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Aeromotive 340LPH pump

Here's a little about the pump we will be using if you want to read more on it go to Aeromotives site. As far as any pump performance concerns specific the the MK IV 1.8T platform we will be working on that.


8.) Q: How much HP will the 340 Stealth Pump support?

A: Ordinarily, Aeromotive will publish a HP rating for fuel pumps, and we could do so for the 340 Stealth pump in the same fashion.  However, the 340 Stealth Pump is typically installed in an otherwise stock, return-style EFI fuel system.  For this reason various OEM components within the fuel system (engineered for a pump with only 1/3-1/2 the flow capacity of the 340 Stealth), could have a negative impact on the flow that can be delivered to the fuel rail, regardless of the new pump’s increased flow potential.  This makes it difficult to project a standardized HP limit for the 340 Stealth Pump that would be correct across the many applications in which the pumps may be used.  Bottom line, fuel system combinations and variations from one vehicle to the next, across the wide range of year/make/models listed in the application guide, are just too numerous to properly calculate maximum HP for each.

One thing you can be certain of, the 340 Stealth Pump you receive has been thoroughly flow tested and verified to meet all specs across the full range of pressure, and to be at or below the spec current draw.  All 340 Stealth Pumps are tested multiple times in production to ensure each individual pump does flow 340 lph and meets all quality and performance specs, 100%.

So, putting aside all the variables, let’s presume the best case scenario: What maximum HP could a 340 Stealth pump support if the system were fully optimized?

Okay, in a bypass EFI fuel system that has been optimized to include:

  • a 72 lb/hr injector (presuming V-8 engines, 150 lb/hr for 4 cylinder engines)
  • 40 PSI base fuel pressure, vacuum line disconnected
  • Boost is limited to 20 PSI (allowing a 1:1 boost reference to 60 PSI max under load)
  • Providing the system has the necessary electrical supply to properly power the pump
  • An appropriate fuel line size equivalent to AN-06 is installed
  • A high-flow filter such as Aeromotive 12301 is installed
  • A decent, high flow fuel rail is employed to feed the injectors
  • A high flow regulator such as P/N 13109 and a AN-06 return line is present

It would be reasonable to rate the 340 Stealth to 700 flywheel HP EFI forced induction, 900 flywheel HP EFI naturally aspirated, on gasoline fuel.  In this example the injector duty cycle for either V-8 or 4-Cyl would be between 80-85%.

For carbureted engines, with optimized fuel system components including a Aeromotive P/N 13204 Carbureted bypass regulator and AN-08 or ½” return line, it would be safe to allow for 900 HP forced induction (blow-through) and 1,100 HP naturally aspirated limit

Remember, these projected HP capabilities for the 340 Stealth Pump are based on gasoline as the fuel and are 100% dependant on all aspects of the fuel system being modified if needed/as necessary to allow it to deliver full capacity to the fuel rail or carburetor float bowl(s).  Aeromotive provides extensive technical information about how to accurately determine the correct fuel pump for any application in the Tech Bulletin Section of our website.  For more detailed information, please see TB:501 Fuel Pumps and Horsepower here:

(Note: 1 lph is roughly equal to 1.6 lb/hr if you wish to convert lph to lb/hr for calculations.)

WARNING: In a stock EFI fuel system where the pump is installed with minimum changes, it would be wise to de-rate the optimized capacity of the 340 Stealth pump by up to 10-20%.

9.) Q: Can the 340 Stealth Pump be used safely in e85 and how much HP will it support?

A: E85 fuel has become a viable option for street performance enthusiasts in recent years.   It has some very significant pros, and equally significant cons, to consider.  It does provide higher octane, and lower charge air temperatures, and is especially popular in forced induction applications, permitting more aggressive combinations of boost, compression ratios and tuning.  It is also less costly per-gallon than high-octane racing gasoline.  That said, fuel usage increases 30-35% to support equal HP, somewhat offsetting the lower cost and requiring the HP rating of all fuel system components, including and especially the HP ratings of the fuel pump and fuel injectors, be reduced by 30-35%.

A crucial consideration regarding whether or not to run E85 is its tendency to rapidly and frequently contaminate and clog/block fuel filters, resulting in significant flow restrictions, which in turn may damage the engine and/or cause premature fuel pump failure.  The reasons for filter contamination problems with E85 include:

  • E85 is an alcohol based fuel, and alcohols are hygroscopic (attract and absorb water from the atmosphere), which can accumulate in and clog fine filter elements.
  • E85 is an agriculturally produced fuel and, being a byproduct of plant material, there have been indications some of this “bio-mass” can accumulate in, and clog fuel filters.
  • E85 has very strong solvent properties, like many alcohol based liquids, which will act to strip accumulated debris and residues from transport and storage containers, and the inside of fuel tanks and fuel lines, which in turn accumulate in, and clog fuel filters.

Aeromotive has conducted extensive testing of the 340 Stealth Pump in E85 fuel, achieving 1,000 plus run hours of service life operating at 60 PSI and 13.5 Volts.  In testing, it was found a filter service interval that gave good fuel pump service life required a new, down-stream filter be installed every 10 run-hours.  It is vital to understand that a blocked filter creates severe flow restriction of pump output, building excessively high operating pressure between the pump and the contaminated element.  If the Stealth 340 is allowed to run in this environment, operating pressures between pump and filter can exceed 90 PSI, creating extreme current draw and reduced cooling flow, resulting in rapid failure of the fuel pump motor assembly.

WARNING: If you plan to run E85 fuel you must be prepared to install proper filtration, and maintain it as frequently as every 10 run-hours.  If not, Aeromotive does NOT recommend you the use of E85 with the 340 Stealth Fuel Pump.  Aeromotive’s new product warranty assures the purchaser their 340 Stealth Pump will be free from defects in material and workmanship for one year from the date of purchase.  Fuel pump failure caused by clogged/blocked fuel filters is not the result of any defect in the pump itself, and is not covered under this warranty.

For a detailed look at post-pump filter options and what a good one should be like, please see Aeromotive Tech Bulletin: Post-Pump Fuel Filtration TB-102 here:

For a specific example of the issues related to a clogged post-pump filter, please take a moment to see the Case History File embedded in TB-102 here:

10.) Q: I heard that to use the 340 Stealth Pump you have to upgrade the OEM factory fuel pump wiring, and possibly the relay and fuse/breaker, is this true and why?

A:  The wiring used to power the fuel pump plays a key role in supporting the electric motor that runs the pumping mechanism.  It’s the combination of motor torque and the pumping mechanism speed it produces that enable the incredible flow the Stealth 340 is known for.  The factory fuel pump wiring and electrical components were engineered for a fuel pump drawing ¼ to ½ the current.  Failure to upgrade this wiring, including the relay and breaker/fuse assembly, may result in a substantial reduction in performance of the new 340 Stealth.

The 340 Stealth Fuel Pump is a break-through in OEM replacement fuel pump technology.  It is capable of flowing 33% more than conventional, performance replacement fuel pumps, and as much as 100%-300% more than the vehicles original pump.  For proper installation and to ensure the optimum performance and service life, please see the installation instructions on page 2 to view the flow and current draw at pressure chart, and the bottom of page 3 for wiring recommendations.  Ensure proper wiring, your new 340 Pump, and your engine, depend on it!

NOTE: For specific wiring kit recommendations, see FAQ #16