been busy figuring the clutch pedal and just about got it then daily a8 went down.
started smoking and low coolant warning......Hose to expansion tank was rubbing head and right over exhaust manifold im surprised it lasted this long. Put a pipe going around that corner and then sealing repairs up the bulkhead AC/bleeder pipe broke and sprayed me. this car got me a second time HOT!! this event reminds me to replace plastic side tanks= aluminum radiator, expansion tank and air bleed pipe coming off radiator!!
however what i have learn about clutch's in this time is hydraulics!! Master needs to be sized to flow enough with petal setup and slave's bore size. AND the aftermarket master come in different size bores weather for same part, exterior dimensions wise! while looking for masters i noticed some cylinders MAY NOT indicate bore size within part number, some are embossed with a bore size.
so id advise just get a matching master cut hole large enough, BUT leave enough material to "grab', to install cylinder while pedal cluster is in car and booster is in the way. then you can slip it in and a custom 'washer' with spacers to bring it to clearance and to back it up.

P.S. At first thought i was gonna replace motor when it started smoking and spend sometime confirming you can run a 4.2 on an engine stand / bench / standalone with motronic 7.1. Previous post stating couple of power wires to ecu should operate it ...nah. for a least the a8 you need to power injectors and spark plugs' primary circuit . Motronic only grounds these items. so i got it to idle with petal connected although did not respond to them. so below connections maybe wrong or the accelerator was bad i dont know at the moment. as well some are found in wiring harness which will differ. some are possibly WRONG and some maybe the same connection just a bunch of notes from different sources but it ran
001 GROUND
002 GROUND
032 GROUND
108 GROUND ??
072 accelerator pedal pin 5 green
073 accelerator pedal pin 2 yellow/lilac
033 accelerator pedal pin 4 grey/yellow
034 accelerator pedal pin 6 brown/green
035 accelerator pedal pin 1 yellow/blue
036 accelerator pedal pin 3 brown/red
065 fuel pump
039 clutch petal
055 cruise control brake pedal pin 4
056 brake lamp pin 2
062 constant 12v
003 constant 12v ??
023 constant 12v ??
021 ECU fuse s102 black/green (Plenum 10-pin connector BLACK)
xxx spark fuse in Plenum black/yellow OR wire @ (Plenum 10-pin connector BLUE pin 1)
xxx injector fuse in Plenum yellow/black or black/grey
xxx ECU power black/green (Plenum 10-pin connector GREEN pin9)
****radiator dimensions about 33x18x2.5

 

After all the transmission measuring I still get tripped up by the clutch. My slave still isn't disengaging the clutch. So to test outside the car.....

I found two different length stock plungers. I measured assembled and found my setup needed half inch extension, just threw a bolt in there and it works!!




Locked the front axles, put in gear, depressed clutch and you can free spin the rear🥰🥳🥳


Just views of clutch petal clusters, holes and spacers for the master cylinders that's I found.
And found out wrong flywheel is why I had to modify starter. Flywheel I had was dual mass but tone ring was spaced wrong. There's a gap in between starter ring gear and tone ring space for starter nose to fit. Swapping in correct flywheel and putting clutch hydraulics in soon. i dont recall which car i pulled it from

 

sorry repeat post, trying match this with audiworld
made the bottom air bag base, design top base and how to extend an anchor point on the chassis and subframe out some to get bag in the clear of everything but the sway bar. i want to keep the stock spring setup.
alt idea is a helper bag INSIDE the rear springs, no changes to car this path.
also got some ideas on rear diff and transmission clamp plates so i can possibly drag race her. remake the rear diff hanger for through bolts to a front plate with a hole for the input shaft. lastly two side plates holding the ring gear from pushing out. then similar setup on the transmission(front diff)