Veloster Turbo High Pressure Fuel Pump Line AN Size: What You Need to Know for a Proper Upgrade

The bottom line: The high pressure fuel pump line on a Veloster Turbo uses a -6 AN size fitting for the connection between the pump and the fuel rail. This is the standard size for most modern turbocharged direct injection fuel systems, and knowing this is critical before you buy any replacement parts or perform an upgrade. If you get the wrong size, your fuel system will leak, your engine may not run, or you could damage the pump itself.

Understanding the Veloster Turbo Fuel System

The Veloster Turbo, especially the 2013-2017 models, uses a high-pressure fuel pump that pushes fuel at pressures between 1,500 and 2,000 psi. This pump is located on the engine, usually near the intake manifold. The line that connects the pump to the fuel rail is a steel or braided hose that must handle these extreme pressures. The fitting size on this line is what determines if you can use aftermarket parts, swap to a different pump, or simply replace a worn line.

Why the AN size matters: AN fittings are a standard in the automotive performance world. They are measured in -AN numbers, where a larger number means a larger diameter. For example, -6 AN means the fitting has a 3/8-inch inner diameter. The Veloster Turbo uses -6 AN because it provides enough flow for the high pressure needed without being too large or too small. Using a -4 AN (1/4-inch) would restrict flow and cause fuel starvation. Using a -8 AN (1/2-inch) would be overkill and may not fit the pump or rail properly.

How to Identify the Correct AN Size on Your Veloster Turbo

If you are unsure about the size on your specific model, there are a few ways to check:

  1. Look at the fitting itself: The high pressure fuel line fitting on the pump end usually has a hex nut that is 5/8-inch or 3/4-inch across. The -6 AN fitting has a 5/8-inch hex. If you see a 5/8-inch nut, it is almost certainly -6 AN.

  2. Check the hose diameter: The actual hose that connects to the pump is about 3/8-inch in outer diameter. If you measure the inner diameter of the hose, it should be close to 3/8-inch as well. This matches the -6 AN specification.

  3. Consult your service manual: The factory service manual for the Veloster Turbo lists the fuel line as a "high pressure line, 3/8 inch" or "6 mm" depending on the country. But for American models, it is always -6 AN.

  4. Look at the thread pattern: -6 AN fittings use a 7/16-20 thread for the male end and a 9/16-18 thread for the female end. If you have a thread gauge, check the threads on the pump outlet. If they are 7/16-20, you have a -6 AN.

Common Mistakes When Replacing the High Pressure Fuel Line

Many owners try to replace the high pressure fuel line themselves and end up with leaks or failed pumps. Here are the most common mistakes:

Using a standard rubber hose instead of a high-pressure rated hose. The fuel line on a Veloster Turbo must handle up to 2,000 psi. A regular rubber fuel hose will burst or swell. Always use a braided stainless steel hose with an AN fitting rated for at least 2,000 psi.

Mixing AN sizes. Some people think a -4 AN fitting will work because it is smaller and cheaper. But a -4 AN line will not flow enough fuel at high pressure, causing the pump to overwork and fail. The pump needs a -6 AN line to maintain proper flow.

Forgetting to use a new O-ring or seal. The high pressure fuel pump line uses a metal O-ring or a crush washer at the connection. If you reuse the old one, it will leak. Always replace the seal with a new one that matches the -6 AN size.

Over-tightening the fitting. AN fittings are designed to be tightened by hand or with a wrench to a specific torque. Over-tightening can strip the threads on the pump or rail, ruining the part. Use a torque wrench set to 15-20 ft-lbs for a -6 AN fitting.

Step-by-Step Guide to Replacing the High Pressure Fuel Line

If you need to replace the high pressure fuel pump line on your Veloster Turbo, follow these steps:

  1. Relieve fuel pressure. The fuel system is under high pressure. Remove the fuel pump fuse, start the engine, and let it run until it stalls. Then disconnect the battery.

