Air & Exhaust

Turbochargers while simple in design, can get very complex in theory. From deciding what compressor trim is desired, to what turbine housing to be used is confusing to most who enter the field of forced induction. This article will hopefully take away all the confusion in turbocharger selection. Terminology Before I can begin writing an article explaining turbochargers, terminology must be learned. Here is a list of the more commonly used turbocharger terms: Compressor - Essential

Everyone seems to grasp that a larger exhaust on a turbocharger vehicle will gain faster spool up, increased power and thus faster acceleration. Here is the theory behind the phenomenon: The turbine housing is merely a volume for which exhaust gas (energy) is transmitted from the engine, to the turbine blade, then dispelled into the atmosphere. In order to better understand how this works we need to take a look at pressure. Turbines in general work off of a pressure differential. A pressure diff

What is an A/R ratio and how is it calculated?: The A/R in a relationship that is obtained when dividing the interior area of the turbine where the inner walls are found, through the turbine housing radio from the center to the tongue as the illustration indicates. A/R values are expressed as .35, .47, .68, .84, 1.00, 1.15, etc. A small A/R indicates a small interior volume in the small turbine and a large A/R indicates a greater volume. At a minimum A/R the motor's respon

There are several different kits and filters available for assisting Cummins Turbo Diesels to breathe more efficiently. The following are some of my personal findings when considering and using BHAF’s (Big Honkin' Air Filter). Firstly, there are air filters on the market that are washable and re-useable. These air filters also claim to prolong the life of the air filter and save money. I have found this claim to be invalid. When a air filter is

Posting the youtube video on the how to         Common areas for  leaking   1. intercooler boots 2. intake shelf gasket 3. grid heater gasket.    Steps: pressurize the system, to ~ 5- 10 psi using the setup in the above video > next use soapy water in a spray bottle to soap up the intake track.  start at the turbo and work your way to the intake side of the engine.  Spray and watch for bubbles in each area.    

Seems to be some confusion around other parts of the interweb so I will go into full blown detail and end it all. Diesels technically need an air to fuel ratio (A/F) of only 14.5:1 to have enough to burn all the diesel, however, in practice this ratio needs to be around 18-24:1. Even higher ratios are sometimes needed to stomp the EGT back down where it belongs. But the misconception is that boost is everything and nothing else matters. Although I said 18-24:1, I will use 18 for this entire arti

The author of this article is a turbo engineer for Garrett. I'm submitting it because it is an informative read and therefore is beneficial to the community. Enjoy. Compressor Efficiency and More by Khiem Dinh Compressor efficiency is a term thrown around whenever people mention forced induction, but what does it really mean? How does it affect an engine's performance? And what role does air temperature play in all of this? The cool thing about thermodynamics is that we can e

Muffler Delete / Straight Piped Another simple enhancement that doesn't cost a bunch of money is straight pipe the exhaust. Beware in some states it is illegal to be without a muffler. Now in some states, a turbo is considered a muffling device. Some people think it just too loud. I will admit that without the muffler in place is it louder. I've been told that my truck can be heard up to a mile away.

Effect of Altitude on a Turbo Diesel This Article covers the effect of being at higher altitude in a Turbo Diesel powered vehicle.  The princples work the same on a Cummins 24v vs common rail and powerstroke or duramax.    First thing we need to look at why altitude plays a role.  We need to remember that at sea level there is about 14.7 psi of pressure in the air you breath.  You can figure out this number by doing some basic math seen be

Operation At the time you turn the ignition key to the ON position the PCM/ECM looks at the IAT (Intake Air Temperature) temperature and determines if the manifold is cold enough to need pre-heating. Typically this occurs when temperatures are below 55-65*F. You'll notice that the battery voltage will fall slightly more than normal during this time that the WAIT TO START light is lit. Once started the grid heater will continue to cycle on and off to maintain prope

HE351ve Holset VGT Controller   This article is for the standalone controller / tuner needed to control a Holset HE351 ve He351 VGT turbo from a 6.7 Cummins.   This controller will help you tune the holset he351ve vgt turbo for your truck.  It is is %100 open source you can tune the turbo in any manner you like.  It will take some trial and error to tune the holet he351vgt, but the pay off is worth it.  The he351ve really shines when it comes to low end power and having a flat torque c

Holset Turbo Specs There seems to be a lot of miss information on this topic, so I'm going to help clear it up some. First off what do the numbers mean, for instance a 56/60/12? The First number is the Diameter of the Compressor Inducer in Millimeters, in this case it's a 56mm compressor wheel. The Second number is the Diameter of the Turbine Exducer in Millimeters, in this case it's a 60mm turbine wheel. The Third number is the exhaust housing size in cm2, I'm not going

Turbo Inspection Operation Exhaust gas pressure (drive pressure) and energy drive the turbine, which in turn drives a centrifugal compressor that compresses the inlet air (boost pressure), and forces the air into the engine through the intercooler and plumbing. Since heat is a by-product of this compression, the air must pass through an intercooler to cool the incoming air and maintain power and efficiency. Increasing air flow to the engin

Switched Grid Heaters For those wanting a switched grid heater, here is how to do it on a 12V from 1989 on up to 1997. The 1998+ trucks throw a code (P0380 and P0382) so for those with that system, you will have to just disconnect the leads that go to the grid heater itself. When winter comes, just reconnect them. The reason for doing something like this is because the truck will run the grid cycle if you run into the store or something an

Cummins Holset HX35 HY35 Silencer Ring Removal Your going to need two small flat screwdrivers to pry the snap ring out of the groove. As you see in the top picture one side has a tip that you can pry against. Once the snap ring is out just tip the silencer ring out. This is your turbo now without a si