Postscript

Written by TsTDI

I hope your head is spinning with all sorts of information you have not known before. The goal of this guide was not to confuse you; however, I wanted to make it blatantly obvious that there is much more to burning WVO than what people think. Although I consider it a hobby, there is a science behind it that allows combustion of vegetable oil to be possible. Understand this guide in its entirety. Every topic, whether confusing or too sophisticated, was written for a reason. I would be happy to answer any of your questions in the future. I want to thank all of those who I included in this thread, especially those who have failed while burning WVO. It is you who allow progress to be made in the world of burning vegetable oils. Thanks for reading and Happy Greasing!

So in my best opinion, I believe I found the key to long term success in WVO. I've done a lot of research, have extensive knowledge on the topic, but after a replacement of my injectors and nozzles, It was quite a humbling experience.

I'll try and keep this as concise as possible. The purpose of this thread is to show how important correctly popping nozzles/injectors are to burning WVO/SVO. I can already foresee the flaming in the future; however, I vowed to keep my conversion and experience open and honest for education. So here you go… unbiased and very honest.

I started to notice very poor fuel economy with my car. I drive a lot of city miles ever since starting my 9-5 and have not utilized burning WVO in the city (see my guide for further details). I always attributed the poor fuel economy to driving in the city; however, I knew diesels don't do THAT bad (roughly 25-30 or worst MPG city with a manual and I was use to 35-40 MPG consistent).

Well, without being completely ignorant, I knew the culprit was my injectors and nozzles. I had replaced only the NOZZLE (pp520) when I first got my car PRIOR to my conversion. I have the exact number of miles in my notes, but I don't have it with me right now (estimated about 35,000 miles ago). I did not have the injectors pop tested, nor did I look into it at the time. However, these were brand spankin new PP520 injectors put on the nozzles over 35,000 miles ago...

I was the second owner of the vehicle and I have to assume that the injectors were STOCK on the car (I purchased the car with 142,000 miles on the clock). I have total on the car, 188,250 now. I’m sure the injectors were due a pop testing service, but I never thought it would make this big of a difference.

Recent thread postings about injectors and WVO had me a bit concerned about mine. It was always in the back of my head and it was starting to show its affects, although so subtle!!!

Poorer fuel economy, higher EGT's (especially on long grades), more boost spiking (excess of 32 PSI at WOT, tuned for 26 PSI), more overshoot (lower RPM's, and more overrunning of the turbo (turbo surge, 4th gear was HORRIBLE for that). Although funny thing was.... power was GREAT, going down the road the EGT's were about what I would expect.

I bit the bullet and found this...

You can see very clearly all the nozzles are coked. However, they are not coked to the point of disastrous effects. Note: although fuel economy was quite down, mid to part range throttle was relatively normal, power was relatively normal and it would take an extremely perceptive person to notice the effects that this amount of coking would cause.

I don't have a crazy high definition camera that can take a picture of the nozzle orifices up close; however, most were coked up though the hole was still visible, some were coked up completely. Obviously, the nozzles just don't look like they should. You can see extreme evidences of coking due to poor atomization of the fuel.

Also note: I pulled my glow plugs out within the last 10k, no signs of this coking pattern. It’s only on the injectors!!! (people have said this is a key to look for).

I've always said the key aspect of WVo/SVo is atomization of the fuel that is in the combustion chamber. There are two key aspects to this. One, getting the oil at the right temperature and two, mechanically everything working sound (specifically the IP and the injectors). I missed the one key ingredient and that was with my injectors. Although, never in my wildest dreams did I think a brand new nozzle/ old injectors result in this amount of coking that FAST!!!

Let it be a WARNING to all those burning WVO. If your injectors/nozzles have not been pop tested lately or if at all, GET THEM POP TESTED. I have done my homework and I know the in's and out's. It wasn't that I was doing something wrong or short purges, this is the nature of the beast and only those blaming me as ignorant, are the ignorant. You can 100% have a running engine operating on all four cylinders going down the road with this problem developing without notice. Never did I notice WVO/SVO smell on shutdown or startup...

