For Bimmer enthusiasts, by Bimmer enthusiasts.

These fuel injectors are a massive upgrade for BMW M10 and M42 motors. The four-hole design provides a better spray pattern for better fuel atomization and a wider spray pattern than the early style single pintle injectors. This not only increases power, but provides better fuel efficiency as less unburnt fuel will be sent out the exhaust. The Gen III body also has some unique advantages over metal body injectors. They weigh about half as much (every ounce counts when getting into hardcore weight reduction), handle heat soak better, and have a slightly wider spray pattern for better atomization, even over metal 4 hole injectors. They'll also never rust.

These also provide a level of safety for your engine in modified cars. Increasing intake airflow and power without upgrading the fuel system can cause lean conditions which can damage or even destroy your engine.

Parts we stand behind.

All of our injectors are genuine, remanufactured in-house, and are covered by a lifetime, unlimited mileage warranty and exchange program. You can buy a set from us, drive 100,000 miles, and swap them for another set for just the cost of shipping! Or, if you upgrade and tune your car and need some bigger injectors, or simply want to switch to a different injector style or color, you can request an exchange for only $20 (plus any additional cost difference between sets, if applicable).

Rebuilding process

The entire testing and rebuilding process takes roughly 24 hours per set and all rebuilding is done on-site in our shop to guarantee quality. The steps are:

Step 1: Visual quality inspection, exterior cleaning, and each injector is marked with a number for testing purposes in later steps. We only service genuine OEM injectors; aftermarket (non-performance) or Chinese injectors are discarded during this step.

Step 2: Injectors are ohm tested with a multimeter, solenoids activated to test for correct opening / closing operation and tested for stuck open / stuck closed conditions.

Step 3: All serviceable parts (filters, o-rings, pintle caps, etc.) are removed and injectors are left in an injector-specific degreaser solution. There is a variety of metal types used in fuel injector construction (steel, brass, aluminum, etc.) and normal degreaser is usually harmful and corrosive to softer metals, so we use a formula and concentration level safe for the metals and polymers used in fuel injector construction.

Step 4: The injectors are washed to remove any residual degreaser solution and placed in several ultrasonic baths to break up built up contaminants. The injectors are pulsed on and off during this process to thoroughly clean the internals. The ultrasonic machine has variable temperature controls and an automatic shutoff in case the solution becomes too hot.

Step 5: Pressurized backflushing (flowing the injectors backwards) is performed to fully remove the contaminants broken down by the ultrasonic cleaner.

Step 6: The injectors are installed on the flow test machine and have a variable RPM test performed. This test "revs" the injectors as if they are on an engine from 0 to 10,000rpm, then back down to 0 again. The purpose of this test is to ensure the spray pattern is consistent throughout the rev range and does not change or falter during acceleration or deceleration. This is an important step that many shops do not test for.

Step 7: The injectors are then both statically and dynamically flow tested for +/-2% of the injector's rating. The static test simply opens the injector and measures the raw flow for a certain amount of time. The dynamic flow tests measure flow at idle, low, mid, and high RPM, respectively. These different test conditions are important as an injector that passed a static test may fail one of the dynamic tests, or vice versa. A weak solenoid, damaged pintle, or damaged internal spring may result in an injector working fine when wide open but failing a flow test when forced to open and close many times during the test. Units that fail the flow test are put through the cleaning process up to 2 more times and tested again. If they still fail after 2 more cleanings, they are discarded.

Step 7: All servicable parts that were removed in the beginning are replaced with brand new rebuild parts. Even parts that aren't 100% necessary to replace, such as pintle caps, are replaced as an extra assurance to the buyer and testament to our quality and work ethic.

Step 8 (metal body injectors with rust / damaged paint only): Both tips of the injector are masked and the injector is glass bead blasted with a special, extra-fine glass bead media. The bodies are then wiped down with isopropyl alcohol to remove any leftover media and a rust inhibitor is applied to the body (This step does not apply to metal injectors with good paint or fully plastic body injectors).

Compatibility Information

M10: Any flow rate other than stock, even slight differences, require a tune or standalone upgrade. The M10 management system isn't robust enough to adjust and trim its own fuel delivery too well.

M42: These injectors are direct plug and play for E30 M42s and have the same flow rate! You'll reap the benefits of both upgrading from a pintle to a four hole system *and* upgrading from a metal body to Gen III design. These are, in my opinion, the best bang for your buck upgrade for the M42. E36 M42s and M44s can use these if paired with intake manifold adapters. Check out the VAC motorsports adapters.