Choosing an A4 for tuning

"Tuning the A4 range of cars."

The A4 range from 1995 continuing the Audi range of high quality executive cars.

In the A4 Audi had a car which rivals the BMW 3 series, albeit without the image.

The range includes a selection of body styles from the Saloon to the Estate model. Reliability is up to the usual high Audi standards and the huge range of engine choices ensure there is a model suitable for most drivers needs.

The A4 is the Audi take on the executive car - something which they have executed very well.

Power/Engine mods.

This list of the stages and sports kits are usually fitted by our members, decide how far you want to push your car before you begin.

Getting the right motorsport inspired upgrade kits for your planned usage of the car is essential. Stage 3 competition upgrades just won't work well on the road making the car difficult to drive.

Competition cams, raise the top end band but as a result the car will not idle smoothly and low end power nearly always suffers.

In a car used daily you need to match your engines power to your typical driving style.

I'd be surprised if you have found a Motorsport camshaft is a pleasure to live with when driving around busy urban areas. This is because a competition cam causes a very lumpy idle, and makes the car more prone to stall or jerk along in stop start traffic, sadly though many ignore this and end up ruining a perfectly good car and having to revert back to a fast road, or OEM cam profile.

Each engine responds better to extreme camshaft durations so set your engine up on a rolling road.

The ECU mapping and fuel pump and injectors also have a large bearing on the bhp gains you'll achieve.

Altering valve durations can alter the bhp band and on most engines the exhaust and intake durations do not need to match, although most cams and tuners use matched pairs there are some advantages to extending the intake or exhaust durations.

Typical stage 1 mods often include: Remaps/piggy back ECU, Intake headers, Fast road camshaft, drilled & smoothed airboxPanel air filters, Sports exhaust manifold,Suspension upgrade.

Typical stage 2 mods often include: Sports catalyst & performance exhaust, high flow fuel injectors, Fast road cam, Ported and polished head, induction kit, fuel pump upgrades,Sports gearbox.

Typical stage 3 mods often include: Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Adding or Upgrading forced induction (turbo/supercharger), Crank and Piston upgrades to alter compression, Competition cam, Twin charging conversions.

You really need to keep as much low end torque as possible and aim to get a long power band across the rev range rather than a narrow top end power spike.

Here are some of the Audi engines we've covered in more detail and most will make suitable engine swaps in your A4 (don't forget that some of these engines have transverse versions).

From a tuning point of view on the A4 range we would recommend the 1.8T power plant which really does stand out as the tuners choice. This engine also came as a Quattro option, losing a bit of economy and acceleration but gaining so much extra traction. The 1.8T provides a good mix of economy and power.

This was later replaced with the superb 2.0 TFSi engine, which is very reliable and easily tunable. For example a remap yields a power figure approaching 270bhp. Later Quattro models were released with a 220bhp engine (BUL code in the LeMans and Limited edition models - it's well worth tracking down one of these if you can).

Tuning tips and articles

Engine tuning Transmission tuning Care care Intake & exhaust mods Improve handling Forums


In the diesel line up we have a maximum power of 150bhp in the 2.5 TDi which provides plenty of scope for power gains when remapped. All other TDi models will benefit from a remap although only the 2.5 TDi will get a large gain for a minimal outlay.

Audi A4 tuning

As far as performance models go the early S4 Quattro and the recent RS4 put Audi back at the forefront as creators of a car which every driver wants. Some may complain that the S4 and RS4 models are ordinary looking but this car appeals to the driver who doesn't want to draw attention to himself making the A4 range a car for the purists.

The car was updated in 2001, the floor pan was extended a little, and a whole selection of more powerful engine options were introduced.

The 2.0 FSi engine gives good power and economy ratio with the A4 Quattro hitting 220bhp by 2006, and Diesel tuners have a selection of 2.5TDi engines ranging from 163 to 180 bhp which are just begging for a remap. A 3.0 NASP petrol engine gave a range topping 220bhp (until the reincarnation of the mighty S4) but is not particularly economical.

Intake and Exhaust Tuning.

The next area for modification is the intake and exhaust. Air induction kits will only help to increase performance if the cars air intake is struggling! Adding an induction kit to most standard engines will see NO POWER GAIN AT ALL. If you have heavily modified your engine and it's need for air INCREASES DRAMATICALLY then an induction kit is the answer and will help remove this restriction.

Derestricting the air feed into the engine is a primary goal of car tuners so get a better flowing air filter if you find that the car is running lean only if you find the car is running lean. Induction kits can sound great but due to the warm air in the engine bay they will not really increase power and often rob you of power.

Sports exhausts will certainly help air flow from the engine but avoid an exhaust that is too large or you could very well end up with a reduced flow rate. So generally speaking, keep to 1.5 to 2.5 inches as a rule of thumb.

Airflow through the head can be dramatically increased with some professional polishing and ported. These should match and be setup to take into account any other engine mods. When you start tuning your A4 you will often find that the standard clutch starts to suffer so get an uprated clutch.

The best mods we recommend for your A4 are fast road camshaft, remap, induction and exhaust, suspension.

NASP engines do not achieve big power gains if you remap them, unless you have done extensive modifications. With turbocharged engines this is another story. A remapped turbo will give impressive power gains and fully release the potential power of the engine.

Adding forced induction or adding a larger compressor will usually require a lower compression ratio or water injection.

