What are Performance Chips

Racing or performance chips: What are they?

Automotive Products, Services, and Articles

EPROM Tuning Chips

The chips referred to when talking about performance chips are EPROM memory chips or Flash EPROM memory chips which contain a program for running the engine (inside the ECM), that is similar to the manufacturer’s programming, except for some parameters that have been modified by someone (the tuner) for accommodating new hardware, like bigger injectors, any type of boost induction, different engine cams, etc, or just to produce the most power, out of the already existing hardware (stock engine for example).

That is the original concept of a “performance chip” or “chip tuning”. Nowadays, you will see the same concept applied to what we described above (EPROMs and Flash EPROMs), but also to “piggybacks”, “resistor chips”, and other devices that some work for real and some others that are simply a scam.

Flash Tuning Chips

Flash EPROMs are similar to the earlier EPROM chips, but they are a newer concept; they can hold a larger memory size, are faster, and can be erased and rewritten electronically, contrary to regular EPROMs, which needed an ultraviolet-light tool for erasing them, so they could be used again.

Another feature of Flash EPROMs is that they can be erased instantly or in a “flash”, which is where their name comes from. Other memory types that could be erased electronically had to be done sequentially or by “pages”, which is, one block of a specific memory size at a time. Flash EPROMs are used in modern cars and can not be used in older models. The 1994 VW Jetta, for example, uses a 27C512 old EPROM chip, while the same model from the year 2001 uses a Flash EPROM 29F400, and the two are not compatible in any way. So we are discussing the concept of older and newer memory chips used for chip tuning as a comparison, but they are not interchangeable.

Piggybacks

The “piggyback” is a circuit, mostly a separate computer, that will intercept the signals coming from the different engine sensors to the ECM and will modify them before feeding them back to the ECM, so the ECM takes different actions, like injecting more fuel, advancing ignition, and so on. This, of course, will not exceed ECM parameters because it is working in parallel with the ECM, but it is still the ECM that will control and take action over the outputs (injectors, ignition, etc.). The benefit of these systems is that they are easy to program and set, and the user can adjust the parameters to their liking. Examples are “Apexi” and “Unichip”.

“Resistor Chips”

The “resistor chip” is nothing more than that, a resistor. Like the piggyback, the concept is to modify a signal from a sensor, usually the IAT, before that signal goes to the ECM. Then the ECM is expected to make changes in favor of performance. This is a passive modification, not like a programmable piggyback, and most of the time it does not work as intended. It only modifies one signal, like the signal from the IAT sensor or the signal from the AFR sensor (upstream oxygen sensor). The trick is an attempt to make the ECM “think” that incoming air is colder than it actually is, that way, expecting the ECM to inject more fuel.

EPROM Chip Important Characteristic

EPROM chips have an “access time” specification, which is the time it takes to output data after it is requested. For microcontrollers inside the ECM running at “X” speed or “X” MHz, the access time must be low enough for uninterrupted data communication and processing. Since ECMs that use these EPROM chips do not run at super high speeds like your laptop does, an access time of 200nS (200 x 10^-9 seconds) is a standard for those chips (up to 1995 models). If you use any EPROM slower than 250nS, the ECM may fail when a rush of data is being processed.

Origins of Tuning

The original concept of “tuning” was adopted for cars with carburetors. They had to be constantly tuned to maintain optimal performance, so it was about optimizing, not adding performance beyond the factory specifications. It was common to re-gap the spark plugs and recalibrate the ignition distributor contact points, and clean the carburetor needles or jets. Now we use the same concept for electronic fuel injection systems, but in a different way. Now it refers to gaining power, either in horsepower, torque, or both. It is hardly about optimizing only.

One “tuning” concept that is also common on the Internet is about painting and remodeling your car’s appearance. It is often done through a computer design program, but that has nothing to do with the focus of this article. They just call it “tuning”, not “chip tuning”.

Does this chip tuning work if no modifications are made to the engine?

Yes, it has moderate results, but yes. There is always a window for more performance because (1) there are laws regulating the emissions produced by the engine, and (2) the need to use low-quality (low-octane) fuel for economic reasons. Both reasons lead manufacturers to produce engines that are set to make less power than the maximum they can naturally produce. The limits introduced to achieve those goals are in the ECM programming. With chip tuning, reprogramming of engine parameters is done in an attempt to gain back the power that was left behind the regulations. This leads to another question: Is it legal? In most cases, probably not. If your car is modified mechanically or by programming, it may fail the emissions test. Another thing is that the speed limit that a car can naturally reach is limited by law in some countries to 180 Km/h (112 MPH), and that limit is programmed in the ECM too. If you modify the ECM program so the car can go faster than 180 Km/hr could be illegal just by doing it, even if you never reach that speed.

