Audi A4 B7 Typ 8E/8H; 2004–2009 Tuning

"Best Power & Performance Mods for your A4 B7"

Those wanting something larger than the A3 will look to the A4 which offers more rear storage and a more substantial frame, however internally the space offered is similar.

My A4 Quattro, with the 220hp 2.0 DTM FSi was a dream to own and drive and still rates as the best car I've had.

The benefits of choosing an A4 though are the excellent choice of engines, and the great handling which make this a very practical car while still having something to offer a driver in terms of response and performance.

This article will focus on improving the handling and performance of the B7 version of the A4 based on my ownership and experiences. (I've had the 1.8T 2.0T 2.0TDi engines and all had plenty to offer and a few quirks you need to be aware of.)

B7 A4 is actually just a heavily facelifted and amended B6 model, boasting revised steering settings, suspension geometry (independent rear suspension) a Getrag 6-speed transmission. Direct injection was added on the Gasolene versions. This platform became the basis of the SEAT Exeo in 2008.

To get the most from the chassis you really need to get an engine with 130bhp or more. Thankfully the diesels and turbo diesels fit the bill nicely with some suitable modifications.

See our video which covers all the principles of Audi A4 Tuning, it contains some tips on turbo swaps and covers performance and handling.

Tuning tips and articles
 

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

We would go for the 1.8T, the 2.0Tfsi the 2.5 and 2.8 V6 engines and the 1.9 TDi 130 and 2.0 TDi (avoid the 115ps version unless you are desperate for economy (although the 2.0 TDi offers plenty of economy) and the non turbo petrol engines do not offer much return when tuned so are best avoided if you are looking for a tuning project, although you can still improve them and tune them.

Max. power & engine specs

Gasolene engines

1.6 102 PS (75 kW; 101 hp)
1.8 T 163 PS (120 kW; 161 hp)
1.8 T quattro 163 PS (120 kW; 161 hp)
2 130 PS (96 kW; 128 hp)
2.0 T FSI 200 PS (147 kW; 197 hp)
2.0 T FSI quattro 200 PS (147 kW; 197 bhp)
2.0 TFSI DTM 220 PS (162 kW; 217 hp)
2.0 TFSI DTM quattro 220 PS (162 kW; 217 hp)
3.2 V6 FSI 255 PS (188 kW; 252 hp)
3.2 V6 FSI quattro 255 PS (188 kW; 252 hp)
4.2 V8 S4 BBK 344 PS (253 kW; 339 hp)
4.2 V8 RS4 420 PS (309 kW; 414 hp)

Diesel engines all Turbocharged

1.9 TDI 115 PS (85 kW; 113 hp)
2.0 TDI 140 PS (103 kW; 138 bhp)
2.0 TDI quattro 140 PS (103 kW; 138 hp)
2.0 TDI 170 PS (125 kW; 168 hp)
2.0 TDI quattro 170 PS (125 kW; 168 hp)
2.5 V6 TDI 163 PS (120 kW; 161 hp)
2.7 V6 TDI 180 PS (132 kW; 178 hp)
3.0 V6 TDI quattro 204 PS (150 kW; 201 hp)
3.0 V6 TDI quattro 233 PS (171 kW; 230 hp)

Revisions to the A4 platform over the years with links to our tuning guides for each.

Our aim in A4 B7 engine tuning should be to increase peak power and Torque at the top end.

The best power gains come from larger engine sizes. The more you start with the bigger the return on investment so engine swaps are good value mods for small engined cars.

I have a guide to Audi Tuning, with a good overview of the best mods and upgrades.

Audi A4 B7 Tuning modifications.

These mods sports parts are usually installed by our members, decide how far you wish to go in your tuning project before you get started.

Here are links to my engine guides, many of these can be swapped in, and I go into much greater detail around the engines and the quirks and best mods and upgrades for them.

Getting the right modified parts for your planned usage of the car is a time and money saver. Stage 3 motor sport parts just don't work well on the road making the car difficult to drive.

Please watch our video which covers the top Audi A4 Tuning Mods. Be sure to subscribe and support our new channel.

