In the Diesel world, performance add-ons have grown in popularity as the engines have become more sought after. Over the past decade, truck owners have realized that in order to get more work done the engine must produce lots of torque. Not only does the engine have to produce more torque, but it also must be able to get reasonable fuel mileage. With growing technological advances, not only could the Diesel engine make more power with the same amount of fuel, but it could also be reliable. One reason that people steered away from Diesel engines was because of the noise. Now these engines are very quiet.
This Tech Tip is From the Full Book, HOW TO REBUILD FORD POWER STROKE DIESEL ENGINES 1994-2007. For a comprehensive guide on this entire subject you can visit this link:
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There’s nothing wrong with obtaining more power. But, for Diesel applications it has to be reliable and still maintain some level of respectable fuel efficiency. If you want to go drag racing or sled pulling, that’s different, but most people who purchased a Diesel truck are looking for everyday applications.
Even if your vehicle is a daily driver, there are still plenty of performance upgrades for the 7.3 and 6.0 engines. In order to tune a Diesel, you really have to use a chassis dyno. Even if you purchase reputable parts from a source such as Gale Banks, it is a good idea to find out what the engine makes with and without the add-ons.
When it comes to chasing more power I recommend sticking with the basics. When looking into performance upgrades for Diesel engines, you will find plenty of cold air kits and exhaust systems. Those who take it a step further may install some carefully-chosen gauges on their pillar post. This is a perfect place to start!
The cold-air kit is one of the best basic upgrades available. The colder the air, the denser the air becomes. The denser the air becomes, the more air can enter the engine. The more air that enters the engine, the more power the engine can produce. You may ask why the factory doesn’t include free-flowing cold-air kits with these trucks? The fact is that stock airboxes are engineered to minimize noise more than to feed free-flowing air to the engine. If you upgrade to a cold-air kit, you may notice it’s a bit louder too. It may also be made of better quality materials than the stock part(s) it replaces. The factory tries to cut costs wherever it can, and this is a good example.
Well, when it comes to cold-air kits, I can only think of one company that has been around for years: K&N Engineering. K&N has been supplying quality gauze filters for more than 40 years. There are several benefits of the gauze element.
First, the gauze element can flow more air than the conventional paper element, so the engine is able to take in more air with the same amount of filter media.
Second, the gauze element never wears out so it can be used over and over. When the filter is ready for cleaning, simply remove it from the vehicle and soak the element with the cleaning solution. Allow the element to air dry, spray an oiling solution into the gauze, and place the element back into the vehicle to be reused again. The cleaning and oiling solution can be purchased from K&N as a filter recharge kit. This ensures proper cleaning and oiling of the filter.
Third, the gauze element can trap smaller particles than the traditional paper element. When should you clean an air filter? Of course this depends on what type of driving conditions the K&N element is exposed to. Under normal highway conditions, K&N recommends cleaning every 50,000 miles.
For Diesel applications, K&N offers replacement OE-style filter elements or cold-air performance systems. Diesel engines are more demanding, so K&N manufactures the air filter elements for Diesel applications with six different types of cotton and deeper pleats in larger sizes. For cold-air performance systems, K&N offers the same air filter along with OE-style tubing that is designed for your specific application. It takes just a little bit of time with some basic hand tools to transform your vehicle with a cold-air performance package.
Remember, every K&N intake kit has been tested on a dynamometer and proven to increase horsepower. If you purchase a K&N cold-air intake system and you do not see any increase in horsepower on a dynamometer, K&N guarantees to refund your money.
Similarly, a free-flowing exhaust system helps scavenge the exhaust gases out of the engine, which allows more air to enter the engine.
There are a lot of exhaust companies out there; you just have to know which one to choose. Finding an exhaust system is best approached as a science. There are pressure waves and pulses that take place in the exhaust system of the engine that increase power or take it away. Since there are several exhaust companies that manufacture quality products, you have to narrow the options by price and customer service. I have often found that quite a few companies never return a phone call or email. But, those companies that take the time to communicate are the ones that get my business.
Similar to the cold-air kit, you may find that the aftermarket exhaust systems are a bit louder than the factory setups, and that they may be made from better quality materials (like stainless steel) or they may have an anti-corrosion coating to protect them from rust. The factory simply cannot afford to put exhaust systems like this under the thousands of trucks built every year. But if you’re an enthusiast who wants more power, the aftermarket has what you’re after.
