Hi everyone!

I'll install a propane/lpg injection on my '92 190D 2.5 turbo.

If you have any suggestions, thoughts, experiences, questions ect. please feel free to write here.

For the whole story check this thread on schumanautomotive.com. I'll try to post pics and videos once the project is finished.

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.

Definitely install a pyrometer prior to adding any additional fuel. I would be very careful about how you boost-meter your propane. It's probably a better bet to go with a commercially available kit, rather than cobble together the various bits and pieces. I opted for the Powershot 2000.

I recently grenaded the turbo exducer wheel on my 603 immediately after a hard run up a hill. My mixtures weren't quite right and it had been knocking a bit under load. The EGTs didn't indicate anything unusual, but nevertheless, the turbo shredded in blaze of blue/black smoke. I strongly suspect the additional fuel coupled with an incomplete burn, stress-fractured the vanes, causing a catastrophic failure mode. You have been warned.

Hi Zeitgeist!

Thanks for the info!

There aren't any commercially available kits over here. My car is probably the first one to be "converted" in my country. The "kits" for sale in the US are way overpriced IMO. Especially if they don't include a tank.

As far as I can see your "kit" has only hoses and valves. How do you turn on the injection? Is it on demand, i.e. you have a switch you can turn on when you need it, or is it sort of automated, like when the engine reaches a certain speed? The "only" feature you might have over "my kit" is the possibility of controlling the lpg quantity from within the cabin. While that's good, I don't think it's very safe for the engine. Power corrupts and you'll back off only when you break something, i.e. your turbo. You should have backed off once you knew the engine was knocking. I'm not going to try that with my car as that's obviously asking for trouble.

Anyways thanks for the friendly warnings ! An insight from people who have installed these injections are very valuable. Bad experiences are also very valuable so I don't have to try something that didn't work for another person.

How's the power increase? Fuel mileage? How's transmission, drive shaft, differential ect coping with the increase in power? I have manual gear box and i guess you have automatic so they might have different tolerances, but still it's good to have some sort of clue.

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.

There is no point to LPG. It's only an additional fuel so you are not gaining any true economy from it and you can get the same (and more) power increase alot more safely by simply turning up the injection pump.

LPG is very risky. Preignition (detonation) can blow out the headgasket or crack a piston easily. It should also be a variable flow system rather than just on-off so that you don't inject too much too soon.

I would definitely try it, but be cautious, start with an extremely small orifice (jet), and very low CFM or (CLM in albania)

IDI engines are not Propane-friendly, at least not in large amounts. Do not add propane @ idle, do not add the propane before the filter

If you hear knocking or pinging, you are adding too much, and your flamefronts are colliding. (its not as good as it sounds.)

Be safe, propane is heavier than air, so it tends to gather in low points, make sure your install is properly vented

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Cheers,
Robert

There is a place and use for ANY modification that produces more power. Some mods are better than others. Propane fumigation offers decent power increases, is fairly low risk with conservative use, easy to install/remove, etc. Turning up the IP will definitely produce more power and is certainly the preferred method of increasing power however there are pitfalls to this method as well. Turning up the IP can easily fry pistons, etc. from excessive EGT's and some IP's are difficult to adjust/modify. Either way its the owners choice to install, operate, maintain, etc. any modification and use it safely. That said, mod away! RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

He lives!...I Was wondering how your car was doing...

Hi guys!

Thanks for the replies and warnings! I've done a lot of research, lets say more than an year. So far I understand the risks involved with lpg.

They system will be installed at a place where they deal with lpg gassers, by people who convert/maintain lpg cars (gassers). That lpg tank itself has a valve, unlike bbq tanks. Fuel delivery from the tank till the engine bay will be done using flame/heat resistant piping. These pipes are regularly used in converted gassers and are meant for automotive use. I see a lot of people in the use just use lpg rubber hoses. While they might be suitable for bbqs I don't think it's very safe using them in cars, where the situations are more demanding.

As I said the system will be controlled by:

1. The ignition key. If the ignition is off, the valve in the tank will be shut off. I'll talk to the mechanic and see if he think it's too much having 3 valves, instead of 2.

2. A switch in the cabin. The switch will control the valve in the tank. It will be connected through the ignition key, so even if I forget the switch on, the system will completely shut down when I turn on the engine.

3. The final valve that will allow the lpg to flow in the intake (pre turbo) will be controlled by a pressure switch (on the way). The pressure switch is preset to open at 5 psi. So no lpg at idle unless the turbo is giving 5 psi at idle. As far as I know the turbo is cut in the first gear in order to save the drive shaft from snapping from the torque. If that's true than no lpg in first gear, which is good.

I've thought of turning up the fuel pump, but an intercooler is a must. Installing an intercooler in a w201 with a turbocharged om602 is a nightmare. There's practically no space in there, unless I get rid of the a/c which is suicidal in 40*c + heat. Plus more diesel means more smoke, which is not very cool .

I agree that lpg is a fuel but it's a very cheap fuel. Diesel here is around $1.2 - $1.30 per liter, whereas lpg is around $ 0.55c - 0.60c per liter. The saving is not huge, but it's an added benefit along with the power. Also lpg helps keep clean the engine and oil, and extra benefit.

As for preignition, lpg has a higher flash temperature than diesel and unless I go nuts and turn the lpg all the way up and ignore the pinging in the engine, then I'm being stupid and I deserve loosing the engine.

I'm very interested in the opinions of the people who have installed this sort of system. The most important for me is what not to do rather than how much power can I get. Safety is primary, then comes the fun! I'm thinking of "upgrading" the braking system to a beefier one if the power gain is large. Too bad I got new front disk brakes in february of this year.

Thanks a lot for you opinions! Please keep them coming!

Deni

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.

In small amounts, LPG will improve the fuel economy of a diesel even though the BTU per gallon of LPG is less than diesel. With some very carefull tests back in the early '80s on my Audi 4000 diesel, I could drive farther on 9 gallons of diesel plus one gallon of LPG than I could on 10 gallons of diesel.
I built an electronic controller that supplied 10 % LPG thruout the entire operating range except idle.

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Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

Are you still running the audi on lpg?

Do you mind sharing the electronic controller you built?

What happened if you supplied more than 10% lpg?

Is that 10% of the fuel used? If yes how didn't you know how much fuel will the engine consume at a certain range?

Thanks!

Deni

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.