Debating an s6 4.2L swap...

[JumboBlack1.8]

As the title states, I'm debating moving on from my built 2L motor and going with a mildly powered s6 motor. I've read all of the motor swap threads out there, but nearly all of yuem are incomplete, especially when it comes to a parts list....

I've got the gist of what needs to be done (grinding pats of the upper oil pan for clearancing, rad support fabrication, minor engine harness adaption to mate to OEM connectors, etc etc).......but does anyone out there have a more comprehensive list of steps and parts? I haven't had a problem sourcing engines, harnesses, or ECUs, but I'd at least like an idea of what I'm getting in to before I start buying stuff...

Also, I've posted a feeder for my current 400+whp setup. Check the classifieds

[Mad Cow]

AFAIK the S6 block simply won't fit because the bellhousing is too long and the intake manifold is too tall to fit under the hood. There was a picture of a half-completed swap in one of Siena's threads and it's clear that it won't fit without a ton of work.

EDIT: I was thinking of the RS6 motor, this thread: http://www.ozaudi.com/forums/showthr...5-A4-The-Facts.

[JumboBlack1.8]

Haha. No worries. Had me nervous for a second

[flynnr]

why? what is the benefit of going NA? you can get as much hp out of a 2871 as the v8 will offer, while being lighter at the same time.

[JumboBlack1.8]

I don't care much for the high horsepower anymore......I'm looking for something NA, with less moving parts, that still has some grunt to it.....Plus, it'll be a unique car that I won't have to constantly be tuning........I just don't have the time to keep up with this motor/tune anymore

[biketsai]

Justin, have you thought about ditching the Maestro setup? or even paying some tuner to help you get it right with a few hours?

I am really eye'in your block!

[JumboBlack1.8]

Yea, I've thought of taking it over to Vast, and having them work their magic......it's still an option, if the S6 motor project proves to be too much for me. I'm still doing a bunch of research at the moment, so this may, in fact, never come to fruition......but I'm leaning quite heavily towards doing it.

[Corrado_Guy]

The swap part isn't too bad, check out MotorGeek as there are a lot of threads about this topic. The biggest issue is the electronics, most V8 motors are attached to automatic transmissions and this is really hard to swap over if you want to have a manual. The immobilizer is a problem as well but I think this can be removed with a chip but you would want to check on this. Most people tend to swap the physical motor and then use stand-alone to make it run. If you have emissions testing where you live this may be a problem.

[JumboBlack1.8]

I've just found this thread over in the C5 Section:
http://www.audizine.com/forum/showth...ht=manual+swap

Evidently, the Euro version of the S6 and S8 came with a manual transmission. Both Vast and JHM offer the European file. According to that thread, JHM is also developing (or already has?) an aggressive tune based off of that OEM European S6/S8 file.......The standard C5 4.2 presents a few more hurdles, since they didn't come from the factory with a manual transmission on either side of the pond. This is one of the reasons why I've chosen the S6 motor over the standard A6 V8 motor

The only things I'm concerned about, at the moment, are flywheel options and cooling. I'm not sure what I want to do with my radiator fan setup, and how to tie that into the OEM ECU.

[revolution337]

I'm actually taking on this swap. I recently aquired a 4.2 from an 02 A6, along with the harness and ECU. And from what I've read (haven't checked myself) the engine I have (code AWN) actually weighs LESS than an AEB, mostly due to the aluminum block. I've been wanting to do this swap for the same reasons you do, less complications being NA, plus it'd be really unique. Cost wise, its cheaper than the BT build I had originally planned too. As stated above, the biggest problem I forsee is the fact that the engine came from an auto, and I plan on running my 01A with the motor. I will deal with that problem later down the road though.

I'd say go for it. Then we can bounce ideas off each other

[JumboBlack1.8]

Shoot an email over to a JHM sales rep. They can do an immoblizer defeat, so the engine will run flawlessly with a manual configuration. They've taken a tremendous interest in the 4.2 V8 market

[revolution337]

Shoot an email over to a JHM sales rep. They can do an immoblizer defeat, so the engine will run flawlessly with a manual configuration. They've taken a tremendous interest in the 4.2 V8 market

Awesome info! I'll have to do that!

As for the cooling situation, what I'm doing is deleting the stock viscous fan and adding electric fans in FRONT of the radiator (trimming the bumper of course). Not sure as to how I'm working that into the stock ECU yet though. The best idea I have for the radiator is just flipping my stock one upside down (inlet/outlet on the passenger side) and make some custom plumbing.

.....and just in case you need some extra motivation

[FNK]

Heres a built thread; LINK

The end result;


Do it!!!

[biketsai]

Just curious, what are the complications with the automatic motor? Will you have the same issue with the crank? If so, hopefully shaving it and adding a pilot bearing would help.

[nate09]

Heres a built thread; LINK

The end result;
video

Do it!!!

Wow, that makes me want to do a V8 swap.