Flo-Pro has always had great customer service and dyno results. Every Flo-Pro system that I have had the opportunity to dyno-test has always lived up to its reputation. On the Diesel systems that I have tested, there has always been an average of 12- to 15-hp gain and a 25 to 30 ft-lb increase in torque. Along with the additional power gain is the great sound of the performance muffler. It brings the voice of the Power Stroke to the community without being obnoxious.
As far as gauges go, they are a great way to see what the engine is actually doing. I often encourage people to install the gauges first to get an understanding of what is going on. Install the gauges and drive for several weeks under different conditions to see what changes take place. Then as different parts are added, there should be changes in the gauge readings. Becoming familiar with your gauges can also help in monitoring the health of your engine and/ or diagnosing performance issues.
An over-the-top gauge is a Diesel air/fuel ratio meter from F.A.S.T. This is something to consider purchasing before you install the exhaust system. The reason is that you need to weld a bung in the turbo down pipe so the air/fuel sensor from the meter can be installed.
The way the meter works is by the sensor reading how much oxygen is in the exhaust system. Diesels run very lean air/fuel mixture ratios. Using this meter is the only way to see what kind of mixture the engine has. Gasoline engines generally run an air/fuel mixture between 12.5:1 and 18:1. (At 18:1, this means that for every 18 parts of air there is 1 part of fuel.)
If you think about it, 12:1 would be a rich air/fuel ratio when compared to 18:1, where the air/fuel ratio is becoming lean. Diesel engines run an air/fuel ratio as high as 80:1. The only time the engine richens is generally at WOT, when the air/fuel ratio is about 15:1.
So if you have plans to install a tuner or programmer into your engine, my advice would be to install an air/fuel ratio meter first. It gives you an idea of how and when the engine is making power and how much fuel is needed to obtain this power.
Even before you add performance upgrades, you need to see what the engine is doing. There are certain parameters of the engine that are not monitored in the factory instrument cluster, so you have no idea what is going on with certain things that influence power. The only solution is to install gauges that can monitor other engine functions. Also, you have to figure out where to put them! Auto Meter has a line of gauges for 7.3 and 6.0 engine applications. Auto Meter also manufactures the pillar pod in which to mount the gauges in the vehicle.
As mentioned earlier, when it comes to aftermarket upgrades you have to go back to the basics. Auto Meter has been building quality components for more than 40 years. Auto Meter has manufactured gauges for all sorts of applications with a variety of sizes and styles. Auto Meter instrumentation has been used in all forms of racing for its accuracy, dependability, and ease of installation.
For a Diesel, the two most desirable gauges measure boost and exhaust gas temperature (EGT). These two gauges are very common, but for the Power Stroke engine, Auto Meter also produces a gauge to monitor the high-pressure oil pump (HPOP). But why should you monitor boost, EGT, and HPOP? Because these three components are vital to engine life and power.
Boost Gauge: Boost refers to the intake manifold pressure that exceeds atmospheric pressure, which is the weight of air that surrounds you. It also depends on your location. The higher the elevation, the less air mass you have so the less pressure you see. (The standard is 14.7 pounds, which is taken from the equation of a column of air in a cross section of one square centimeter from sea level to the top of the earth’s atmosphere).
So what is the purpose of the boost gauge? To monitor turbocharger performance. The object of the turbo is to take in air and compress it, and then force it into the intake manifold. This in turn makes air more dense, which forces more air into the cylinders. This is how a turbocharged engine creates more power. The boost gauge tells you how the turbo is doing and what kind of pressure is needed to make power. As engine modifications are performed, boost from the turbo is influenced.
EGT Gauge: This gauge is also known as a pyrometer. Most overthe- road trucks have this gauge in their instrument cluster. Exhaust gas temperature is important to Diesel engines because they are controlled by fuel. The intake manifold of a Diesel engine has no throttle plate to control air. The only way to control air is to adjust the amount of fuel. The more fuel the engine receives, the more power the engine makes, which causes the exhaust gas (as it exits the combustion chamber) to become hotter. There is a point at which the engine will melt down.
When exhaust gas temperature gets high, you have to back off the throttle. So it is a good idea to know how hot the exhaust gets, especially when performing other modifications, to ensure you know when to back off the throttle to avoid engine damage.
