Q & A: Which SVO (Straight Vegetable Oil) Conversion Kit Should I Buy?

INTRODUCTION:

The number one question we receive concerning our SVO conversions is, I have a diesel Mercedes and live in Anycity, USA. I want to get it right? There are so many choices on the market that it is confusing to know which one I should buy. Everyone claims their system is the best. What kit do you recommend?

Keep in mind we are the only company that offers SVO conversions specifically designed for Mercedes Benz. We do not sell kits for any other diesel vehicles! We also know these older diesel models better than anyone else. If you are looking for a Mercedes diesel to convert or already have one that you are considering converting, you have come to the right place. We have a number of options available to you. We can't tell you which one you should buy because we don't know your specific situation as well as you do. The following common questions and answers should help you decide which conversion is best for you.

Contrary to first impressions, you can run any of our STC (Single Tank Conversions) 100/200/1000/2000 systems anywhere. When it gets close to freezing and below all you have to do is blend the SVO with diesel or biodiesel or switch to running on straight diesel. If you live in a cold climate and want to extend SVO operations then you can add one of our DTC (Dual Tank Conversion) upgrades any time. The key factors in making a decision on what conversion to install in your diesel are climate, driving habits, simplicity of installation and operation, and budget.

So you see, we really can not answer that question for you. Since we do not know your driving habits, your mechanical expertise, whether or not your goal is to get completely off petro-fuel, or how much money you want to spend - It is much better if you try to answer that question for yourself. The following Q and A should give you the insight to make a decision that is best for YOU!

QUESTIONS AND ANSWERS:

Q. I am a little confused. What is the main difference between a STC (Single Tank Conversion) and a DTC (Dual Tank Conversion)?

Answer: The STC only uses the factory fuel tank. That tank alone holds the straight vegetable oil, biodiesel or diesel. Viscosity of the fuel is lowered by blending the fuels together. Since there is only one tank both installation and operation are simple. The DTC uses two fuel tanks AND adds extra heat to the back end of the system. That extra heat reduces viscosity of the fuel and when it gets really cold, you can switch to your secondary tank to shut down and start up on diesel or biodiesel. A DTC conversion has many more things to install and more wiring and plumbing to complete. Operation is more complicated as you will have dash switches to remember how to operate properly!

Q. I like the price and simplicity of the STC. What do I have to do to operated the STC when winter comes?

Answer: We operate a number of STC conversions in our own diesels here in the Pacific Northwest. It does not get as cold here as it does in the midwest or back east, but this past winter we did have temperatures down to 0 degrees F. We typically run on straight veggie from March to late November. Our unique electric boost heat chamber allows us to start up on straight veggie down to about 38 degrees F. When the temperature gets down below that we start blending diesel fuel into the tank. At first 20 percent is enough to reduce viscosity. When it gets down to below 30 degrees F we start adding 50 percent diesel to the vegetable oil. From 20 to 25 degrees F we add 70 to 80 percent diesel to the mix. When it gets below 20 we found it best to switch to running on straight diesel. As far as system operation, nothing needs to change until you switch to running on straight diesel. When that happens you will need to open the hood, turn off the electric boost heater, and turn the valve to the return fuel position. So you can see that switching back and forth between different fuel sources is very easy. You can run on straight diesel or biodiesel anytime you can not find or you run out of SVO!

Q. What is the main difference between the STC 100 and the STC 200?

Answer: The STC 200 is the STC 100 with all the performance uprades included at a price savings. These are the upgrades we recommend every kit should have for maximum power and ease of starting. Your conversion will work without these upgrades in warmer climates, but if your budget is not limited and you want better acceleration, better mileage, quicker fuel filter changes, and longer fitler life we highly recommend the upgrades.

Q. What is the main difference between the STC 100 and the STC 1000?

Answer: In design and function there is no difference. Other than price, the main difference is the difficulty and amount of time it will take you to build and install it. With the STC 100 you will have to cut, drill, assemble, glue, wire, bolt the VFM component together, and cut and route hoses yourself. It will include everything you need but you will still have to build and assemble it. If you purchase the STC 1000, all you have to do is take it out of the box and install it in your car. Even the hoses are cut to length and labeled for you! Everything down to the last bolt and clamp is included for you. The STC 1000 will save the average home mechanic 6 to 8 hours of labor.

Q. What about the STC 2000?

Answer: This is the STC 1000 on steroids. We have customers who want all the performance options right off the bat. So we decided to package all the upgrades with the STC 1000 and offer a bundled discount. The upgrades included all aid in increasing serviceability and performance, especially in colder weather.

CLICK HERE to read more about our STC conversion kits.

Q. If I decide to go with the STC 100 / 1000 is there anyway to add the performance upgrades later?

Answer: The answer to that question is a resounding yes. We offer a number of add-ons to our systems that are all easy to install after the fact. None of them will require you to undo work that you have already one.

