Diesel Tuner's Blog

What you need to know about Boost Testing your truck!

Written by Paul Wilson | May 6, 2016 2:00:00 PM








Too often trucks come into our shop experincing high EGT's, turbo lag, excessive smoke output, and bad fuel mileage which are all symptoms of a boost leak. It is so common to develop a boost leak that we now require all trucks to have a leak down test done prior to strapping them down on the dyno. What's funny is, most truck owners that we do identify boost leaks on never even knew they had one. The reality is that even if you can hit peak boost, you may have a leak, especially if you have a variable vane turbo. Variable vane turbos will change vane position and other operations to try to compensate for the reduced level of boost pressure in the intake system. Leaving you driving around without an idea that your turbo efficiency has taken a hit. 

 

 

 

 

 

Identifying and Diagnosing Boost Leaks

Leaks can develop by corrosion of the intercooler pipes, blown or torn boots, loose clamps on intercooler piping, or even a cracked intercooler. Many times a leak starts small but over time becomes more prevalent. Again, most people do not know they have a leak until the charged air system is pressurized and tested. Soapy water and looking for bubbles is strenuous and time consuming, feeling each boot does not tell you anything, and running a smoke machine through the intercooler piping does not pressurize the system hard enough to expose all of the potential leaks. 

 

 

The Importance of Boost Testing

This is why boost leaks kill diesel engines. Boost leaks can result in a smokey, laggy, dog-of-a-truck, which runs hot and burns excessive fuel. Basically, the exact opposite of what you want from your diesel.

Boost Testing your diesel is essential! Every truck that comes in the shop, gets a boost test. Most of the time customers report still seeing peak boost on their gauges despite a boost leak. However, common symptoms of a boost leak include Increased Smoke, Higher EGTs, Excessive Lag, and Loss of Power.

If you work with diesel trucks long enough, you’ll see leaks just about everywhere in the charged air system at one time or another. Remember, the charged air system includes anywhere from the turbocharger to the intake manifold. Your Intercooler system, Exhaust Gas Recirculation components, and even the Turbocharger compressor cover can all develop boost leaks.

Over the years, we have tried just about everything you can think of to boost test a truck. From smoke testers to PVC adapters and just about anything else you can think of. There are very few kits out there that truly and accurately test the entire charged air system.  

That’s why we spent the time and resources to develop the Stealth Boost Tester line.  Now you can easily and accurately test your engines entire charged air system. The kit is made entirely of premium parts, designed to last, and built to rigorous standards. 




Choosing the Right Stealth Boost Tester Adapter for You 

You can choose from either a Compressor Inlet Adapter or Turbo Faceplate Adapter to go along with your kit depending on your style of turbo.

The Compressor Inlet Adapter is a billet adapter that connects to your Compressor Inlet with a heavy-duty, 4ply boot, and 2 high strength T-Bolt clamps. Removing a Cold Air Intake in most trucks is a job that only takes a few minutes and requires the most basic mechanical skill. The same goes for installing and using the Compressor Inlet Adapter. Your billet adapter even comes with how many inch-pounds the T-bolts need to tighten too.

The Turbo Faceplate Adapter connects directly to the inlet of the turbocharger.  If you have a sheet metal intake that’s not designed to hold compressed air, or a brand new turbo upgrade, you may prefer this option. Just as the name implies, the billet adapter connects directly to the face of your turbocharger.

Both the Compressor Inlet Adapter and Turbo Faceplate Adapter feature a conveniently placed and sealed fitting, allowing them to work with our high-quality regulator. This regulator is a crucial component when using the kit. If you have ever used a bad or failing regulator you know how frustrating it can be. You’ll notice the liquid-filled gauge here. That prevents erratic reading from pressure spikes and external vibrations. And of course, the regulator made from high-quality materials designed to last.