[TConklin821]

I don't know much about it, but I say do it. Why?

BECAUSE RACE CAR.

Okay, seriously though. I would take a nice, powerful V8 NA over a Turbo I4 any day. The sound of the 4.2 with the right exhaust is pure sex.

[biketsai]

I don't know much about it, but I say do it. Why?

BECAUSE RACE CAR.

Okay, seriously though. I would take a nice, powerful V8 NA over a Turbo I4 any day. The sound of the 4.2 with the right exhaust is pure sex.

When you put it this way, why not ditch the B5 and go for a B6 S4?

[ZimbutheMonkey]

Not sure if you're parting out the motor, but the intake cam and valve springs/retainers are tempting.

[revolution337]

When you put it this way, why not ditch the B5 and go for a B6 S4?

because the B5 is way better looking than a B6 (I'm a little biased ) plus its more unique

[biketsai]

because the B5 is way better looking than a B6 (I'm a little biased ) plus its more unique

Without a doubt! But Im just looking at it from the financial aspect.

[TConklin821]

Without a doubt! But Im just looking at it from the financial aspect.

I would love to. The B5 DOES look better. I just can't afford a B6 S4.

[NeedingAnAudi]

I'm considering picking up a v8 a6 and doing this. I've followed all the build threads on here, siena, the russian etc... and I only have one problem. I'm not the greatest at wiring and custom tuning yet, so a full harness and v8 ecu would allow me to make the swap look oem. Plus then I could get a free apr tune from work

[revolution337]

I'm considering picking up a v8 a6 and doing this. I've followed all the build threads on here, siena, the russian etc... and I only have one problem. I'm not the greatest at wiring and custom tuning yet, so a full harness and v8 ecu would allow me to make the swap look oem. Plus then I could get a free apr tune from work

This is exactly what I plan on doing. I'm want to make it so that its like the engine came in the vehicle from the factory. Full OBD functions, functional cluster, no CEL, passing emissions (this is going to be the tough part), DD-able, etc.

[flynnr]

http://minneapolis.craigslist.org/hn...649931128.html

/ thread :)

haha. seriously though, with the money and TIME it would take to do this, you would be better off finding a cheap b6 s4...

not to mention, the moving parts thing... i would think that the s4 would have a lot more moving parts... think - twice as many cams, pistons, valves, exhaust mani's, gaskets, seals, places for leaks, etc.

if you arent looking for high horsepower, and want NA, why not just buy a 2.8 b5 a4???

[revolution337]

why not just buy a 2.8 b5 a4???

because they are poop.

[JumboBlack1.8]

Just curious, what are the complications with the automatic motor? Will you have the same issue with the crank? If so, hopefully shaving it and adding a pilot bearing would help.

There aren't very many (if any) mechanical complications that I've found in my research......AFAIK, the 40v motor doesn't have an exceeding short crank like the automatic cranks found in our motor. The only issue is finding a flywheel with the correct bolt pattern (I believe its a 10-bolt configuration)....and modifying the B5 S4 transmissions/engine adapter plate to a 5speed tranny

[JumboBlack1.8]

I don't see how everyone imagines that this will be a bank-account shattering build......It'll be SIGNIFICANTLY less that the original cost of building my current motor.....The only things I need to buy are the engine, harness, ecu, motor mounts, clutch (might use my current one), correct fly wheel, new radiator fans, engine adapter plate, a tune from JHM or Vast, and some other odds and ends......I can't imagine it costing more than $4k. A ton of people (yourselves included) dump far more money into a standard BT build.

As far as buying a B6 S4 goes......I've spent a good amount of time in that forum, and I simply do NOT trust the reliability of that motor.....There are too many instances of them failing from normal use. I no longer have even the slightest interest in owning one

[revolution337]

There aren't very many (if any) mechanical complications that I've found in my research......AFAIK, the 40v motor doesn't have an exceeding short crank like the automatic cranks found in our motor. The only issue is finding a flywheel with the correct bolt pattern (I believe its a 10-bolt configuration)....and modifying the B5 S4 transmissions/engine adapter plate to a 5speed tranny

It is a 10 bolt. From what I've gathered I believe you can use either a V8 flywheel, or a 2.7t flywheel (or something custom obviously)

[RBWagon]

This interests me because i was talking to my friend about this swap when i first got my b5 avant... he kinda shot me down so, now I feel revived... But a 5 speed tranny huh? why not the 6?

[revolution337]

This interests me because i was talking to my friend about this swap when i first got my b5 avant... he kinda shot me down so, now I feel revived... But a 5 speed tranny huh? why not the 6?

you could really use either, I just happen to already have a 5 sp

[NeedingAnAudi]

This interests me because i was talking to my friend about this swap when i first got my b5 avant... he kinda shot me down so, now I feel revived... But a 5 speed tranny huh? why not the 6?

6 speed would just be another cost on the list.

