S4 on the operating table - a look underneath with the guts removed

[westwest888]

Enjoy.

Crank and cats [looking directly up into engine bay]:



Dual mass flywheel and front differential with front half shafts visible [amazing engineering to line this up]:



Front control arms with spherical bearings, back of the AP racing calipers, stainless line going into it:



Brakes and eurocode sways:



Transmission. Front 1/4 is flywheel+clutch. Middle 1/2 is 6 forward gears, 1 reverse. Rear 1/4 is the center torsen differential.



Sports rear differential:



Milltek front section, blue from heat. No one makes a system like this for the B8. Best on the market.



Milltek rear section:



Rear subframe mount and rear cast links:



Rear subframe and diff:



Apikol diff mount:



Shifter linkages. The transmission is a good length in front of the shifter in the cabin:



Below the cat you can see the steering linkage poking out from the cabin:



A lonely driveshaft. I'm not sure why it's two pieces.

[MrFunk]

You need to clean your wheels better.

[drob23]

Nice shots, always interesting to see the innards.

[SwankPeRFection]

The driveshaft is in two pieces usually so that it can break in half should there be a wreck for safety reasons. Subarus have the same thing...

In that first pic, what you're looking at is not just the crank. That's the crank side of the dual mass flywheel the other half is on the trans side attached to the clutch. I have to be honest, I've not actually seen a setup like that, but on most cars when you pull the trans off, you can actually see the flywheel and the clutch remain with the crank on the engine side. The teeth on the outside of the flywheel are of course for the starter.

Oh and you might want to go have the TSB for the rear diff seals on the driveshafts done on your car. It's leaking just a bit.... or is that brake fluid?



*Edit*
Upon further analysis of your pics, it looks like someone pulled the second half of the flywheel off the main part by undoing the 6 bolts that hold it together and then put it back on the bell housing side. Am I missing something here....? WTF?

[Usa]

No one makes a system like this for the B8. Best on the market.

Agreed :)

[ejohnson]

Thanks for posting these, fun to see.

Also, inb4 this turns into a flamefest.

[SteveYem]

Thanks for the photos! I take it the transmission has to be removed in order to replace the cats?

[westwest888]

The driveshaft is two pieces so the rear suspension can travel, says the technician. Makes sense now.

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[SwankPeRFection]

The driveshaft is two pieces so the rear suspension can travel, says the technician. Makes sense now.

Sent from my Nexus 5 using Tapatalk

No dude, the rear suspension travels up and down and the rear shafts allow it to do so like the fronts do. There is some minor movement in the diff mount point in the rear under torque, but not nearly as much as you think. The rear diff doesn't just move around like it's all loose up in there. lol

[westwest888]

Agreed :)

The Audi cats really do some great work burning up everything that comes off of the engine. I put my finger on the inside of the Milltek downpipe and it was so clean it barely blackened my fingerprint. Every last bit of oil and gas burns up in that cat. I won't be replacing them with a lesser cat or header.

[westwest888]

Flywheel comparison head to head

Old


New


Bonus pic: right side of trans

[The_Transporter]

Oh and you might want to go have the TSB for the rear diff seals on the driveshafts done on your car. It's leaking just a bit.... or is that brake fluid?

Differentials have a tendency to 'sweat,' which is normal in most cars, however, might be a different situation with the S4...

[Tweakophyte]

Cool pics... on principle.

[westwest888]

This thread has enough evidence to settle arguments for years to come. Arguments I haven't even thought of.

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[BlackHawk23]

Am I going crazy or are the boots on those bearings tearing?

[westwest888]

Initial impressions: car is running great. The idle RPM hasn't moved, like it feared it would. The car is about 60% easier to stall than before, which you'd expect with a LWFW. The clutch feel is close to an e46 M3 - it's more involved to drive. I won't need to grandma shift any more for that dual mass to catch up. In fact I'll have to shift faster because the revs fall more quickly. I don't notice that the car revs more easily when in neutral feathering the gas, though I suspect that the computer limits the throttle there.

I stalled the car in reverse. I have to get used to the new engagement point. The forward 1st gear still has the rev feature where you let the clutch out gently and it controls the throttle. It seems like the computer corrects half way through and adds more throttle, not expecting it to need so much.

