I’m doing a rebuild on my rally car, which also sparked the development of the Fatech dash a little over two years ago. Since then, I’ve gained some experience and knowledge about this engine, so I’ll share this process with you, and hopefully, someone will benefit from it in the future.
Engine
N52B30 – BMW’s last naturally aspirated engine. In my opinion, the keywords for this engine are Weight and Valvetronic. Although many are wary of the latter, I believe it’s a very good alternative to ITBs. Especially if the engine has lightweight cams and N54 intake, the throttle response is very sharp. Many N52 engines built for racing remove the Valvetronic to install an aftermarket ECU. By now, with the original ECU development, I’ve reached a point where I don’t need any additional modules from the original car, and I can also remove the original soft limiter. The soft limiter limits the Valvetronic’s work starting at 6850 rpm. So in my case, I don’t see the need for an aftermarket ECU and can use the Valvetronic system. More on the ECU topic later.
Lightweight Cams
During the rebuild of my second engine, I discovered that the intake and exhaust cams on this engine were significantly lighter. There isn’t much information about this online, but from what I’ve been able to find out, starting from 2007-08, the cams for this engine were produced using a different method, resulting in both cams being about 600-700g lighter. Lightweight cams can also be found on the N51 engine, which are a 1:1 fit.
The codes for the lightweight cams are:
Intake – 7560932
Exhaust – 7560934
Engine Chain Sprocket
In the case of this engine, this is the weakest link when it comes to increasing power. Namely, this sprocket is held in place only by tension force. If you increase the power of the car and remove the soft limiter, there is a very high risk that this sprocket will slip. Fortunately, there are some solutions for this.
One option is to buy a ready-made piece where this sprocket is rigid. They sell it, for example, in Finland by IRPNORDIC.
Another option, which I also did, is to have a key machined. The work was done by Steelmet OÜ.
Flywheel
For the flywheel, I used a product from the British company TTVracing. They have two flywheels in their range, for a 240mm and 184mm clutch. For both, you need to have the center bore enlarged by a lathe, if you use, for example, a ZF E46 gearbox. Otherwise, the gearbox spline won’t fit through the flywheel.
Exhaust Manifold
For my engine, I used a tubular exhaust manifold sold by Fmic. But the installation was extremely unpleasant. The bolt holes are not precise, so a lot of modification and fiddling is required. Not recommended.
Fuel Pressure
These engines run on 5bar fuel pressure like S54. So when you swap it to for example E36, E46 or E30 chassis you have to change the fuel pump and add a pressure regulator aswell.
Next part I will be going over the wiring harness and MSV70 ECU mods.