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Alright well I figured it was time to change out the spark plugs in my 98 230. I was just wondering what difference there was between spark plugs, I have 2 to choose from.
one with 3 electrodes
and one with a standard electrode.
I tried doing some research on the topic and all I got out of it was difference in heat...
im going to assume the one with 3 electrodes is better because its more expensive... <-- non professional opinion.
thanks guys.
 

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Iridium spark plugs

Hi: I noticed that there are no responses to your question. The standard replacements are listed on top of the electronics cabinet in the engine compartment.
I am trying a set of the the new NGK Iridium plugs because I have converted my SLK to LPG. Being more difficult to ignite, the Iridium plugs create a larger hotter spark and resist corrosion. The reason you might be interested is because they claim to last 100,000 miles. The price is high, but maybe the benefits will more than pay back the cost.
Cjohnson
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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cjohnson,


Welcome to the World’s Premier Mercedes-Benz SLK Community from Valrico, Florida!




You might want to post an introduction in the ‘New members introduce yourself here’ section, if you haven’t already.




If you haven’t, please use the 'search' feature at the top right of the page for your questions as they have probably been asked before. Remember, ‘Search’ is your friend.
In addition, if you haven’t, please post your question in the appropriate discussion forum for a quicker response. Be patient and a knowledgeable member or guest will address your question.



Thank you,
Jeff
Founding Member/Moderator
 

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SLK running on LPG... Interesting!! Although I'm not doing it to my car, it would be nice if you could show us the setup. And welcome to the forum Cjohnson.
 

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Where did you put the tank??

Hi: I noticed that there are no responses to your question. The standard replacements are listed on top of the electronics cabinet in the engine compartment.
I am trying a set of the the new NGK Iridium plugs because I have converted my SLK to LPG. Being more difficult to ignite, the Iridium plugs create a larger hotter spark and resist corrosion. The reason you might be interested is because they claim to last 100,000 miles. The price is high, but maybe the benefits will more than pay back the cost.
Cjohnson
Wow!! Where did you put the tank?
 

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LPG tank in SLK

Hi guys:
Gasolina is 8 dollars a gallon over here, so LPG is attractive at 4 dollars.
The tank is toroidal and fits into the recess for the collapsible spare. It only holds 27 litres but there are plenty of places to fill up.
The system is made by an Italian company called BRC and has it's own ECU that piggy backs with the onboard ECU.
As far as I can tell the performance is equal to gasoline and the MPG are about 10% less.
The system starts on gasoline until warm enough to vaporize the LPG and switches automatically. When the LPG tank is empty the system automatically switches back to Gasoline. If I can get a decent picture of the engine compartment and toroidal tank, I will post it here.

Do you know of a place to buy performance ignition coils and high tension wires made for the M111?
Best regards Chuck Johnson
 

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That is something I cannot believe, that the engine performs the same and the mileage has dropped. No way! Usually a LPG running engine performs almost the same but with higher mileage due to the fact that it burns more LPG to generate the same power as gasoline. And the explanation is that the LPG has a lower energy density than either petrol or fuel-oil, so the equivalent fuel consumption is higher.
 

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cjohnson

Hello again:
Just want to clear up a couple of points about LPG performance and fuel consumption.
There are several references on the web where you can see that Dynamometer tests verify the 3-5% loss in power compared to gasoline. In any case, a push of a button and the system changes back to gasoline.

I did cause confusion by saying that MPG's dropped. My meaning was that it is not as good as gasoline. I can see where someone might read my remark as a drop in consumption, which is not what I meant to convey.

In actuality, the poorer fuel mileage varies depending on what car /engine combination are being converted to LPG. The LPG dealer can probably tell you better than me what to expect based upon his experience. ( LPG is available in most of Europe at half of the price on gasoline.)

Other factors are the need for NGK iridium sparkplugs and properly performing spark coils and wires.

Most dealers will also install an upper cylinder lubrication system which is necessary to limit valve seat regression. This is usually not a problem for a quality built engine that has properly hardened valve seats and sodium filled valves (like Mercedes)

I hope this clears up any confusion.
Best regards Chuck J
 
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