Michael Galimi
June 1, 2009
Swapping in an Aeromotive Stealth fuel system requires dropping the factory fuel tank and replacing it with this new one, complete with sump.

There are two key ingredients that an engine needs in order to run: fuel and air. The air segment is the easy one, thanks to the abundance of airflow products like blowers, turbos, and fancy engine parts. Moving to the fuel part, there are many solutions to help feed dead dinosaurs to a hungry engine. Those solutions are in the form of adjustable fuel pressure regulators, larger fuel pumps and injectors, as well as multi-pump combos. Like the air induction side, there are so many parts and pieces that navigating through them all can be difficult. That is, unless you open an Aeromotive Fuel System catalog and flip to the section with prepackaged systems, which is what we did.

Like most people, we prefer making simple and straightforward modifications to our Mustang(s). This scenario was no different when it came time to update the fuel system in our '89 Mustang LX. To say it simply, the car has been neglected over the years, and it was time to update the aging fuel system. Some might remember this coupe from the Feb. '09 issue of MM&FF article, in which we slung a Granatelli Motor Sports front suspension under it.

Aeromotive provides fittings, tank, fuel pump, filters, Y-ablock, fuel rails, and wiring components in the Stealth System. It's designed for '86-'93 EFI Mustangs, but the company's catalog has enough parts and pieces for custom systems to be built for any application.

Replacing the worn-out setup is an Aeromotive A1000 5.0L Stealth Fuel System (PN 17147), which includes every bit and piece, from a new fuel tank to the fuel rails. The Stealth moniker describes the hidden fuel pump (submerged in the sump) and it runs silent, barely audible when running and pumping fuel--more on that later.

Over the years, the coupe has seen several different combinations, all of them utilizing a Vortech S-trim blower. In the forefront of every engine combo was an upgrade to the fuel system to keep up with the increased airflow. The first round of fuel mods were a 110-lph in-tank fuel pump, Vortech T-Rex booster-pump, fuel pressure regulator, and larger injectors. That was followed up with a larger in-tank pump (155 lph) and dual external pumps, still with the stock fuel lines. Another increase in horsepower required more fuel to feed the hungry 5.0L. The final system consisted of larger feed and return lines, a single Paxton pump, a pick-up tube (eliminating the in-tank feeder pump), and ½-inch fuel rails.

The First order of business was removing the old setup, which consisted of a Paxton pump and filter as well as larger fuel lines. The system was installed back in the mid '90s and served us well, but the time has come for an upgrade to handle today's rigors of fuel consumption.

Time, unfortunately, has caught up with the car, and the pump quit working for unknown reasons. The corroded wiring probably had something to do with it. Rather than fully diagnose and attempt to fix the problem, we felt it was better to install a new and improved system. Fuel-pump technology has advanced rapidly since the Paxton fuel combo was installed. Also, we plan to add a stroker engine with a 76mm turbocharger later this year, so the coupe will require significantly more fuel when that swap happens. We ventured to DMC Racing where we hoisted the '89 LX on the lift and began pulling off the old stuff.

As we stated earlier, evaluating fuel system parts and pieces could take you in a circle as you try to mix and match your way to the perfect setup. "The complete system eliminates the guesswork. It's easier for the customer in terms of servicing and less chance of failure (Editor's note: pump failure) due to improper installation or pump mounting," comments Jesse Powell of Aeromotive. In the past, users battled for proper pump placement, which caused a host of problems, including pump failure. Most of the failed pumps we have come across are due to poor wiring or bad placement. Improper pump mounting makes it struggle to suck the fuel out of the tank--ultimately the pump burns out.

Casey Upton of DMC Racing lowers the stock fuel tank on to a rack. Two straps and a cover need to be removed in order to get the tank out of the car. A little wiggling is required to get the filler neck to slip out of the tank.

The Stealth system places the pump and the pre-pump filter in the sump, which offers several advantages. The first is resolving the aforementioned installation difficulties that have caused durability issues. "Fuel pumps operate best when placed closet to the pick-up point. The A1000 in the Stealth system is only 3 inches away from its pick-up point. Another advantage is that by submerging the pump in the sump, it's happy, runs cooler, and is quiet. Just look at the OEs, they run the pumps in the tank, too," adds Powell.