Best mods for your A4 B7

  1. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to raise the intake air supply, allowing you to utilize more fuel and make higher power. Although one of the most challenging mods but provides the best gains.
  2. Brake Upgrades - Improve your A4 B7's stopping power needs to be high on your agenda.
  3. Lightened Flywheels - a lighter flywheel will enhance the engines free revving nature. In some cases flywheel lightening is not recommended for all A4 B7 engines.
  4. Air Induction kits and high flowing exhausts - NB: on their own these mods will NOT ADD HP on most cars, but they enable you to release power after other upgrades by losing a restriction.
  5. Fast road cams are one of the most significant mechanical changes, but they must be fitted by someone qualified to set them up properly and tracking one down may be hard but you'll probably find a local firm to regrind a stock cam for you.
  6. A4 B7 Handling Mods (Suspension) - Replacing worn bushings and shocks radically improves your A4 B7 handling Coilovers and Bushings are the usual go to mods
  7. Mapping - A4 B7 remapping ensures the biggest gains in terms of cost, aftermarket ECUs, and inline Tuning boxes are all alternatives.
  8. Flowing and porting the Head - Head work will get air flowing into the engine while removing turbulence or restrictions.

A4 B7 Tuning Stages

Typical stage 1 mods often include: Suspension upgrade (drop 21mm - 39 mm.), Panel air filter, Alloy wheels, Sports exhaust, Remap, Lighter flywheel.

Typical stage 2 mods often include: Power/Sport clutch, Ported and polished head, Fast road cam, high flow fuel injector, fuel pump upgrades.

Typical stage 3 mods often include: Sports gearbox, Internal engine upgrades (pistons/head/valves), Adding or upgrading forced induction (turbo/supercharger), Engine balancing, Competition cam.

Peak power is all well and good but for a daily driven car you need a wide power band and perhaps extending the rev range.

Let's look at these in more detail, in the meantime please watch our video on the best car mods, so you can maximize your return on your tuning investment.

The quarter mile times are a good guide to how much faster your A4 B7 will be after you've applied some tuning mods to it. We recommend a quattro setup for power over 220hp or you'll be held back with traction issues and problems.

Quarter Mile times        
Base Power Quarter Mile Weight Tuned Power Quarter Mile
90hp 20.24 1500kg 110hp 18.96
100hp 19.56 1500kg 120hp 18.43
150hp 17.15 1500kg 175hp 16.31
163hp 16.69 1500kg 180hp 16.16
172hp 16.4 1500kg 195hp 15.75
180hp 16.6 1500kg 220hp 15.15
190hp 15.89 1500kg 250hp 14.54

A4 B7 B7 Suspension Mods.

Suspension plays an essential function on the track since it allows for quick turns. Because the track is forgiving, you may employ harsher suspension and lower the vehicle for improved aerodynamics and a lower centre of gravity to improve performance.

It is possible that the rubber suspension bushings on your Audi A4 B7 may deteriorate as the vehicle becomes older, resulting in the sound of squeaks, rattles, and bumps in addition to the suspension not being as tight as it might be.

You should begin by enhancing the original Audi setup, and replacing it with polyurethane bushings would be a fantastic option in this regard.

So, what elements and considerations must you take into consideration while setting up and selecting the suspension for your everyday driver?

Speed bumps, uneven terrain, passenger comfort, and road noise must all be taken into consideration while developing a car's suspension system.

The majority of new autos are equipped with soft suspensions which does not maximize handling or driving enjoyment. Track cars are configured to accommodate a variety of driving styles and preferences; as a result, the ideal configuration is not only subjective, but also dependent on the circuit characteristics.

A good suspension system ensures that the tyres remain on the road at the optimal angle for optimum contact area. Body roll must be kept at a minimum, and the car's centre of gravity must be as low as possible. Torquecars advises a 30mm drop for A4 with modified suspension such as coilovers, the DTM and S Line models already have lower suspension.

Common Suspension Mistakes & Urban Myths.

