B99 in 2009 TDI
I'm surprised by VW's position, but expect it is mostly CYA for loose screws behind the wheel. Looking at the BS with B99 reblending and the necessity of registering to buy B99/100, not to mention the active and admitted conspiracy of oil interests in many other venues to protect their investments and fortunes, I suspect there is a lot of political nonsense around these issues.
I took the plunge and bought a 2009 Jetta TDI I plan to run on B99. My understanding is that the only issue is that the lower volatility of B99 over D2 causes an accumulation of B99 dilution in the crankcase.
Issues of seal deterioration would be present even with B5, and I have seen only very minimal problems with this even in my '81 caddy, and none in my '98 TDI. Many others have reported the same reliability of the pump, plumbing and seal systems with B100 in many other VW's including pre PD TDI's. I think absent gelling and increased viscosity at low temps (especially given that the new fuel filters are heated), there are likely no other issues to be confronted beyond the post-injection lube oil dilution problem.
Even this problem of oil dilution from regen post injection seems relatively small, and likely easily managed by a decreased oil change interval. Due to particulate contamination of lube oil in diesel engines, I have always halved the recomended oil change interval in all my diesels, as do many mechanics. Increasing that to a third of the recommended cycle, 3000 miles, which is the interval I have used in all my more modern engines (I have used 1500 in older and worn engines).
With the reported 300 mile regen interval, that is 10 regens in a 3000 mile oil change interval. With a gallon of oil in the crankcase, how high can the dilution possibly get? I understand that with Canola (rapeseed) based B100 in Europe, VW is fully warranting the vehicles. The difference between soy and canola based B100 would mostly likely be only of gel point and temp. dependent viscosity rather than vapor pressure, lubricity or solvent action.
The data, the best I can find, here:
www.biodieselconference.org/20...hnical Johnson.pdf -
while superficially alarming, is so poorly scaled as to be fairly useless without the accompanying text and more complete graphics. Poor Ed Tufte would be disgusted by this.
Surely the rings cannot possibly be that porous, altho at the low pressure of the exhaust stroke, especially with an unbroken-in engine, it could be a significant portion of the injection volume. Injection volume is reported by the VAG COM, so I will monitor this as much as I can and see what I get. I'm planning to use a small dedicated tablet so that I can continuously monitor and capture the ECM data.
I think I may wait until after my first 3K mile, probably even my 10K oil change before switching to allow a more complete break-in. The rings after all are really the only engine component actually needing a break-in
In my experience running both B99 and D2 in a number of engines, including stationary gensets, I have observed that the particulate mass for B99 is significantly below D2. I have also seen serious filter clogging by wax crystals with even very good home brew, tho not with commercial ASTM B99. Gel points seem to vary widely. I suspect this may be the cause of the CEL reported by Neurot, as there is a specific particulate filter warning light.
I'm wondering if a chip tuner could reduce the scheduled regen frequency to suit the lower particulate with B99? There is a pressure differential sender shown in the illustrations, obviously used to trigger the DPF warning light, but I presume also as a secondary threshold to trigger regen cycles beyond the mileage scheduled regens.
I anticipate that here in warm So Cal, with a 3K mile oil change interval and ASTM virgin soy B99, I will have little trouble.
I will report all the data I can. I suspect I can catch the regen on my Vag Com by injection volume. I will try and capture and graph a regen event to get some hard numbers on the volume change and potential oil dilution rates.
I would think that VW would have made the cars B99 compatible if possible, but again, they need to build cars capable of being reliably operated by idiots. If I were testing these engines for fuel recommendations relating to warranty issues, (especially given the stringent emission control warranties required in CA) I would use a worst case standard, and might therefore specifically prohibit the use of B11 and above, as VW has done in the 50 state cars. As a certified non-idiot, I have some faith I can manage this system reliably.
Time will tell. Stay tuned.
