Better to drive hard when on WVO?

vwmikey99

Veteran Member
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Jul 18, 2005
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Richmond Hill, ON
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2015 GLK 250 + 2017 Tacoma + 2014 Jetta
Just something I was pondering the other day...

Would most think it would be better to drive hard on WVO, help keep the kaka floating out of the motor? or perhaps on the last purge of the day, give her a bit of a beating?
 

philngrayce

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Oct 18, 2004
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Connecticut
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'02 Jetta, '06 Jetta, Both Gone '13 Leaf, Gone Liberty CRD, Subaru Forrester and MB300SD
I do drive hard, and I've had great success with WVO. Purely anecdotal, of course.

I do think hard driving is better for the EGR buidup thing.
 

nicklockard

Torque Dorque
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Aug 15, 2004
Location
Arizona
TDI
SOLD 2010 Touareg Tdi w/factory Tow PCKG
Not owning a WVO rig myself, I would think "yes."

It's good to drive any Tdi hard. These machines need a good workout on a regular basis.
 

TDICult

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Glasgow Scotland
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Audi A4 1.9 TDI (AFN)
Cannot say i have noticed any difference. At the present time I am trying to save fuel to I tend to keep the revs between 1500 and 2200 RPM. Been doing that for months and no effect on performance.

In the last month been doing a lot more start stop around town and the foots never flat on the floor again no noticable difference.

It could be argued that flooring it puts more strain on the fuel pump and I am sure somewhere someone had a list of older bosch fuel pumps that all had generally failed while heavily loaded going up hill.

In general most folk produce smoke when they floor it and this is likely to lead to more deposits. This has to be balanced with the fact when you floor it for long periods the temperatures in the exhaust and in the engine in general go up, helping to burn off deposits.

If you are using WVO you are in it to save money and the planet etc so it does not seem to make sence to drive the car very hard.

Best
 

vwmikey99

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Location
Richmond Hill, ON
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2015 GLK 250 + 2017 Tacoma + 2014 Jetta
I would have thought you'd be getting less deposits when it is smoking out the back?

I've been handing out plate fulls of french fry juice to those who tailgate me...is that actually going to add build up?
 

vwcampin

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Omaha
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2002 GLS TDI Auto
vwmikey99 said:
I would have thought you'd be getting less deposits when it is smoking out the back?

I've been handing out plate fulls of french fry juice to those who tailgate me...is that actually going to add build up?
Smoke is a sign of unburnt fuel. Excessive smoking while on WVO, can definitely lead to WVO getting past the rings and through your intake, etc.
 

vwcampin

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Omaha
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With a two tank WVO set up, you start and stop on diesel. Before you turn your engine off, you "purge" which means that you switch back to diesel which clears the lines of WVO so you are starting on diesel.

*that is the simple explanation(there is much more detail as to how many valves you have, driving on diesel after purge, before shutting down, etc.)
 

kingkos

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Location
"The Hammer", Ontario
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2003 Jetta wagon TDI
scmentz said:
total noob question:

what do you mean by purge?

thanks
duhhhh.....puking after I eat a big meal in order to maintain my girlish figure.:D

actually, purging refers to the shut down cycle of a 2-tank WVO system, whereby the fuel being supplied to the Injection Pump comes from the diesel tank, but the fuel being returned from the IP goes to the WVO tank.

This is important since when you switch from WVO to Diesel before you shut down your engine, there is always about 500mL or so of WVO in the IP that you dont want to get returned to your D2 tank. Instead it will get returned to your WVO tank, along with a small amount of D2.

edit ****vwcampin beat me to it and posted while i was writing.

scmentz....any relation to bkmetz, a good friend to the WVO community and supporter of alternative fuels everywhere?

steve
 
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DarrenUK

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May 23, 2003
Location
SE England
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Skoda Octavia 1999
I'd say its not a bad idea to occasionally drive hard. I've seen the carbon build up in indirect injection diesel engines that have never been driven hard (only ever run on diesel) and it was not pretty.....

