[tlow98]

Originally Posted by Matte90330

If I was to do this swap by getting a totaled 335 and swapping over everything would the vin encoded on those modules from the donor car have to be changed to my vin for things like emissions?

Depends on your state's emissions. Also the vin in the CAS and the ECU must match or it won't start.

If the state plugs in for OBDII they'll realize the ECU does not match the car. Some coding will need to be done regardless in order to get everything to truly play nice, so just have it all changed at once would be my advice.

[JuniorB]

Are your adding fi to this build? What's the reason behind it?I originally wanted the twin turbo so I bought a n54 with a spun bearing,67k on her.ive been told my ecu can be kept and reworked for this motor. Don't count the n52 out just yet,they make na motors strong for a reason,I'm pushing nitrous on mine,holding fine. It seems your going thru to much for an na motor.Ifs it's true that the allusi block is stronger,why go thru the hassle? It gets to the point na isn't fun anymore and 250 hp isn't enough.

[Hobbs64]

Junior,

It will be interesting to watch you and Don, and see exactly where are the limits of the N52 block and crank? As I explained to Hass, I've built a couple of BMW engines past engineering capacity. The problem with the spray-wire and alusil blocks is that they can't be worked on easily. Once you do something stupid, you are looking at a new block. I'm building a foundation to do anything I want. I will most likely go turbo, but I don't have to resolve that for a couple of weeks. Right now I going to switch to the N54 bottom-end and trans. All of that can be run off my ecu and wiring. When I go FI the N52 is a better head than either the N54 or the N55.

[Efthreeoh]

What is the approach for the fuel system? So you are going to run a N52 head on a N54 block. Use a N52 ECU to control the Valvetronic. The N52 doesn't use the HPFP but you are going to run a supercharger, so I'd imagine you'll need higher flow fuel injectors (from a N54?) and use the HPFP. I guess the N52 ECU can be programmed to run higher flow injectors?

[Hobbs64]

If you look at DigiDon's turbo build thread, he is running bigger injectors. The idea is to keep my ECU and wiring with this set-up.

[hassmaschine]

again, N54 uses direct injection. N52 is port injection. Nothing on an N54 or N55 fuel system can be used on an N52.

[Hobbs64]

My apology. I didn't mean to imply that Don is running N54 injectors. Don can speak for himself, but if you read his turbo build thread, he figured out the larger injector/fuel piece.

[hassmaschine]

I was referencing Efthreeoh - I should have quoted him.

[JuniorB]

We have to find out what bolts to what. Can the hpp run e85 on the stock n52 injectors? I think it's going to be cheaper to run the n54" for the twin turbos,the price for a,single turbo on a n52 is going to be astronomical,but the Bastet is out.

[Hobbs64]

Junior,

I'm curious why you think the N52 with a single will be costly (comparatively)? As long as you build the N54 bottom end like any other N54. It is neither more, or less than any other N54. The only piece I'm still putting together in this puzzle is the piston dome. Lots of shops have opinions about what to use. I think at the end of the day, I am going to use an upgraded forged 10.2 piston. It has a dish, not a dome. The configuration is conventional, and so long as the relief cuts in the piston will accommodate the larger valves, it all works. Do you know of anyone that has cc'd the combustion chamber of either the N52, 54 or 55? I am assuming the volume and configuration are very similar.

If the runners of the N55 exhaust manifold were not undersized, I would use that set-uip as well. What do you think I'm missing here?

[hassmaschine]

Originally Posted by JuniorB

We have to find out what bolts to what. Can the hpp run e85 on the stock n52 injectors? I think it's going to be cheaper to run the n54" for the twin turbos,the price for a,single turbo on a n52 is going to be astronomical,but the Bastet is out.

again, NO.

the HPFP runs up to 4000psi. The N52 runs at 72 psi (5 bar).

Nothing, and I mean nothing, from an N54 fuel system is useful on an N52.

[Hobbs64]

No turning back now. Short block arrives on Friday! Pics will follow as we put it together.

[hassmaschine]

sweet

[Efthreeoh]

Originally Posted by hassmaschine

again, N54 uses direct injection. N52 is port injection. Nothing on an N54 or N55 fuel system can be used on an N52.

This why I see a disconnect. The N52 ecu doesn't support turbos, the N54 ecu does support Valvetronic nor port injection. The N55 ecu does support Valvetronic and port injection, but does it support any block sensor inputs, crank sensor, knock sensor, etc. And the Valvetronic on the N55 head is probably different than the N52 system, so can it control the N52 Valvetronic considering its also looking for forced induction data.

[hassmaschine]

actually, that is not true. The interesting thing is, the software in the N52 computer is the same basis as the N54 (they both started as MS45 when under development, then went to the MSx70 platform, and finally MSx80). The main difference is the hardware (direct injection vs port injection).

There's nothing about the N52 fuel system that says it can't support a turbo. People (and manufacturers) have been turboing port injection engines for years.

[JuniorB]

Correct,the n54 does have tremendous psi. Honestly if you look at the big.picture,for na,stay n52 or sn54.I think building a n54 with twins may be you best power opinion,if you want an i6,the sn54has the better power capabilities.

[tlow98]

Originally Posted by Hobbs64

No turning back now. Short block arrives on Friday! Pics will follow as we put it together.

Nice! This Frankenstein is sounding more interesting all the time. Consider me a convert. I'm down to see what goes on in here.

[hassmaschine]

Originally Posted by JuniorB

Correct,the n54 does have tremendous psi. Honestly if you look at the big.picture,for na,stay n52 or sn54.I think building a n54 with twins may be you best power opinion,if you want an i6,the sn54has the better power capabilities.

I think that all went right over your head...

[JuniorB]

What ever that meant? I just tore my nn52 down,its going to be alot more to build a 54 than a 52. A very expensive job for this project if you build it. The gaskets are another problem, danthe Hpf be blocked off? Most manufacturers use the same products,so it could happen. I wouldn't underestimate the n52 quite yet

[JuniorB]

My apologies,sometimes I don't recall shit. I just tore my n54 down,they are expensive to build,I didn't know you could bore a allusi block,but the n54 definaly has some beef to it. I was looking at the hpfp,you have to remove it and block it off,or just sleeve the n52.

[Hobbs64]

Junior,

The N54 is not allusil. It has iron sleeves. Yes, I will have to block off the HPFP.

[JuniorB]

I know they don't,but if you wanted a stronger block without the hassle,you could sleeves it. Since Hass is reading this also,I need to ask a question. My project is going to be putting the n54 in my car inplace of then52.. I bought a whole car for this. The donor car is a 08 535xi,its been rolled,but the drivetrain is intact,im only taking the motor and related electronics. Do i have to change my vin to the 08 and use that,use a 335 07 EC,or can my n52 EC be reprogrammed? Thank you for your experience on this.