Project B7 420-R. Base Car ‘12 Seat Exeo ST Sport Tech.

[Nollywood]

Hey guys!

I trust everyone’s well.

Over the next few weeks, I will be documenting my build. I started in the B6 section of Audizine. obviously with a B6 Avant Quattro as my base car, but I am now having a change of direction.

I am looking at B7 Avants. I will either purchase a 2007/8 B7 Avant Quattro, or as prices for non-Audi B7 models have dropped...

No, not a Volkswagen Passat B7. I don’t dig the transverse engine layout. How it came to be regarded as a B7 chassis, I have no idea.

I will be looking at the B7 Seat Exeo ST. For those not in the know, this is the B7 Avant in the Seat range! ST is Seat’s version of Avant. It was built from 2009 - 2014, with some cars registered as late as 2015! What better way to get a new-ish B7?

I’m looking at the 2012 MY. And I’m looking at the Sport Tech trim. This has all the toys - BOSE, Xenon headlamps (not that they’ll be staying anyway) and of course, the latest LED RNS-E. It also has leather sport seats, with bolsters much larger and body-hugging than B7 A4 Sport seats.

Yes, FWD only, but with the s**tload of work I’ll be doing to it, both body and engine / transmission, converting it to Quattro is cake. I have converted a 2004 B6 A4 Sedan, and it was a weekend’s work, all bolt-in.

 

[Nollywood]

I will be updating this thread as I go on. Some relevant snippets from the B6 project will be posted here. Timelines may be off, as I will be copying and pasting a bit of what’s already been covered elsewhere, but please bear with me.

The main ingredients:

POWERTRAIN

Built C5 RS6 motor.
OEM C5 S6 8-bolt crankshaft.
Vibra-Technics aluminium Motorsport engine mounts.
Vibra-Technics aluminium Motorsport transmission mounts.
Steel single-mass 8-bolt flywheel.
Custom intake plenum, with liquid cooling.
Custom exhaust manifolds, V-banded.
EFR 6758 twins, V-band fitment.
OEM B8.5 S4 radiator.
Wagner C5 RS6 intercoolers.
Custom wiring harness.
Built 01E 6-speed manual, from 2002 C5 A6 2.5 TDI. Geared to do 37.2 mph / 1000 rpm in 6th.
B5 S4 front subframe, with solid aluminium bushings.
OEM B7 RS4 exhaust, from CAT’s back.
B6 A4 2.5 TDI manual front axles.
B6 A4 2.5 TDI driveshaft.

EXTERIOR

OEM B7 RS4 rear quarter panels.
OEM B7 RS4 side skirts.
OEM B7 RS4 rear doors.
OEM B7 RS4 / B8.5 S4 front fenders.
OEM B8.5 S4 bonnet.
OEM B8.5 S4 lock / radiator carrier.
OEM B8.5 S4 BiXenon headlamps.
OEM B8.5 RS4 front bumper.
OEM B8.5 RS4 grille.
OEM B8.5 S4 aluminium electric folding mirrors.

CHASSIS

OEM B7 RS4 wheels. I have these, but spec is subject to change (what isn’t)?
OEM B7 RS4 front spindles.
OEM B7 RS4 brakes.
Ohlïns suspension, with remote reservoirs. Spec to be determined after car is built and corner-weighed.

INTERIOR

This will stay close to stock, with the exception of:

OEM Recaro wingbacks, personalised for my car, embossed logo and green stitching.
OEM B7 RS4 or stock Seat Exeo sets trimmed to match fronts.
OEM TTRS flat-bottomed steering wheel, with green stitching.
OEM B7 RS4 gear knob and gaiter.
Custom Carbon Fibre trim, with green in the weave, to match the Audi Apple Green Metallic exterior paint.
OEM B7 RS4 charcoal headlining and associated pillar trims.
OEM B7 RS4 instrument cluster.

There’s plenty I haven’t included, which I will update later. I will also be selling off a lot of parts I purchased when the project car was B6-based. I will also be parting out my Denim Blue car. Obviously, the Quattro drivetrain sans 02X transmission will be retained.

The rear subframe will be removed and inspected. If it is rusty, it’ll be tossed in favour of a replacement. Otherwise, it’ll be sand-blasted, treated against future corrosion, then painted in the original satin black, and fitted with solid aluminium bushings.

 

[Nollywood]

C5 RS6 motor:

C5 S6 crankshaft:

C5 RS6 stock ECU and harness:

 

[Nollywood]

OEM B7 RS4 CAT-back. Donor car had only covered 11,500 miles before upgrade to Milltek:

 

[Nollywood]

B8.5 S4 electric folding mirrors:

 

[Nollywood]

OEM B7 RS4 9.0’ x19” wheels, refurbed with diamond-cut faces, grey inserts:

 

[Nollywood]

OEM B7 RS4 panels:

 

[Nollywood]

OEM B8.5 S4 fenders arrived a couple of days ago:

 

[Nollywood]

Most older-generation Audi engines had rough valve covers. Not much was done to make them look pretty, as they were covered in tons of plastic. The C5 RS6 was no exception.

I decided to at least smarten the motor up, as I won’t be covering it up with plastic, or carbon fibre. I purchased a pair of D3 A8 4.2 non-FSI valve covers. They will be painted to match the exterior of the car:

Stock C5 RS6 valve covers. Urgh!

