Turbo boost:  How can I get more boost?  Now lets stop and think about this question.  How can I get more turbo boost?

First of all what makes turbo boost?  Is it the turbocharger, or the volume of exhaust being forced through the turbine housing which in turn spins the turbine wheel?  Or could it be the piston pushing the exhaust out of the cylinder during the exhaust stroke?  And don’t forget about the mufflers.  If they are too restrictive the exhaust can’t pass through them effortlessly.  Then the mufflers become the final dam.  DAM:  Think about that word what is a DAM?  It restricts the flow of whatever mass is in front of it.  It is a restriction.  Turbine housings are a dam and a velocity improver.  Now, mufflers are massive restrictors and the final dam in the exhaust system but, we still need some type of muffling device.  Straight stacks with no muffling device is a nuisance to the public.  There are straight through mufflers available that do not restrict the flow of exhaust and they have a nice deep mellow sound to them.  Turbo boost will increase slightly, exhaust temperature will decrease and fuel mileage will improve.

We do have these mufflers in stock and can UPS them to you.  They replace the stock muffler that is mounted on the cab or behind the bunk.  The current price is 158.00.

For the Kenworth W900L and the international with the reverse flow muffler under the bunk, we will soon have a high flow system for those trucks.

Now back to the first dam, the turbine housing.  Back in the 1970’s turbochargers were much larger and the fins on the compressor wheel and turbine wheel were much smaller than the turbocharger of today.

Today’s turbo’s are much more efficient with the smaller turbine housing, the velocity of the exhaust is much greater and the turbine wheel is accelerated much quicker.  Being the turbine wheel is connected to the compressor wheel (fresh air side) it also spins much sooner and faster producing turbo boost.  All of this sounds great however, there is a price to pay for the quick boost and that is greater backpressure in the exhaust manifold.  The piston in the engine must now push harder to get the exhaust out of the combustion chamber.  So where does the piston get it’s power to push the exhaust out?  It robs the power from the piston that is on the firing stroke.  So the greater the back pressure is in the exhaust manifold, the harder the piston on the firing stroke has to work to push up the piston in the exhaust stroke.  And you the driver keeps pushing further on the throttle giving the engine more fuel, creating more exhaust and making the pistons work harder.  Think of a gasoline-powered racecar with headers, it runs very free.  There are no dams in the exhaust system, no turbo or muffler.  Now think about your ACERT Caterpillar twin turbo, and mufflers with catalytic converters.  There are 4 dams in the exhaust system, 2 turbine housings, a catalytic converter then the muffler.  A 550 H.P. twin turbo Cat produces 49 to 51 psi of turbo boost and a single turbo Cat produces 28 to 32 psi of boost for 550 horsepower. 

Do you think the piston on the ACERT engine has to push harder to get the exhaust through the 4 dams?  I do and it’s strictly my opinion.  A diesel engine only needs enough turbo boost to keep the exhaust temperature between 1300 and 1400 degrees on the hot side before the turbo or 1100 to 1200 degrees on the cold side, the exhaust pipe.  Engines with aluminum pistons should not exceed 1200 to 1300 degrees hot side or 900 to 1000 degrees cold side.