Performance Chips

Chips are found in 1986-1995 BMW computers – roughly from E24 to E36 models. The chip is a computer EPROM located on a plug inside the engine computer (ECU). Chips contain the software that manages engine operation. Within the thousands or millions of lines of computer code are instructions and data that tell the engine how much fuel to use, when to fire the spark plugs, when and how much to change the camshaft timing, what idle speed to use, and a whole lot more. All of this data is contained in something we call “maps”. By altering the values in these maps we change how the engine performs. Make the right changes and the engine just works better – whether it makes more power, runs smoother, or gets better fuel economy.

BMW chips make big gains on 1980s-1990s BMWs because of the fuel that was available at the time. Since the stock computer lacked the ability to self-adjust, as on later models, BMW had to set the tuning for low quality fuel. Performance chips, on the other hand, have revised settings for premium fuel (91+ octane). With higher grades, the engine tuning can be more aggressive; we can run more ignition timing and alter fuel delivery to make more power before the engine experiences “detonation” (don’t worry – in most cases this does not mean the engine is exploding).

A Performance Chip is one that has the data altered, usually to make more power and torque or to account for a specific hardware change to the engine spec (cams, higher compression, bigger fuel injectors, etc). The quality of the tuning depends on the experience level of the person making the changes. Not just anyone can open up the code and make safe, meaningful changes. The best tuners are computer hackers and engine builders who know a) how to crack and modify the computer code, and b) how to tune the engine to make more power without adverse affects. And it helps to be an expert in the particular vehicle you’re tuning. Generally speaking, a tuner that can modify a BMW is not going to have the same success with a Chevy. Therefore, the most important consideration when buying a performance chip is the reputation of the tuner.


Tuning Glossary

Below is a list of terms and definitions you will encounter when learning about tuning and software.

Adaptation – a feature on modern BMWs that enables the DME to make realtime changes in fuel so it can meet pre-determined targets for efficiency and power.

AFR – Air/Fuel Ratio, is the expression of how much fuel is mixed with air in the exhaust stream. The ideal ratio for fuel and oxygen for burning is 14.7:1. However, BMW engines rarely aim for this target. These engines make more power at a richer AFR (12.5-13.5 is typical on naturally aspirated engines). But while cruising or low load conditions, the AFR will run lean (15.0 or higher) for better fuel economy.

CARB – California Air Resources Board, a semi-autonomous regulatory agency that establishes air quality standards for California. These emissions laws affect all cars registered in the state and sometimes supersede federal regulations.

Chip – a computer chip (EPROM) installed in the DME that contains the software. 1982-1995 BMWs have a replaceable chip in the DME. 1996 and later computers have a flash memory chip.

Closed loop – a DME operating strategy where it makes realtime changes in engine operation based on data from the O2 sensor. Closed loop is in effect from idle to approximately 70% throttle opening.

DME – Digital Motor Electronics. This is the computer that manages engine operation and performance. Also known as an ECU.

ECU – Electronic Control Unit or Engine Control Unit. This is the computer that manages engine operation and performance. Also known as a DME.

EPROM or EEPROM – Erasable Programmable Read-Only Memory or Electrically Erasable Programmable Read-Only Memory. Otherwise known as a chip.

EWS – a theft-protection system on 1993-later models that syncs various systems in the car so that the car only starts with the key. In other words, it cannot be hot-wired. Since 1995 the DME has been an integrated part of the EWS system.

Flash – a way of overwriting existing data in the software without replacing a physical chip. BMW computers have used flash memory chips since OBD-II standards in 1996.

Flash Counter – an internal limit on how many times a DME can be flashed with a new version

Jim Conforti – computer engineer and BMW tuner, famous for his OBD-I performance chips and OBD-II Shark Injector

Lambda – another but lesser-known method for measuring AFR. The AFR of 14.7 is equal to a Lambda of 1.0. BMW Lambda should be around 0.92-.95 for power output and 1.1-1.3 for cruise.

Lean – using less fuel (the opposite of rich)

OBD – On Board Diagnostics, the self-contained diagnostic and communication system in a BMW. The DME is at the heart of this system. There is a diagnostic port located in the engine bay (1977-2000) or in the dashboard (1996-later).

OBD-I – an emissions and communications standard recommended by the US federal government. For BMWs, OBD-I applies to 1986-1995 models. Nearly all OBD-I vehicles have a single oxygen sensor ahead of the catalytic converter.

OBD-II – an emissions and communications standard required by the US federal government. For all cars, OBD-II applies to 1996+ models. Nearly all OBD-II vehicles have multiple oxygen sensors to evaluate the performance of the catalytic converter and the rest of the emissions system. There is one or more O2 sensors ahead of the catalytic converter and one or more after the cat. Modifying or removing OBD-II software that affects emissions is against federal, and possibly state, law.

Open loop – a DME operating strategy where it ignores data from the O2 sensor and reverts to preset tables and maps for engine operation. Open loop is in effect at full throttle (> 70% throttle opening).

Oxygen sensor – a sensor that measures the oxygen content in the exhaust and compares it to outside air. The DME uses this data to evaluate the efficiency of the engine. Most stock O2 sensors measure in a ‘narrow band’ (see Wideband below) of 12.0-16.0 because that’s all the DME is equipped to record. The oxygen sensor was invented by Bosch engineers in the early 1970s. Also known as a Lambda sensor.

Piggyback – a module that intercepts sensor data, modifies it, and sends the new data to the DME. By altering the signals from various sensors you can trick the DME into using alternate maps to make more power. Piggyback units are used when the factory DME cannot be tuned or the tuner does not fully understand how to tune it.

Rich – using more fuel (the opposite of lean)

Shark Injector – a DIY software flashing tool, developed by Jim Conforti

Wideband O2 Sensor – a sensor that measures the oxygen content in the exhaust and compares it to outside air. Wideband measures AFR in a broader range than a stock O2 sensor – typically 10.5-straight air.

The Shark Injector

This programmer with the funny name is probably the greatest software tool ever brought to the tuning market. It’s a self-contained programming device that plugs into the diagnostic port on your 1996-2006 BMW. From there it will re-program the engine computer with performance software.

Here’s where it gets amazing: on just about any engine computer there are different versions of the stock software (like Windows updates). The performance software must be based on one of these versions – there is no ‘one size fits all’ file. The genius of the Shark Injector is that it automatically identifies the version in your car and loads a matching performance file. Most other programmers require you to read your stock software and email the file to your tuner to be modified. There’s downtime and margin for error. The Shark automates the whole process. It’s no wonder the process was patented.

The Shark can be used to install performance software and it can be uninstalled too with the same tool. There is no limit from the Shark on how many times the software can be installed/uninstalled but the engine computer has its own internal flash limits. The Shark only works on one vehicle at a time. Otherwise, the manufacturer wouldn’t sell many… It keeps track of the vehicle by recording its VIN.

The Shark Injector is only a tool. It’s the software that gets loaded into the DME that you want. Currently, the Shark Injector contains software developed by Jim Conforti, Eurosport, and Turner Motorsport. As awesome as the Shark tool is, the software is a little underwhelming. For the most part the software is tuned conservatively. Conforti did not take great chances with tuning these engines, in the interest of longevity. He sacrificed horsepower gains to ensure no long term engine damage results. In my opinion, he could have been more aggressive to get more power and would not have lost any reliability. Turner Motorsport purchased the Shark Injector business from Conforti in 2015 and there is the possibility they will re-release revised tunes.