Aeromotive's sump tank is a factory-style tank, so it installs as such, requiring no custom brackets or hassles. The only problem we encountered was a worn-out filler-neck grommet, which forced us to call up Latemodel Restoration for a replacement part. The sump at the bottom of the tank lets gravity feed the gasoline rather than the factory setup, which sucks it up. The A1000 pump and stainless steel Pre-filter (with 100 micron filter) sit in the sump fully submerged, and it will also have fuel ready to be inhaled by the pump thanks to a baffle system.

The wheelwell liner on the passenger side was removed to gain access to the old fuel lines for removal. The new Aeromotive lines were run behind the liner as well.

We selected the A1000 fuel pump because it fit our requirements with the forthcoming turbo engine. Aeromotive rates the pump at 1,000 hp in forced induction applications utilizing an EFI system. Sans power adder, the A1000 is capable of feeding 1,300 hp, also with EFI. Moving to carburetor induction setups, the ratings increase to 1,500 (naturally aspirated) and 1,200 (turbo or blower). Powell says there is a safety margin built-in so the pump can support slightly higher output.

Some longtime fans of the Aeromotive products might be wondering about the A1000 ratings, they are higher than the original ratings when the pump was released several years ago. Powell has this to say: "Electric motor technology has been improved three-times over what it used to be. The new electric motors pump more and are far more efficient. This is the third generation A1000 and it is almost 50 percent better than the original pump, but we rate it only 40 percent higher because our pumps are underrated." He also goes on to say that the third generation A1000 is rated as high as the older Eliminator pump, which is one step above in terms of its capabilities. The A1000 and Eliminator pumps can be used in EFI and carburetor applications; the only difference is the fuel pressure regulator.

This rubber grommet was the only casualty as we pulled the tank down. It split as time and weather took its toll on our '89 coupe. One call to Latemodel Restoration solved our problem. The unfortunate part is that we couldn't fill the tank until the part arrived as the filler-neck would leak without it.

Aeromotive supplies all the fittings and plenty of braided line to plumb the feed and return lines, connecting the fuel rails and tank. Also included is a post-pump filter and mounting bracket. A Y-block is mounted on the shock tower under the hood, and the supply line is split in two in order to feed each fuel rail. Unused fuel exits the rails and connects to a fuel pressure regulator, where a -6 line is attached to the bottom and runs back to the Stealth tank.

The driver's side ½-inch fuel rail has two outlets: one on the underside in the center of the rail and the other at the front end. Those who run a stock size distributor cap need to cap off the front port and utilize the center one. This is because the lines will not clear the distributor cap. MSD makes a smaller cap for those who prefer to run straight lines. We chose the underside port due to convenience; we weren't concerned with the perceived flow-rate changes from using a 90-degree fitting. The main goal in any fuel system is to have as few bends as possible, but we weren't pushing our setup to the max, making it easier to plumb the system.

Casey Upton of DMC Racing began working under the hood and ran the lines back to the tank. It was easier to cut and adjust up front; then do one more AN fitting installation in the back of the car at the end of the day. Upton mounted the fuel pressure regulator on the firewall, easily accessible for fuel pressure adjustments. Using a lift made this job much easier, but it can be done in a driveway with some jackstands.

Fuel pressure is adjusted using the setscrew on the top. Loosen the locking nut, then use an Allen key to dial-in the desired fuel pressure, and lock down the nut to preserve the setscrew's setting.

Upton removed two major components, the passenger-side wheelwell liner and the upper intake manifold. The liner was removed so we could run the fuel lines. The upper intake manifold had to be removed to gain access to the fuel rails. Since our car was already equipped with an external fuel pump, most of the wiring was in place. Aeromotive includes detailed instructions for those who are modifying a stock Mustang.

The Stealth system is designed specifically for '86-'93 Mustangs with EFI. But don't let the designated years deter you from using a Stealth kit, as Aeromotive makes universal kits for any application. The '86-'93 tank will fit any Stang back to '79 because they share the same platform. Powell says that with some modifications to the filler neck, he believes the tank can also fit Mustangs up to '04. Aeromotive doesn't specifically make kits for those year Mustangs, nor does it make a specific kit for modular motor applications, but Powell says the catalog is very extensive and enthusiasts can build a system for virtually any application.

Using a lift and Upton's vast experience in all-things Mustang, the fuel system was installed in less than one working day. We unfortunately didn't get to fire up the car because the filler neck grommet was wasted. The A1000 pump is ready for action and thanks to it being stealthy, the pump won't be whining about working hard under boost.

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