-34F on veg oil this morning!

[DanHoug]

just a personal landmark... ran on veg oil during my commute and saw -34F on the outside thermometer!

took about 20 miles to heat the car up enough to switch over but no problem once it was on oil. at low speed, like in towns, the engine liked running with the advance pulled out when it was this cold... but i'm running a bit retarded right now and should tick the timing forward a bit.

and yes, the engine temps cools way down at those outside temps when not running at highway speed. i'm not clear on the relationship between thermal efficiency vs. fuel efficiency. my Toyota Corolla gets close to the same MPG as my IDI Jetta but has absolutely no problem producing enough engine heat to keep everything at normal running temp. anyone care to opinionate on this?

-dan

[82vdub]

That definately is cold, even for a car to start.

and yes, the engine temps cools way down at those outside temps when not running at highway speed. i'm not clear on the relationship between thermal efficiency vs. fuel efficiency. my Toyota Corolla gets close to the same MPG as my IDI Jetta but has absolutely no problem producing enough engine heat to keep everything at normal running temp. anyone care to opinionate on this?

I've always attributed this issue with the fact that diesel fuel is a leaner burning fuel. Leaner meaning that more energy per unit is transfered into actual energy, and not waste product such as heat.

[DanHoug]

i agree. BUT since diesel has more BTUs per unit volume than gasoline, why isn't the mileage dramatically better than a high efficiency gasoline engine that is producing lots of extra heat, aka my Corolla?

not arguing with you, just trying to figure it out. seems there's more 'waste' heat in the Corolla, but why is the MPG so close to the diesel?

-dan

[82vdub]

I've wondered the same thing, even while typing what I did. I don't know the real answer.

[the vegenator]

How do you keep your diesel warm overnight? Block heater? Electric veg warmers? Also, do you route your hoses through your cabin?

I used to put cardboard in front of the radiator on my Chevy van during that brutal Indiana winter (0 to 20 degrees . Is this a bad idea on a vw diesel?

I've been thinking about taking a trip up to Grand Marais, I fear how my diesel will handle it...

[DanHoug]

block heater necessary for starting... just has a 500watt job and it does fine after about 4 hours. i also have a battery maintainer that is on the same circuit as the block heater. all of that on a timer that comes on at about 3am for my 7am departure. car must be plugged in at work, too.

regarding rad blocking... i removed the grill and have the entire front of radiator compartment blocked off. a bit ugly but very effective. you must have some airspace between the rad and the cardboard so when the rad fan comes on, it can pull air thru the rad-- if the cardboard is tight against the rad, you'll overheat as the fan won't draw air thru. but other than that, 100% blockage of all the grill openings works fine until outside temps warm up, then the fan runs too much.

yes, the veg hoses are routed thru the interior. this greatly reduces the conductive loss to have still, warm air around them. and they are out of the way of road damage.

if you have a block heater, you'll be fine in Grand Marias... be mindful of GFI outlets however... the road salt on the exterior of the heater plug will trip GFI circuits when the relative humidity rises a bit. just keep the heater plug clean and the GFI will not trip.

-dan

[82vdub]

I used to put cardboard in front of the radiator on my Chevy van during that brutal Indiana winter (0 to 20 degrees . Is this a bad idea on a vw diesel?

I once ran from Green Bay to Manistique in -10F temps with cardboard blocking 100% of the radiator on my 82 Rabbit. Temp gauge didn't read any higher or lower than it does normally, with the radiator being completely blocked. Was just fine.

[the vegenator]

It sounds like you've thought of it all. It's really good to know you're powering through it during a season which I usually give up in.

I'm actually curious now - how do you process your fuel? I'm piecing together a filtration system and I could use some tips on a winter-proof system.

As for driving up north, I think my veg system will need some extra winterizing if i want to run veg in sub zero temperatures.