[SilveR316]

I guess I must have missed this... but which clutch did you put in?

[achilleas101]

Front control arms with spherical bearings, back of the AP racing calipers, stainless line going into it:



Brakes and eurocode sways:

did you notice that your front lower CA's ball joint is torn?

[integroid]

Yeah, which clutch setup did you end u going with?

[westwest888]

Yeah, which clutch setup did you end u going with?

http://jhmotorsports.com/shop/catalo...si-p-1560.html

Stage 3 disc is a Ceramic and Metal Backed Organic disc meaning that the material that contacts the pressure plate is an organic material with metal integrated into the material. The side that contacts the flywheel is ceramic. This combination of materials will give you a much more direct engagement as compared to the stock disc, while still remaining very easy to daily drive. This clutch disc is recommended for FULL BOLT-ON cars that are driven aggressively and/or light duty track use.

[westwest888]

did you notice that your front lower CA's ball joint is torn?

Still passes visual inspection. That's just a dust boot. The joint is working rather well :) I'll have to keep an eye on it. My suspension is due for a major service in about a year and we'll address it then.

It's actually the rear lower control arm on the passenger side. The flash is on with the camera so that gap is more pronounced.

[schirm]

http://jhmotorsports.com/shop/catalo...si-p-1560.html

Please let me know how you like it, I am pulling the trigger on the same one next month.

[westwest888]

Please let me know how you like it, I am pulling the trigger on the same one next month.

I've spent some time recently driving the car over Memorial Day and on some short, in town trips. First, the car is definitely more challenging to drive. It's about 3x easier to stall or slip the clutch if you drive "the OEM way". The light flywheel limits the amount of time you have to engage before the car stalls out. The car seems to prefer a very direct engagement, almost like every move from a stop is a low RPM launch. It sort of bucks off the line if you just let the computer do the throttle in 1st and you can feel it slip if you are too slow on the engagement. It likes perhaps 800 extra RPM of throttle input and a quick release of the clutch, and the car jumps forward as you'd expect.

Another consequence of this upgrade is the car will rev to 7500 RPM if you hold the gas until the ECU ramps you down at redline. I discovered this over a weekend at the track, and it took me a while to figure out what had changed. It used to stop at 7250. I appreciate having the extra gear and speed in gear, even if it wears on the engine internals faster. I don't need 200,000 miles out of this block.

It's harder to practice the new clutch technique with passengers. The smoother you try to make it, the more unsorted it gets. It just wants a swift, even clutch release short of dumping (accelerating release).

[priceprince]

Good to know about the difference in daily driving with the upgraded clutch. I think I'll be sticking with oem when I have to replace mine.

[The.Wizard]

Some great shots of some of the gubbins, thanks for sharing a good luck with your upgrades hope you get plenty of enjoyment in your driving and keep us updated.

[shadycrew31]

Still passes visual inspection. That's just a dust boot. The joint is working rather well :) I'll have to keep an eye on it. My suspension is due for a major service in about a year and we'll address it then.

It's actually the rear lower control arm on the passenger side. The flash is on with the camera so that gap is more pronounced.

"Becuase my shop said so" -Westlogic

[DATZ]

"Becuase my shop said so" -Westlogic

The same shop that recommended the Revo tune as the "conservative" option.

[westwest888]

The same shop that recommended the Revo tune as the "conservative" option.

All those guys are parting out their cars because their Stage XVIII pulleys shook their B8 loose, and now it runs rough. No issues with my Revo. Porsche sells the 3.0TFSI in a few of their SUV's and sedans. They've got it tuned up to 420 HP and 390 ft/lb, right in line with what Stasis thought was reasonable.

[Intrepid One]

I am a new owner and appreciated the pics..The engineering that goes into making everything fit and function is quite remarkable..thanks..S

[Jones2012s4]

All those guys are parting out their cars because their Stage XVIII pulleys shook their B8 loose, and now it runs rough. No issues with my Revo. Porsche sells the 3.0TFSI in a few of their SUV's and sedans. They've got it tuned up to 420 HP and 390 ft/lb, right in line with what Stasis thought was reasonable.

Shook their B8 loose?

Right...

Come on now.