Other Modifications

Besides EPROM chips, piggybacks, and resistors, there are other methods that people try in an attempt to get more power out of their cars. An example is to use a direct connection in the engine fan, claiming that keeping the engine at a lower temperature will allow for more advanced ignition timing and produce more power out of it. Their rule is, each certain amount of degrees cooler, will allow for an extra degree of ignition advance. Another modification I have seen often is the EGR or “Exhaust Gas Recirculation”. This is a system that is installed in all cars. It allows a certain amount of exhaust gas to be injected back into the intake manifold when the engine is not at idle speed. This is done (1) to keep the temperature of the engine lower and (2) the most importantly, it helps reduce nitrous oxide emissions produced by the engine in the combustion cycle. Nitrous oxides only happen at high temperatures and high pressures. If the combustion chamber gets hot enough, it will mix nitrogen with oxygen, producing nitrous oxide gas, which, like carbon oxide gas, is poisonous too. Where does the engine get the nitrogen? From the same place where it gets the oxygen, from the air in our atmosphere. The atmosphere is about 20% oxygen, 79% nitrogen, and 1% other gases. That’s the air we breathe.

So why is the modification or elimination of the EGR desired by performance enthusiasts? Because recirculating exhaust gas introduces inert gases to the intake, producing less power. With less oxygen, less combustion temperature, and less power. But we are talking about a difference of only 1 or 2 fewer horsepower here. The EGR valve remains closed (deactivated) at low engine speeds to avoid disturbing idle or cruising speeds and opens at a certain engine speed, so in reality, I would not tamper with it, as there is no perceptible difference. Anyway, if you are going to eliminate the EGR anyway, it will be a good idea to keep the engine fans running at all times or program them to run at a lower temperature, as lower engine temperatures will be needed in that case.

Still another modification is a completely reprogrammable system, but those are the fewer that are purchased because they are expensive; and many times an expert is required to do a basic programming to at least start the engine, and then go from there to a complete tune. These units need to be programmed from zero to match the engine functions and parameters of your car. Once working, you may make any change in the parameters to optimize the engine even further..

Back to Chips. What Changes Are Made?

As mentioned earlier, an exact copy of the stock software is made, and then some modifications are made to some parameters, depending on the purpose and needs.

The modified areas usually include “Fuel Maps”, “Ignition Maps”, “Air Flow Maps (MAF)”, RPM limiters (Revlimiter), Vehicle Speed Limiters (Speed Governor), the EGR (Exhaust Gas Recirculation), Variable valve timing (VVT-i, VTEC, MiVEC, Vanos, etc.) and some sensors like “Knock Sensors”, “Oxygen Sensors”, “Barometric Pressure Sensors” and “Manifold Absolute Pressure (MAP) Sensors”. All those are controlled by the ECM.

The tuner, which is the person who is trained to do these modifications, knows what modifications to do and to what level. Most of the time, he or she uses specialized tools and software. But the tuner does not necessarily know where in the ECM program memory the parameters that he or she needs to modify are. That is the job of a team of researchers that develop systems to do so. Instead, the tuner knows what to do in terms of injector opening timing at certain RPMs, or at certain engine loads, how much ignition advance in degrees, and stuff like that.

Protected Chips and Piracy

Since the experimentation and development of good and effective performance chips takes a lot of money, time, effort, and knowledge, and the means to do it are often exclusive, performance chips are often protected to avoid illegal or unauthorized copies.

Copies of the work of others are continuously done and sold by unscrupulous people who want to make a few bucks out of others’ hard work and investments. This is not only unethical but also hurts the market. When a company or a group of people invest thousands of dollars in developing a product and cutting costs to the most they can, so the product can be sold at a competitive price, and another group of people who haven’t invested a penny on the project, start copying and selling the product at a small fraction of the original price, the market value for that product falls, or at least, is seen as less valuable. Why would someone pay $299 for a chip if others offer the exact same copy for $50?

In an attempt to avoid the above scenario, some chip developers have had to invest even in another product, which, of course, will raise even more the product’s final price. That other product is the “anti-copy” socket, in combination with an encrypted chip, to protect the chip contents from being copied.