[DanHoug]

at the very begining of my blog, i have some picts of my filtration setup.

http://kaxeengineer.blogspot.com/

essentially, i heat the unfiltered veg oil in turkey fryers to 150F, filter that thru paper cones, then pump thru a 20 micron whole house filter and then gravity drain into a 5 micron bag nested inside a 1 micron bag.

this works well and i can filter about 15 gallons per hour with 2 fryers going. my veg oil filter last between 7k-10k miles then i change when filter vacuum gets too high.

-dan

[BlueDog]

I wonder if it's possible to use a 12v heater element, similar to a water heater one, installed into a wall of a small fuel tank for the purpose of keeping the fuel warm when I go to start the car. This would get it's power from a battery separate from the starting battery. The element I am considering is 600 watt 12 volt. I believe I could simply turn on the heater about 3 or 4 hours prior to driving my Jetta and the fuel would be warm. I wonder how long the battery would have enough power for this. Can I install a small circulation pump to circulate the fuel from this separate tank and through the fuel lines and filter and back to the tank when the engine is not running, thereby keeping the whole fuel system warm?

[bscutt]

600 watts at 12 volts is 50 amps, about what glow plugs draw. Your battery won't last long at that rate and you're talking some heavy duty wire to handle the current. You would need a deep cycle battery too since this would fully discharge the battery fairly quickly and that would kill a regular battery pretty quickly (as in permanent damage to the battery). Find a battery with high-amp-hour rating, divide that dating by 50 amps and you could get a feel for how long you could run that heater - assume you will only get about 50% of the amp-hour rating since it's capacity trails off as it discharges.

[DanHoug]

you won't be able to circulate thru the IP and so warm fuel will have no benefit on starting.

just put your efforts into a block heater, battery heater, and battery maintainer and you'll start at -60F. if you want, wrap some heat tape around your fuel filter and plug that in too.

-dan

[BlueDog]

I looked back at my post and noticed I neglected to mention I run my Jetta 1.6NA on 100% biodiesel. At least I do for 9 months a year. I want to do so for 12 months a year. Even at a 80/20 ratio of dinodiesel to biodiesel the fuel gells and clogs the fuel filters. Some heat tape around the fuel filter will solve this? There is a filter in the tank that clogs as well. I found a calculater on the internet that tells how long of batery life I can expect. A separate deep cycle battery or (2) 6 volt golf cart batteries certainly give the best option. I suspect the 600 watt heater element would cycle on and off somewhat if hooked to a thermostat set at about 45 degrees F. Maybe a bypass in the fuel line before the I/P might be in order. So I guess I'm interested in continuing to investigate this idea. But, if the filter heater is all I need than it's a done deal. That's all I need to do?

[DanHoug]

battery storage just isn't a practical technology to try to keep a system warm in a car. you'll experience a horrendous charging load when you start the car and need a current limiting battery isolator to keep from burning up your charging circuit and draining your starting battery when parked.

for fighting your B80 gelling problem you need a couple items:

- i would install an in-line, coolant based fuel warmer to keep the filter open while you are running, or a 12v heated fuel filter. eg. Racor. or even just use plumbing heat tape around your stock filter and a 110v inverter.

- use a block heater several hours prior to your start

- remove the in-tank screen so you can pull slurpy fuel without restriction. cold B100 won't flow thru a filter but you can suck it thru a fuel line. you could also install a 'Hot Fox' heated fuel pickup but it would be a nasty install on a plastic fuel tank.

-dan

[BlueDog]

Yeah, you're probably right Dan about the capacity of the battery. I just doubt that simply keeping the filter warm, such as a heated Racor, is enough. The B20 in the tank and in the IP would gell while it's sitting in the parking lot at work all day. I suspect that if I can't keep the whole fuel system at about 45F or so for a few hours before and while driving home, it's going to fail. According to the battery calculator I would need about 475 amp hours for 3 hours of running the 600 watt 12v heater. This battery would need to be separate from the car starting and charging systems. I'd have to recharge it overnight at home using a conventional battery charger.