Mercedes Benz SLK Tuning

"Tuning guide to the most effective Mercedes SLK modifications."

Mercedes produced the SLK, 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.

The SLK is a good tuning project to execute. We see car enthusiasts wasting money on their SLK doing the wrong mods and then having to start over. Follow our pointers to avoid wasting your money

Don't just look at the peak power figures, you need to see the whole torque curve when determining if a mod is right for you SLK.

Sadly with smaller engine sizes you are wasting your time spending money on modifications, so if this applies to you get yourself an engine swap then apply the following mods.

Engine Tuning.

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

Getting the correct grade of sports parts for your planned usage of the car is a time and money saver. Stage 3 (competition) mods just don't work well on the road difficult in stop start traffic.

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Stages of Tune

Stage 1 mods: Remap, Panel air filter, Alloy wheels, Sports exhaust, Lighter flywheel, Suspension upgrade (drop 25-35mm).

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

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

Peak power is nice in motorsport but for a daily driven car you need a wide torque band and perhaps extending the rev range.

The whole 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 tuning project, the best sport kits and all aspects of modding cars.Fast road cams offer one of the biggest torque gains for your money as far as a bolt on parts goes on a NASP engine.

The intake and exhaust durations play a large part in your cars power band, but be careful here, getting this wrong can upset the idle and make the car hard to drive in traffic. You'd need to follow a cam upgrade with other mods and finish with a performance chip for the best performance gains.

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

Using higher octane fuel is another option if you find you are suffering from pinking or premature ignition on your Mercedes project after fitting other tuning parts. Upgrading the injectors is another beneficial modification and will deliver sufficient fuel.

Uprate the fuel pump to cope with the extra fuel requirements of your tuned SLKs uprated injectors.

Intake and Exhaust Tuning.

Breathing mods are usually next up. Induction kits are only beneficial to increase power if the cars air intake is struggling! Adding an induction kit to most small engines will see NO 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.

Derestricting the flow of air 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 sporty but due to the warm air in the engine bay they will not add noticeable power and usually rob you of power on most cars.

Sports exhausts increase the flow of air through the engine. But if the exhaust pipe is too large, ie: it's over 2.5 inches bore, you will lose a lot of the exhaust flow rate and end up losing power and torque.

Head work including a gas flow (ported and polished) and 3 or 5 angle valve job will really help to release the potential of the engine. In nearly all cases of SLK tuning your clutch will start to complain and this needs to be uprated - read our overview on clutches for more information. The best mods in our opinion for your SLK are fast road camshaft, remap, induction and exhaust, suspension.

Turbo engines are just begging to be Remapped. You will see massive power gains on most modern turbo charged cars including diesels making a remap one of the most cost effective and massive modifications for your money.

We've also come across some owners experimenting with twin charging applications and making some very high power gains.

Adding forced induction will see big power gains but this is usually too expensive to be cost effective. Turbos are generally harder to add than a supercharger. With a turbo the boost curve is related exponentially to the engine speed making it harder to map.

The nice steady boost and rpm characteristics of the supercharger make them easier to map. Alternatively you could perhaps install water injection to minimise knock.

Handling/Suspension upgrades

Handling modifications are top of many to do lists for the SLK.

Fully adjustable suspension allows you to fine tune the handling of you SLK usually improving your drive.

We would go to a maximum drop of 25mm - 35 mm on most models. You risk grounding out if you go lower than this.

Alloy wheel upgrades.

Alloy wheels can help the brakes cool down and are generally lighter than steel ones. If you are serious about performance then you will need to carefully choose your tyres - ideally with a directional tread pattern tyre. The downside to large alloy wheels on your SLK is that you're altering your final drive ratio and this will have a negative effect on performance and acceleration.

For this reason endeavour to keep the overall rolling diameter of the wheel the standard factory sizes. In all cases without going over 17 inches.

There is a more updated version of this Mercedes SLK Tuning article on TorqueCars.com.

For more information 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 tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help improving this article, so please send us your feedback in the comments box below and pass on any tips, points or facts we have wrong or have not covered.

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This article is flagged for an update, so please pass on specific tips below that I can include. All articles, and content was written by me, Waynne Smith TorqueCars founder. Some outlines are just too general so I appreciate your feedback and suggestions. This entry was filed under Mercedes. You can leave a response below or join our forum to discuss this article and car modification in detail with our members.

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