The pyrometer is a great tuning and learning tool. Most owners do not realize just how hot the exhaust can get, especially when their engine is in a hard pull. Under normal driving conditions, the EGT generally ranges from 500 to 600 degrees F. When the vehicle is loaded and under a pull, temperatures of 1,000 degrees F or more can be reached.
HPOP Gauge: This was a great idea introduced by Auto Meter. As RPM comes up in the Power Stroke engine, so does the pressure from the high-pressure oil pump. This is so higher injection pressures can be reached to obtain more fuel atomization for more power. Not only is the gauge great for monitoring the HPOP, but also to educate the owner of the pressures needed to maintain the engine speed.
This gauge can also be used when tuning with aftermarket software. As more engine power is programmed into the PCM, the greater the demand for high-pressure oil. With the Power Stroke there is a point at which no more power can be achieved because the HPOP cannot keep up. This is very evident if you decide to install bigger injectors. A lot of times when using the gauge, the signs are evident for the need of a bigger HPOP.
There are products that owners often overlook, but are very important when it comes to making power and for reliability of the engine. For instance, no one ever considers changing the harmonic dampener. People often associate this name with the harmonic balancer, which is slang in the automotive world. It is used by manufacturers as a balancing tool, but its primary function is to dampen harmonics, not balance them. If you want to do your engine a favor and make more power, install a Fluidampr.
Fluidampr is a division of Vibratech Industries manufactured by Horschel Motorsports. Fluidampr is made in the United States and has been around since 1946. What makes the Fluidampr so unique is the silicone gel and internal inertia ring inside the dampener. Stock dampeners are made of rubber and are only effective in a narrow RPM range. Over time, the rubber becomes weaker. As the rubber continues to deteriorate, the less the dampener can absorb. Engine harmonics create a frequency that destroys the engine unless they are absorbed. The more power the engine makes, the more the harmonics change in frequency. Before long, the result is damage to the bearings and crankshaft.
By using a Fluidampr on your engine, especially if the engine has been modified, there can be as much as a 16 hp and 35 ft-lbs increase in torque. That should tell you that harmonics are a big problem in Diesel engines.
A question I am often asked is “Which programmer would you choose to gain power in the Power Stroke engine?” That’s a tough one to answer since there are a lot of reputable companies offering tuning modules for these engines. They all are competitively priced and very reliable. It really depends on the specific application and what the truck is going to be used for. It also depends on how many aftermarket parts are already installed on the vehicle. Most companies offer tuning packages that are going to make power, but it is nice to know exactly what changes are taking place to achieve that power. The best choice is to have someone with a chassis dyno with tuning capabilities and experience tune your Diesel engine.
When modifying and making serious changes to the Power Stroke engine, I often rely on Aaron Lail at Tru Dyno Sports. Aaron has been doing performance calibrations with aftermarket EFI and OEM systems for gas and Diesel applications for more than 15 years. He has a vast knowledge of Diesel tuning and offers a variety of custom tuning programs that he has developed using his Mustang 1100SE Eddy current chassis dyno.
Turbos and Intercoolers
One thing that you may experience is that when you place some bolt-ons and programmers on your Power Stroke, you reach a plateau. You wonder what to do next in order to achieve more power. With the Power Stroke, air is not the issue as much as fuel. I can tell you that if the engine is intercooled, you can change intercoolers and turbos to help the air situation a lot.
If you want to change the turbo, stick with an experienced company such as Garrett, which was the original manufacturer of the turbo for the Power Stroke engine. Garrett offers some impressive upgrades. If you are looking for something in the aftermarket, check out turbo packages from other companies such as Turbonetics.
Injectors and HPOPs
The stock fuel capacity of the injector for the 7.3 engine is 96 cc. There comes a point with an aftermarket programmer where the injector is cycled to its maximum and still can’t keep up with the demand.
In order to combat this problem, you have to install a bigger capacity injector. In order to find the appropriate injector, you have to find the right aftermarket manufacturer. The main thing is not to just create a bigger injector but to be able to flow test them so they both flow the same and you have a matching set.
The HEUI design makes for a more elaborate way of testing injectors. Special machines are built to flow-test HEUI designs but are rather expensive. Full Force Diesel has the equipment and years of experience. The company offers different levels of injectors for different applications of the Power Stroke.