Don't assume that buying a non-adjustable suspension package that lowers a vehicle 60mm is a good choice and expect it to be flawless it is likely the camber changes will ruin the cornering and you'll get tires rubbing on the arches.

The vast majority of kits are advertised as universally applicable, which means they may be used on almost any vehicle. But the idea that one suspension can handle all engine, wheel, and A4 B7 weights is just not true (the diesel engines are pretty heavy).

The drive shaft and gearbox might be damaged if the final drive to the wheel hub angle is off.

As a result, scouring and early tyre wear are increased when the ride height is altered.

You should never purchase reduced springs and use conventional dampers, or update dampers and use reduced springs. It is important to look at the suspension system as a whole.

Cars appear better when they are lowered. Because of this, you lose ground clearance, your tyres scrape against the wheel arches, and speed bumps become insurmountable obstacles.

Remember that speed bumps will strike the sump and take off the bottom of the engine and most of the front skirt of a lowered car. Lower does not always mean better.

A 35-millimeter drop is recommended for most road vehicles, but an A4 B7 with improved suspension only needs a 30-millimeter drop from TorqueCars (sporty versions which already have lower suspension).

Tolerances may be much lower if the automobile is lowered, although this might pose a variety of problems.

Stability may be improved by lowering the car and decreasing airflow beneath the vehicle, which minimises the risk of overheating.

Lower springs and shocks must be matched to each other. This is a bad idea since you're asking a piece of metal designed to function with a tolerance to do something it wasn't designed to accomplish.

Cut springs will shatter or break without warning - NEVER CUT YOUR SPRINGS!

Ideally, you should acquire a suspension package that can be quickly modified on the automobile to fit your driving style and coilovers fit this bill nicely.

I rate the following brands.

  • Koni
  • Bilstein
  • Eibach
  • KW

A4 B7 Brake upgrade mods

In addition to larger brake discs, don't forget to replace your A4 B7's brake pads, since they are just as crucial, if not more so, than the discs themselves.

The ability to rapidly come to a halt while travelling at high speeds is made possible only by having good brakes. In order for a braking system to function, the friction pad is pressed on the disc, turning motion into heat.

By dissipating, this head causes the automobile to go more slowly ahead. It is common in night-time racing for the brakes to shine brightly with heat after extensive braking.

Your foot pressure is amplified by a servo, which is a gizmo that utilizes engine power to multiply your foot pressure when you press the brake pedal.

A brake fluid-filled tube delivers the additional pressure to the friction pads (liquids do not compress like air).

Additional stress is put on the brake fluid by the hot brake pad end, which may cause the braking fluid to become hotter than it should be.

Air bubbles in brake fluid cause a spongy feeling at best and may prevent the brake from functioning completely at worst, which is why you should replace the fluid periodically. Brake fluids are hygroscopic (they collect water particles) and can boil at high temperatures.

(See the article on Brake Fade for additional information on this issue.)

There are several factors that affect how well your brake pads perform, including how well your discs function.

As a result of the vented disc's centre channel, greater and quicker cooling may be achieved.

Pads are kept "clean and sharp" with the help of Drilled discs, which increase the air-to-disc ratio, thereby reducing gas buildup. Better cooling is a benefit of larger discs, however a new alloy wheel may be required.

Material used to make the pads. However, even though they make a lot of noise and dust, high-friction brake pads are necessary.

Compounds used to make racing pads are designed to withstand greater temperatures.

It's not a good idea to use race-grade brake pads on the street since they only operate when they're really hot.

There is an excellent balance between braking and wear with Pagid and Black Diamond's quick road pads.

Although driving technique affects pad and disc wear, certain high-performance brake pads emit practically no brake dust and last longer than the standard pads I was using.

If you're not a mechanic, read ahead. To minimise accidents, Torquecars recommends hiring a professional to handle the brakes.

Discs and pads are often upgraded. Increased friction and heat dissipation are two immediate advantages of a bigger disc.

In addition to having more control over your vehicle, a big disc conversion kit will let you to identify the moment of lockup more easily.

