[projectvoltron04]

Hello everyone,

I am looking to acquire a decent e91 to n54 swap. I have been doing quite a bit of research over the last few weeks and I have a few questions I haven't been able to find more definitive answers on.

A little bit of background on me first. I have owned another Twin turbo swapped euro wagon in my past and I wish i had never gotten rid of it. I had a 2005 Audi A4 2.7 v6 twin turbo swapped that I had FBO and upgraded hybrid rs6 turbos on. It was making roughly 450awhp and was perfect for my wants and needs. But I sold it trying to be financially responsible and have regretted it ever since.

I mush prefer the look of the e91 to the audi b6/b7 avant platform.

On to my questions.

Would pre lci or Lci be an easier swap? (I prefer the Lci e91)


I would acquire a donor 335i/ 335xi/ 335i xdrive. I have read that if you have a pre lci e91 a pre lci 335 would be best. Is this true? or would in not matter if I have a lci e91 and pre lci 335 donor?

I want an awd e91 and would want to swap an awd 335 platform into it. I am under the impression that all of the front subframe and crossmember would bolt straight across. Is there anything else that won't align?

I am open to either manual or automatic but prefer Manual of course.

I would eventually want to be right around the 500whp mark either with upgraded twins or a STK. with twins that puts the torque levels also over the 500wtq levels with twins. It would be less and a more graduale curve with a STK. Would the 335xi trans handle that either manual or Automatic?

The swap itself is pretty straight forward as in unbolting front and rear subframe, susension, and all realted bits and swapping over along with evap stuff. then you need to swap donor dme virginized and recoded to match with the e91 CAS and Keys.

That's about it for now. Sorry for being longwinded but I just want to be thorough and get some more opinions.

Thanks,

[smallseafishie]

Your e91 shell doesn't really matter if it's LCI or not. It however does HAVE to be a AWD shell as the transmission tunnels are different. I'd STRONGLY suggest buying a whole e90 335xi for the swap instead of sourcing parts separately. Too many differences between the 328xi to 335xi.

For your swap, you'll need to swap over the engine harness, DME, CAS, Rear differential and half axles, drive shaft, and of course the engine, transmission, and the transfer case. Front brakes are different too so i'd just drop the whole front subframe from the chassis and roll everything over. That'd also include the radiator, and the radiator fan. You'll also need to transfer the exhaust, the rear trunk bin / tray and the heat shield, the charcoal canister lines and the vacuum lines to for the exhaust solenoid. I'd swap the rear brakes over - e91 share the same rear hubs as the 335i sedans. Since the rear hubs aren't changing, LCI or not is moot as that that's where the track size difference is.

You'll need to get a MSport e91 rear bumper with a 335i dual exhaust diffuser. The e91 rear bumper is unique from the sedans and 2 doors.

No need to virginize keys if you move the CAS and DME over. You'll just use the 335xi keys instead.


good luck!

[projectvoltron04]

Originally Posted by smallseafishie

Your e91 shell doesn't really matter if it's LCI or not. It however does HAVE to be a AWD shell as the transmission tunnels are different. I'd STRONGLY suggest buying a whole e90 335xi for the swap instead of sourcing parts separately. Too many differences between the 328xi to 335xi.

For your swap, you'll need to swap over the engine harness, DME, CAS, Rear differential and half axles, drive shaft, and of course the engine, transmission, and the transfer case. Front brakes are different too so i'd just drop the whole front subframe from the chassis and roll everything over. That'd also include the radiator, and the radiator fan. You'll also need to transfer the exhaust, the rear trunk bin / tray and the heat shield, the charcoal canister lines and the vacuum lines to for the exhaust solenoid. I'd swap the rear brakes over - e91 share the same rear hubs as the 335i sedans. Since the rear hubs aren't changing, LCI or not is moot as that that's where the track size difference is.

You'll need to get a MSport e91 rear bumper with a 335i dual exhaust diffuser. The e91 rear bumper is unique from the sedans and 2 doors.

No need to virginize keys if you move the CAS and DME over. You'll just use the 335xi keys instead.


good luck!

Thank you for the reply!

I will try source both AWD vehicles then. Its damn near impossible to find a 335xi donor vehicle. So that's going to take me a little while to source. But oh well

I was planning on swapping over by unbolting the suspension and crossmember components and transplanting them into the other respective cars

Are the rear subframes the same also so I could swap over the whole rear end also?