Handling/Suspension upgrades

Improving the handling for car owners first priority in your A4 tuning project.

If you set the toe out to 0.8 to 1.3 degrees on the front, and add some negative camber then cornering will radically improve.

Drop the car by as much as 30mm - 42 mm. and fit performance stiffer dampers, bigger drops will need other modifications in most instances.

Alloy wheel upgrades.

Due to the fact that alloys are less heavy they improve performance and they can help to cool the brake disks. If you are serious about performance then you will need to carefully choose your tires - ideally with a directional tread pattern tire. The drawback to large alloys on your A4 is that you're altering your final drive ratio and adding unsprung weight, so this will have a detrimental effect on performance.

Because of this endeavour to keep the overall rolling diameter of the wheel the OEM setup.

On the A4 we suggest sticking with 18 inch wheels, although the 19's look nice they do suffer from tram lining and are quite heavy. The wheel size can be adjusted via an OBD menu option to ensure the speedo is accurate, so when you change wheels consult your dealer and ensure that the studs used are correct.

When it comes to tire choices, I found Dunlop Sport Maxx, Goodyear Eagle F1's, Michelin Pilot sport and Continental Premium contacts all worked really well on my A4. I didn't like Pirelli P6000's at all the wet grip and general feel was so bad I pulled them off after 4 months. I will be trying the Pirelli P Zero nero's next though so will keep this article updated.

If you would like to know more, or just get some friendly advice on Tuning your car please join us in our friendly forum where you can discuss A4 options in more detail with our A4 owners. It would also be worth reading our unbiased Audi tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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A4 Tuning

A4 buyers guide and weakspots.

When buying an A4 avoid the low spec basic models as these are hard to resell, get the S line or limited edition models with leather seats.

The Quattro models and Avant models hold their value better and are the most sought after.

There are some minor weak spots on the 2.0 TFSi and DPF equipped engines to look out for. Firstly you must use the correct oil specification, failing to do so is just asking for trouble.

DPF equipped diesel engines: If you only drive short distances and the engine doesn't warm up the DPF filters are known to clog. Even motorway runs are sometimes not enough to clear it all out.

Running the car at high RPM for 15 minutes will generally do the trick, it also pays to drive it fairly hard.

Cars that are driven carefully and at the lower RPM band tend to suffer more from soot build up. We have written a DPF cleaning guide to help.

The 2.0 TFSi engines are very strong and provide excellent power to economy but you need to watch out for 2 things that will eventually go wrong. If you catch this early enough you will avoid problems and should regard these as service items. (Later engines address these issues to a large degree.)

Firstly the cam follower that drives the mechanical fuel pump has a special dark low friction coating on it. It looks a bit like a thimble that sits on the bottom of the fuel pump.

Check this every 30,000 miles for wear. If the coating has worn down and exposes a metal surface this will quite quickly wear through the follower and the cam shaft will become worn resulting in lost fuel pump pressure. It is a simple check and as long as you are careful about the extremely high fuel pump pressures is a simple DIY job, little more complex than doing a set of spark plugs.

Secondly the direct injection engine suffers from carbon build up on the valves. The fuel is not being injected over the valves so there is effectively no cleaning taking place.

Most direct injection engines suffer from this and after 70,000 miles a decoke is recommended.

The RS4 engine with direct injection is even more prone to carbon build up. The carbon build up will rob you of power rather than do any major damage but cleaning out the head will dramatically increase the performance.

We have seen no evidence to suggest that water/alcohol injection sufficiently cleans the intake valves. Running fuel cleaner also does very little as the fuel does not get sprayed on the intake.

They say prevention is better than cure so what can be done to prevent this carbon build up issue. Using good quality clean burn fuel free of bio elements, the higher octane fuels also tend to burn cleaner. Get the engine up to temperature as soon as you can (don't idle it but just drive it steadily at around 2000rpm till it warms up) and keep the engine operating at 3000rpm for 15 minutes per week. At this RPM range the engine is designed to run hotter and this can help burn off some of the carbon deposits.

Keep an eye on the recirculation valve, the oil this sprays into the intake when it goes is cited as a major cause of the carbon build up. If you notice high oil consumption then get this valve checked ASAP.

Cleaning the head is usually done by removal and refitting but we have seen some excellent results from intake cleaners that are sprayed at high pressure into the intake.

An inspection probe through the intake or via the spark plugs will give an indication on the state of carbon build up.

The DIY spray cans of carbon cleaner do at best a minor job, the trick is delivering the cleaner evenly to all of the valves. For best results take off the intake manifold and spray the cleaner directly onto the problem area and leave it to soak. (Always follow the manufacturers instructions though, I don't doubt that some formulations should not be left on for long periods of time.)

The VAG group are researching self cleaning valves with catalytic coatings, small amounts of fuel sprayed in the intake and "leaking valves" to help burn off the deposits.

To read our tuning tips, engine tuning tips see our tuning articles and please join our forum where you can chat and swap ideas and tips with other enthusiastic Audi A4 owners.

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Your Constructive comments on this article

2 Responses to “A4 tuning”

  1. brad says:

    what do I start with to tune my2007 Audi A4 Quattro

  2. Marty says:

    I have a 2001 Audi A4 B6 1.8t avj 110kw

    K04/015 turbo and front mount intercooler cold air intake pod filter what is the cheapest tune you have
    Could I get a tune for 550cc injectors or is it cheaper to stick with stock injector ?

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