D3 A8 non-FSI valve covers:

And the matching front timing belt covers:

How they’ll look painted - this was my last B5 V8 swap, that ran a BFM motor from a 2004 D3 A8:

- - - Updated - - -

 

[Nollywood]

My aim with the motor, is to go stage 3 from the onset.

Since it’s out of the car, and I’m doing a rebuild, it makes perfect sense. I am building it to support 850hp. I may end up with 700hp instead. Who knows? But I at least want the option of a higher “ceiling” so if I decide to push the envelope further, at least I can.

 

[Nollywood]

My choice of engine mounts has always been Vibra-Technics. They are a British firm, so little known outside the EU. I have used them since my VW Golf I/II and Audi Coupe Quattro B2/3 days, and I have never managed to bust them, despite beating on the cars all day long, with hard launches.

The mounts:

 

[Nollywood]

When I built my first B5 V8 back in 2008, there were no online resources to guide me, as the 077-series V8 had never been installed in the B5 chassis by a privateer.

As a result, there were no flywheel options, for the 10-bolt 32V 077-series V8. I approached TTV back then, as I lived a 5 minute walk from Toby Crisp. I explained what I wanted, gave him a B5 S4 8-bolt flywheel, the flexi-plate of the 32V auto, and got his firm to knock up a suitable flywheel, making it -11.2mm, which meant losing the B5 S4 spacer.

I subsequently got these flywheels made for 8 and 10-bolt applications. I then thought the 1.8T 228mm clutch could do with a 240mm upgrade. Handing over a crusty B5 1.8T flywheel, and using the existing profile of the B5 S4, the 1.8T 240mm flywheel was born. Meaning they could run a single-mass with 6-bolt fitment, and the B5 S4/RS4 clutch.

Back to the present. I am running a TTV flywheel, as I always have. This will be mated to an uprated B5 RS4 full-face clutch. I don’t like 6/8-puck clutches. They feel nasty for daily driving, and they chew up flywheels pretty early.

My set-up:

 

[Nollywood]

There are a few styling cues I wish to retain from the Seat Exeo ST. Starting at the read - I like the way the screen dips to a point on the tailgate. It gives the B7 a more modern look. I will be cutting up a B7 A4 Avant tailgate skin, and blending it into the B7 Seat ST tailgate.

A hell of an operation, that requires a lot of skill and patience, so the metal doesn’t warp:

B7 Audi Avant and B7 Seat ST rear ends compared:

 

[Nollywood]

Seat Exeo interior is bolder too, I like the mix of TT / B6/7 Convertible touches:

B7 Audi A4 interior:

B7 Seat Exeo interior:

 

[Nollywood]

Rolling shots of B7 Audi Avant, and B7 Seat ST:

 

[Nollywood]

One of the issues encountered by C5 RS6 owners converting their cars to manual, is coding.

By this, I mean coding the ECU to have the characteristics of a manual. This allows the idle to be lower, prevents “rev hang” when clutching down for gearshifts, and generally makes drivability smooth. It also permits cruise control to function.

As the C5 RS6 had no manual option, the ECU has no option to be soft coded to control the engine as a manual. It will also trigger the ABS and ESP warnings, they will be non functional as a result. As the ECU will be looking for the absent TCU in the original Tiptronic car, a CEL will be triggered, putting the ECU in limp mode.

I am avoiding this, by running 2 x B7 2.0T ECU’s. And a custom wiring harness, based loosely on 2 B7 2.0T items. The B7 ECU’s of course will be 100% compatible with the B7 ABS module, and more importantly, the B7 RS4 instrument cluster.

 

[Nollywood]

It’s almost unheard of for a Seat Exeo to make big engine numbers, but that’s exactly what’s going to happen here.

The Exeo was available with gasoline motors, but I haven’t seen any here in the UK. So the first item to come out of the car, besides the engine, with be certain wiring harnesses:

Engine bay.
Central distribution harness (dash).
Left kick panel harness.
Right kick panel harness.
Rear section harness.

The only harnesses that will remain, that have nothing to do with the car being an oil-burner or gasser, are:

Left front door harness.
Right front door harness.
Left rear door harness.
Right rear door harness.
Left lamp / license plate lamp harness.
Right lamp harness / rear wash / wipe harness.
Ceiling wiring harness.
Tailgate wiring harness.

It’s possible to retain all the wiring, and add the gasoline-specific wires - fuel pump relay, fuel pump etc, but I won’t this build to be OEM, with little or no splicing of wires.

All the removed harnesses will be replaced with the wiring from a 2007 B7 2.0T gasoline.

 

[Nollywood]

Complete B7 RS4 Avant charcoal head lining, with associated pillar, sun visors, grab handles etc. The driver’s visor has the Audi garage opener, which is great.

 

[Deleted member 103408]

Is there a big weight difference in new vs old engine and do you have to change anything on the suspension.

 

[Nollywood]

Is there a big weight difference in new vs old engine and do you have to change anything on the suspension.

The 4.2 V8 40V N/A is 200 kilos, which is exactly the same as the iron block 2.7 V6 BiTurbo 30V Audi engine.

The C5 RS6 4.2 V8 BiTurbo 40V 230 kilos.

Suspension spec is in the opening thread, I believe the 2nd post where I listed the ingredients.