• Our copper coil coolant-based filter heating can be added to the STC kit to help keep the filter element warm, thus increasing flow rates, eliminate waxing, and extend usable filter life.
• Our aft mounted electric boost pump can be added to help move the thick oil up through the steel fuel line to the engine compartment, increase fuel pressure to the injection pump, increase filter life, and greatly speed the air bleeding process after filter changes or other system maintenance. (Highly recommended)
• Our DTC 100 can give you a simple and easy-to-install diesel purge and back up fuel system

Q. Are there different types of dual tank conversions (DTC)?

Answer: Yes, there are two different basic types. Here is a quick overview of what is involved in converting to two types of dual tank operations:

1. Quick Purge and Emergency backup DTC. This will provide you will diesel purge capability if you get caught in cold weather with a tank full of SVO. It will also give you an emergency back up fuel system if you are out on the open road and the WVO fuel system starts to falter (usually due to plugged filters). This is a fairly simple and easy to install dual tank upgrade. It only requires a simple tank, extra 5/16 inch fuel hose going from trunk to engine compartment, electric fuel source switching valve, and fuel hose routing modifications. We offer an DTC upgrade kit that will work on all our STC conversions and can be added at any time. This is our DTC 100 TWX (temperate weather) upgrade. This is NOT a complete ready-to-install kit. It is a builders short kit - meaning you will have to build the key component and purchase some items from other vendors.

2. Cold Weather DTC with coolant Heated Main Tank Fuel Sump and Fuel Path. This type of dual tank conversion will require much more work but is necessary if you live in a climate where you have a lot of days when the temperature gets below 32 degrees F and you desire to run on 100 percent WVO as much of the year as possible. It will require you install an enlarged fuel tank outlet hose, a heated fuel sump in the spare tire well, a coolant hose and fuel hose insulated bundle under the car, aux diesel fuel tank of your choice, extra wire and switch connections, fuel source switching valve and fuel hose routing modifications. We offer a cold DTC upgrade kit that will work on all our STC conversions and can be added at any time. This is our DTC 200 CWX (cold weather) upgrade. This is NOT a complete ready-to-install kit. It is a builders short kit - meaning you will have to build the key component and purchase some items from other vendors.

CLICK HERE to read more about our DTC conversion upgrades.

Q. I live in the cold north. What should I do then to get started?

Answer: We recommend you begin by purchasing the STC of your choice and installing it. Even if it is winter time you can still operate your diesel by running a mix of diesel or SVO and diesel. This will allow you to become familiar with the challenges of running on WVO and how our conversion deals with them. Once you get some operational time under your belt you can begin designing what you want in a kit. Purchase our DTC 200 and begin collecting other needed components to upgrade to a DTC. This can be done anytime in the future without spending extra money or having to redo any installation work you have already done. Our complete STC to DTC Installation and Build Instructions will guide you every step you take. They will also recommended sources for other components and parts you will need.

Q. I see that you don't offer a way to heat the oil inside the fuel tank. How can I expect the vegetable oil to flow out of the tank in sub-freezing temperatures?

Answer: The sump heater included in my DTC kits will do the same job without creating the problems of constantly heating up and cooling down the vegetable oil. (ie. condensation in the tank, reduced filter life, molecular breakdown of oil leading to poor combustion, etc.). Remember, when you are running in looped mode only 1 to 2 gallons of fuel PER HOUR are moving out of the tank up to the engine. You DO NOT need to cook the oil inside the tank to get it to flow easily - you only need to get it to 60 to 70 degrees F. And it is only a very small amount of oil that needs to be heated. The sump gets hot enough that it warms the oil back to my custom oversized outlet in the tank. Since the heated sump sits below the level of the tank outlet, gravity does the rest. My sump heater has proven to work very well right down to 0 degrees F.

Q. Do you have any more written information about what is required to converting to SVO?

Answer: Yes, I have written a number of specific manuals to cover almost all questions people might have about converting. If you would like more details about the basics of conversion see my manual - An Introduction to SVO Conversions for Mercedes Diesels. If you want more information about securing a good fuel source read my guide- Collecting and Filtering Waste Vegetable Oil. If you are interested in the more technical aspects of conversion see - Advanced SVO Theory and Operations. Any finally if you want to locate and purchase a good candidate for conversion you must read my manual - Mercedes Diesel Buyers Survival Guide. This alone could save you hundreds and possibly thousands of dollars!

Q. If I can only afford one add-on to my system which one is the most important?

Answer: First off - I personally believe that EVERY conversion should have an aux. fuel boost pump at the back end of the system. We have had and have heard off SO many performance increases by just adding this fuel pump that we have become real believers. Unfortunately, many do not want to pay for the cost of this pump. The system will run fine without it, so we have decided to make it an add-on to keep the cost of the basic kit down. By the way, this fuel pump can also be added at anytime in the future. The fuel pump increases fuel pressure to your engine driven lift pump- thus increasing usable filter life, smoother idle at startup, and in many cases increasing horsepower by 10 to 20 percent. With all our experiences with different types of conversions just having this pump to bleed the air out of the fuel system it more than enough for us! NOTE for you 60x. engine owners. If you have one of the newer 601, 602, or 603 diesels with the self priming lift pump I believe our boost pump is a MUST. When those self priming lift pumps age they have a very hard time pulling veggie oil up to the engine compartment when the temp of the oil is below 70 degrees F.

