Vegtherm Questions

[docsavage]

For any of those using a Vegtherm on their WVO system, I have a question. Do you have any idea how often it comes on?.

I ask this because I want to decide if it is needed. After my 30 k commute home I thought I would measure the temperatures in the engine bay. I used one of those IR thermometers and took readings on the injectors (85-90C), coolant hose (80 C), and block (90 + C). These were after about 20 minutes sitting (had to find the thermometer). I think that with such a small engine compartment with relatively low air flow the temperatures in there would be enough to keep the veg oil warm enough (70-90 C, i think) prior to going into the injection pump. Any comments??

James

[Adam]

It looks like the guys at Golden Fuels would agree with you:


I'm using a VegTherm myself. I assume it would allow me to switch over a lot faster, but maybe I'm just buying into the marketing hype.

Lots of interesting Golden Fuel posts on Youtube: http://www.youtube.com/user/GoldenFuelSystems

[josh]

Is there a downside to to much heat?

[docsavage]

The vegtherm is on a temperature control to turn itself on and off. I would rather not pay for something that is only used for a couple of seconds. That video shows what I have suspected, I think I will skip the electric heater and stick with the heated filter and tank - just to keep it flowing in the colder weather from the back of the van.

James

[josh]

James,

Are you welding your own tank? or just using that one you found? I was just thinking I need to get a huge one welded... would you be up for it? or not that confident in your welding?

Josh

[Adam]

Damn, I could have bought a lot of white spirits for what I've spent on my Plant Drive kit. Anyone tried this?

[docsavage]

Josh,

I'm using the tank I got. I don't have the proper welder to weld the thinnner aluminum of a fuel tank. I also decided to go with a smaller tank for weight savings as well. 20 gallons of oil is getting close to 200 more lbs.

James

[EricN]

I have the VO controller in mine with the fuel temp sensor in the return line about 6" from the pump. I am not running on SVO yet so just plain diesel, idling, fans coming on so I am up to full operating temp, the fuel returning from the injection pump is 90F, about 80 degrees short of the recommended 170. I suspect they are probably pretty close with using the injection lines as a heat exchanger but I would be a little more comfortable if my fuel return from the pump was closer to 130-140.
Please bear in mind I have yet to actually drive the truck.

[docsavage]

Thanks Eric, thats good information.

You don't have to do this, but I would be interested to know if the temperature goes up more after driving for 10 minutes. Also, it would be useful to know the fuel temperature before it goes into the filter to see what the rise is across the system. The veg oil will be heated in the filter to 80 F then a rise of 50 F in the engine bay would be into the temperature range required.

Please keep us posted on the temperatures as you get more data.

James

[Adrock]

quick question... where does the return fuel come from? I know its excess, but where is it shaved off?

[docsavage]

In the injection pump.

[EricN]

quick question... where does the return fuel come from? I know its excess, but where is it shaved off?

To further clarify, I assume you are asking "why is there fuel returning?" There is a massive volume of fuel supplied to the injection pump so there is no chance of running empty. At higher rpm/load when there is alot of fuel required, there wont be as much fuel left over to return back to the fuel tank, at idle, there is quite a bit. This is more based on my experience with gas EFI engines, but I suspect the operation is extremely similar.

As for more temp specs, I can't drive it yet as it is not insured. I did run it today, up to temp, this time I held it at 2500 rpm and kept the engine cover closed. Static temp before starting was 77 F. Still running on just diesel so no pre-heating at all. I let it go for about 20 minutes total. I managed to get to 114 F.
It hit 90 F fairly quick from cold, maybe about 5-7 minutes. Then it started slowing down but still going. When it hit around 105 it started really slowing down, about a degree a minute. I suspect this is mostly the fuel in the tank warming up as well as the components of the engine compartment heat soaking. I am sure it would have managed to get hotter if I let it go more.I am guessing that with a looped return it would get a bit warmer, maybe 130 or so. If you aren't in any hurry, I am hoping to have this thing on the road in a week and a half. I just need to find a time to steal some tig welder useage again and the tanks should be finished. My gut tells me that around 120 is, maybe 130 is all the injection pump is going heat the diesel fuel with no preheating and no looped return.
Now, add in vegi oil with all its preheating, that in itself will warm up the injection pump too since the oil going in will be hotter. Frybrid doesn't use any electric heat at all if I remember right, it is all coolant based and works fine.
So why would you use vegtherm? If you want to run on veggie before waiting 20 minutes for everything to warm up enough, then you will need the electric heat to get it all going. After it is warmed up, vegtherm will probably never need to turn on again.

[Adam]

If you want to run on veggie before waiting 20 minutes for everything to warm up enough, then you will need the electric heat to get it all going. After it is warmed up, vegtherm will probably never need to turn on again.

I'm thinking about getting the VegSensor to turn the VegTherm off once everything warmed up and the VegTherm is no longer needed. Not sure if it is necessary though, any opinions?

[EricN]

I think it is a pretty good idea personnally. Less load on the electrical system. Imagine vegtherm running with the ac on full heat to defrost the windows, at night so the lights are on and your rear defogger working and you are commuting in rush hour so no chance to get above idle for more than a few seconds. I dont know what the alt is rated at but I bet it will be kind of pissed about working that hard if it doesn't really need to.

[Adam]

Imagine vegtherm running with the ac on full heat to defrost the windows, at night so the lights are on and your rear defogger working and you are commuting in rush hour so no chance to get above idle for more than a few seconds.

Hmmm, well, my AC seized a few weeks ago and I work from home just south Nanaimo, so "rush hour" isn't an issue. But I do have lights and a defogger, so for $15 I might give it a go. Besides I might have to get the AC fixed so I can make ice in my CoolBox.