Hello everyone,

I have had this 528i for 2 years now and I'd be interested in adding a little more vigor to it. I hope this is a good place to ask these sort of questions.

1. I have looked into RaceChip, similar piggyback chips, and ECU flash programming, but I am not convinced these will do all that much to a NA engine. Also the fact that the best known ECU tuner companies offer nothing for this model is discouraging.
2. Then I thought maybe one could add a little turbo charger. There are not many 6 cylinder chargers, none for BMW, and only a few generic ones. God knows if there is even enough room to fit one in the engine bay. Seems very compact and tight already. Anyone tried?
3. And of course, I also ran into NOS systems. They almost seem the easiest to install in terms of effort/hp, especially a dry system that only sprays N2O into the air intake. It raises questions though about how safely it can be done without risking hurting your vehicle. More power sounds like more stress on the engine, the gaskets, the transmission, and the brakes, just to name a few. Can a stock BMW handle the extra 50-100 horses? If someone has experience with NOS systems I have some additional questions regarding the location of the Air Mass Flow Sensor location and whether or not it can sense the additional N2O, or whether that needs to break up into N and O (through heat) before it can be sensed?

If you have any recommendations, I'd love to hear them.

Thanks much

-Iko

Hi Iko

Welcome to the Forum

Your basic engine is capable of handling about 300bhp beyond that then serious bottom end changes need to be thought about. 

It depends on how far you want to go but breathing is top of the list, so my thoughts would be look for the cylinder head from a 3.0i this would give bigger valves an more lift if you got it with the inlet and exhaust manifold I would expect around 220/230 bhp with very little issues with your engine assuming it is in good condition to start with.

Forced induction brings a whole lot of additional considerations whether it is positive super charging (belt driven), turbo charging or NOS systems a simple fact is more air needs more fuel. So the fuel supply needs to be considered, fuel pump, injectors and ECU map, then the exhaust needs to be able to get rid of the extra gas, the cooling system also needs to be up to the extra heat generated. As already stated if your engine is in tip top condition then around 300bhp will be the limit on a stock bottom end with stock pistons and rods. To go further I would expect to line bore the block have the crank crack tested and nitrided and balanced then fit forged pistons and rods, upgraded oil pump. We haven't even discussed the drive train yet.

Another option would be to scour the web for a complete engine or better yet donor car such as E90 335i (300+hp) E39 330i (270hp) I dont think there would be much difference in cost either way

However the simplest would be trade up to a 530i or 540i less pain and you get the whole package brakes steering suspension the whole thing. Or a 535d similar hp but way more torque, and with a remap more torque than the M5 and its torque that accelerates your car? Worth considering

Hope this helps not hinders

Dave