Simple family cars with modest brake discs may often be upgraded at a low cost by purchasing brake discs and servos from an equivalent performance model.

On a modest family vehicle, you can often swap in the performance variants brakes (if they fit into the alloy wheels or you need to get bigger rims).

It is possible to swap out the hubs on VW, Audi, Porsche, Skoda and Seat vehicles.

As a last step, callipers and pistons are used to provide the clamping force (which push the calipers).

The quantity of brake fluid used must be the same as what was in the donor car's master cylinder when the calliper was removed. When the brakes are engaged, the pedal will likely shift closer to the floor, causing a change in the pedal stroke and feel.

Overboring or replacing the OEM master cylinder may be necessary to match the capacity of the donor vehicle's master cylinder.

Increase the pad, calliper, and piston count to get the most out of your new discs.

Remapping the Audi A4 B7 B7.

What makes OEM maps so bad? A single configuration for everyone generally requires some tweaking considering local fuel emission standards and temperatures.

Temperature changes, small flaws, and adverse weather are all included into timing maps. It's not uncommon for nations' CO2, HC, and NOx emission goals to vary.

Manufacturers do not want consumers to be inconvenienced by mechanical or fuel efficiency issues. This includes regular service, dirty plugs and leads, clogged air filters and partly blocked injectors. So on. remap Any engine upgrader should consider remapping.

Because different countries use different fuel grades and have differing degrees of unfavorable weather, a compromize is required to keep all automobiles working properly internationally.

Each car's output varies by 20bhp depending on component quality and assembly. Instead of customising timing maps for each car, they utilise a one-size-fits-all strategy.

In order to reduce insurance costs and improve fuel efficiency, manufacturers use remaps to optimise engine power.

Plus, the typical TorqueCars reader will be upgrading components, so a remap makes sense.

All current turbocharged engines benefit from remaps, which give 20-30% more power. TorqueCars highly advises remapping turbocharged automobiles with turbochargers

Remapping Issues and Drawbacks What are the hidden costs?

Service your car more regularly, possibly reducing the interval. A map optimised for high octane gasoline will need you to repair components that fail due to the added workload. Additional power puts more pressure on components like turbos, fuel systems and pistons etc...

Months after a remap, an engine's weak areas resurface. For help diagnosing remap issues, see our article.

Generally, any turbocharger and clutch deficiencies will show up following a remap.

Also, turbos may fail, and critical components like pistons and bearings must be maintained. NASP remaps? A remap will only add a few BHP without a turbo (10 percent is typical).

TorqueCars encourages non-turbo cars to modify first (cams, pistons, increase compression, engine balance, air intake, exhaust, head work, bigger valves etc...)

After that, a remap may help you get the most out of them.

Turbocharged engine care

A remap frequently adds boost from lower rpm, making the turbo operate quicker and hotter.

If you don't let the turbo cool, the oil may deteriorate, necessitating a costly turbo repair. Installing a turbo timer will also help cool the engine.

Be wary of peak power claims. Note: Some tuners are known to create a power blip or surge to draw attention and capture headline power statistics.

See the graph below for an example.

Rather, concentrate on the overall torque curve. More power at the bottom over strains the turbo and can produce traction problems, while more power at the top stresses the turbo and components.

The red plot indicates an increase in power but a decrease in power everywhere else, while the green trace shows a steady rise in power across the RPM range.

It also displays peak power at 4000rpm, which is excellent for an engine that redlines at 7000rpm, giving you a good distribution of additional power where you need it the most.

We want to see a lovely smooth torque climb over the whole rpm range on a chart, with no dips or troughs.

Turbo modifications and upgrades for your A4 B7

Big turbos give you more power, but they also wear down your engine and make it hot. On a petrol engine, a turbocharger may spin at temperatures of 1100°C and speeds of 100,000-150,000rpm.

These speeds can be doubled with certain turbo setups and new models. Lubrication, cooling, and balancing are all required at these speeds. Oil seal failure, blockage, and bearing wear are the most typical issues.

