Some pictures.

B5 1.8T crossmember - the cut out section will have appropriately shaped steel welded in:

 

More pictures:

 

As I may have mentioned, the B6 S4 decats I bought did not fit. Well they did, but with their dummy catalysts quite high up - B6 S4's have them in the same location as B5 1.8T models, rather than alongside the transmission (B5 2.8) they were pretty tight against the B5's frame rails. They would vibrate like crazy, and the heat in contact with the frames...

I have now ordered a pair of Milltek B6 S4 decats. They are pretty similar to C5 S6 items, just pipes, no dummy cats. So fit will be fine. At least I can then get the underneath buttoned up - exhaust, driveshafts, propshaft and lower arms. I still haven't got a 4.11:1 rear differential yet, but if it comes to it, I can remove the rear differential from my B5 2.5 V6 TDI Quattro, and replace that one later.

I can't wait to drive this car.

 

There hasn't been much happening with B5 420-R.

I am waiting for my Milltek downpipes to be delivered. They are decats, but my car will need cats to pass emissions. I do have a friendly tester who will look the other way, but it's worth having a pair of cats anyway. I will most likely purchase a pair of Magnaflow 200 cell HFC's, and stainless V-band kits.

Then cut out a similar length section from each downpipe. The cut sections will be V-banded, so will the HFC's making swapping between cats and cecats easy.

These are what I ended up pulling the trigger on:

 

Nollywood,

What a fascinating chronicle of patience and perseverance; swapping and bartering; sourcing and resourceful modifications.

I can't wait to see the pics of the completed project, and if possible please post a video clip of the car running with full sound. I'll bet it is outrageous!

Well done and I'm really pulling for your successful completion.

 

Thanks man!

 

Update: 09th January, 2016.

My Milltek de-cat pipes arrived yesterday, and today I installed them.

For those who may be interested, Milltek no longer produce de-cat pipes for the C5 S6. The set I purchased are for the B6/7 S4 with manual gearbox. They are well made, and pretty pricey, as you would expect of Milltek products. It was a big gamble, as I had no idea if they would fit a 40V in a B5.

They fit as well as the original pair fit the 30V. The only bug is the bracket that bolts to the transmission. It interferes with the 01E mounting brackets - the B6 S4 runs a DTS-style gearbox cradle. I ground them off, I'll get appropriate brackets welded in the right place to bolt to the 01E once I can drive it to a shop.

One more aspect to note - the B6 S4 downpipes don't have gaskets to fit the manifolds. The collars are free floating, with the ends of the pipes flared to mate to the headers, which are domed to match, forming a gas-tight seal. I opted to run B6 headers too, which are a direct fit to the 40V motor.

B5 V6 / C5 V8 downpipes have fixed collars, and utilise steel laminate gaskets to seal against the headers, which have flat mating surfaces. The B6 S4 downpipes will NOT work here. Options are:

Cut off the Milltek flared ends and floating collars, and weld on V6 flat ends, with fixed collars (complicated).
Fit B6 S4 headers (easier).

I have fitted the B5 RS4 propshaft, so it's bolted to the 01E and the central mount is bolted to the frame. The rear end is not bolted to the differential, as I need to replace it with the correct 4.11:1 ratio unit to match my 01E. This means I can't fit the rest of the exhaust yet.

Clutch is fine, I've also set the shift lever position, allowing me to fit the inner sound deadening, shifter surround and my custom aluminium shift ****.

Next will be the installation of the front axles and lower arms.

 

 

Update: 10th January, 2016.

A satisfying day.

I installed the Milltek de-cats yesterday, so I was able to fit the S4 front axles. o2 sensors fitted too.

As I posted previously, the angle of the aluminium radiator pipes was wrong, and will need addressing. I have cut the inlet and outlet pipes at the right angle to be welded to the radiator. The modified 4 cylinder front crossmember also needs to be welded (boxing the notch). I've loaded them into my B5 2.5 TDI V6 Quattro's trunk, they'll be dropped off at the shop tomorrow.

Aircon hard pipes to compressor have been connected, with new O-rings.

For an OEM airbox solution, I had purchased 2 to choose from - C5 S6 and B6 S4.

The S6 airbox can be used, but I'll mean either running the S6's throttle body intake, or cutting the D3 A8's intake pipe down. I'm not keen on treading this path.

The B6 S4 airbox is better suited to the BFM engine and throttle body intake, which is what I ended up using. I need to cut off the lower mounting pegs, and make my own to fit the rubber bungs in the B5's frame rails.

My motorsport trans mounts are not right - they are too thick, meaning the 01E's shift linkage it really close to the transmission tunnel roof. I have spoken to the supplier, and they are sending me another set. The ones I have are okay for an 01A, where the shift linkage goes into the transmission tail, they are sending me a set that will work with the 01E. In the interim, I'm using the stock 30V mounts.

Some pictures of current progress.

Pictures showing B6 S4 airbox. Ignore the spiffy MAF connection, I haven't fitted a worm clip, as the airbox is coming back out, so I can install the SAI pump below the frame rail:











Under shot showing Milltek de-cat pipes:

 

I've got an engine pull over the weekend, so nothing much will change on B5 420-R.

Powertrain-wise, before I can crank the motor, I need to plumb in the oil lines to and from the RS6 C5 sandwich plate, to the 10-row oil cooler. The same needs to be done for the 01E.

I still need to get the appropriate 2 female connectors into terminal 1 of the red chassis plug, and terminal 5 of the brown plug. These are for the reverse lamps, an easy fix.

SAI pump needs to be mounted, and plumbed in. Electrical connector is already in place.

Radiator needs to have the pipes welded in place, and my notched 4 cylinder crossmember boxed up. After these are all fitted, I can fit the bumper.

Most importantly, I need to get the rear differential swapped, then the rear of the propshaft and the rest of the exhaust can be fitted.

Getting there.