http://www.walmart.com/ip/Diesel-Kleen-Plus-Cetane-Boost-80-oz/16644702
I run it in my trucks and in all of my equipment. That's 14 diesel engines running everyday for over a year now without 1 fuel related problem.
The problem is the new Ultra Low Sulfur Diesel fuel that our gobment has forced us to burn. Diesel engines like greasy slimy diesel fuel. The ULSD is crap. It does not have enough lubricants and the cetane is 6-10 points lower than it should be. In the processing of the ULSD, they basically bubble hydrogen gas through and that strips the sulfur (which was a great lubricant) and all the other impurities out of it. It also drops the cetane count. (the octane equivalent for diesel). They are then supposed to add a lubricant and cetane booster back in, but they don't put enough.
Add Diesel Kleen to your fuel and you will not believe the difference in performance. If you drive the same with added horsepower, your fuel economy will improve. I get around 2 mpg better.
As far as noise goes, the only thing that quiets diesels is more fuel. At idle they are running so lean that they are barely running. With the added cetane, the burn is hotter quieting the engine noise some. The best way to quiet down a 7.3 is the regulated return mod. In the standard fuel rail of a 7.3 cylinders #1 and #8 are at the dead end of the rails. #1 is fine, but the firing sequence has #8 firing just after #7 which starves it for fuel. It is so bad that the #8 injector is different that the other 7. The RR mod removes the dead end condition and improves fuel pressure across rail.
The Filter Bowl delete solves a common problem with the 7.3, the plastic filter housing. It gets rid of the plastic housing,wedged in between the turbo and HPOP, (the hottest place on the engine) and replaces it with a canister type filter on the fire wall away from the heat.
If your 7.3 is still stock, it make around 235 hp and around 350 ft/lbs of torque. The reason these engines had a 100k mile warranty is they are de-tuned about 50% of its capacity. These mods along with the aFe air box will allow your truck to run better and prepares it for some massive improvements with even a mild tuner.
Probably more info than you wanted but my livelihood is based on diesel engine reliability, plus toying with diesel engines is my second favorite hobby so I tend to get a little geeky about it.