 

Maximizing Performance with a Stealth Boost Tester

The unique advantage to this setup is that it allows you to accurately test the entire charged air system in just seconds. Our mechanics love it because of its premium quality, accurate results, and precisely fitting adapters. By investing in a Stealth Boost Tester, you ensure that your truck is operating at peak efficiency. No more guessing about potential boost leaks or dealing with subpar testing methods. Our kit allows you to quickly identify and fix any leaks, ensuring your engine gets the air it needs to perform its best. This means lower EGTs, reduced smoke, and improved fuel mileage – the exact performance enhancements every diesel owner desires. Don’t let a hidden boost leak rob your truck of its power and efficiency. Equip yourself with the best tools in the industry and keep your diesel running strong.

 




A Step-by-Step Guide to Boost Leak Testing with the Stealth Boost Tester:

1. Mounting the Adapter

  • Begin by selecting the appropriate adapter for your turbo system – either the Compressor Inlet Adapter or the Turbo Faceplate Adapter.
  • Securely mount the adapter to the compressor inlet or turbo faceplate using the provided heavy-duty, 4-ply boot and high-strength T-bolt clamps.
  • Ensure all connections are tight and secure.

2. Connect Your Regulator to the Adapter

  • Attach the high-quality regulator to the conveniently placed and sealed fitting on the adapter.
  • Ensure the connection is tight to prevent any air leaks.

    Important Note: DO NOT plug the hot side pipe, this takes the y-bridge out of the test loop (a common leak spot). The engine will hold the pressure. If you hear any hissing, you've found a boost leak.  Fixing the leak will lower EGT's, improve spool up, and improve peak power. 

3. Connect Air Supply to the Regulator

  • Before connecting your air supply, make sure the main valve of the regulator is closed and the regulator valve is loosened all the way so that air will not flow from the regulator.
  • With both the main air valve closed and the regulator valve closed, hook up your compressed air supply.
  • With the compressed air supply connected, begin to open the main air supply valve while checking the gauge on the regulator to ensure your air pressure stays at 0.

4. Gradually Increase Pressure

  • Start increasing the pressure supplied by the regulator by screwing the knob on the side of the regulator in.
  • Increase the pressure in small 5psi increments to ensure your system is gradually pressurized.

5. Stabilize the System

  • Once you have reached around 20 PSI, let the entire system acclimate for around 60 seconds to ensure you are maintaining a stable pressure.

6. Close Off the Compressed Air Supply

  • Once you are sure your pressure is stable, use the main air supply valve to close off the compressed air from the system.

7. Monitor Pressure Drop

  • With your compressed air supply turned off, your gauge should begin dropping.
  • Look for a rate of around 1-2 PSI drop in pressure per second.
  • Anything more than a 2 PSI drop in pressure per second would indicate a boost leak.

By following these steps, you can effectively diagnose and address boost leaks, ensuring your diesel engine operates at peak efficiency.



What To Do After Preforming A Boost Leak Test


Whether you just got done installing a new turbo or you just want to make sure that your old one is in good shape. It's important to verify that your turbo is reaching and not exceeding the level of boost pressure that it is rated for. Below is a reference chart that provides safe levels of boost pressure at varying degrees of elevation for our entire line of Stealth Turbo Chargers. Please use this chart along with an in-cab monitor to verify that your turbo is reaching and NOT exceeding the proper boost pressure. Exceeding or failing to reach proper boost pressure levels can result in premature turbo failure that will not be covered by warranty. Also be sure that you are referencing the "Safe Max Boost Level" for your intended elevation of operation and not just the highest boost pressure. 



If your turbo fails to meet or exceeds the maximum rated boost pressure, it could indicate a need for a tune adjustment or point to an issue with your turbocharger or turbo actuator. This situation may lead to suboptimal performance, increased exhaust gas temperatures, and potential engine damage. It’s crucial to diagnose and address these issues promptly to ensure your engine operates efficiently and safely. Regularly checking and maintaining your turbo system can help prevent these problems and keep your vehicle running at its best. 

 

Warranty Information 

View The Stealth Turbo and Boost Tester Warranty Information Here.