Examining the Kit
I received a box from Wildcat Diesel Performance containing their maximum flow, fuel line upgrade system. The kit contains everything needed to upgrade the factory fuel lines to -8AN lines from the steel line near the fuel tank up to the VP44.
Installation I began by removing the intake horn and lines that go to the intercooler, then totally removing the fuel system from the VP44 on back. I also installed the custom 12mm x 1.5 -8AN adapters at this time. Comparing the size of the -8AN adapter and braided line to the factory lines is amazing. The factory lines must be a large restriction to flow for a truck that has been modified.
Once I had the lift pump removed I went under the truck to remove the factory Teflon line from the steel line. I pulled the factory Teflon line down so I could work with it easier. At this point the siphoning effect from the tank had not crossed my mind. Quickly realizing my mistake I clamped off the fuel line, but not before a considerable amount of fuel had poured onto the floor and me. This was diesel shower number one.
You should not perform this upgrade with a full tank of fuel. Looking at the line it was clear that I would receive another diesel shower once this line was removed from the steel line. Trying to be better prepared, the replacement line was pinched off on one end and the clamp was slid on and made ready. The factory line appears to be heat shrunk onto the steel line, I removed this line by cutting it slowly with a sharp utility knife. The Teflon line was removed quickly and diesel shower number two had begun.
An attempt was made to install the replacement line quickly, but the diesel fuel made the line slick enough that a quick install did not happen as rapidly as was hoped for. Finally getting the new line slid on enough to stop the flow of fuel, I took a minute to allow the fuel to drain down my arm. After sliding the new line on further down the steel line, I secured it with a hose clamp. The new line was then snapped into its holder and routed up to the engine bay.
As I was lying there covered in diesel fuel and looking at the sizable pool on the floor, it occurred to me that the lift pump in its factory installed location does not have to work as hard as I had thought to pull fuel from the tank. This was an eye opener for me, as I have always heard that the reason the factory lift pump were failing was because of the distance it has to pull fuel. With the siphoning effect it only has to pull fuel the difference from its height to the level of the fuel. Not the distance of the line.
After putting some floor dry down to soak up the lost fuel, The lift pump was bolted back up and new line was trimmed to fit and pushed on to the push lock fitting. It was recommended to use some thin oil on the fittings to make it easier to slide the new lines on and I highly recommend this procedure. . |
The next step was to temporarily install the filter housing so I could measure and cut the stainless braided line to fit. The first cut was the line that runs from the VP44 to the outlet of the filter housing, carefully routing it safely around the steering pump.
The line from the inlet of the filter to the outlet of the lift pump was next, and made long enough to form a loop to make alignment easier. To cut the line I first wrapped the line with black electrical tape at the desired location, then using a Dremel tool with a cutoff wheel I cut the stainless braid. The interior line was cut with the utility knife. Leaving the tape on I slid the fitting over the line. Then after removing the tape I pushed the ferrule under the braid and the fitting was slid over it. All of the connections were done in this manner.
With the filter housing removed the 90-degree fittings were installed onto the line trying to get proper alignment. The braided line is stiff and can be tough to get into just the right position. Attaching the new line first to the outlet of the lift pump, then to the inlet of the filter housing after it was reinstalled.
A straight connector for the VP44 was installed and then a 90-degree fitting for the outlet of the filter housing, again trying to get the alignment as close as possible. The adapter at the outlet of the filter is tapped for a 1/8 inch pipe fitting for connection of a fuel pressure gauge. I installed the fitting and line for the pressure gauge while the filter housing was out of the truck. The connection at the filter can be a bear to get aligned and started. Everything was reinstalled and double-checked for fit.
Now it was time to prime the system and check for leaks. I bumped the starter and heard a rush of fluid onto the floor. It was not long before I realized that the water drain valve had been opened. At least this time I was not under the flow of fuel and diesel shower three was avoided. Once the system was primed and the truck started it was pulled out of the way so I could use a full bag of floor dry. If you install this system the same way I did, make sure you are prepared for the clean up.
Results
My original setup had me measuring the fuel pressure pre filter. My pressure at idle was 14.4psi and cruise was 11.2psi. At the track I would see pressures drop to 3psi. With the Wildcat Diesel Maximum flow system I now see idle pressure at 13.6psi and cruise is 12.6psi. I also notice that it is much harder to pull the pressure down to an alarming level with the horsepower level that I use for daily driving.
I replaced the lift pump and went to the track. Idle pressure is now 14.4psi. Cruise pressure is 13.0psi, and I saw pressures around 8.8psi at the track. The fuel lines made a huge difference in WOT pressures, and well worth the diesel showers in my opinion.
Written By,
Charles Wilt
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