I have progressed my veggie system into the engine bay and am now looking for suggestions on how set it up. I am going go from a HIH to a cummins 10 micron filter and then to the 3 way fuel valve. I am going to loop the return line and am wondering what is the best way to do it. I would assume to just loop the return line between the 3 way valve and the IP.

I am also going to put a manual 3 way valve on the looped return line so I have the option to run straight diesel and return it to the diesel tank like originally designed.

Any pictures would be great...

86 VW Jetta

I would tee in right before the 3way valve into the VO line. If you control 2 3ways seperatly you can purge any air and a little VO to the diesel tank whenever you want.

Zack

Are you saying to control two 3ways with one switch so when I switch "on" I am running a looped return with the veg oil and when I am switched "off" I am always running a "return to tank" with diesel?

I am skeptical about sending VO to the DSL tank. Once it is in the DSL system I have no way of warming it. On cold days couldn't it clog the lines??

But then again how am I supposed to purge air out of my VO lines???

As you can tell I am newbie.

I run a third solenoid for purging air and chunkies from the loop, sending them back to the vegy tank.
http://www.geocities.com/vwfatmobile/Fuel_ins_and_outs.html

quote:

I would tee in right before the 3way valve into the VO line. If you control 2 3ways seperatly you can purge any air and a little VO to the diesel tank whenever you want.

The VW diesel uses so little fuel at idle that almost no heat is being added to the loop. Without having a heated section in the loop your fuel temp will drop off. You won't be to idle well at 35F and driving through town at 18F will be rough at the stoplights.
Thats why I send my return line to the output of the filter... so it can run

John,

quote:

I run a third solenoid for purging air and chunkies from the loop, sending them back to the vegy tank.

Most people filter their vegetable oil to ensure that "chunkies" do not enter the veggie system

Hi CFO,
If you are putting together a system you may want to consider a semi loop or on demand design.. there's a diagram on my install page if you are interested... You would want to look at the diagram labeled IP with internal lift / fuel pumps

Can I heat the looped return line and still run diesel through it? How does the engine perform on really hot diesel?

Contrary to what some folks here will say you can heat diesel without any problems...

I would question the 'don't heat diesel' advice - especially if you are running a rotary IP which is not a Bosch (or Bosch copy).
Heating the diesel fuel will heat the IP which otherwise acts as a huge heat sink when the fuel supply is switched to PPO (aka SVO).
I would maybe quesrtion the wisdom of running for extended periods on heated diesel - maybe have a way of switching out the heat if this is necessary.

[QUOTE]Originally posted by cfo2316:
Are you saying to control two 3ways with one switch so when I switch "on" I am running a looped return with the veg oil and when I am switched "off" I am always running a "return to tank" with diesel?

I am skeptical about sending VO to the DSL tank. Once it is in the DSL system I have no way of warming it. On cold days couldn't it clog the lines??
[\QUOTE]

I mean control each valve with its own switch, by doing it individually you can reduce cross contamination (i.e. turn on VO feed valve, wait a couple seconds turn on return valve vis-vera) This will allow that diesel ahead of the feed valve and in the engine to go back into its return line. The Frybrid controller has this delay built in. Purging would work the same way.

- On the cross contamination point purging air in your VO line back to the diesel tank would be negligible IMO, you are talking a very small amount of VO to occasionally purge the air that accumulates, I cannot seeing this make any difference in your diesel system. Also by controlling the valves seperatly you will get less cross contamination thatn using a 6 port or wiring them together...

Zack

quote:

I am skeptical about sending VO to the DSL tank. Once it is in the DSL system I have no way of warming it. On cold days couldn't it clog the lines??

You can install a 3 port valve return the all the fuel to the veg tank... this prevents contamination of the diesel... If you build the system with a small loop and feed it with 2 electric FP's the vollume of veg will be less than 1/3 of a cup... you can also install a quick purge... I suggest having some return by installing a restrictor fitting..