New Products / Parts

Summit Racing Unleashes New MAX-efi 500 Electronic Fuel Injection System (Video)

Summit Racing MAX-efi 500 Throttle Body

The Summit Racing MAX-efi 500 throttle body resembles a carburetor, yet houses four fuel injectors. (Image/Summit Racing)

Upgrading from a carburetor to electronic fuel injection (EFI) is often considered the holy-grail of aftermarket engine mods. We’ve got nothing against the venerable carburetor, but for those looking for no-hassle, day-in, day-out consistent performance, EFI is the way to go.

The problem has been that early retrofit EFI systems were often complicated and expensive. Thankfully, the aftermarket has stepped up in recent years, making fuel injection an attainable conversion for most gearheads.

And nowhere is that more evident than with the newest entry to the market—Summit Racing’s MAX-efi 500 system. It can handle up to 500 horsepower, and is designed to be both easy to install and easy on the wallet.

Summit Racing MAX-efi 500 Product Information

Here’s the skinny:

  • The Summit EFI system uses a carburetor-style throttle body. That allows you to install it on practically any intake manifold with a four-barrel square- or spread-bore carburetor flange.
  • You can keep your stock throttle cable. The throttle body uses standard linkage, which means it also works with your automatic transmission’s TV cable.
  • It’s self-tuning. After a few intuitive set-up screens on the included touchscreen programmer, the system will automatically adjust the air/fuel ratio to suit your altitude and driving conditions. The programming can be manually adjusted too, if you’re comfortable custom-tuning an EFI system.
  • You won’t need to change your ignition. The MAX-efi 500 system is compatible with darn-near every OE and aftermarket ignition system, Summit Racing officials say.
  • Built-in vacuum ports. You can still get vacuum for your power steering, brakes, and other accessories via the hose barb connections on the throttle body.
  • Neat and tidy. The fuel rails and all sensors (except coolant temperature and O2) are integrated into the throttle body. The ECU is small enough to be remote-mounted virtually anywhere under the hood.
  • No welding. To install the O2 sensor, simply drill a hole in your exhaust tubing and use the kit’s included hose clamps to secure the no-weld bung to the tubing.
  • No electrical engineering degree required. The wiring harness is labeled clearly and uses-factory style terminals and connectors to ensure daily driver reliability.
  • Aftermarket support. The system uses common, over-the-counter sensors and components, in case you ever need replacement parts.

What do you get? The system comes with the throttle body; wiring harness; standalone ECU; programmer with mounting bracket; and oxygen, TPS, TMAP, and IAT sensors.

What will you need? If you’re running a low-pressure mechanical fuel pump, you must upgrade to an electric fuel pump capable of operating at 58 psi. You’ll also need to ensure your fuel plumbing system can handle the additional pressure.

What it is NOT for. It’s designed for naturally-aspirated engines only. The Summit Racing EFI system is not recommended for turbo-, supercharged, or nitrous oxide applications.

Summit Racing tells us that the MAX-efi 500 system is intended to be a smart solution for folks looking for an EFI conversion for stock or modified street and track cars.

Want to see and learn more? Check out this video:

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  1. Jason (Redline) says:

    I have a 1998 vortec 454 that i rebuilt with stock bottom end,stock pistons, vortec heads with beehive springs,screw in studs for adjustable valve train,roller tip rockers,air gap intake,750hp Holley,msd hei, comp thumper roller 279TH7 cam. It has a 107LSA .Have power steering asist. Brake booster, 5spd trans so wasn’t concerned about vaccum for anything but Hei….Will this EFI system work and preform well with my motor or will my cam cause problems for it at idle????

    • Hey Jason! We sent your question to Summit Racing’s tech department. Here’s your answer:

      The Summit MAX-efi 500 is designed to work with radical cams and lots of valve overlap. Because it’s not reliant on vacuum to meter fully atomized fuel, it runs better under low-vacuum, part-throttle conditions than a carb can. The O2 sensor continuously trims the fuel curve under steady state cruise and WOT. The user fine tunes the choke and accelerator pump fueling to their liking.

      The system is designed to self tune with a MINIMUM of 6 inches of manifold vacuum.

  2. Can this be used without the O2 sensor? My marine application has “wet” cast exhaust manifolds.

  3. BrIan Nutter says:

    The Summit Racing MAXefi system relies on it’s o2 sensor to constantly trim the fuel. It’s not rated for Marine use, but give Summit a call and they can give you a solution.

    • Mastermech48 says:

      Not knowing your system specifics, Investigate the feasibility of fabricating an adapter between the engine exhaust manifold [s] and your follow on exhaust tubing. Both may be water cooled. By installing an adapter between the two components to hold an o2 sensor with a bypass cooling tube you may accomplish your needs. As long as the manifold has a water jacket and the follow on piping has water injection into the exhaust tubing after the inserted o2 spacer, it should work.

  4. Hi, y’all – I have a 1994 Trans Am built to a blue printed and balanced 383, and is loosely based on the Gen II LT4 withg AFR 227 heads and a Lunati 292 cam. Myt set up is intended for street and strip use. I have an Edelbrock LT4 Performer Air Gap intake that I don’t believe will support the 500-525 hp I think it will make. It is currently and OBD I set up, but I am not committed to that. I am looking for a single plane set up, and thought I would end up carbbing it. This could be a game changer – I would like to hear your input on my project. Currently have the 4L60, but will swap to either a 4L80 or 700R4 or T56 Magnum, so I am not necessarily dependent on the PCM for tranny operation, unless I stay with the 4L80.

  5. OnAllCylinders says:

    Franklin, it does look like a good option for you. You’ll need to bump your fuel systems pressure from 43 to 58 psi, but that shouldn’t be hard. You will need to have your own ignition, but in the case of the LT1/LT4-people usually install a distributor in place of the oil pump drive. The MAXefi-500 will take it’s tach signal from the distributor.

  6. Thank you very much, I will look further into this – I appreciate your help!

  7. Gregg Guenthard says:

    Does the system require of fuel return line?

    • OnAllCylinders says:

      The Summit Racing SUM-240500 requires 58 psi of fuel pressure and there are three ways to achieve it. An in-tank pump or frame rail mounted pump is the most common. In-tank pumps are a little more expensive, but quieter.
      If you use an in-tank or frame rail mounted pump, a good solution for a regulator is A C5 Corvette fuel filter. It contains the 58 psi regulator inside. It’s mounted in the back of the car just forward of the fuel pump. There is a return line going back into the tank, but it’s very short….just the single high pressure line runs up to the engine bay. CMB-03-0263 has the required fittings to make life easier.

      Another option is a Hyperfuel G-Surge fuel reservoir part number HPF-40007. It’s mounted in the engine bay area. It’s fed by the original engine mechanical fuel pump and fuel system. It acts like a float bowl that surrounds a single high pressure (58psi) pump that runs to the throttle body. Because the mechanical pump doesn’t encounter resistance entering the reservoir, it’s capable of flowing the fuel required to support up to 500 horsepower.

  8. I have a1965 corvair corsa 140 hp 1 x 4 wilk it work on that?

  9. It’s a bird, it’s a plane, it’s a… Fitech with a Summit sticker.

  10. Pingback: Video: Summit Racing's MAX-efi 500 Handheld Controller - OnAllCylinders

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