reading happens to coincide with LPG consumption for this particular setup.

I think every LPG car I've checked (from a quick check of the MID) it tends to read somewhere between petrol consumption and LPG consumption on gas, which is about what you'd expect. Engine load is slightly higher for a given output because the vapour injected displaces some air (hence petrol ECU is using slightly longer durations, hence MID reads lower MPG). Then there's an additional factor that LPG has a lower calorific value, which isn't accounted for at all.

By far the biggest unknown is probably the difference between individual system calibrations, though.

Kevin

Yep... But I'd love to know how!

Tunnie... I think it's your way with words that got the reaction, and understandably TBH

I've met you in person and know that's just the way you are and that there's nothing else to it... Has Zirk?  :-? I had a similar thing with another member a while back... Was just my poorly worded statement that came across wrongly

[tunnie]

Tunnie... I think it's your way with words that got the reaction, and understandably TBH

What can I say, i say what i think 

Maybe instead of "mid talks 'dangle berries'" it should be "mid will behave like a government, lie" 

In defence, that original comment was made to the OP who knows me well, and as far as I know took it the way intended 

[cem_devecioglu]

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

It's just turned out that way due to a quirk of calibration, I think.

I'm sure it can't work by design. If nothing else, LPG is being injected as a vapour so you couldn't predict liquid consumption using injector duration in the same way that the MID does for petrol. It depends on the relative temperatures and pressures of the liquid and vapour as to how much liquid is flowing.

As I said.. Luck of the draw that the reading happens to coincide with LPG consumption for this particular setup.

I think every LPG car I've checked (from a quick check of the MID) it tends to read somewhere between petrol consumption and LPG consumption on gas, which is about what you'd expect. Engine load is slightly higher for a given output because the vapour injected displaces some air (hence petrol ECU is using slightly longer durations, hence MID reads lower MPG). Then there's an additional factor that LPG has a lower calorific value, which isn't accounted for at all.

By far the biggest unknown is probably the difference between individual system calibrations, though.

Kevin

imo, there is a simpler way.. for a specific calibration (after its done) calculate the miles done and used lpg and compare with mid.. you will find some ratio which wont change highly with temp..

[Lazydocker]

...snip...
imo, there is a simpler way.. for a specific calibration (after its done) calculate the miles done and used lpg and compare with mid.. you will find some ratio which wont change highly with temp..

That's what I've done... I know that I can get about 300 miles to the tank in normal, mixed driving and 350-380 on a run

[zirk]

I still don't see how it can possibly read spot on :-/ LPG produces less bang per injection cycle on a direct comparison, volume for volume comparison... Simple fact. LPG needs more volume to produce the same mass of fuel for burning, therefore it must use more LPG than petrol to produce the same bang

I just can't understand how the MID is 100% accurate... Something clever must have been done and I just can't work out what :-/

Well having read the posts on how the MID takes its info form the petrol ECU when running on gas, I don’t know why in that case it appears to read spot on, all I know is the MID is telling me that Im doing less MPG on gas than I am on petrol, around 10% less on a run. The trip distance and trip gallons used confirm this as well.