January
2010
"STORIES"

As the world of diesel engines keeps changing, those of us who specialize in high performance diesel engines must also keep changing. Innovation requires an open mind and a breakthrough can take some time.

On Thursday, the 10th of December, we had a breakthrough. Fernando, our resident mechanical engineer; Nathan, one of our diesel engine technicians and I took advantage of an uncommon opportunity when a Freightliner equipped with a DDEC IV-EGR Detroit came in our shop. This engine was one of the first Series 60 EGR applications.

We had been studying the EGR engines since 2003 when they were first implemented. Today we are quite familiar with a multitude of problems associated with them.  Our goal was to figure out how to make these engines more efficient, burn cleaner, live longer and eliminate the problems associated with the complex and expensive VGT (variable geometry turbo).

 This DDEC IV EGR powered Freightliner came to our shop to have a turbo boost and pyrometer gauge installed, along with our straight through performance quiet muffler.  This truck was equipped with a 2:64 rear gear ratio and a 10 speed direct transmission.  A gutless wonder she was, dropping 2 gears on most hills, drinking fuel because of low power and a clogged muffler and all of the garbage that various dealerships have put into the ECM to try to improve the fuel mileage and performance.  Remember, without performance there is NO fuel mileage.  I feel sorry for owner-operators who are driving gutless wonders and wish to help them be happy with their truck.  After lunch I mentioned to the owner of the Freightliner that we have been studying the DDEC IV-EGR and asked if he would be interested in testing some changes we wanted to make to improve his engine.  He had to be in Long Island, N.Y. to deliver his load the next morning so any changes we were going to make had better work. 

At 9:00 pm that evening we backed it out of the shop and went for our test ride and were very pleased with the results, 35 psi of turbo boost bobtailing and 37 with the loaded trailer grossing 79,000 lbs.  Only 1 minor check engine light came on and we knew how to fix that problem.  Later that night I called Brandon, the owner-operator to see how the truck was pulling.  He answered the phone "I love this truck; I went over Snowshoe Mountain in 10th gear at 25 to 27 psi of boost and never slowed down." 

Now think about this, Brandon is fairly new to the wonderful world of owning a truck, however he hated his "gutless wonder" - no power, no fuel mileage, and he was told by a Detroit Diesel Dealership that his engine was worn out and they had a dyno sheet to prove it.  A crate engine with 420,000 miles on it and they said it will never run because it needs rebuilt again.  This is the second engine in this 2004 truck.  Let me tell you guys, this engine is NOT worn out and is running great with 585 horsepower and will cruise along at 6 to 8 psi of turbo boost on the level at 60 mph.  We do not have a fuel mileage report yet because of the experimental ECM on the truck will not accurately calculate fuel mileage because it is not calibrated to his rear gears.  I will let you know in future articles how the fuel mileage is doing. 

  This truck had 2:64 REAR GEARS and I want you to think about this; when we build the Signature Series Glider Kits we install the 2:64 rear gears so truck will run effortless across the highways. Many people think a truck with high gear ratios like this will lose power on the hills and mountains.  However the opposite is true. The truck will effectively gain horsepower because the double overdrive 13 and 18 speed transmissions have higher parasitic losses due to friction in high gear.  We know for a fact that the double overdrive Allison Automatic loses about 40% of its horsepower in the transmissions highest gear.  This Allison is only a 6 speed transmission however the torque converter locks up in 2nd through 6th gear which means it doesn't lose any power due to torque converter slippage.  So if the Allison is loosing up to 40%, what is your 13 and 18 speed losing? 

Many owner-operators think their 13 and 18 speed Eaton Transmission is a single overdrive and when they split down ½ gear they are in direct.  This is not true; you must go down 2 gears or 1 full gear to get into direct, which is the work gear, the gear you should be using to pull a hill.  All 13 and 18 speed Eaton transmissions today are double overdrive when there is a 3:36 to a 3:73 gear ratio rear end.  When you're pulling in direct gear only about 11% to 12% of the power is lost in the drive train and that is why when a truck is on a dyno it’s always run in direct gear.  So let’s do some calculations and see how much power is lost in 13th or 18th gear, vs. direct gear.  A 550 Caterpillar with 3:55 gears puts out about 490 hp to the rear wheels in direct gear and that is a 12% loss of power.  Now if 30% of the power is lost in 18th gear, then only 390 hp would be delivered to the rear wheels.  That is approximately a difference of 100 hp when pulling in double overdrive.  The fuel mileage will improve by at least ½ mpg running in direct gear with 2:64 rear gears. 

Now I'm not saying the 2:64 gears are for everybody, if you're heavy hauling, logging, dump trailer, or running mostly on 2 lane roads, then this combination may not be for you.  But if you're running across the interstates with 80,000 or less gross weight you just might want to think about the 2:64 gears.  Now let's take this one step further, I prefer a splitter type transmission, such as a 13 or 18 speed Eaton and there is a single over 18 speed that was available in the 1990's.  I happen to own one and love it.  If I build you a glider kit and we use the 2:64 gears then I will install one of these single over 18 speed transmissions for you, however you will want to run in direct and only use overdrive when driving down a long grade, bobtailing, running empty or just want to speed. I prefer the splitter transmission because you can be in the perfect gear for any condition, many times you will only need to drop ½ gear such as driving in heavy winds.

I also want to mention that we will be having a class at Kevin Rutherford's CMC seminar this summer in Kansas City.  This class will be a "hands on" introduction where I will teach you how to install turbo boost and exhaust gas temperature gauges, change crankshaft dampers, and install performance mufflers for all of you owner-operators that are NOT mechanically inclined. I will be the instructor so bring your tools and coveralls. 

Written by Bruce C. Mallinson, Pittsburgh Power Inc., 3600 S Noah Dr., Saxonburg, Pa. 16056. Phone 724-360-4080. Email: bruce@pittsburghpower.com