[200q20v] 2pc EM p/n

[QSHIPQ at aol.com]

Not with you Phil.  First off Ken, the 034 145 880 number is part of the 2pc 
manifold "complete", it's the late style mounting bracket that supports the 
back of the EM (attaches to 2 trans bolts).  You also will want the later 
style (longer) EM studs, and the late style washer/nut combination.  These 
parts can be used on the single pc manifold as an "upgrade" as well.

WRT Phil's comments on the 2pc EM...  The motor mount should be replaced to 
address the pulling of the #1 EM stud, and the loosening of the turbo to 
downpipe nuts.  IME, the motor mount really isn't the primary problem wrt 
cracking of the manifolds, either the single or the 2 pc.  The cracking, IME, 
results from the heat cycling of the manifold, causing warping of the EM, 
which causes stress cracks on the manifold itself.  Stock turbo EM's tend to 
not have any cracks, tweeked cars almost always do, single or 2pc.  

One of the best mods you can do for either the single or the 2pc manifold is 
to heat cycle it, then remove it and have the head mating surfaces ground 
flat.  IF you have the head off at the same time, you also want to have the 
head to EM ground flat as well.  I've done several 1pc manifolds over the 
years, and find that grinding them flat and reinstalling them with the 
superceded studs and washer/nuts, virutally eliminates the cracking problems. 
 Running lean, or with a leak in the head to downpipe circuit can change this 
in a hurry.  The real problem with the I5 turbo EM, is it's length and 
closeness to the turbo causing heat related failures.

Right hand motor mounts should be replaced as a matter of course every couple 
years.  Heat shields are important to the longevity of the superceded 
hydraulic mounts.  In the 44t chassis, that hose that goes from the oil 
cooler duct to the motor mount is key to keeping the motor mount intact.  
Unfortunately for the urq boys, more fabrication is necessary to assure the 
hydraulic mount doesn't fail.  Heat shielding is NOT enough.  IME, the 
hydraulic mounts need cooling airflow to them, and the urq doesn't have it 
from the factory like the 44t does.

IME, motor mount failures don't cause cracking manifolds.  Motor mount 
failures cause #1 stud to pop, then #5 upper if not addressed, then #2 lower, 
then downipe/turbo studs pop.  All this *can* happen to a manifold that's not 
cracked, btdt on my 83 urq.  Running a turbo motor with leaks in the EM/Turbo 
circuit cause heat related cracking, but this is all secondary (incidental) 
to the motor mount failure.

Your best prevention to popping studs and cracking manifolds?  Get or heat 
cycle the EM, machine it, use new mounting hardware.  Use or retrofit -880 
bracket to either the single or 2pc manifold install.  Make sure your Cat 
support bracket is installed and not rusted thru (you can retrofit the pre 84 
urq downpipe support bracket to all turbo cars as well, it's a good mod)  40k 
changes of O2 sensors maximum.  Ck the motor mount regularly, especially in 
tweeked cars.  Get cold air to that motor mount to extend it's life.  Also, 
take a couple minutes after hot driving to allow the EGT to lower.   Shutting 
down hot turbos increases heat stress on all turbo components.

WRT discussions on the Dialynx.  My take on the Dialynx manifold is this:  
They attempted to correct the inherent design problem of the single piece 
manifold, *before* audi addressed it with the 2pc manifold design.  It's not 
"bad" per sae, just a link in the progression from the 1pc to the 2pc audi 
part.  In fact, a Dialynx manifold ground flat can last a long time as well, 
and is built like a tank IMO.

My .02

Scott Justusson
QSHIPQ Performance Tuning
'87 5ktqw 2pc manifold
'84 RS2URQ
'83 URQ single pc no cracks






Phil writes:
I'm entirely convinced that the cause of cracking is right hand engine 
mountfailure causing the sump to sit on the subframe.  The resulting 
HAMMERINGupwards on the bottom of the block just makes the already 
questionablesuspension of the whole turbo and downpipe weight on the manifold 
franklyludicrous.Twp-parts also crack.  If you don't fix the engine mount and 
heatshieldissues, in about 10,000 miles.  You might make the argument that 
only thefront part of the two-part cracks, but the saving is minor.  We do 
not fittwo-parts to ur-quattros, and I'm beginning to wonder whether 
they'rejustified on Type 44s.