BMW M52 Tuning
M52B20, M52TUB20, M52TUB24, M52B25, M52TUB25, M52B28, M52TUB28, S52B32

"All you need to know about tuning the BMW M52 engine!"

The BMW M52 really good project engines and with carefully chosen sports parts like remaps, turbo improvements and camshafts you will really increase your driving fun.

TorqueCars will provide a guide to M52 tuning and report on the premier modifications for your car.

History, Power & Specs of the Engine

  • M52B20
  • 110 kW (148 bhp) at 5900 rpm 190 Nm (140 lbft)  at 4200 rpm 1994-1998
  • M52TUB20
  • 110 kW (148 bhp)  at 5900 rpm 190 Nm (140 lbft) at 3500 rpm 1998-2000
  • M52TUB24
  • 135 kW (181 bhp)  at 5800 rpm 240 Nm (180 lbft)  at 3600 rpm 1998-2000
  • M52B25
  • 125 kW (168 bhp)  at 5500 rpm 245 Nm (181 lbft)  at 3950 rpm 1995-1998
  • M52TUB25
  • 125 kW (168 bhp) at 5500 rpm 245 Nm (181 lbft) at 3500 rpm 1998-2000
  • M52B28
  • 142 kW (190 bhp) at 5300 rpm 280 Nm (210 lbft) at 3950 rpm 1995-1998
  • M52TUB28
  • 142 kW (190 bhp) at 5500 rpm 280 Nm (210 lbft)  at 3500 rpm 1998-2000
  • S52B32 
  • 179 kW (240 bhp) at 6000 rpm 325 Nm (240 lbft) at 3800 rpm 1996- 2000

Tuning the BMW M52 and best M52 performance parts.

Best M52 upgrades

The best M52 mods on an engine are typically the ones that give the best power gain for you spend.

We won't be swayed by popular M52 mods, they need to be cost effective.

Altering your M52 camshaft will make a dramatic difference to the engine engines power. Choosing a higher performance camshaft profile raises the engines power accordingly.

Fast road camshafts normally increase the power over the rev band, you could drop a little low end bhp but the higher rpm power will be lifted.

Race camshafts, increase the higher rpm power band but as a result the car will not idle smoothly and low end power nearly always suffers.

A Race camshaft makes it harder when on the daily commute, because the lumpy idle will make the car prone to stall and smooth driving at low rpm becomes impossible. If you are developing a track car this doesn't matter as you are in the high end of your RPM range anyway and that is where you want the power to be.

You should ideally match your bhp range to your cars usage so for a road car stick with a fast road M52 camshaft

Each engine responds better to more aggressive cam durations check your engine on a rolling road.

The engine timing and fuel pump and injectors also will say much on the torque gains you'll hit.

Longer valve durations can alter the torque 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.

Typical stage 1 mods often include:
Sports exhaust manifold, drilled & smoothed airbox, Fast road camshaft, Panel air filters, Remaps/piggy back ECU, Intake headers.

Typical stage 2 mods often include:
induction kit, Sports catalyst & performance exhaust, Ported and polished head, Fast road cam, fuel pump upgrades, high flow fuel injectors.

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

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

Mapping will help release the full potential of all the upgrades you've fitted to your M52.

(In some cases, as the factory ECU is locked flashing is not an option, so an aftermarket ECU is the route to take, and many of these will outperform factory ECU's but make sure it has knock protection and that you get it setup properly.)

It will usually give you around 30% more power on turbocharged vehicles and you can expect to see around 15% on NASP engines, but power output often rely on the upgrades you've fitted and the condition of your engine.

It is the aim to any engine performance tuning project to force fuel and air into the M52 engine

The intake plenum transmit the air from the filter and allow it to be pulled into the engine cylinders with fuel for the squish phase.

Structure and rate of flow of the Intake headers can make a big improvement to fuel atomisation and engine efficiency on the M52.

I usually find headers are improved through motorsport parts, although a few car makers provide reasonably well designed headers.

Adding a M52 larger valve kit, getting port work and head flowing will also lift torque, the fantastic side effect is it will permit a better torque increase on other upgrades.

