Particulate Trap
By Bruce Mallinson
TruckJobSeekers The Magazine
1/2/2008
Owner-Operators, please do you homework before you order a new truck with a Particulate Trap as a muffler. These traps may be extremely restrictive and will not be able to be removed so now you cannot have the beautiful straight 7 or 8-inch stacks. That look will be long gone and further more the particulate trap will have 4 sensors to monitor how much soot it has collected. As the soot accumulates, one of the sensors will send a signal to the ECM to fire an injector behind the turbocharger. That’s right. An injector that is behind the turbo in the exhaust pipe just to make fire to try and burn off the soot in the trap that is supposed to be a muffler. Now as we try to gain every 1/10 of a mile per gallon of our precious fuel, we are going to dump it overboard just to make heat. The particulate trap can run as hot as 1,200 degrees and it will be behind your bunk or right behind your right side steering tire. Talk about restriction, this thing will have it!
While I was working the Dallas Truck Show, I was one of six men listening to a person from one of the truck manufacturers speak about the particulate trap and how the EGR System works in conjunction with the trap. Once he finished talking I asked him what is the amount of backpressure between the turbo and the particulate trap. His answer was, “It doesn’t matter what you do with the exhaust once it leaves the turbocharger.” Not wanting to make him feel bad I held my comments. Think about that statement, it doesn’t matter what you do with the exhaust once it leaves the turbo. Let me ask you this, why did we put dual exhaust on cars back in the 50’s and 60’s? Why do we put headers on racecars? Simply put TO GET RID OF BACK PRESSURE!!!
Backpressure from small turbos and restrictive exhaust systems creates excessive pressure on the piston while it’s on the exhaust stroke. Now what drives the piston during the exhaust stroke, the piston that just received a shot of diesel fuel and is being slammed to the bottom of the cylinder bore to turn the crankshaft. All that piston wants to do is turn the crank, not push the piston that is trying to get rid of the exhaust through a tiny orifice called a waste gated turbine housing and then onto the restrictive mufflers and now a particulate trap. Why do we gain fuel mileage when we increase the turbocharger size and install free flow mufflers? Because we relieve the pressure off the piston during its exhaust stroke and allow more power to go to the crankshaft. It’s that simple, free flowing or free running trucks will last longer between rebuilds and gain better fuel mileage.
Now back to the Particulate Trap. If I were an owner-operator, I would not purchase a new truck with a trap. I would allow the fleets to do the experimenting and we will know within about 2 years what kind of problems are going to arise. The fleets have spare trucks, you don’t, so let them be the guinea pigs.
If you want a street rod, you have to build it, or if you want to re-do any old car or truck you should do a body off the frame restoration. It’s not hard to remove a hood, cab and bunk from a truck frame. With those components removed, it’s easy to re-bush the suspension, change fuel and air lines, replace all of the rubber mounts and in fact you should use the polyurethane bushings. These bushing will out last you and they eliminate unnecessary movement of the suspension. New rubber is good, polyurethane is GREAT!
If you rebuild your truck, you will enjoy it much better and you will take much better care of her because of the sweat equity you put into making her a great truck.
For those of you that have to have a new truck every 2 or 3 years, good luck. Will your fuel mileage be less than what you’re now getting? Yes, absolutely. How much less? According to what I've been told by some of the OEM’s, a few tenths. Remember every 1/4 mpg is 1,000 gallons of fuel every 100,000 miles. Please maintain and rebuild your existing trucks and save yourself a lot of aggravation.
Have you ever heard of a “cooling valve” in a DD4 Detroit Diesel Engine? I haven’t; however, a young man came to our booth in Dallas and mentioned that he was told he could not turn up his DD4 because he did not have a cooling valve. It's quite interesting, the things that will come out of the mouth of a service manager when he is trying to get you to leave with your truck.
Another one is, "I have a 3406E Caterpillar Engine which produces 435 horsepower and I want to rebuild it to a 550 hp engine.” This particular customer was told that it was impossible to go from a 435 to a 550 hp engine. Now why would that be? After all the engine block is the same and so is the camshaft, connecting rods, head, exhaust manifold, rod and main bearings and the rocker arm assemblies. So we change the pistons, rod and main bearings, injectors, ECM, turbocharger and now we have a 550 hp engine. The same thing used to happen years ago when an owner-operator wanted to rebuild his NTC 290 into an NTC 400 and many local service managers said it could not be done. Well we've done it time and time again, and now we are doing it with Caterpillars and Detroits. There are a lot of great service managers and when I have the opportunity to speak or deal with one I make a special note about them. You should be careful of the negative thinking ones you have to deal with. Always get another opinion if you're not comfortable with what you have been told.
"Constipation is Constipation" and it does matter what happens to exhaust once it leaves the turbocharger. Even if you ran the exhaust pipe to the rear of the trailer and put a restriction there it will still affect fuel mileage and create backpressure.
Please test drive a new truck with a Particulate Trap with a loaded trailer before you purchase it, there just may not be any help for several years for you if your unhappy with the fuel mileage and performance. You just may go broke during that time and loose everything. There is nothing wrong with driving a truck that has over 1 million miles on her. If you're leased to a company that requires you purchase a new truck every 3 or 5 years, lease on to another company that uses good sense. By the way, my newest vehicle is a 1996 Dodge Cummins pick up and it's in perfect shape. Pittsburgh Power owns 3 mid 90 Dodges, 1 SAAB Turbo, and a 1989 Kenworth and they are all in perfect shape.
My newest vehicle is 10 years old. My Harley is a 2003, my snowmobile is a 2004 800 REV. There is nothing wrong with having an older vehicle as long as you keep her in pristine shape.
Take your existing truck, install a Pittsburgh Power Computer, straight through mufflers, a larger turbo, new crank damper and a Pittsburgh Balancer and you’ll love the way your truck runs. The fuel mileage will improve also.
