I tried an experiment this week. I put straight B99 in the Jeep for the first time. I did notice the harder starting when cold or warm that some have posted, but that is not why I am posting. I haven't run all the B99 out yet, so I don't know what the mileage is. It was not the best scenario for getting good mileage anyway, and I would need to run another tank under more normal circumstances to have a comparison. What I am really curious about is this... I am certain that the torque converter was spending more time locked in than normal. Normally, I notice the converter lock and unlock almost immediately. Even if it would stay locked, any increase in throttle would cause it to unlock. All that was much improved on high concentration of biodiesel. I assume higher cetane gets the credit for the change in behavior, but how does it know? The only theory I have is that if the computer sees too much of a drop in RPM when it locks the torque converter, it immediately unlocks it. With the biodiesel, I could let the converter lock in and let the torque do the work - like I would with a manual tranny. I think the higher cetane is producing more torque, and allowing the engine and trans to work together like they should. I have been using cetane booster on straight D2 and B20, but around here the pumps are not marked with cetane ratings, so I don't know where I'm starting from. I think I read once that if the fuel vendor has added cetane boost just to get the fuel to 40 or 42, you won't get it much higher than that by adding cetane booster yourself.

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Matt B.

05 Limited CRD. Bought it new. 112k on the clock now.

GDE Eco-tune, rear differential drain plug (drilled and tapped the pumpkin), transmission pan drain plug, Fumoto oil valve, fuel filler neck restriction removed, front hitch, Hayden fan clutch, Sears P1 battery since 08, Mobil 1 5w40, 5 volt glow plugs, DIY timing belt at 109k