I'd also avoid long periods of low load running.

I also turn off the engine rather than leaving it idle - especially when it is cold. This is running diesel fuel but more so when running biodiesel or SVO / WVO
 

vwcampin

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Omaha
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2002 GLS TDI Auto
scratchy,
are you talking about on WVO, or build up in general. With diesel, the switch to ULSD should have remedied a lot of the build up issues. In regards to running WVO, there are some who block their EGR, or replace it with a race pipe that you can buy from one of the vendors on here. You can also see the thread by T'sTDI here where he was taking VAG COM readings and installed a resistor to fool the ECU into thinking the fuel was cooler than it was.
 

Todd B

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None. 2002 gone to TDI grave.
I have a couple of friend that fog demineralized water into the air inlet on their gassers vehicles to blow out the carbon once and awhile. One friend of mine has a Chevy truck with the 5 liter Vortex engine that failed the emissions test on HC just by a hair. He fogged the engine with water while reeving it up. He said that he got some black soot coming out the tail pipe. Took it for a retest and the HC was way way down. He passed with lots of room to spare. I have never tried it but I don't see why this wouldn't work on a diesel.
 

T'sTDI

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Location
Maryland
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2001 Jetta
Blocking the EGR is a great way of preventing carbon buildup. You'll note on most failed heads that have burned VO in there lifetime, there is a lot of buildup of carbon on the back of the intake valves. This is a tribute to a working EGR and what effects it can have while recycling VO fumes in the intake tract.

To put this simply, we have seen the horror that the EGR causes on all newer diesels. Look up any pictures of clogged intakes. Those are typically pictures of people burning regular d2. When you mix in a deposit forming fuel that VO inherently is, just think of the problems that are associated.

Rerouting the CCV to a catch can is also another great way of limiting deposits. Basically for the same reason as above.


Although I have taken precautions... I still am rather skeptical of extreme carbon buildup. There are many people that have still run function EGR systems and have surpassed 100k. Phil is one, and Chase is another, and I'm sure there not the only ones. It seems to me that if your doing your stuff right (not switching until operating temp, not switching till you've reached the desired fuel temp, and purging for at least 30 sec (GC) you really shouldn't have any problems.

Smoking out the back of your exhaust is a very bad thing!!! You are smoking due to unburned fuel and washing the cylinder walls with VO. Over time this will wear the cylinder walls and eventually make it to the rings where most people are having there problems (i.e burning oil, low compression, poor running engines) O yeah, this will become a source of your carbon buildup and eventually will ruin your engine.

I have a water/injection setup put on my car specifically for burning WVO. Since I am taking every precaution to deposits (even though I am still skeptical,) water/ injection is a great way to remove deposits (which is basically what you were doing Todd B.


***Where I believe the problem lies***

Timing, or should I say lack there of.... Our sophisticated IP's can be a real pain in the a** for us WVO'ers. The pump adjusts timing due to extreme fuel temps, which in our case is always when we are running VO. As vwcampin said, see my thread for more of an explanation but I have seen that the ECU is capable of pulling back timing 2-3 deg.

My timing on my car is mechanically set advanced, around 2 deg or so. Even with a mechanical advance, the ECU was still able to pull back timing to be a tad bit retarded at low RPM, low load conditions. With the fuel temp resistor in effect to essentially fool the ECU into thinking the wrong fuel temps, I was able to limit this to where I am happy. I never see less than a deg of advance on VO. The information complied from a variety of sources says advancing 2 deg on VO will be much better for combustion. (when your not burning the stuff completely, your causing deposits)

Another place of concern is the injectors and popping pressures. If pop pressures aren't within spec, atomization is hindered greatly. (the fuel is already thicker then diesel, even heated) I feel this needs to be monitored also, a great way of doing so is monitoring measuring block 13 on VAG COM. Or pulling the injectors out to see if they are to spec.

Both of these factors contribute to combustion. Both being extremely important.
 
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