CLICK HERE to read more about our unique boost pump. Even if you only run diesel fuel this is one of the best performance upgrades you can do on your diesel.

Q. Can you assure me your kit will provide me with years of reliable and hassle free operation?

Answer: I often receive emails from people who want a conversion that is 100 percent reliable and totally hassle free. Unfortunately, that does not exist. If someone tells you it does, they are not being honest. You need to have your wits about you. There are hassles involved, there is a learning curve to go through, and remember, and you are adding a non-factory fuel system that if not installed or maintained properly could cause you problems and even leave you stranded on the side of the road. Running straight vegetable oil in a diesel engine is still considered - experimental. The fuel is free but there is still no "free lunch." On the flip side, if done properly a conversion can be a very rewarding and even profitable experience - and you will love being the hit of any party or gathering when the subject turns to running on free fuel!

Q. You mention problems. What kind of problems might I run into when converting my diesel to run on SVO / WVO.

Answer: Most problems encountered will be related to one or more of the following:

1. Improper installation or operation of the kit. This usually translates into incorrect hose plumbing or wiring connections. When installing your kit you must read ALL instructions very carefully and double check your work. That will avoid 90 percent of all installation problems. The other 10 percent might be due to a malfunctioning component or improper operation of the valves. Once your installation is ironed out all future problems will be somehow related to the following three key factors in this order.

2. Air in the filters and fuel lines. This happens at installation and anytime you change a filter or open up your system for maintenance. You must make sure ALL air is out of the system. And just because your engine starts that does not mean you don't have air!. You can not believe how many times users have driven off after a filter change only to have the car quit 3 to 5 miles down the road. After filter changes run the car for ten minutes with fuel return on return mode. Don't take off on a long trip right after installation or service.

3. Plugged fuel filter(s). Filter life is related directly to the cleanliness and quality of the oil you put in your tank. They can last 500 miles or they can last 10,000 miles. When you start to experience a loss of power it most likely means your filter is plugging up. Replacement filters are cheap. Don't try to push them to the max and ALWAYS carry a spare in the trunk.

4. Poorly tuned or worn engine/engine components. Converting your diesel to run on veggie oil does not make mechanical problems go away. The requirements for an efficient and reliable conversion or a healthy and well tuned engine. If not then converting to veggie might just give you loss of power, poor fuel economy, excess smoke and harder starting. The key engine factors that might cause this are:

• Valves out of adjustment
• Poor engine compression
• Internal engine timing off usually due to stretched timing chain
• Badly worn fuel injectors or injector coking (partially due to ill-tuned engine)
• Worn injection pump / delivery valves
• Badly worn engine driven lift pump
• Lean fuel mixture at injection pump
• Partially plugged fuel tank screen
• Plugged air filter
• Exhaust system restriction (plugged muffler(s)
• Weak or burnt glow plugs

Q. What are the key ongoing maintenance issues I will have to deal with when running SVO?

Answer: From our experience of running our own diesels on SVO over the past four years here is what you should expect to have to deal with. 1. Fuel filters will need regular changing. Always carry spare elements in your trunk along with any tools needed to change them. 2. Fuel injectors will need routine cleaning to remove the coking (hard crusting) from the tips. I recommend they be removed and cleaned every 12,000 miles. I now offer an instruction manual and injector tool cleaning kit to help you accomplish that task. Replace the nozzles of your injectors with the ones we sell from Monark. Their advanced tip design has proven to require less cleaning than those from Bosch. 3. The glow plug pre-chambers will carbon/coke up faster when running SVO. To keep your engine starting smoothly and to extend glow plug life, remove your pencil glow plugs (series glow plug chambers don't have the same problem) every 12,000 miles and ream the pre-chambers out with the glow plug reaming kit we sell on our website. 4. And finally do regular visual inspections on your system. Check for leaking fittings, loose hose clamps, chaffing hoses and tight electrical connections. It is best to find these types of problems before they cause trouble on the road.

Q. What is the best thing I can do to prepare my diesel for conversion

Answer: Other than the basic tune up requirements listed above and explained in more detail in my - Diesel Performance and Tuning Manual there is one thing I believe is a MUST. if you are converting to SVO and desire the best engine performance and fuel economy I highly recommend you install new Monark Diesel Fuel Injector Nozzles. These nozzles are much more efficient than the original Bosch. They have a finer mist spray pattern and don't have the troublesome tiny cross and longitudinal bore holes in the tip of the nozzle. This new design results in better starts on SVO, less injector coking and required cleaning, more power especially when the engine is cold, and better fuel economy. I have been testing these injectors on my bench tester with cold SVO - and yes - the Bosch nozzles will squirt while the Monarks will still spray a mist even when the oil temperature is close to freezing. I am also discovering that the Monark glow plugs work better with SVO due to a tip design that gets hotter right at the tip. CLICK HERE to view our Monark solutions. I am currently working on an inexpensive injector bench tester (under $200) that will allow you to test and balance your SVO fuel injectors on your own.

To see and read more specific information about our SVO conversion kits CLICK HERE.