Audi S4 Tuning

"Thanks for reading my Audi S4 tuning guide."

Based on the great A4 platform a set of performance upgrades were added to make the S4 version, and over the years it has been revised and improved.

The S4 is a awesome project car to do. If you do your homework then you can create an awesome S4 but don't be fooled there are lots of competition inspired parts out there that will simply not suit it read our unbiased guides first.


Tuning tips and articles

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

See our video which covers all the principles of tuning your Audi.

Handling/Suspension upgrades

Handling modifications are high on the agenda for the S4.

If you set the toe out to 1-1.7 degrees on the front, and add some negative camber then cornering will usually be enhanced.

We would go to a maximum drop of 24mm - 38 mm. on most models. You risk handling compromises if you go lower than this.

Turning our attention to the S4's engine we need to get a bit more power out of the top end.

S4 make good sleepers if you debadge them and fit the most powerful engine upgrades and handling upgrades you can !

Engine tuning mods.

This list of the stages and modifications are usually fitted by our members, decide how far you want to go before you start.

C4 (Type 4A, 1991–1994)

  •  2.2 L I5 20V DOHC Turbo (08/91-07/94)
  • 4.2 L V8 32V DOHC (10/92-07/94

B5 (Type 8D, 1997–2002)

  • 2.7 L V6 30v DOHC 'biturbo'

B6 (Type 8E/8H, 2003–2005)

  • 4.2 L V8 40v DOHC

B7 (Type 8E/8H, 2005–2009)

  • 4.2 L V8 40v DOHC

B8 (Typw 8K, 2009–2016)

B9 (Type 8W, 2017 -)

Getting the correct grade of modified modifications for your planned usage of the car is vital. Stage 3 motor sport parts just won't work well on the road and will make the car undrivable.

Please watch our video which covers the 5 principles of tuning your car. Be sure to keep up with our latest YouTube content and subscribe.

Best Engine Mods for your S4

  1. Engine Tunes - engine tuning/remapping provides the most advantage in terms of cost savings,  aftermarket ECUs, and piggyback ECUs are all alternatives.
  2. Fast road cams are one of the most significant mechanical changes, but they must be installed by someone who knows what they're doing and they are not always easy to source but you might find a local firm to regrind a stock camshaft.
  3. Intake and Exhaust - Note that on their own these mods will NOT ADD POWER in most cases, but they can help enhance power after other mods by removing the restriction.
  4. Upgrades to turbochargers and superchargers - forced induction is the most efficient approach to increase air supply, allowing you to burn more fuel and make more power. It is one of the most costly upgrades but provides the best gains.
  5. Head work - The goals of porting and flowing the head are to get air flowing into the engine while removing flow restrictions and turbulence.

S4 Tuning Stages

Typical stage 1 mods often include: Remap, Sports exhaust, Suspension upgrade (drop 24mm - 38 mm.), Lighter flywheel, Alloy wheels, Panel air filter.

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

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

The early FSi engines had problems with carbon build up on the intake valves, a common issue with direct injection and it seems exacerbated on  the larger V6 engines.

Peak power is nice in motorsport but for a drivable and fun car you need a long power band and perhaps extending the rev range.

The point of our hints is to give a little insight into the world of tuning performance parts and point you in the right direction, our forum is where you can ask for more detailed advice and tips on your modified car project, the best tuning upgrades and all aspects of modding cars.

One of the biggest mechanical motorsport parts you can do on your NA (naturally aspirated) engine is to fit a fast road camshaft .

The exhaust and intake valve durations play a huge role in your cars power band, but be careful here, getting this wrong can upset the idle and make the car awkward to drive in traffic. You'd need to follow a cam upgrade with other mods and finish with a tune/remap to fully realise your gains.

You will need to ensure that the engine is not starved of fuel so will need to uprate the fuelling.

If you find you get flat spots and surges after your sports kits you should check the fuelling and try a higher octane fuel as well. To get sufficient fuel you may need to improve the injectors on your engine.

Uprate the fuel pump to cope with the extra fuel requirements of your tuned S4's uprated injectors.

Intake and Exhaust Tuning.

Breathing mods are usually next up. Induction kits are only beneficial to add power if the air intake is restricted! Adding an induction kit to most low power engines will see ZERO LOW END 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.

Maximum power gains come from a full induction kit with a cold air feed on heavily tuned engines, this can be sited within an air box but a performance panel filter should suffice for most applications. TorqueCars suggest you use a panel air filter as these are easy to clean and maintain and generally perform better than paper ones.

Sports exhausts equal out the flow of air through the engine. But if your exhaust pipe is too large, ie: over 2.5 inches bore, you will lose a lot of the exhaust flow rate and end up lacking power and torque.

Getting the head polished and ported will allow you to get more air into each cylinder.

This is definitely a job for a pro with a flow bench. In nearly all cases of S4 tuning your clutch will start to suffer and this needs to be uprated - read our overview on clutches for more information. The best mods in our experience for your S4 are Remapping or piggy back ecu, fast road cam and air intake and exhaust.

NA (naturally aspirated) engines do not achieve big power gains if you tune/remap them, unless you have done extensive modifications.

With turbocharged and supercharged engines this is another story.

tuned/remapped turbo will give big power gains and take full advantage of the strength of the block. Adding forced induction will see big power gains but this is usually too expensive to be cost effective. It is generally easier to bolt on a supercharger than it is to install a turbo. It is harder to map a turbo as the boost increases exponentially with revs.

The nice directly proportional boost and rpm characteristics of the supercharger make them simpler to map. Alternatively you could perhaps add water injection to cut down knock.

Alloy wheel upgrades.

Alloy wheels can help the brake cooling and are generally lighter than the steel ones. 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 S4 is that you're altering your final drive ratio so this will have a negative effect on performance and acceleration.

Because of this try to keep the overall rolling diameter of the wheel the standard factory sizes. In all cases avoid going bigger than 17 inches on early s4's and on later models stick with 18 inches.

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 S4 options in more detail with our S4 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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