There are two methods to improve your turbo. a turbocharged hybrid (based on your OEM casing but with internals from another turbo or with a different design)

Install a bigger turbo, which requires more pipes and effort. The first option simply replaces the original, however it needs remapping to get the full benefits, while most hybrid turbos will work OK on standard maps at lesser boost levels.

The shape of the air intake aperture, the compressor wheel, and the turbine profile are all investigated. Depending on your demands, they may spin faster, compress more air, or boost at high or low RPMs.

Because road vehicles need low-down power, a smaller turbo produces a flatter torque curve with less lag.

Stronger bearings, better balance, and stronger seals are all features of a hybrid turbo. RPM reduction improves reliability and boost.

A Guide to Volkswagen and Audi Group Turbochargers by VAG

There are several turbocharged engine options available, so we'll examine some of the most popular turbos from the VAG group, as well as the differences between them and the optimal upgrade selections.

We also look at the turbo's power limitations, which may be surpassed but will reduce the turbo's lifespan.

You'll usually hear a whining or siren sound before seeing smoke before the turbo finally breaks.

You should start searching for a new one at this point. A malfunctioning turbo may cause a lot of damage if the compressor fails and is dragged into the engine.

Differences between K03, K03s, and K04:

A comparison Ffrom 1996 to 2000, the K03 turbo was available, after which it was replaced by the K03s turbo.

Powerplants Come in a Variety of Shapes and Sizes The K03 turbos are used in the 1.8T AGU engines. These engines have a MAF sensor, a cable-operated throttle, and injectors that are smaller than typical.

K03s turbos are used in AUM engines with MAF and MAP sensors. The improved drive-by-wire throttle on these engines improves both fuel economy and performance. Two of the most well-known manufacturers of K03, K03s, and K04 turbos are Stigan and BorgWarner.

KO3 and the KO3s Differences

The most major difference between turbos is the number of blades. The K03 has eleven blades, however the K03s only has eight.

Although the turbos have similar footprints, the actuator that opens the turbine bypass valve varies widely, with most variations having a two-port actuator.

180-horsepower engines often employ actuators with higher quality and opening force due to the greater boost pressure.

Many manufacturers employ a similar strategy of increasing the compressor on the intake side of a hybrid turbo to improve power.

The least amount of power you'll acquire is from the basic K03, which means it can only comfortably approach 190 horsepower with the correct modifications and upgrades.

The turbo's lifetime, on the other hand, will be reduced the closer you go to the safe limits and the more you stress it.

The K03s generates more power than its older sibling, the K03. With K03s, the safest power output is roughly 215 bhp; any more than that, and turbo life is compromised.

There have been tales of people producing up to 250 horsepower with this turbo, so there is some room for experimentation, but anticipate a shorter turbo lifetime.

K03s feature a power gain of at least 25 bhp over K03s, with the possibility for considerably more if you're prepared to sacrifice turbo life or do more maintenance.

K04 has a significant advantage over K04. In comparison to the K03 and K03s, the K04 is much larger and produces vastly greater outcomes.

With the right hardware, the K04's performance numbers can be raised to 350 bhp, however the safe limit for the KO4 is 220 bhp.

The turbos came in two sizes: K03 and K03s, which were both smaller than the K04.

For the following reasons, many drivers choose to replace or upgrade their turbochargers: Turbocharger improvements are one of the most effective ways to improve a vehicle's performance.

Turbos need to be replaced on a periodic basis since they degrade with time. The most current turbos use newer technology advancements and provide additional options for car owners.

Turbo Upgrades: How To Pick The Best

In order to determine which turbo unit is the best, you must check your supplier carefully since there are many fakes and low-quality models available.

If you install a cheap turbo upgrade, we promise you'll have to do it all over again in six months. In terms of options, look for a turbo that may provide the following:

A billet aluminium aluminium compressor wheel (light and strong) The Vanes (Maximizes the boost available) a device that opens and closes the wastegate (sharpens throttle response and maximises your power gains) The tiniest minutiae might be the difference between a successful project and a complete waste of time and resources. A remap is an absolute must after a turbo upgrade.

