Original post in the a4 section here https://www.audizine.com/forum/showt...s4-Avant-build
Maybe I should have posted in the Avant section.
So I have a deal in place to buy a 2011 s4 swap for my 11 Avant. My Avant burns a quart of oil anywhere from 3-800 miles. Why it varies so much I don't know to be honest. No oil puddles or leaks, and I've had it professionally looked at and confirmed its the piston rings and not the turbo or otherwise. It also has 120k miles and needs timing done so its a time bomb for sure. I need a new engine so I've been looking at 8.5 a4 motors and S4 swaps as an option for a while so I generally have the scope.
I will get everything I need but not the whole car, as I don't really need the interior/lights/body/glass/brakes etc. The seats of the s4 are gone and I already have the black interior and headliner with Alcantara a4 seats so while a whole car would be nice for a full s4 swap, I can live with my interior and a s4 power-train.
I know there are a lot of question threads on this forum about s4 Avant swaps and I'm not trying to add to the hypothetical what-if pot. However, its a lot of money and its definitely not super well documented; I've read the few threads where people have done one and unfortunately the details on those threads is pretty sparse. Definitely good info and some key details, but a lot is missing.
So with that said, here is what I know I need. Some obvious parts and some not.
Engine
DSG Transmission
supercharger assembly
engine harness
s4 radiator
s4 intercooler
Exhaust -headers through mufflers
rear valance (already have the right bumper)
s4 rear differential
s4 rear axels (sport diff axels are shorter)
Additional wiring for sport diff pinned into harness
ECU
Gauge cluster, Immobilizer ring
Modules
So physically I can swap the parts. Not a trained mechanic or anything of the sort but I swamped a 5 speed jdm motor into my 4 speed auto Prelude back in the day, and added the 5 speed bits like the clutch master cylinder, clutch pedal assembly, shifter linkage etc. to get it running. Wired the gauge cluster so it was always in "park" so I could start the car, otherwise the neutral safety lock wouldn't allow it. Backyard at its finest but the end result was great and incognito except for the automatic gauge cluster. The owner of the s4 has agreed to help install this if I proceed so I'm confident we can get the parts pulled (the s4 is partially stripped already) and I'm confident we could physically get the s4 bits in.
However, the electrical modules have me worried. Older Honda parts all swap, so it really was not an issue to get them running. I read that all modules need to be swapped. I wonder if that's true, partially true depending on the specific accessory, only true if going from b8 to 8.5 or ...?
Per 300zx2g35's thread (https://www.audizine.com/forum/showt...-S4-Conversion) He went from b8 to b8.5 and updated the wiring harness from a b8.5 Allroad so 8.5 parts like the adaptive headlights would function correctly. In post # 50 300zx2g35 said "B8 to B8 is the easiest as you just need to swap over the motor/trans and the motor harness. No need to do a full teardown like I did. Then the model (Prestige, Premium plus) is just determined by the avant you pick up". Sounds like he is saying modules don't need to be swapped. He didn't go this route, so its not fact, but he is obviously very knowledgeable. VWrcer (https://www.audizine.com/forum/showt...ant-conversion) did a swap and said you have to do all of the modules. No explicit details and cant find a build log.
Is there a online list of the modules? - if they just swap onto the b8 harness I could move them all over. Would have to strip the interior but it might be a little more work to save a huge headache. My car is a 2011 A4 prestige, while the doner s4 is a 2011 Premium Plus. The options are similar - Nav, 3g, key-less entry, BO. My car has push to start where the s4 does not. The s4 has the ADS suspension while my car does not. Overall pretty similar though.
Any thoughts or forum links on the modules would be appreciated- this is easily my biggest road block. I don't want a car down permanently due to coding problems.
300zx2g35 thread noted the following not obvious issues
1. "Had to swap the gas tank and evap system as the A4 had 3 lines going to the engine bay whereas the S4 only had 2 plus the evap plug was different and I had already upgraded the fuel pump in the S4". Is this a a4 to S4 issue or b8 to b8.5. I can have the s4 owner look but if anyone knows.
2. Power and ground for electric steering (b8.5 issue so shouldn't matter)
3. Soundactor - can run the wiring
4. Brake light switch - switch to s4 to eliminate "Implausible signal" error for sport diff
Anyone know of anything else to consider or have threads saved with more details? I reached out to the OP's listed above and below to see if anyone will talk with me about it.
vwrcer did a swap but most of his links are dead so I cant find details
losik4 did a swap as well but only put up a few posts on it that I could find (http://www.audizine.com/forum/showth...1#post12663352)
GMG swap - minimal details- https://www.audizine.com/forum/showt...32-B8-S4-Avant!!
Thanks for any info you care to share in advance.
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Originally Posted by Zingrox
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