Does anyone know the power limits on the manual awd drivetrain? I have been able to find approx. numbers for the automatic but cant find manual.

[Timothi2]

Rear subframes are identical, no issues there. I swapped a rwd 335i subframe onto my wagon when I was doing the swap. Everything else that was said is correct! Pretty straightforward swap, the only annoying bits are the coding and making sure all the wiring is going to work, if you're planning on adding options that didn't come with the wagon. Feel free to check out my thread or PM me if you have any other questions!

As for the power limits on the manual drivetrain, that's a bit of a heavily debated issue. The 335iS clutch holds up to around 500 ft-lbs, from what I've heard but then again I've heard a lot of things hahaha. Weak link on the XI drivetrain seems to be either the front diff or the transfer case (can't remember which exactly, its been a while), when I was doing research that's what seemed to break the most. However, keep in mind that it's all based on how you drive. From what I remember, there was someone pushing about 600 ft-lbs to the wheels on a stock drivetrain with upgraded clutch and flywheel. If you're somewhat careful and ease into things you should be fine pushing 500. If you're going to be launching hard constantly with 500whp, you're definitely going to break something. The power isn't the problem, it's how suddenly it's applied to the rest of the components in the drivetrain.

If you want, I'll be selling my wagon in a bit lol. While I love it to bits, I want to build an even crazier one, potentially with a supercharged s65. Figured I might as well let someone else take and enjoy the wagon before I start hacking it up for an m3 conversion

Feel free to check out my insta too, it's got a lot of pictures!
Tag is @sleeper_e91

Good luck!

[CDirks]

Sub'd. The world needs more N54 E91's.

Funny enough a buddy of mine has a B7 A4 that he's been debating putting the 2.7 in recently. If he did, I'd have to nut up and find an N54 donor myself

[projectvoltron04]

Originally Posted by Timothi2

Rear subframes are identical, no issues there. I swapped a rwd 335i subframe onto my wagon when I was doing the swap. Everything else that was said is correct! Pretty straightforward swap, the only annoying bits are the coding and making sure all the wiring is going to work, if you're planning on adding options that didn't come with the wagon. Feel free to check out my thread or PM me if you have any other questions!

As for the power limits on the manual drivetrain, that's a bit of a heavily debated issue. The 335iS clutch holds up to around 500 ft-lbs, from what I've heard but then again I've heard a lot of things hahaha. Weak link on the XI drivetrain seems to be either the front diff or the transfer case (can't remember which exactly, its been a while), when I was doing research that's what seemed to break the most. However, keep in mind that it's all based on how you drive. From what I remember, there was someone pushing about 600 ft-lbs to the wheels on a stock drivetrain with upgraded clutch and flywheel. If you're somewhat careful and ease into things you should be fine pushing 500. If you're going to be launching hard constantly with 500whp, you're definitely going to break something. The power isn't the problem, it's how suddenly it's applied to the rest of the components in the drivetrain.

If you want, I'll be selling my wagon in a bit lol. While I love it to bits, I want to build an even crazier one, potentially with a supercharged s65. Figured I might as well let someone else take and enjoy the wagon before I start hacking it up for an m3 conversion

Feel free to check out my insta too, it's got a lot of pictures!
Tag is @sleeper_e91

Good luck!

I have been following your swap thread for a while. Alpine white with saddle brown interior is way high on the list of the e91 I want. They are pretty hard to find. Especially n54 swapped and manual. But I don’t think I’ll be able to afford your car when you sell it. This is a project I’m going to attempt over a period of time. I just want to have my ducks in a row when I do pull the trigger.

When the time gets closer I will probably end up dm’ing with questions I’m too stupid to figure out for myself 😂

[RocknRollOutlaw]

I don't have anything to add other than good luck. Even in countries where the E91 335i was sold they are rare, the manual even more so, as I have one. The world needs more! Best of luck with the build.

https://m.imgur.com/a/cH0DvEB

[projectvoltron04]

Originally Posted by RocknRollOutlaw

I don't have anything to add other than good luck. Even in countries where the E91 335i was sold they are rare, the manual even more so, as I have one. The world needs more! Best of luck with the build.

https://m.imgur.com/a/cH0DvEB

In super jealous. You guys get all the cool cars!