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Frequently Asked Questions

Q. What is a “diesel performance” modification?

A. There are many modifications and applications that are commonly considered as “diesel performance” upgrades. Diesel performance is recognized as anything that helps your engine function more fully and improves its capabilities. This can include but is not limited to increased diesel fuel mileage, increased horsepower, lower exhaust temperatures, etc. The most prevalent modifications made to achiever better diesel performance are:

  • Performance Air Intake Systems
  • Fuel Delivery Enhancements, both Mechanical and Electronic
  • Diesel Exhaust System Upgrades

Q. What does a Performance Air Intake System do for my diesel or turbo diesel engine?

A. There are several key changes that a Cold Air Intake makes to your stock intake system. These include substantial improvements to the filter, optimization of the inlet pipe length and diameter to match engine resonance, and use of heat shields and enclosures. All of these changes result in colder air, and more of it, for your engine. Cooler air inlet temperatures translate to more power during the combustion process because cool air is denser than warm air. This will lead to increases in horsepower and torque and will help to lower your exhaust gas temperatures, or E.G.T’s.

Q. How can I get more fuel delivered to my diesel and what will that do for me?

A. There are a number of ways that you can get more fuel delivered to your turbo diesel engine. The optimal way to increase fuel delivery varies depending on the age, make and model of your diesel. For older diesels (like the 1989-1998 12V mechanical Dodge Cummins, especially the Bosch P7100 pump) you can manually tell the pump to increase the fuel delivery rate. With electronic pumps, enhanced fuel delivery can be achieved in many ways. Popular performance diesel upgrades include electronic performance tools like chips, programmers, and tuners. Other common diesel fuel injection modifications include upgraded injectors, injection nozzles, injection pumps and lift pumps. Increased fuel delivery will allow your turbo to spool up faster which will give your rig more power.

Q. Why should I upgrade my diesel exhaust system?

A. Performance Diesel Exhaust Systems are designed to remove the air flow deficiencies in your current factory exhaust system. An upgraded exhaust system will have a larger diameter and a smoother mandrel-bent radius. This will relieve engine exhaust backpressure, increasing fuel mileage, horsepower and torque. Depending on the exhaust system material chosen and the type of muffler employed sound levels and tone can be improved, enhanced or reduced according to your personal preference.

Q. What is the difference between performance diesel exhausts made from 304 Stainless Steel, 409 Stainless Steel, and Aluminized Steel, and how do I know which exhaust is right for me?

A. 304 Stainless is an Austinitic grade stainless steel with 18% chromium and 8% nickel. It offers exceptional resistance to corrosion and typically comes with a lifetime warranty, making it a great choice for diesel owners in areas with lots of salt and water. It resists heat scaling up to 1650 degrees F, and the near mirror-like finish is easily maintained. If you are racing or pulling and going to be running EGT’s above 1,450 degrees F with any regularity, investing in a quality 304 Stainless exhaust is a necessity. Or, if you have your truck lifted up for the world to see, 304 Stainless exhausts give a real wow factor; after all, if you just spent thousands on a lift and wheels, you don’t want a dingy looking exhaust to ruin the look of your custom diesel rig.

409 Stainless is a Ferretic grade stainless, with 19% chromium. It has more of a matte-polish look, and will resist heat scaling up to about 1,450 degrees F. Corrosion resistance is still strong with 409 Stainless, and most manufacturers warranty these exhaust systems for 5 years to life. For diesel drivers in most climates, 409 Stainless will give a great look with sufficient corrosion protection to give many years of flawless service.

Aluminized Steel is a high-gauge sheet metal which has been given an aluminum and silicon alloy coating. Corrosion resistance is still pretty good, and heat scaling isn’t a problem unless your EGT’s are getting above 1,250 degrees F on a regular basis. Average warranties run 1-5 years on Aluminized steel. If you don’t offroad much or if you live in a dry or temperate climate, Aluminized Steel is typically a suitable choice. No matter which exhaust material you choose, know that Parleys Diesel Performance only carries exhausts from reputable and experienced manufacturers; you can rest assured you’ll get a quality built exhaust when ordering from us.

Q. Can I still upgrade my exhaust system if I have an emissions control device?

A. Absolutely! There are many high-quality performance diesel exhaust systems available for installation after the Catalytic Converter or after the Diesel Particulate Filter which will still improve fuel economy, horsepower and torque.