In many cases, changing the vehicle's ECU programming is required when a factory turbo is replaced with a more powerful aftermarket turbo. Error codes will be issued if this stage is omitted, and the engine will run lean or enter limp home mode as a consequence. Using a stock ECU will not allow you to enjoy the full advantages of your upgrade, thus you must utilize a new ECU.

Despite the fact that newer and better turbos are continually being added to automobiles, switching a turbo is not as straightforward as one would think. Changing a VAG group turbo to a different model isn't any different from the other options. You'll typically need to do the following steps to complete the process:

  1. Changing out the old fuel injectors
  2. Changing the exhaust pipe's diameter
  3. A new fuel pump may be installed easily.
  4. Changing out the boost control circuit board
  5. Adding cooling systems like intercoolers
  6. The waste gate needs to be replaced
  7. Using catalytic converters with less restrictions
  8. Replacing exhaust mufflers

Depending on the vehicle, it may seem like there is a lot of work to be done. Audi turbos might be difficult to transfer to other models because of their unique longitudinal engine compartment layout.

It's possible that the intercooler may need to be enlarged, and there may be restrictions on where the exhaust and intake pipes can go.

Note the A4 B7 Turbo Limits on Power

With a few tweaks Re-mapping of K03s 210 to 220 horsepower is what you can anticipate from your K03 turbo with a Stage 1 Remapping (Air filter, exhaust, bolt on modifications).

Below we show a safe and max, the former retains factory reliability and longevity and the max will cause much greater wear to the turbo, so bear this in mind and aim for somewhere in between the two figures depending on your aims in your A4 Tuning project.

Turbo Safe Max Maximum
K03 190hp 220hp
K03s 215hp 250hp
K04 220hp 350hp

Your A3's K03 turbo should generate between 210 and 220 hp with a Stage 1 remap's modest changes (Air filter, exhaust, bolt-on modifications) but I feel this is pushing it too far.

Although for more power and with the K03s you can go to stage 2 Remapping (requiring cat replacement and  exhaust and intake enhancements, and intercooler upgrades) which may generate power that ranges from 230 bhp to 250 bhp, depending on the modifications,

Stage 2 remapping necessitates the use of an intercooler to reduce the air temperature, and without one, you'll be restricted to lesser power output.

Re-mapping of the K04

Stage 1 changes to the K04 turbo increase its maximum power by around 25 to 30 horsepowe.

However we've seen several High-quality fuel (98+ Ron) and an improved FMIC (Front Mount Intercooler & cat replacement and  exhaust and intake enhancements) are among the many changes required to achieve such a high level of performance (your OEM clutch will slip at this point).

A lighter flywheel

By reducing the load on the engine, a lighter flywheel is able to provide more power. As the name implies, a race-tuned engine has a higher maximum engine speed than a standard engine. Engine momentum and inertial spin are both reduced when the flywheel is lighter, which is clearly evident while driving uphill.

When you're going uphill, you'll lose more speed with a lighter flywheel. Even when momentum is maintained, the slope has an enormous influence on the engine's output in contrast to heavy flywheels. In races where the track is flat and rapid engine speed changes are necessary, the engine is modified to meet the flywheel capacity (high revving).

The increased responsiveness of the engine generally requires frequent heel-and-toe gear changes and more care with acceleration and braking by the driver.

For optimal torque and unhindered revving, a variety of flywheel weights are available. You don't want to go too light on a street car since your tick over may suffer. In the TorqueCars automobile forums, you may talk to other users about your application.

With a precise balance and a variety of metals, flywheels found in shops are both strong and light. To get the most out of a new flywheel, you should replace your old one.

A spring connects the two separate surfaces. Allows the rotational acceleration and deceleration of the wheel to be dampened by the spring.

They smooth out diesel engines and lessen the risk of reversal in four-cylinder engines.

WARNING: DO NOT FIT A LIGHTER FLYWHEEL TO THE DIESEL VERSIONS - THEY WILL HAVE A LUMPY IDLE AND BECOME HARD TO LIVE WITH.

