a few questions on setting up a wvo system

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bbob203
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a few questions on setting up a wvo system

Post by bbob203 »

1. what is the best place to splice into the coolant system?
2. when running a hose in hose system what are the ideal diameters for the coolant line and the fuel line?
3. best routing for lines? fuel filter heated first? heat exchanger first?
4. I'm going to be running a hot fox. is a heat exchanger up front neccesary?
5. best way to splice the pex/aluminun tubing fuel line into the filter.
91 jetta gl na german built
91 jetta gl ecodiesel
greg lousy
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Re: a few questions on setting up a wvo system

Post by greg lousy »

I've been running my 81 caddy on WVO for about two years. I'm no expert but I can easily answer your questions.

1. splice one end of your WVO coolant loop line into the the "to heater" hose and the other end into your "from heater" hose.

2. Generally HIH consists of a 3/8 aluminum fuel line going through either 5/8 or 3/4 hose. I suppose you'd get less resistance with a 3/4 hose, but mine is 5/8 and works just fine. Of course its a different story with pex fuel line. I haven't used pex in HIH because I've read about a lot of problems that result.

3. First of all, read the answer to 4.
This may sound strange, but it is becoming a common consensus and it is definitely my experience (I have rerouted my coolant lines 4 times looking for the right flow).
You want to run parallel loops for your heating devices. I would recommend making a loop to the flat plate heat exchanger, then looping your other elements off of that loop (starting before the FPHE and returning after). This way your FPHE will receive coolant most directly, when as hot as possible. You could put everything else on one loop, or put your HIH and Hotfox on one loop, and your heated filter on another.
Also, you definitely want to hook up your HIH loop so that the coolant flows through the HIH first, then hits your Hotfox, then returns (with coolant will flowing counter to the fuel). This way the hottest coolant will heat the fuel as it approaches the engine.

4. You definitely need a flat plate heat exchanger. This will be the main heating element in your system. The purpose of the Hotfox is to heat the WVO just enough to make it flow smoothly, 70 to 100 degrees farenheit is fine. In the summer time you could even shut off the coolant flow entirely to this part of the system. You actually don't want to heat your tank excessively because when WVO is heated and cooled repeatedly in this manner it can "polymerize". The molecules form long, gooey chains.

5. generally, you go from your aluminum or pex line into a regular 3/8 fuel hose, then attach to your filter normally. The aluminum fuel line that would come in a pre fab HIH, I believe is 3'8 - external diameter, where regular fuel hose is 3/8 internal diameter. I've just got the hose over a few inches of the aluminum and hose clamped which has worked fine. I'm thinking about sealing the connection with 3M marine sealant, because air leaks are always a concern, but I haven't had any problems. I suppose you could also do something fancy with compression fittings, but it hasn't come to that. If your going from a pex fuel line, a hose barb union would be standard - some people use push-lock fittings, which are probably better.


Also - I highly recommend putting ball valves in all of your coolant loops, so you can adjust the flow to the different elements and make seasonal adjustments.
- depending on where you live, Hose on Hose (where your fuel line is sandwiched between the coolant lines going to your Hotfox and then insulated) may be a better option than Hose in Hose. Like I said, for this part of the system the main thing is just to get the WVO to a temp where it flows easily. Leaks occur often where the fuel line enters and exits the coolant line - its sort of a dicey connection that is constantly heated and cooled.

- Definitely research the implications for your specific car (is it one of the jettas?)
I know there is at least one concern for later models that I did not have to worry about with my 81 caddy

- here is a forum that's been helpful to me. Just be warned that it can be confusing, there is a lot of information there, and a lot of opinions, as this is a developing subject

http://biodiesel.infopop.cc/eve/forums/ ... /898605551

- greg lousy
Various vehicles in various states
bbob203
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Joined: Fri Jun 24, 2011 10:50 am
Location: erie,pa and akron,oh

Re: a few questions on setting up a wvo system

Post by bbob203 »

Greg,

Thanks for your response it was all the kind of straight forward answers I've needed. Currently my wvo conversion has taken a back seat in place of a td engine swap into my 91 jetta. I live in louisville ky area so i think an insulated HOH might be better just because it warm here for most of the year. Good advice on the ball valves to adjust the coolant flow i hadn't thought of that definitely don't think heating of the tank much if at all would be necessary in the middle of summer.
91 jetta gl na german built
91 jetta gl ecodiesel
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