Full Force Diesel coats the barrels and plungers of the injectors with tungsten then flow-tests and adjusts them to within 1 percent of one another. Each injector also comes with an 18-month warranty.
Something that you need to keep in mind about the Power Stroke injector is the HPOP. Increasing the injector capacity means that you need something bigger to drive it. Owners often find that when increasing the injector size the HPOP cannot keep up with the demand, and pressure often drops under hard acceleration. This occurs when someone installs a serious programmer with a hot tune. In order to overcome this, the HPOP volume must be increased to keep up with the injector’s demand.
Gary Stecher manufactures an HPOP for this specific need. The pump is better known as the “Stealth.” Stecher Performance has been developing a better HPOP for the Power Strokes for years. While the Stealth pump may be a little pricey, it is the best one on the market. The Stealth HPOP out-flows any of the competitors’ pumps without a pressure drop. This makes for more fuel atomization and power from your Power Stroke engine.
With 7.3 trucks, I often find that owners choose the manual transmission. When the Power Stroke Diesel came on the scene, people were skeptical of an automatic transmission behind a vehicle made for towing. Most owners elected to have a manual transmission for more reliability and ease of repair.
Most owners were unaware of the “dual mass flywheel” in a manual transmission. It was designed for the high-compression Diesel engine. It consists of one flywheel centered on top of another flywheel with a friction disc between the two. The flywheels were dampened by a set of springs located on the engine side at the back of the flywheel. The springs were used to dampen a lot of the engine torsional vibrations, which also was easier on the transmission. The use of this flywheel made for more of a cushion and car-like experience in a larger vehicle. The only problem was, after time, the springs in the flywheel wore out.
The flywheel springs wearing out wasn’t the problem, it was the replacement price. The price of a replacement “dual-mass flywheel” was around $700, not counting the cost of the rest of the clutch. Owners often found that there were aftermarket companies offering a traditional (one-piece) flywheel design to replace the dual-mass version at half the cost.
The great thing was that the flywheel never needed to be replaced again. Since most of the replacement flywheels are imported, the level of quality is really not what you would expect for performance. The imported versions work great for stock applications. But, if you are going to make more power and change your flywheel and clutch, choose top-quality parts. The best thing to do is go with a complete kit from Centerforce.
Centerforce is a division of Midway Industries, which manufacturers clutch and pressure plate systems for high performance in the United States. Centerforce was started in 1982 by hot rod legend Bill Hays. Bill’s design was the Centerforce Weighted Clutch System. This system incorporated a competitionrated clutch and pressure plate with non-asbestos friction facings. The weighted design was developed to increase clamping loads and easy pedal effort.
Centerforce also carries this same clutch design and a singlemass flywheel for Power Stroke applications. The clutch is rated for 720 ft-lbs of torque and the flywheel is made from billet steel and is SFI approved.
Even though the single-mass flywheel is installed, there have been no reports of transmission damage due to torsional vibrations from the engine. Yes, your Power Stroke engine may make more than 720 ft-lbs of torque but that is at WOT. Under normal driving conditions with power enhancements, this clutch and flywheel kit is more than enough—plus it will last for a long time. Centerforce also offers a clutch and pressure plate for 6.0 applications.
Exhaust heat can be a destroyer of the bearings inside the turbo if the engine has not had time to cool down. The typical driver pulls in somewhere and shuts the engine down without letting it idle. This may be detrimental to the bearings of the turbo as this causes “coking,” which is what happens to the bearings of the turbo when the exhaust temperatures are hot and the engine is shut down. The excessive temperature starts frying the oil that is in the bearings, which leaves a nasty film. This film slowly takes its toll on the bearings causing damage to the turbo shaft, which damages the wheels of the turbo. With a Diesel engine, you want to let the engine idle for a few minutes to lower the exhaust temperature. The ideal exhaust temperature for shutdown is around 300 to 350 degrees F.
Sometimes having to let the engine idle to cool down may not be convenient. But, there is a device called a turbo timer that allows the engine to run with the ignition key removed and the doors locked until the optimum temperature of the exhaust is reached. After the safe temperature is reached, the engine shuts down. This is a great form of insurance and is a wise move if you do a lot of heavy-duty work or racing with your turbo Diesel.
Written by Bob McDonald and Republished with Permission of CarTech Inc