My ML350 2003

[cRiPpLe_rOoStEr]

Originally Posted by teoman

My lpg is manifold injected not port injected.

I suppose this is good for economy.

I assume you're talking about a positive-pressure (multipoint) setup instead of a closed-loop (throttle-body or single-point injection), but even though the LPG would go a shorter distance across the manifold compared to a throttle-body injection, trying to get it injected in the liquid phase could still increase the risk of getting the intake manifold frozen.

[teoman]

I have been researching LPG and water injection lately.

LPG burns slower at slower RPMs and it burns faster at faster RMPs. Some tuning needs to be done for LPG converted vehicles. And from what I hear, it is usually a compromise (if dual fuel ability is to be maintained).

On the other hand, when water is injected the burn rate of the fuel slows down. Which could theoretically bring LPG closer to gasoline.

So after some study, if i can get LPG to behave like gasoline, my standard tune for the car would work very well in my opinion. That is what i would like my current goal to be.


I am adding some articles that i find to this thread mainly so that I can find them later on.
https://www.omicsonline.org/scientif...AME-SR-591.pdf

[cRiPpLe_rOoStEr]

I'm more used to CNG than LPG, but since the LPG is vaporized prior to the injection it does sound quite odd that you would at a first stage have to add some heat to the fuel and then cool down the intake stream with a water injection.

[teoman]

I have the opportunity to get bigger rims and tires. But they will be wider. Will i lose or gain mileage?

[ECO-AKJ]

Most likely lose, the more tire on the road, the more resistance.

[teoman]

I have hooked up torque and have been trying the pulse and glide. I am trying to keep load at %80 but the car accelerates pretty fast and i seem to prefer %70, less chance of the automatic transmission lowering gears.

Obviously it is like a brick and slows down fairly quickly. The cruise control (which is actually just a speed limiter) is fairly nice for pulse and glide.

[teoman]

Best tank of lpg so far:
207 km with 38L. (18.3L/100km) 12.8 mpg

When i started this thread I was at 180 km per 38L (21.1L/100km) 11.14 mpg

Well ****, if it was any worse, i would be in single digit territory.

I shall do further upgrades and fixes. The abs and the egr has to be fixed. Will report back how that improves mpg. (Note lpg has less energy per liter tha gasoline and diesel).

[teoman]

I want to do a radiator and oil flush.

For the oil, i want to run it with ATF for 15 minutes. Then fill with 0-40 mobil 1.

For the coolant, i want to do a flush with a bit of vinegar, the with a bit of soap followed by distilled water and finally the coolant.

Do you guys recommend anything else? Or will I corrode the aluminium block with the vinegar?

[cRiPpLe_rOoStEr]

I've seen kerosene being used for oil flush, but have never seen anybody using ATF for that.

[rwhyde]

Well, you certainly have your work cut out for you, but any improvement will or should be noticeable. Being a heavy vehicle reducing friction and drag will make a big difference. I second pumping up the tire pressures that will offer the quickest/easiest thing to do. On your coasting, moving the shift lever into neutral should help some as Mercedes tend to use a lot of engine braking, ( I have several and service many others), far more than our previous Toyota Highlander or my Prius. Next, I would look for at an oil change to the differentials checking the factory specs and ensuring I had the lightest weight synthetic lubricant the met MB specs in those to lower friction. The engine in this vehicle is pretty efficient, but is burdened with carrying a heavy load. Trying to lighten throttle application on take-off will yield a lot of improvement. Look for ways to unload the engine, A/C, alternator and other electrical loads to further improve mileage. Your weather might not permit that.