Q. Will diesel performance parts and diesel performance modifications harm my turbo diesel?

A. Fortunately there are a number of ways to safely increase your diesel’s horsepower, torque and fuel economy while minimizing the risks involved. Diesel performance can do as much harm or good to your vehicle as you let it. If you jump into diesel performance without being educated it can and will harm your vehicle. That is why at Parleys Diesel Performance we want you to be as educated as possible before you make your purchase and even after you have made your purchase. Here are the main problems you will face and the solutions to those problems:

  • Exhaust Temperatures - High exhaust temperatures are your number one enemy. There are, however, a number of diesel performance parts designed to help with this very problem. If exhaust temperatures are a problem that you currently face or if you are planning on increasing your truck’s horsepower you will need to upgrade with a performance air intake system and a diesel performance exhaust system. You will also want to monitor your exhaust temperatures by using exhaust temperature gauges. When installing gauges, remember that the three most common you’ll want messure EGT’s, Transmission Temperature, and Boost Pressure.
  • Diesel Fuel Injection Systems - With the lubricity, or the ability to lubricate the internal parts of the injection system in diesel fuel getting lower and lower throughout the country due to ever stricter emissions laws, the need to take care of your diesel fuel injection system with aftermarket products is critical. Regardless of if you choose to make diesel performance modifications or not, it is critical for you to use diesel additive to increase the lubricity of the diesel fuel that you are using. Obviously, if you are using more fuel in your modified diesel, the use of diesel additive is mandatory. It is also important to consider the amount of fuel necessary to keep up with the demands made by today’s high horsepower tuners and programmers. Upgraded lift pumps and fuel injection pumps will ensure your diesel gets the fuel it needs to perform.
  • Transmission - Transmission slippage and damage can occur when you try to get lots of extra horsepower and torque to the wheels. There are many steps you can take to extend the life of your transmission and upgrades you can make if your transmission is already slipping. To extend the life of your transmission routine maintenance is important. Use a high quality synthetic transmission fluid to improve fuel efficiency, reduce transmission temperatures and increase transmission life. Synthetics deliver maximum protection for towing and other severe-duty applications. Transmission performance upgrades like deep transmission pans, shift kits, and torque converters will also extend the life of your transmission. Using a Mag-Hytec transmission pan or similar transmission pans gives you a larger reservoir of transmission fluid with increased lubricant and cooling capacity. Automatic transmission shift kits provide crisper shifting by eliminating shift overlap and speeding up shift actuation, resulting in a better shift and reduced wear. An aftermarket performance torque converter can take increased power from your engine and deliver it to your transmission effectively

Q. Some diesel performance chips and diesel performance programmers and modules say that they can be changed “on the fly.” What does “on the fly” mean?

A. “On the fly” refers to the ability to be able to change power levels on the go or as you are driving.

Q. Why would I want to inject water and methanol into my diesel engine? Wouldn’t burning alcohol make for extreme temperatures?

A. The injection of a water and methanol mix into your air intake charge has many benefits, one of which is the almost counter-intuitive fact that water and methanol injection lowers air charge temperatures by over 200 degrees Fahrenheit. The cooler air charge density translates to a 3-5 psi boost increase. Exhaust Gas Temperatures (EGT’s) are also decreased by approximately 250 degrees. Horsepower increases in diesel trucks and cars using water-methanol injection average 50-100 HP. Fuel economy improvements average 1-3 MPG. Emissions of NOx and carbon particulates are reduced dramatically. Towing capabilities are greatly improved too, since you have more power and cooler EGT’s.
To find the right water-methanol kit for your truck, click on Snow Performance, then enter your vehicle type to see the perfect kit.

Q. I want to install diesel exhaust stacks on my truck, but I’m worried about rain getting in my exhaust system. Which exhaust stack tips should I look at to avoid this problem?

A. If you live in an area where it doesn’t rain too much, or you normally park your pickup truck in a garage, then this isn’t a big deal. If you’re out driving in the rain, the temperature of your exhaust and stacks is sufficiently hot to instantly vaporize any rain that gets in. If your truck will be parked outside in an area with frequent rain, you’ve got to give your options more thought. One popular choice is the use of rain caps. Not only do these look pretty cool, but they keep all the water out of your stacks when your truck is off. The only problem with rain caps is that they only fit straight cut stack tips. If straight cut stack tips aren’t your preference, what then? Try other popular choices like curved cut, aussie cut, or bull-hauler cut stack tips. Go to our Exhaust Stacks page to see all the great choices that will keep the rain out and look great while doing it!