[ThePeoplesChamp]

I think your current engine is far more impressive than the swap.

[viceprp]

Awesome info! I'll have to do that!

As for the cooling situation, what I'm doing is deleting the stock viscous fan and adding electric fans in FRONT of the radiator (trimming the bumper of course). Not sure as to how I'm working that into the stock ECU yet though. The best idea I have for the radiator is just flipping my stock one upside down (inlet/outlet on the passenger side) and make some custom plumbing.

.....and just in case you need some extra motivation

Jk35's motor?

[revolution337]

Jk35's motor?

Yessir

[viceprp]

Yessir

Really good guy. Could have waited and had it shipped in my car .. . . lol

[beemercer]

Cool thread, very interested in seeing this develop. OP where in Boston are you?

As far as the swap I'd go with an S8 motor if you can find one, otherwise an S6 motor. I'd avoid the A6 4.2.

Since you'll most likely be using a manual its best to flash in a stock Euro S6 file. It is floating around (nefmoto I believe) and there are instructions on how to flash it (contact rednecktruck, he did his recently). That will get you running for free. If you are inclined a file like whats in my car at the moment will really liven the car up. I would forgo the VAST tune, the man who wrote that tune now writes for JHM and the JHM version is far more updated. My next revision should have SAI delete, cat delete, rear O2 delete and launch control, plus its significantly faster and sharper on throttle response.

The reason I say to go with the S6/S8 motors over the A6/A8 4.2 is mostly the cams and how the intake manifold works. The IM stages are operated via a vacuum solenoid that opens when the ECU tells it to, the issue is that the 3 and 2 stage IMs open at different times. Since the only factory manual tune is for the S6 its best to try and keep your setup as similar to that motor. Tuning off the automatic file is fruitless.

As far as driveline the A6 01e bolts onto the motor and only requires a bit of clearance around the starter iirc (redneck truck has a whole manual swap writeup in his signature for an A6 4.2, it will outline setting the driveline up). The 2.7TT flywheels and clutches work directly on the motor, mine has a VAST LWFW and Stg4 clutch.

When you put it this way, why not ditch the B5 and go for a B6 S4?

The B6 S4 motors are a disaster in a lot of ways compared to the other V8s.
-Timing System: timing belt motors have the simplicity of a timing belt and standard accessories, which drops the cost of servicing both; the BHFs have chain driven accessories and a difficult to service timing system (some work can be done with the motor in the car, more indepth work requires the motor to come out)
-Rods: the S6/S8 motors have forged rods similar to the older 32v 4.2 motors, the A6/A8 4.2s have essentially the same rods as a 2.7TT, the FSI V8s have forged rods, the BHF has thin powdered metal rods with a tapered wrist pin (can handle ~450whp max)
-Pistons: iirc all the 40v 4.2s have cast pistons, the fsi motors have forged pistons
-Block Construction: The timing belt motors are lower silicon with chemically stripped bores, the timing chain motors have a higher silicon content and mechanically stripped bores. The issue is that the higher silicon content causes the block to expand slower, but since the piston metallurgy wasn't changed the pistons expand at the same rate and contact the cylinder walls (very small tolerances in the Alusil motors) causing the unfortunately typical cylinder wall scoring in the B6/B7 S4s
-Cams: The S8 cams have the same lobe design as the S4, the S6 apparently has an S8 intake and A6 exhaust cam, the A6 has both cams low lift. So if you have an S8 cam set theres no difference
-Intake Manifold: The S6/S8 intake manifold has the best multistage design for the V8 motors. The S4 IM drops a flap right in front of the TB and doesn't seal the long runners when it switches to the short runner. The A6/A8 manifold is a disaster, 3 stages and both flaps move right in front of the TB
-Exhaust manifold: The S6/S8/Early A6/A8 manifolds have a bigger outlet and 4 separate runners, the later A6/A8/S4 manifolds have a shared runner and smaller outlet


The biggest issue with the S4 motors is the cylinder wall scoring, and since most of the cars are gonna have some good miles on them you can't really take the necessary steps to ensure it doesn't happen (remove the precats, very diligent oil change intervals).

[biketsai]

^ Great info. I definitely did not know there was that big of a difference between the V8 motors.

[JumboBlack1.8]

Beemercer.....Thanks for all that info! I wasn't aware that there was a difference between the S6 and S8 motors.

I live in Brighton, but I do all my work at my parents' house in Milton.

I'd love to get the ball rolling on this ASAP.....I will keep this thread updated as I get closer to making a decision

[John Gutmannnn]

Listen Jumbo...If you have to ask then you...

Sorry, I had to!

Will be watching this thread, I was checking out B6 S4s as well but haven't done much research on them.

-John

[JumboBlack1.8]

Anyone know of any S8 part outs?? I'm having a hard time finding a motor......I got a BUNCH of emails from junkyards about S6 motors.....but I have yet to source an S8 setup

Any help would be much appreciated