Lucky enough for me, I spotted the issue before it became disastrous.

I think I've found the element of luck or the x-factor that makes it work or perhaps I should say not work? It’s certainly a relative term for everyone and whether or not WVO "works" or doesn't work. Sure a car can burn it, but for how long? Why did some people go 100k and some people only make it 10-30k? Well, look how fast my BRAND NEW nozzles took to coke to almost trash on incorrectly popping injector?

This is very humbling because I advocated WVO for so long, but at this point, I just don't quite know. I know my operating procedures were top notch; however, if you have to control a million variables to make it right, it’s hard to say it will work for the average Joe. The average Joe would not have picked up on my problems and fixed them before they became disastrous. He probably would have driven the car another 10-20k miles before it was tow truck time.

I replaced my old injectors with straight from Bosch, T4 764's and wow what a difference. I forgot the slight nailing that diesels had at idle. Fuel economy has been tremendously increased, probably by about 10 MPG!! Smoke at idle and hints of diesel smells at lights are now non-existent. Low RPM power has been vastly increased, turbo overshoot and surging has been virtually eliminated.

I'm not sure if I'll 100% say WVO does not work because don't get me wrong, it worked for me for about 30,000 miles. The car itself is in great working order and I could put oil in my car today and continue to run it on my new injectors but is it worth it? In my opinion... no its not. Injector units and new nozzles ran me about 800 dollars... I mean we could consider injectors wear items because in reality they are (even on diesel fuel); however, I think WVO drastically increases the wear on injectors to the point where they are operating subpar at best.

However, if you want to pursue WVO, please consider regular 20-30k pop testing intervals as best practice habits. It will prevent catastrophic failure of your engine!!

So there you have it TDIclub community. I wrote the most extensive guide on the internet and also followed it up with a non-biased, WARNING with emphasis on the WARN part that if your ignorant to your injectors popping correctly, your just plain ignorant.

All this work couldn't have come at a better time because I just recently lost my oil source

Another easy decision on my part to not pursue this hobby in the future.

Other than a non correctly popping nozzle/injector combination as my culprit in not seeing long term success... I might have to put some of the blame on the oil itself. It was finely filtered with a centrifuge and finished filtering in a 5-1 micron bag (not concerned about the filtration); however, the oil was extremely FFA laden. We originally got the source in the hopes of creating biodiesel and the oil titrated over a 20. In terms of biodiesel creation, this would be considered absolute trash. We opted to burn it straight.

The acids within the oil very well could have degraded parts in the injector prematurely to also cause my problems. I was under the impression that long purges and drives on diesel before shutdown could avoid this problem.... I might have guessed wrong. This is just another thought to put down in the web space as other helpful ideas to consider before delving into WVO or reconsidering it.

So ask me today whether WVO can or can't be done. I’m pretty much on the fence... I did more things to their car to adjust my engine to burn WVO then more people even consider. I adjusted timing parameters, final heating through line injectors, EGR delete, CCV delete and the fuel temp resistor mod. My nozzles still coked to the point of almost not working.

That’s all she wrote folks... Questions and comments welcomed. Honestly the conversion was never about right or wrong, just about education. Between my guide and this thread, there is plenty out there to get you started on burning vegetable oil. Whether or not you see long term success is up to your ability to pay attention to everything.... literally everything.

Non-biased results

Roughly 27-30k miles on WVO… 46,000 miles since conversion

At $3.50 a gallon and 45 MPG average (which is what it is currently and yes I had my car converted when diesel was $5.00 a gallon)

Roughly “saved” 2,100 dollars. However, my kit cost about that much and my injectors and nozzles were $800. In the end, the project cost me money but it was never really about that to begin with. I had a lot of fun and I got a lot of enjoyment out of the hobby. What a conversation starter!!! Those real world figures are estimated on a conservative basis…

Cheers!