Some of our members are replacing DMFs with solid and lighter flywheels, however we recommend reading our tutorial on DMF to SMF conversions first.

Uprated injectors will enable you to supply sufficient fuel to the engine.

Uprate the fuel pump to cope with the extra fuel requirements of your tuned A4 B7's uprated injectors.

Audi A4 B7 Intake and Exhaust Mods.

Next, we'll evaluate the engine's intake and exhaust systems to make sure they're operating effectively. A complete induction system yields the greatest improvements in power. We recommend using a panel air filter instead of a paper air filter on relatively small power engines since you will lose low-end power.

Performing port work and head flowing on the A4 B7 engine's heads will also enhance torque and, more significantly, provide a chance to boost the torque increase on other tuning items.

It's unlikely that widening up the intake port to match the intake manifold would help much unless there is a step that impedes airflow. The exhaust ports are best suited for most DIY port matching work, as a consequence.

However, if the port size has become a bottleneck in a highly tuned engine, it may be necessary to enlarge the port size.

Use of channels that are somewhat smaller and have fewer bends or angles generally improves flow rates.

In order to eliminate turbulence on the downflow side, both port apertures should be roughly the same size; this is why many current intakes are built from moulded plastic, which is lightweight and can be produced to a very accurate form. This will limit power.

As seen in this illustration, a highly tuned rally vehicle engine's intake manifold (x) connects to the engine port (y) smoothly.

Unlike direct injection engines, fuel injectors (f) spray fuel into the intake manifold and benefit from a direct route to the valves.

Additionally, the intake angle has been reduced so that the flow of air is almost straight down into the engine, although this can't always be achieved on all engines.

Exhausts with a diameter of 1.5 to 2.5 inches are generally the most effective for increasing horsepower, not the largest one you can find.

A good fast road power clutch will help to keep that power going where it should. Never skimp or expect a standard clutch to cope. Remaps offer significant power gains on all turbo charged cars. On NA (naturally aspirated) engines the benefits are doubtful, but will help unleash the potential if you have done a lot of mods.

Audi A4 B7 Wheel Modifications.

Alloy wheels are better for the brakes since they are lighter and more efficient than steel ones. Big alloy wheels may look good on the A4 B7, but their performance will be negatively impacted.

My A4 came with my favourite Audi rim, the DTM style 7 spoke (14 if you are picky!) and this was an 18inch rim, which suited the car well.

19's fit ok, but they did compromise the ride, and I didn't get a chance to try out 17's but expect these to give more comfort on the roads and better wet weather performance as per my current A3.

As you increase in size, your peak speed will decrease as a result of the altered effective final drive ratio. Aim to preserve the wheel's overall rolling diameter the same as when it came from the manufacturer.

We do not suggest exceeding 18 inches in any situation. To suit Porsche brake conversions, several of our members have used bigger 19 and 20-inch wheels, however they all suffered tram lining and other difficulties with the higher rim sizes.

A4 B7 Common Problems and Issues

There are a few problems and issues to look out for on these, but I've split these off into other articles.

There are a few problems and issues to look out for on other popular vag group engines, but I've split these off into other articles.

  1. 2.0 TFSi carbon buildup issues - direct injection engines require an intake clean.
  2. 2.0 TFSi problems - N75 and N249, high oil consumption,  Cam Follower wear, Water Pump failure, and Turbo issues
  3. 2.0 TDi problems - Flywheel, Oil pump,  Lumpy Idling
  4. 1.8T Problems - Diagnosing the common faults and issues
  1.  

Please join us in our forum to discuss the A4 B7 options in more detail with our A4 B7 owners. It would also be worth reading our A4 B7 tuning articles to get a full grasp of the pros and cons of each type of modification.

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Performance Wheels

A look at high performance wheels
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Spray Painting

How to spray paint a car
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Scratch Removal

Scratch removal
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Drag Techniques

Drag racing techniques, launch and gear changes.
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Save Fuel

5 top fuel saving tips
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MPG Calculator

MPG calculator UK miles per Gallon – calculate MPG
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