Turbo upgrades for the M52B20, M52TUB20, M52TUB24, M52B25, M52TUB25, M52B28, M52TUB28 & S52B32

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 M52

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

If an engine is fitted with a turbocharger parts are relatively easy and we find turbo charged engines will have harder and stronger components.

However engines will need better parts at higher power limits

We recommend you find these limitations and upgrade to higher quality crank and pistons to utilize the power.

We see many people spending a fortune on turbo charger upgrades on the M52 only to suffer the humiliation of seeing the car explode when it's been finished.

Larger turbo units commonly experience low end lag, and little turbo units spool up quickly but do not have the high rpm engines power gains.

Thankfully the market of turbo units is always moving on and we now see variable vane turbo units, where the vane angle is altered according to speed to lower lag and increase top end bhp.

Twin scroll turbo units divert the exhaust gases into two channels and flow these at differently profiled vanes in the turbo charger. They also increase the scavenging effect of the engine.

It is common that there is a limitation in the air flow sensor AFM/MAF on the when loads more air is being pulled into the engine.

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

Adding a supercharger or additional turbo will make large power gains, although harder to configure. We have this in depth look at twinchargers if you want to read more.


You will need to ensure that the engine is not starved of fuel so will have to pay attention to the fuelling when you start extending past 20% of a performance increase.It makes sense to over specify your injectors flow rate.

As a rule of thumb add another 20% when fitting an injector, which takes into account injector deterioration and allows some 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.


You only need to upgrade your exhaust if the current exhaust is creating a flow problem.

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

Sports exhausts can help increase the flow of air through the engine.

But if your exhaust pipe is too large, ie: it's over 2.5 inches bore, you will lose much of the exhaust flow rate and end up losing power and torque.

Usual exhaust restrictions are traced to the filters installed, so adding a faster flowing sports alternative is the answer. This keeps the car road legal and will flow much better due to it's higher internal surface area and design, so has the added benefit of keeping your car road legal. The alternative decat should be considered an off road only mod, as removing a catalyst is illegal in most territories and regions for road registered cars..

Weak spots Issues & problem areas on the M52

These engines generally prove to be reliable and solid as long as they are regularly serviced and maintained.

Carbon build up in the head, particularly around the valves which will sap power or create flat spots, this is a larger issue on direct injection engines but should be looked out for on all engines. We have tips on removing carbon build up.

Some of our members have had issues with flat spots or glitches after applying mods and upgrades or tuning, this is not usually related to this engines design, so instead see our article on diagnosing flat spots and problems after tuning which should help you get the bottom of this issue.

Regular oil changes are vital on the M52, especially when tuned and will help extend the life and reliability of the engine.

If you would like to know more, or just get some friendly advice on Tuning your engine please join us in our friendly forum where you can discuss tuning options in more detail with our owners. It would also be worth reading our unbiased tuning articles to get a full grasp of the benefits and drawbacks of each modification.

Please help us improve these tips by sending us your feedback in the comments box below.

We love to hear what our visitors have got up to and which tuning mods work best for you on your car. Which helps us keep our guides and tips up to date helping others with their modified car projects. Your feedback and comments are used to keep this page up to date, and help improve the accuracy of these articles which are kept updated and constantly revised.

If you've enjoyed this page we would be very grateful if you could share a link to it on your favourite forums or on your social media profiles, it helps us keep going.


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

One Response to “M52 Tuning”

  1. reinaldo godoy says:

    really good

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).

Popular articles

Tuning Diesels
Remapping ECU
Double Clutch
Induction Kits
Customize a car
Chip Tuning
Modded Car insurance
Track day insurance
Remapping Diesels
MPG Calculator
DPF unblocking tips
Tuning in Forza

Porting Polishing

Principles of porting an engine and big valve conversions

Superchargers Guide

Superchargers – A guide to supercharger kits benefits vs disadvantages


Dashboard styling, guages and digital dashboards

Re Upholstery Cars

Re-upholstery for your car from seats to dashboard.

Uprated Fuelling

Fuelling uprating the fuel system

2010 Car News

Review of 2010 car news and car developments

MPG Calculator

MPG calculator UK miles per Gallon – calculate MPG