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[JamesV6CDX]

Since conversion, I've been getting about 21mpg on gas under all driving conditions, which equates to about 45mpg in cost terms.

Last night, I spent 2 hours re-mapping the LPG Ecu. I re-calibrated the ECU, so Instead of 8 points on the map I had 4. I didn't add any more, and set it up using just these 4 points. I got it as close as I could, with +/- 5% deflection, and it was running great.

Today, I filled the LPG tank. I did a run from Cardiff, to Gloucester, Cheltenham, and then back to Cardiff. Not hanging around, average of 79mph. Some sitting in traffic, and mostly A roads back, to aviod Severn Tolls.

In total, I did 156.7 miles. I re-fuelled with LPG when I got back to Cardiff (same garage/pump) and to the top, it took  22.79 litres - £10.46.

That's 157 miles to £10.46. At 45.9p/litre, this worked out at 31.3 MPG on gas. That's equivilent to over 65mpg in petrol costs  

[Jay w]

Since conversion, I've been getting about 21mpg on gas under all driving conditions, which equates to about 45mpg in cost terms.

Last night, I spent 2 hours re-mapping the LPG Ecu. I re-calibrated the ECU, so Instead of 8 points on the map I had 4. I didn't add any more, and set it up using just these 4 points. I got it as close as I could, with +/- 5% deflection, and it was running great.

Today, I filled the LPG tank. I did a run from Cardiff, to Gloucester, Cheltenham, and then back to Cardiff. Not hanging around, average of 79mph. Some sitting in traffic, and mostly A roads back, to aviod Severn Tolls.

In total, I did 156.7 miles. I re-fuelled with LPG when I got back to Cardiff (same garage/pump) and to the top, it took  22.79 litres - £10.46.

That's 157 miles to £10.46. At 45.9p/litre, this worked out at 31.3 MPG on gas. That's equivilent to over 65mpg in petrol costs  

hell that is good, i am getting early 20's currently.....

i have found that i am heavier footed now the car is on gas, something to do with the fuel being cheaper  

[Danny]

i'm thinking you're the chap i need to see when i want an LPG conversion on my car

[Kevin Wood]

Blimey! that's good.

Give me a shout when you have your "gadget" and we'll see if we can work out what's going on inside the petrol ECU.


Kevin

[Jay w]

Since conversion, I've been getting about 21mpg on gas under all driving conditions, which equates to about 45mpg in cost terms.

Last night, I spent 2 hours re-mapping the LPG Ecu. I re-calibrated the ECU, so Instead of 8 points on the map I had 4. I didn't add any more, and set it up using just these 4 points. I got it as close as I could, with +/- 5% deflection, and it was running great.

Today, I filled the LPG tank. I did a run from Cardiff, to Gloucester, Cheltenham, and then back to Cardiff. Not hanging around, average of 79mph. Some sitting in traffic, and mostly A roads back, to aviod Severn Tolls.

In total, I did 156.7 miles. I re-fuelled with LPG when I got back to Cardiff (same garage/pump) and to the top, it took  22.79 litres - £10.46.

That's 157 miles to £10.46. At 45.9p/litre, this worked out at 31.3 MPG on gas. That's equivilent to over 65mpg in petrol costs  

couple of things i wnted to pick your brain about re mapping........

Looking at the chart you have the multiplier and the milliseconds, here's hw i have been setting it up, i just want to check i am doing it right

When the car is on gas it gives a LPG injector opening time on the right of the screen, this is the same for all 6 injectors, above it is the timing for the petrol ones, watching the difference between the two at a given point you then use the multiplier axis and plot the graph accordingly
i.e if the lpg injectors were open 1.3 times longer than the petrol ones at the set point then you would plot the 1.3 multiplier at the ms point on the graph?

that may not make a lot of sense, if it doesn't t me know and i will get a graph and give actual examples

other Q i have is the fuel gauge, have you got yours to work yet? mine just shows full all the time?

[JamesV6CDX]

The crude answer is that you are right, the key is injector opening durations.
My fuel gauge is also showing full all the time. I'm going to approach the tank manufacturer, and find out exactly what values the valve should send back at what time, and try and get some voltages from them.

Tbh, I would expect 35mpg from a 2.5 manual, on petrol, on a run. So 32mpg on gas is probably about realistic, with a well setup SGI system?

