Last updated: 17-Oct 2022

Disclaimer: Any modifications done to your car is at your own discretion and at your own risk. Do note that manufacturers will void your car’s warranty in the event of any modifications done to your car.

Don’t forget to check out Part 1 and Part 2 of my BMW 320d modifications.

Part 3

After completing both guides on how you can modify your 320d, here is part 3 and the final bit of the modification guide. The previous two guides are catered toward those who want to maintain their cars as a daily driven machine and at the same time tackle the winding roads. This guide is for those who want to get the most out of their diesel machine here in Malaysia (diesel cars aren’t that very popular at the moment).

So who in the right mind would want to do that? Well, if there is anyone about out there in the world, who knows, they might just want to turn it into a race car but honestly, most would turn the 330d and the 335d into race cars especially for endurance races. I have seen an episode of Top Gear where Jeremy, Richard and James used an older E46 330d as a race car for the Silverstone Endurance Race. Locally we have several endurance races and I haven’t seen any diesel cars among the mix yet.

Power Modifications

We tackled power mods on the first section but lets look at other alternatives available for the N47 diesel engine.

• Water methanol kit – I found that there are several brands of water methanol kits available and the one which caught my eye is one made by Snow Performance. For the N47 engine, it is advisable to go straight to a stage 2 kit with the controller so that you can enable the water meth whenever you want. Part for the N47 engine can be found in this link. So far the dealers who carry this in Malaysia and provides installation is After12 in Sunway, Clovertech Garage in Kota Kemuning and Works Engineering in Sunway. I found a video on YouTube that with the right map and the water meth kit, the car managed to produce 254hp on the dyno machine.

• Larger Turbo – As time has passed on, there are several available off-the-shelf hybrid turbo units you can use to modify your car. Car Throttle has a nice video about upgrading their E46 320d with a hybrid turbo achieving 300hp and 650Nm of torque. In order to also achieve those power, they upgraded their gearbox with a Sachs Racing clutch kit which can withstand up to 780Nm of torque. Here is the link for the SACHS Racing clutch kit for the ZF6 on the E90. Here are some places you can purchase your turbo kits (GotTuned, DarkSide Developments) or, if you are in Malaysia, hit Tong Turbo Engineering for more information about upgrading the turbo.

• Upgraded Power Clutch Kit – With more power means also more torque, you would definitely need to upgrade the clutch in order to handle more torque and SACHS racing has you covered here. Quoted as “SACHS Power Clutch Kit for easy installation with your original flywheel. Transmittable Torque 780+Nm for Sports driver and Race track”. Yup, no more issues handling more torque on your ZF gearbox.
• Larger injectors – With most other crazy diesel mods around, larger injectors are one of the essential parts to upgrade in order to get better performance out of the engine. Take this crazy mod, a quattro Scirocco mod where they used 1600cc injectors on the Audi diesel engine. There are some folks who upgraded their injectors by using those from the 3.0L diesel engines or from the x34d series models.

Interior Modifications

BMW Performance race seats – BMW Performance do have a range of their Performance semi bucket seats which costs quite a fair bit. You can check them out at ECS Tuning. They are essentially Recaro CS Sportster seats but because it has the BMW logo on it and decked out in Alcantara, it costs a lot more. The difference with this is that it also comes with side airbags and is heated as well.

Recaro Semi-Bucket seats – There are plenty of bucket seats available from semi bucket seats to full race bucket seats. If you want one for your daily drive, you can opt for a semi bucket seat especially the Recaro Sportster CS range or you can check out the Recaro SR range as well. If you are located in Klang Valley in Kuala Lumpur, you can head over to Sunway and visit H Performance there. They are a local distributor of Recaro products ranging from various seats from the Recaro catalog. Do note that if you indeed decide to change your seat, here are a couple of things you need to watch out for.

1. You need seat rails, two options available, a locally welded one made by H Performance or you can get one direct from Recaro. If you do choose to obtain the one from Recaro, you would need to wait for them to order it in as it takes about 3-4 weeks for it to be made and then shipped into Malaysia.
2. After installing the seats, you need to watch out for the airbag sensor. The moment you remove it, if your E90 320d is the LCI model, you will have 2 airbags and the active head rest to remove. Please note that the error will pop up on your iDrive and dashboard but you can get a coder to code out the error.

Extreme Modifications

• Reduce that weight! – Weighing in at more than 1500kg, the E90 320d as well as the F30 320d is a heavy car. Shedding some weight is an important bit and if you are serious about making it into a track car, that means stripping out the interior, aircon and other parts which makes the car comfortable. You can also reduce unsprung weight by using lighter brake calipers and rotors as well as lighter rims (try out the Japanese made Enkei’s 18″ rims which weigh around 8kg per rim).
• Roll cage – Adding a roll cage will definitely improve the car’s rigidity. Since there aren’t that many available ones here, a custom one has to be built. I haven’t seen an E90 race car yet here locally so the process of building the roll cage will most probably be a trial and error basis.

Image Source: Turner Motorsports and ECS Tuning