Yeah tune+ won't put it back into any engine. They delete it on all their builds. The increase in nvh is so minimal, I wonder if it was always there and I didn't notice because I wasn't looking for it.
They've recently been gutting the carriage and re-installing them without the BS in them. I haven't noticed much of any NVH with mine. I can feel a little more movement of the engine through the chassis now but that's only when I pay specific attention to focus in on it. Most people would never notice it.
Inline 4 engines have perfect primary balance but have a secondary imbalance (twice crankshaft speed at half the intensity) due to the Pistons moving faster at the top than at the bottom due to geometry. In smaller engines with short strokes (sub 2 liter) it is so minor that it can't be felt by the occupants and balance shafts are omitted. Our engine is basically a stroker version of the 2.0 in the focus st. The balance shafts are two intentionally unbalanced counter rotating shafts in the oil pan that mask this vibration by cancelling out the motion before the occupants can feel it. Unfortunately in our application it is driven directly by a gear pressed into the crank and transmits it's cancelling vibration directly to it. After studying the design of the ring gear, crank, and shafts themselves as well as some studies on metallurgical harmonics, I found enough circumstancial evidence (not direct as I don't have access to failed engines or Ford research) to formulate a hypothesis that a slip of the ring on the crank by as little as 2 degrees can change the vibration from cancelling to interference.
Thanks for the in-depth explanation. I wonder if anyone could get a Ford engineer to explain exactly why they included it if seemingly no negatives can be found to removing it. They must have found something to be worth the R&D and cost to implement.
Yes, some magazines have already called the engine un-refined and truck like (The ford Ranger actually used this block 2.3 NA without balance shafts). And under the right set of circumstances (like when idle drops real low for a few seconds after the cold start cycle is over) it becomes far more noticeable than when the shafts were in it.
There's a documentary on Netflix called A Faster Horse. It's about the development of the sixth generation Mustang, and the history of the model in general. In it, chief engineer Dave Pericak and chief technical officer Tom Barnes can be heard discussing NVH on several occasions. This Mustang was designed to compete worldwide with a number of highly refined cars from manufacturers known for their attention to detail. That Ford was dilligent about NVH concerns isn't surprising.
Couldn't have said it better myself.
C'mon. You didn't even try! :cheers:
Bringing this 6 year old thread back up; if you started another thread couldn't find it in search. My lightly modded EcoBoost (intercooler, Ford Performance tune) grenaded #3 at 119k miles while leisurely accelerating onto a freeway onramp. I now have the MAP performance Stage 1 shortblock with BSD and am curious if your theory has held up and this may help cure the #3 Ecoboom failures. Does anyone have an update/answer?
