Mercedes Benz SLK Tuning

"Thank you for reading my SLK tuning guide."

Mercedes produced a stunning compact roadster in 1996. The SLK name comes from the German words for Sporty Light Short, this later became known in 2016 as the SLC Class with the roadsters attracting an SL prefix.

  • R170 1996-2004 (Facelift in 2000 with new engine range)
  • R171 2004-2010 a stronger and ore aerodynamic model and revised faster folding roof system. - 163bhp 1.8l or 272bhp 3.5l V6 Petrol engines (SLK 200K & SLK 350 respectively) power increased on these models in 2005 to 185bhp and 305bhp where the SLK350 name dropped and was replaced with SLK300.
  • R172 2011 New design and revised engine options.

The car is fun to drive and fairly practical with a decent boot size. Parking sensors make sense as visibility is not fantastic when parking. It competes well with the TT and Z4 and the rear wheel drive SLK wins a firm place in our hearts and minds.

You can do a lot to improve the performance of your SLK with our step by step tuning tips. The key to SLK tuning is finding the right mods you can waste loads of money if you do it wrong.

Tuning tips and articles

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

Many SLK owners uprate the handling of their cars with tuning suspension modifications as a priority, this will certainly increase your enjoyment of the car. Drop the car optimally somewhere in the region of 35mm and fit motorsport grade stiffer dampers, bigger drops will need other modifications in most instances.

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

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

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.

Power mods.

The following modifications are usually carried out by our members, decide how far you wish to go in your tuning project before you begin.

  • SLK 200 KOMPRESSOR 1,796 cc (1.796 L) (M271 engine)
    163 PS (120 kW; 161 hp) at 5,500, 240 Nm (177 lbft) at 3,000-4,000 2004–2008
  • SLK 200 KOMPRESSOR 1,796 cc (1.796 L) (M271 engine)
    184 PS (135 kW; 181 hp) at 5,500, 240 Nm (177 lbft) at 3,000-4,000 2008–2011
  • SLK 280 2,996 cc (2.996 L V6 (M272 engine)
    231 PS (170 kW; 228 hp), 300 Nm (221 lbft) 2005–2008
  • SLK 300 2,996 cc (2.996 L) V6 (M272 engine)
    231 PS (170 kW; 228 hp), 300 Nm (221 lbft) 2009–2011
  • SLK 350 3,498 cc (3.498 L) V6 (M272 engine)
    272 PS (200 kW; 268 hp) at 6,000, 350 Nm (258 lbft) at 2,400-5,000 2004–2007
  • SLK 350 3,498 cc (3.498 L) V6 (M272 engine)
    305 PS (224 kW; 301 hp) at 6,000, 360 Nm (266 lbft) at 2,400-5,000 2008–2011
  • SLK 55 AMG 5,439 cc (5.439 L) V8 (M113 engine)
    360 PS (265 kW; 355 hp), 510 Nm (376 lbft) 2004-2011
  • SLK 55 AMG Black Series 5,439 cc (5.439 L) V8 (M113 engine)
    400 PS (294 kW; 395 hp), 520 Nm (384 lbft) 2006–2008

Getting the correct grade of performance upgrades for your planned usage of the car is essential. Stage 3 competition upgrades just won't work well on the road difficult in stop start traffic.

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 mods for your SLK

  1. Brake Mods - Enhancing your stopping power ought to be listed in your priority list.
  2. Tunes - A Remapped SLK ECU provides the most advantage in terms of your investment, replacement ECUs, and inline Tuning boxes are all alternatives.
  3. Fast road Camshafts are one of the most significant mechanical changes, but we strongly suggest they be setup by someone qualified to set them up properly and tracking one down may be hard but you might find a local firm to regrind a stock cam for you.
  4. Internal engine mods - crank, pistons, conrods & compression ratio including balancing and blueprinting
  5. Lighter flywheels - a lower weight flywheel will improve the engines ability to rev freely. Not a great mod for all SLK engines.
  6. Intake Mods and Sports Exhausts - NB: on their own these mods won't ADD TORQUE , but they permit you to release power after other mods by minimizing the restriction.
  7. SLK Handling modifications - Fitting a more sporty Suspension kit greatly enhances your SLK road holding and cornering. Coilovers and Bushings are the usual go to mods
  8. Upgrades to turbochargers and superchargers - Adding a turbocharger is the most efficient approach to increase air supply, ensuring you are able to use more fuel and make more power. It is one of the most costly mods you'll see massive gains.