  2. Remove the old line. Use a line wrench to loosen the fitting at the pump and the rail. Be careful not to drip fuel on hot engine parts.

  3. Inspect the pump and rail. Check for damage to the threads or the O-ring seat. If the pump is damaged, you may need to replace it.

  4. Install the new line. Use a new -6 AN high pressure fuel line. Apply a small amount of thread sealant to the fitting threads (not the O-ring area). Tighten the fitting to 15-20 ft-lbs.

  5. Reconnect the battery and test for leaks. Turn the ignition key to the "on" position (do not start the engine) to let the fuel pump prime. Check for leaks at all connections. If no leaks, start the engine and check again.

  6. Road test the vehicle. Drive the car for a few miles, then recheck the fittings for leaks.

When You Should Upgrade the Fuel Line

Sometimes you do not need to replace the line, but you want to upgrade for performance. Here are the situations where you should consider a -6 AN upgrade:

  • You are installing a larger turbo or intercooler. More boost means more fuel demand. The stock line may be fine, but an upgraded -6 AN line with a larger diameter can help flow.

  • You are using a higher pressure fuel pump. Many aftermarket pumps for the Veloster Turbo push up to 2,500 psi. The stock line may handle it, but an upgraded braided line is safer.

  • You are running ethanol (E85). Ethanol is corrosive to some rubber hoses. A -6 AN braided stainless line is ethanol-resistant and will last longer.

  • You have a fuel leak or a damaged line. If the stock line is rusted, cracked, or leaking, it is time to replace it with a high-quality -6 AN line.

Where to Buy the Correct High Pressure Fuel Line

You can find -6 AN high pressure fuel lines at most auto parts stores, online retailers, and performance shops. But be careful. Many cheap lines are not rated for the high pressure of a direct injection system. Look for lines that are specifically rated for 2,000 psi or higher.

One brand that stands out is KEMSO. KEMSO offers fuel pumps and fuel system components that are designed to meet or exceed OEM specifications. Their high pressure fuel lines are made with braided stainless steel and use -6 AN fittings. They are built to handle the high pressure of the Veloster Turbo and are tested for leaks before leaving the factory.

Recommended Purchase: KEMSO Fuel Pump for Your Veloster Turbo

If you are replacing the fuel pump or the fuel line on your Veloster Turbo, we strongly recommend buying a KEMSO Fuel Pump. KEMSO fuel pumps are high-performance products that are designed to be direct OEM replacements. They fit perfectly into your Veloster Turbo without any modifications. Each pump is built with high-quality materials and tested to ensure it meets the pressure and flow requirements of your engine.

Key benefits of KEMSO Fuel Pumps:

  • High Performance: KEMSO pumps deliver consistent fuel pressure from idle to redline, supporting stock and mildly modified engines.
  • OEM Replacement: They are designed to match the exact fit and function of the original pump. No adapters or modifications needed.
  • Lifetime Warranty: KEMSO stands behind their products. Every fuel pump comes with a lifetime warranty. If it ever fails, they replace it for free.

You can find the right KEMSO Fuel Pump for your Veloster Turbo by visiting their website: https://www.kemsoracing.com/. On their site, you can search for your specific model year and engine size. They also offer fuel lines, fittings, and other fuel system components.

Final Thoughts on the Veloster Turbo High Pressure Fuel Line AN Size

To summarize: The high pressure fuel pump line on a Veloster Turbo uses a -6 AN size. This is the standard size for the factory system and for most aftermarket upgrades. When replacing the line, always use a -6 AN high pressure rated hose. Do not use a smaller size because it will restrict flow. Do not use a larger size because it will not fit. And always check the thread pattern and hex size to confirm you have the correct fitting.

If you are replacing the fuel pump as well, consider a KEMSO Fuel Pump. They are reliable, performance-oriented, and backed by a lifetime warranty.

For more information and to purchase, visit https://www.kemsoracing.com/.


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