As I said, the fuel leaks common when owners switch to R99 is well documented with 1.9 TDIs. In fact, I tried mixing it 50/50 with D2 in my '03 golf and I developed a small fuel leak on the return line to the injection pump. The next tank I filled up with pure D2 and the leak miraculously went away... The common fix for people who like to use this fuel in 1.9s and chase down fuel leaks is to replace rubber parts with Viton.I wouldn't run an additive with mmt in my gen 2 Cruze diesel. If concentration is too high or with regular use you can foul sensors or catalytic converter. Not worth the risk to me.
There are a number of fleets that have switched over to R99 without any reported issues like leaks etc.
R99 does have approximately 5 percent less btu per gallon so reduced mpg is expected.
But if the overall mileage is the same due to reduced regen and regen duration, then who cares?
I will be running R99 as a very low risk method to drastically reduce my probability of having dpf issues on short trips etc. The only downside might be getting a little less mpg, but getting a little less mpg.along.the way is fine with me and well worth the trade off.
And on longer trips I will mix in diesel #2 for economy/cost effectiveness....
There isn't any evidence that MMT fouls sensors or the Diesel Oxidation Catalyst found in our DPFs. In fact, Manganese Oxides are used in the manufacturing of some Oxygen sensors as the electrode material.
MMT has been shown to actually clean DOCs in modern diesel engines. It also reduces exhaust PM and NOX formation.
Phosphorous and Sulfur scavenging have been demonstrated during diesel combustion. Aftertreatment protection from P & S helps to preserve catalyst conversion efficiency.
MMT was shown to reduce PM accumulation in a DPF by 20% with a dose as small as 10ppm. That is .00001%MMT decreases the rate of soot accumulating in a DPF. There is also a significant reduction in soot oxidation temperature leading to regeneration
Soot is the worst thing for sensors. It is composed of unburned hydrocarbons and when it is introduced by EGR and mixes with oil becomes a placque. This placque is what plugs up intake manifolds, swirl valves, turbochargers, basically anything in the intake and exhaust system.Soot is the result of incomplete combustion.
How can an additive that reduces soot by up to 75% be harmful?
Any study that shows MMT is harmful to catalysts was not performed on a diesel engine and is probably 40 years old. My experience using it in 4 different diesel vehicles with DPF and DOC are all positive.
I get better performance with CARB D2 mixed with an MMT additive than with straight R99. Without any side effects like reduced fuel economy and low end torque found with R99. This is a running average which includes regeneration frequency.
I was an R99 fanboy too and knowing it's a LCFS is pretty cool. However it's subsidized by the state and if people had to pay the true cost it wouldn't be half as popular here in CA as it is.