Tech Article Title Author Date
An Introduction to Chip Tuning Rodney Spear 1999

The following is a response I posted a while back to someone with a basic question about chipping. I believe it covers the basics and is accurate. Since this comes up so often I figured that it would be a useful FAQ. Perhaps it will even encourage others to submit more detatiled FAQ's (ie. Alan Adamson's Chips&Salsa series). In any event, here goes:

First off there's tons of info in the archives. You can also find some good information on various tuners' sites, both Wett and Tap's sites have good discussions of the warranty issue. In addition, Don P.'s site the Audiport contains lots of good information the results of his chip survey (ongoing I think).

Chipping increases horsepower and torque by adjusting the air/fuel mix, timing, and a bunch of other engine management elements (now computer controlled) that real gearheads would be better equipped to identify than me. In general, hp gains for normally aspirated cars (those without turbos or superchargers) from just a chip are relatively modest (5-10%). In the case of the A4 1.8t the chips also control the boost supplied by the turbo. The chips increase the boost in addition to making all the other changes mentioned above resulting in more power (about 30% in the case of the A4 1.8t).

A turbo increases the power output of an engine by forcing more air into the combustion chamber. Exhaust gasses spin the turbo up and it forces air into the engine, hence turbo lag (the time it takes for the exhaust to make the turbo spin fast enough). The turbo in the A4 is small and works at low boost pressure, as a result lag is almost imperceptable. Normally, the engine runs in a vacuum state (the engine is sucking air in, like a normally aspirated engine), when you need to accelerate, the turbo comes into play, forcing air in. This is significant because the changes made by chipping are quite minimal most of the time. Also, the car does not stay at full boost very long in most cases (exceptions being situations like drivers ed. track events). As a result of all this movement, a great deal of heat is generated (if you pop the hood af an A4 1.8t at night after some hard driving, you'll see the turbo glowing red hot). Max. stock boost on the A4 is .5 bar (about 7 psi), most chips are .8 bar (about 10-11 psi) or 1.0 bar (about 14 psi). The stock turbo is manufactured by KKK (German turbo company, not morons in white sheets), the model is the K03 (the next larger turbo they make is the K04, you'll hear folks talk about K04 kits here off and on).

The warranty IS affected. The Magnusson-Moss Warranty Act seems to indicate that Audi must prove that the chip (or any other modification) caused the problem in order to deny you warranty coverage, though like any law this is open to interpretation by lawyers and the courts. The reality is if a dealer says they won't cover XYZ repair because your car is chipped, are you going to go get a lawyer? Most service departments are fairly reasonable on this topic so discuss things ahead of time with the service techs and or service manager. Reliability will be affected because the chip puts more stress on the engine. The question is how much will it be affected. These cars are relatively new. It is therefore hard to guage both long term reliability AND the impact that chipping will have. In the coming years more data will be available, until then we can only speculate. Also of note is the fact that in Europe Audi sells the A4 1.8t with 180 hp as an option. Most chips increase power to 180hp to 200hp depending on the chip. For these reasons, it is likely that driving habbits and propper maintenance (regular oil and filter changes, use of good gas, allowing warm up and cool down time for the turbo, etc.) will have a greater impact on engine longevity and reliability than chipping or not chipping. As for cost, there is a wide range of chips out there prices range from about $200 for the Neuspeed .8 bar chip up to about $1,600 for the Oettinger 1.0 bar chip. At this time there is no one chip that is the best. Generally, the 1.0 bar chips are quicker than the .8 bar chips. It is important to note that each engine is slightly different and gas quality varies from place to place, chips will not work the same from car to car, therefore tuners will fine tune their chip if a customer has a problem (such as pinging or detonation). Finally, although most chips are for the 1.8t, there are a couple for the 2.8 30valve engine, but the performance gains are not as great (for the reasons discussed above).

Much of the information presented above was learned here on AudiWorld from knowledgeable persons too numerous to mention.