The basic principles of Audi AAN engine power tuning:

The whole idea of tuning for added power output is to burn more fuel in a given time. This generates more heat energy, which then drives the pistons with more force and thus produces more power from the engine. Increased fuel requires increased air to burn the fuel properly. The most efficient way to do this, in a turbocharged engine, is to increase the air density by increasing the boost level and cooling the air so that more air mass is fed into the engine.

Ideal Gas Law
P(ressure) * V(olume) = n(umber of moles) * R(constant) * T(emperature)
-or-
PV = nRT
The item to maximize is n.
n = PV/RT

To maximize n both P and V are increased (if possible) while T is lowered. V is basically constant in a given engine since it is the volume of the cylinder. This leaves increasing P and decreasing T as ways to increase the amount of air in the cylinder.

Additionally, it is generally advantageous to advance spark timing so that peak cylinder pressures are coming on as the piston reaches TDC (top dead center).

These functions are accomplished by a combination of several techniques. The stock 2.5 bar pressure transducer (PT) which is capable of measuring Manifold Air Pressures (MAP) of up to 1.5 bar or about 21 psig of boost is replaced with a VMAP capable of measuring pressures of up to 3.0 bar or about 28 or 29 psig. This allows increasing stock boost levels of 14 to 15 psig up to pressures of 21-22 psig safely (or even higher given proper additional engine modifications such as a larger turbo and higher flow injectors, etc., as is done with the RS2 mods).

Two computer chips inside the Engine Control Unit (ECU) manage the operating parameters of the engine. The boost chip contains pressure map information which allows the ECU to manage boost level control and accurately reads "elevated" boost pressures. The boost chip also helps manage the wastegate frequency valve to prevent the boost levels from getting too high resulting in damage to the turbo by over-spinning it. Shrapnel from a blown turbo is not a good thing.

The fuel/timing chip provides maps for fuel for the ECU which receives air flow data from the mass air flow detector (MAF) and calculates the proper length of time to pulse the fuel injector for each cylinder in order to deliver the proper amount of fuel for the amount of air present in the cylinder. This, of course, requires that the chip "knows" the injectors used. If too much fuel is delivered the fuel mixture is too rich and fuel economy becomes rather dismal and, if the mixture is extremely rich most of the time, the catalytic converter can overheat and essentially melt down. Again, this is not a good thing. If too little fuel is delivered the mixture will be too lean and exhaust gas temperatures can soar and end up melting valves and pistons, etc. This is also not terribly desirable.

The fuel/timing chip also provides for control of spark timing. Timing can be safely advanced from OEM settings with a significant increase in power level for the engine. Advancing the spark as much as possible is a big help. Advancing the spark too far, however, can result in knocking which can damage the engine. This is, again, not a good thing.

You can see that proper tuning becomes something of an art form - a balancing act. MRC chips are developed by adjusting all operating parameters to as close to the line as possible and then backing off enough so that safety and durability of the engine is not compromised. It is perhaps possible to squeeze out a little more performance but only at the risk of engine or turbo damage. We do not and will not do that kind of tuning.
Our line of chips:


Stage 1. Retains the OEM 2.5 bar PT and adjusts boost levels a little to stay within the accurate measuring range of this PT and adjusting the timing as much as possible consistent with engine safety. Performance is mildly enhanced by perhaps 20 hp or so to the 245-250 hp range from the factory rating of 227 hp. While we can provide such chips we really recommend the stage 2 chips as a much preferable yet still affordable first upgrade.

Stage 2. Replaces the OEM 2.5 bar PT with a 3.0 bar VMAP (or a genuine Bosch 3 bar PT if available - these are taking on the appearance of being made of unobtanium) allowing greater boost levels (in the 21-23 psig range while remaining within the fuel delivery capability of the OEM injectors and using appropriate software to manage fuel and timing appropriate to these boost levels. Performance is increased to approximately 280 hp. This is a significant performance improvement beyond the 227 hp stock level. Other than the chips and the VMAP the engine remains completely stock. This is probably our best “bang for the buck” upgrade.

Stage 3. This level of performance enhancement is usually referred to as an "RS2 mod". Our Stage 3 mod uses the same VMAP (or Bosch PT if available) as Stage 2 but software is provided to accommodate higher flow RS2 level turbos and higher flow injectors to accompany those turbos. Maximum boost levels of 26-28 psig are available. Performance is improved to the 360 to 380 hp level. This, of course, requires the addition of an RS2 turbo, exhaust manifold, and higher flow injectors.

Higher stages. Custom software is available for other turbo, injector, intercooler, cam, piston, etc., combinations with power levels of 400 to 500+ hp right on to full racing engines. If you have needs going beyond the RS2 level, please inquire.

3B engine: We have similar tuning available for the Audi 3B engine. The 3B engine is very similar to the AAN engine and was, basically, a predecessor of the AAN engine. Contact us for information regarding these mods.

Fuel available. Our chips are designed to function best with 93+ [(R+M)/2] octane fuel. If such fuel is not available in your area we can supply replacement chips which are designed for 91 octane fuel by backing off timing and decreasing boost a bit (at a concomitant small reduction in output). There is no extra charge for supplying 91 octane chips rather than 93+ octane chips but please let us know if such chips are required.

Additionally, RS2 level chips designed for use with 100 octane [(R+M)/2] fuel are available at extra cost. Higher octane fuel is more resistant to knocking and therefore permits greater timing advance thus improving performance. Normally these chips would be used as temporary replacement chips for track use only with the appropriate fuel and would be replaced with your "regular" chips at other times. If these chips might meet your requirements, inquire.

Potential Problems:

Operating an engine at higher performance levels can lead to other engine weaknesses becoming exposed. One example of this is a fairly common ignition problem. A basic fact is that a higher voltage is required to force a spark through a higher pressure gas. If the stock ignition system has, through age, become weak then it is possible that the spark may become so weak that it is no longer capable of jumping the plug gap when pressures are high (under greater boost). If that happens then the engine will misfire at higher mixture pressures. If the stock ignition system is in good shape this is not a problem but if it has degraded over time then the weakness can become exposed. The cure for this, should such a miss develop, is to replace the offending weak coil. Alternatively, the entire ignition system can be replaced to allow use of readily available and less expensive components from the Audi A4 1.8t engine. The expense of such a modification is comparable to about the expense of replacing two stock AAN coils. Should you be interested in such a mod please inquire. MRC does not supply them but we can point you in the right direction.

Back

© Chips-Ur-S.com 2005