[Jay w]

  cheers for that.....

i have some time over the Xmas period put aside for the rocker covers , breathers, oil change and cats, i have a feeling that i won't really be able to set up up properly until i get them done..

as it is i am happy with mine and i have noticed the misfire seems to have disappeared of its own accord as well

[Kevin Wood]

The real key is to get the petrol injector times to be the same for a given condition of engine speed and load on petrol as they are on LPG. This is what the 2 curves show in the mapping display. The LPG injector time you need to achieve this is not that relevant. In this scenario the petrol ECU is not having to correct the fuelling away from the petrol equivalent when on LPG. This is important because the petrol ECU is not making adjustments under all engine conditions, only when load and speed are relatively constant. Getting this right gives the correct fuelling not only in closed loop running when cruising when on LPG but also when it's open-loop (acceleration, blipping the throttle, etc)

Bear in mind that you are looking at the 2 times against manifold pressure, which is an indicator of engine load, but the multiplier just converts petrol injector times to LPG injector times regardless of load. It also doesn't consider RPM so try to collect the petrol and LPG curves under roughly the same driving conditions, and during conditions when it'll be in closed loop mode (cruising at various speeds and loads - maybe drive the same route twice at the same speeds, once on petrol, and again on gas).

When I mapped the Westfield (on petrol, of course, but the principle is the same) I saw the same as James. I very quickly got it driveable but it took considerably longer to get it perfect. Sometimes too many mapping points can be your achilles' heel if you don't actually need them.

Kevin

[Jay w]

The real key is to get the petrol injector times to be the same for a given condition of engine speed and load on petrol as they are on LPG. This is what the 2 curves show in the mapping display. The LPG injector time you need to achieve this is not that relevant. In this scenario the petrol ECU is not having to correct the fuelling away from the petrol equivalent when on LPG. This is important because the petrol ECU is not making adjustments under all engine conditions, only when load and speed are relatively constant. Getting this right gives the correct fuelling not only in closed loop running when cruising when on LPG but also when it's open-loop (acceleration, blipping the throttle, etc)

Bear in mind that you are looking at the 2 times against manifold pressure, which is an indicator of engine load, but the multiplier just converts petrol injector times to LPG injector times regardless of load. It also doesn't consider RPM so try to collect the petrol and LPG curves under roughly the same driving conditions, and during conditions when it'll be in closed loop mode (cruising at various speeds and loads - maybe drive the same route twice at the same speeds, once on petrol, and again on gas).

When I mapped the Westfield (on petrol, of course, but the principle is the same) I saw the same as James. I very quickly got it driveable but it took considerably longer to get it perfect. Sometimes too many mapping points can be your achilles' heel if you don't actually need them.

Kevin

I can get the two curves parallel to each other with the LPG one being higher, from there i have been trying to being the LPG down to sit on or slightly above the petrol one.

I am going to try doing a recalibration and starting from scratch this weekend, i have done about 2k miles now and things have settled down a bit now

[Paulus]

Since conversion, I've been getting about 21mpg on gas under all driving conditions, which equates to about 45mpg in cost terms.

Last night, I spent 2 hours re-mapping the LPG Ecu. I re-calibrated the ECU, so Instead of 8 points on the map I had 4. I didn't add any more, and set it up using just these 4 points. I got it as close as I could, with +/- 5% deflection, and it was running great.

Today, I filled the LPG tank. I did a run from Cardiff, to Gloucester, Cheltenham, and then back to Cardiff. Not hanging around, average of 79mph. Some sitting in traffic, and mostly A roads back, to aviod Severn Tolls.

In total, I did 156.7 miles. I re-fuelled with LPG when I got back to Cardiff (same garage/pump) and to the top, it took  22.79 litres - £10.46.

That's 157 miles to £10.46. At 45.9p/litre, this worked out at 31.3 MPG on gas. That's equivilent to over 65mpg in petrol costs  

SNOT FAIR  

[ffcgary1]

That is a great saving on fuel there james and i bet there are a lot of others on here saying to themselves i wanna bit of that.

[Paulus]

I wanna bit of that.  

[Jay w]

i'm trying to get a bit of that  

[tunnie]

is it worth me getting a bit of that  

[Kevin Wood]

is it worth me getting a bit of that  

.. But you've already got an LPG Omega

Just need to pop another gearbox in and maybe an SGI front-end!

Kevin