Tuning the Mercedes M297

"Comprehensive guide to tuning the Mercedes M297 engine!"

We often are getting posts asking how to improve the M297 from people wanting to know what are the ultimate M297 mods that work. So let us look into Mercedes M297 parts and outline the best modifications on this great engine and point out some problems along the way.

The Mercedes M297 are popular tuning projects and with the best parts like a remap, turbo kits and camshafts you will certainly maximise your driving enjoyment.

In this article we examine M297 tuning and show the best modifications.

When talking about the ultimate parts for your M297 engine, we are going to focus on the parts that give the best value for money.

The camshaft profile plays a big part in the engines power output so camshaft upgrades make quite a large difference. The intake and exhaust durations will alter depending on the chosen camshaft profile, so large torque gains are on offer for camshaft upgrades.

NB: Fast road cams normally boost the bhp through the rev range, you could drop a little bottom end bhp but the high end rpm power will be lifted.

Motorsport and race cams, boost the high end rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

On a typical daily driver should ideally to match your bhp range to your preferences.

I'd be shocked if you have found a M297 Motorsport and race cam is a pleasure to live with when on the daily commute.

Each engine responds better to more or less aggressive cam durations so view each engine as unique.

The map and injectors and fuel pump also will make differences on the power gains you'll get.

Extending exhaust or intake durations can alter the power 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.

M297 Tuning Stages

Stage 1 M297 modifications: Drilled & smoothed airbox, Remaps/piggy back ECU, Fast road camshaft, Intake headers, Sports exhaust manifold, Panel air filters.

Stage 2 M297 modifications: Fast road cam, induction kit, Sports catalyst & performance exhaust, high flow fuel injectors, fuel pump upgrades, Ported and polished head.

Stage 3 M297 modifications: Internal engine upgrades (head flowing porting/bigger valves), Engine balancing & blueprinting, Twin charging conversions, Competition cam, Crank and Piston upgrades to alter compression, Adding or Upgrading forced induction (turbo/supercharger).

Plan your options and then find your parts and set yourself a power target to save yourself from expensive mistakes.

ECU mapping helps fully realize the full potential of all the tuning parts you've done to your M297.

It will usually give around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but figures achieved will depend much on the tuning parts you've done and the condition of your engine.

It is the main goal to any engine upgrade project to force more fuel and air into your M297

Intake take the air during the suck phase from the filter and allow it to be fed into the engine cylinders.

Design and flow rate of the Plenum can make a large improvement to fuel atomisation on the M297.

Most intake manifold are needing an upgrade, although some manufacturers provide reasonably well designed intake manifold.

Fitting big valve kits, carrying out port matching and head flowing will also raise torque, and more importantly will give you increasing the torque increase on other tuning parts.

Turbo upgrades for the M297

NASP engines need quite a lot of work when you add a turbo, so we have a separate guide to help you take into account the pros and cons of going this route on your M297

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes impressive power gains.

If your motor is fitted with a turbocharger upgrades are more reliable and most turbocharged engines will have strengthened components.

There are weak spots for every engine, with some being very over engineered and some just sufficiently able to handle stock power

Research these limitations and fit forged components to survive the power.

We see many drivers spending a fortune on turbo charger upgrades on the M297 only to suffer the humiliation of seeing the engine block explode soon after it's used on the roads.

Larger upgraded turbochargers tend to experience a bottom end lag, and smaller turbochargers spool up more quickly but won't have the peak end bhp gains.

Over the last 20 years the selection of turbo units is always developing and we are seeing variable vane turbo units, allowing the vane angle is altered according to speed to lower lag and increase top end torque.

Twin scroll turbo units divert the exhaust gases into 2 channels and feed these at differently designed vanes in the turbo charger. They also improve the scavenging effect of the engine.

You'll commonly see there is a limit in the air flow sensor (AFM/MAF/MAP) on the M297 when loads more air is being drawn into the engine.

We note 4 bar air sensors coping with quite large power gains, whereas the OEM air sensor was restricting torque at a much lower level.

Adding a supercharger or additional turbo will make large bhp gains, although more challenging to setup. We have this article on twincharging if you want to read more.

Uprating M297 fuel injectors

Don't dismiss the need raise the fuelling when you are increasing the power - it makes the car more thirsty. It makes sense to over specify your injectors flow rate.

As a rule of thumb add 20% when fitting an injector, this takes into account injector deterioration and provides a little spare capacity should the engine require more fuel.

We think this one is common sense, but you'll need to match your fuel injector to the type of fuel your car uses as well.

Best M297 performance exhausts

You may need to replace your exhaust if the current exhaust is creating a restriction.

On most factory exhausts you'll find the exhaust flow rate is still good even on modest power gains, but when you start pushing up the power levels you will need to get a better flowing exhaust.

Note that with the widest exhaust you can buy you'll slow the exhaust rate - the best exhausts for power gains are usually between 1.5 to 2.5 inches. It is the shape and material more than the bore size.

Common exhaust restrictions can be traced to the emissions filters installed, so adding a better flowing sports alternative will help avoid this restriction.

Problems and issues to look out for on the M297

The M297 engines, if regularly serviced and maintained, are generally very reliable and have few issues.

Regular oil changes are vital on the M297, particularly when the engine has been modified and is putting down more power than the manufacturer intended.

For more information on Tuning your M297 engine please join us in our friendly forum where you can discuss tuning options in more detail with our M297 owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

We need your help to complete and improve this page, so do give us your feedback in the comments box below.

We really like hearing from our readers, and hearing about which modifications were the most effective for them, it helps us improve our recommendations and articles to reflect current trends in modifications and ensures that our M297 guides and tips are kept up to date.

PLEASE HELP: I NEED YOUR DONATIONS TO COVER THE COSTS OF RUNNING THIS SITE AND KEEP IT RUNNING. I do not charge you to access this website and it saves most TorqueCars readers $100's each year - but we are NON PROFIT and not even covering our costs. To keep us running PLEASE Donate here

If you liked this page please share it with your friends, drop a link to it in your favourite forum or use the bookmarking options to save it to your social media profile.

Please watch this video on our new YouTube channel.


Please use our forums if you wish to ask a tuning question, and please note we do not sell parts or services, we are just an online magazine.

Help us improve, leave a suggestion or tip

Your Constructive comments on this article

Member Benefits

Join our forum today and benefit from over 300,000 posts on tuning styling and friendly car banter.

You will also have full access to the modifed car gallery, project car updates and exclusive member only areas.

(All car owners of all ages and from all countries are welcome).