Has anyone ever taken an n14, removed the turbo, changed the heads and made it into an n12? Humor me here and tell me what else it would entail and why it definitely won't or possibly might work.

Long story about why I'm asking, but it is a serious question.

 

I have no info and do not know if this is actually true, but i would assume the blocks are different.

 

It would be cheaper and easier just to sell your car and buy a non-turbo. The ECU and wiring harness would need to be changed out as well, or you would get a ton of check engine lights for missing sensors related to the turbo and intake air management. I'm not even sure it would run if you just removed the turbo, slapped on non-S intake and exhaust manifolds and did nothing else.

 

I would consider a standalone Honda B-series or K-series swap before I tried to make that work.
Similar to what they do to the classic Mini.

 

Just pull the turbo, build a header, reroute the intake, and BAM! done. Just make sure all the sensors stay in service, and should be ok. It will be slow, but, sounds like you're prepared for that.

 

"Theoretically", we already did this. The car won't start now, however, and we haven't yet figured out why that is. Every sensor from the original motor went to the new one. They were fine. Can't understand why it won't start. Cranks forever, tries to fire, never quite makes it.

 

Ok, so I think it’s time to tell the long version of the story....

Did you change ECUs? Is the immobilizer preventing ignition?

 

To answer the original question, I am not aware of anyone downgrading N14 to N12. I personally did an upgrade from N12 to N18 and N14 to N18. As @njaremka said, it is time for the long version of the story..lol.

Generally speaking, removing the turbo and rerouting the intake wont help. The ECU is mapped to actuate the associated sensors including the fuel line pressure sensor. Also, the LPFP is not the same in terms of fuel delivery. N14 withought a turbo does NOT equal an N12, even if you swap the head. The pistons are different.

For this to work, you need at a minimum the following:

N12 head (complete with all attachments)
N12 pistons
N12 intake manifold and attachments like throttle body, map sensor, maf sensor, gas tank vent valve...etc
N12 exhaust system
N12 timing chain
N12 ECU needs to be married to the original CAS or buy a matching CAS and key fob. if you marry the donor ECU to the original car, you need to code the car and modify some of the options fitted.
N12 cooling fan
N12 fuse box (near the ECU) Or rewire it
ECU body side plug rewiring to work with the donor N12 ECU.
N12 LPFP
N12 fuel line
N12 engine harness

 

Well, it's not that long a story, just somewhat complicated. To put it in simplest terms, this is a car someone wants to give to their kid, and didn't want them to have turbo though I personally don't see it being THAT big a difference. The block was bad on the original n12, but we had a good n14.

A mechanic friend thought he could do the swap and supposedly did lots of research. 6 weeks later and bmw service is telling us we can fix it ourselves but they haven't actually said what is wrong. The car had a few electrical gremlins when it came in (not told about this until later) but it *was* running. Now it's not.

Codes are coming up for engine coolant sensor (173B). Errors shown in the cluster are 3 lights out, abs and I think the airbag. Can't recall for certain.

I don't know exactly what mechanic did and we're not speaking now (in part because of this issue) so he won't tell me.

We're supposed to swap 2 non-turbos in a pair of r53s but now I'm scared to do it.

The donor car is still here, but the other is at bmw atm.