SLK Tuning Stages

Typical stage 1 mods often include: Alloy wheels, Panel air filter, Engine Tunes/Remapping, Lighter flywheel, Suspension upgrade (drop 30-40mm), Sports exhaust.

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

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

Your aims when modding your car should be a nice flat torque output. You don't want all the torque to be at the top end unless you are creating a competition car.

The point of our advice is to give a limited introduction of modifying upgrades and point you in the right direction, our forum is where you can ask for more detailed advice and tips on your car tuning project, the best modified kits and all aspects of modding cars.Fast road cams offer one of the biggest performance gains for your money as far as a bolt on performance upgrades goes on a NA (naturally aspirated) engine.

It maximises the intake and exhaust durations and pushes up the power if done right. Ideally you'd add other mods and finish up with a reflashed ECU. TorqueCars would caution you not to go with a motor sport cam as this upsets the engines idling and general town driving characteristics.You will need to ensure that the engine is not starved of fuel so will need to look at the fuelling.

Mercedes used a Supercharger on many engines throughout their range, and with a simple overdrive pulley you can boost the power output significantly. Add in twincharging, or a larger compressor and you can see some really impressive power gains.

Most power losses, and erratic idling after motorsport kits are done can usually be traced to timing or fuelling issues.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 SLKs uprated injectors.

SLK Intake and Exhaust Tuning.

The next area for modification is the intake and exhaust. Air induction kits only help to add performance if the cars air intake is restricted!

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 airflow into the engine is the primary part of performance tuning so get a better flowing air filter if you find that the car is running lean.

Induction kits can sound great but due to the warm air in the engine bay they will not do much to increase power and often rob you of power.

Sports exhausts can help equal out the flow of gases through the engine. But if your exhaust pipe is too big, ie: it's over 2.5 inches bore, you will lose a great deal of the flow rate and end up lacking power and torque.

Head porting and polishing the head will allow you to maximise your air/fuel charge.

Leave this to a professional though with a proper flow bench and machine tools In nearly all cases of SLK tuning your clutch will start to suffer and this needs an upgrade - read our tips on clutches for more information.

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

With turbocharged engines this is another story. A tuned/remapped turbowill give significant power gains and fully release the potential power of the engine.

We've also seen some tuners toying with twin charging applications and making some impressively high power figures.

Despite the large cost involved adding forced induction to a NA (naturally aspirated) engine will give large power gains.

Turbos are usually harder to add than a supercharger. With a turbo the boost curve is related exponentially to the engine speed making it more challenging to map.

The nice correlating boost and rpm characteristics of the supercharger make them more straightforward to map. To cope with forced induction you will usually need to decrease the compression ratio of the engine .

SLK Alloy wheel upgrades.

Alloy wheels will help the brakes cool down and are generally lighter than the steel ones.

Please note that although they can look cool on the SLK large alloys will actually decrease your performance.

The larger you go the lower your acceleration will be - this to the change in your effective final drive ratio.

Due to this we would advise sticking to a maximum wheel size of 16 inches, although we know some of our members have fitted larger wheels with no problems.

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 SLK options in more detail with our SLK owners. It would also be worth reading our unbiased Mercedes Benz tuning articles to get a full grasp of the benefits and drawbacks of each modification.

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One Response to “SLK Tuning”

  1. Marcos Pillot Jr says:

    I own 1999 mercedes-benz slk kompressor r170
    what is the best pulley upgrade forsale and would an external blow off valve help with pulley upgrade?
    thank you and Godspeed

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