More 2pc manifolds

[JShadzi at aol.com]

I am leaning toward Scott on this issue also.  It always blows my mind that, from the factory, Audi created no support bracketry for the exhaust manifold, other than a bracket lower down on the downpipe.  I suspect the reason is that any solid bracket would fail quickly with the wild expansions the turbo manifolds experience.  The TA race cars used a heim jointed support bracket to hold the weight of the turbo, the factory should have done the same.

The weight of the turbo/down pipe assembly is considerable, imagine the beating the poor exh. manifold, and em-studs take in a car cruising down the road hitting all kinds of road irregularities-all on top of the poor manifold glowing bright red over 1000F.

I think the best solution is a custom one, create a bracket with heim-joints that can move with the manifold, but prevents shock from the chassis from "bounching" the exh. manifold, thus keeping stress and shock out of the picture.

Of course, I have taken a completely different route with 80tq, I am building a heavy gauge stainless tube header, I will be posting pictures in a week or so, or email me and I will send a pic to you.

Javad Shadzi
80tq.com

In a message dated Fri, 26 Oct 2001  1:27:51 PM Eastern Daylight Time, QSHIPQ at aol.com writes:

> A couple of points to ponder Phil. You have deleted or don't consider the 2 pc or superceded 1 pc manifold support bracket necessary. FYI, ALL 10v N/A cars use EM support brackets. If N/A cars use them, all we turbo guys are adding is more weight. Hmmm.
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> Hydraulic motor mounts were on all 44 chassis cars since 1985. 1985, 86 or 87 10v non turbo cars consistently spit out exhaust manifold studs, when the motor mounts fail. Usually in the following order 1 upper, 5upper, 2 lower, 1 lower, following that rule of thumb is the turbo cars as well. N/A cars don't crack manifolds. It would be my conclusion then, that it's not the hydraulic motor mount that's the problem, it's the heat that's the problem. Add in lack of EM support, heat becomes more critical.
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> RE: No cooling ducts on urq's motor mounts. It was added to the 44t to help cooling of the motor mount located next to a hot turbo. FYI, non turbo 10v cars also have an exhaust system and heat shield close to the motor mount, and that motor mount fails too. Hence, cooling ducts to the motor mount are a good idea. Hydraulic mount failure is not limited to turbo cars at all.
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> The 2pc manifold is a good upgrade to all 10vt cars. Downpipe? Ding it, grind it, heat fit it. 100,000 rpm vortex? The urq downpipe is larger in diameter than the 200tq already (and part of the problem in 2pc urq fitment). Phil, you have posted before, that to clear the 2pc manifold you need 6mm clearance into the urq downpipe. Guess what? The urq downpipe is exactly 6mm larger than the 200tq downpipe. Sooooo, the ding might affect performance, but I'd expect no less performance than the 200tq downpipe. To really address the restriction in the downpipe, the turbo vortex is messed up at the cast flange at the front end of the downpipe anyhow.
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> The N/A cars have the same problems with failed hydraulic mounts popping manifold studs, not cracking manifolds. The 10v N/A cars also support the EM, all of them. Not supporting a 10vt EM manifold causes heat failures, and more of them. 
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> IME, anyone claiming motor mounts causing EM stress cracking, hasn't looked at a N/A car with a failed motor mount. Failed motor mounts cause stud failures in manifold attachment, heat cycles cause stress fractures in the manifold. 
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> My .02 arbitraged thru the peso.
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> Scott Justusson
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> Phil writes:
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> Yes.  It doesn't bother you, but Audi has deleted the one-part manifold
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> originally fitted to the MB and MC engines, replacing it with the one-part
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> fitted to the WR and WX.  The difference is in wastegate control - the WR/WX
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> uses exhaust gas pressure conveyed from an orifice just above the turbo
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> mount and the MB/MC use (depending on engine level) either unthrottled or
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> throttled inlet manifold air.  If you're ordering a one-piece for an MC, you
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> have to order the plugging screw - it's listed on the FPA, though not
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> clearly.  Otherwise a normal stainless bolt will do.
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> We see about five ur-quattros a week in the workshop.  Two will usually be
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> for cracked manifolds.  We've never fitted a two-part.  It doesn't fit
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> anyway - you have to bash one hell of a dent in the downpipe to clear it,
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> centimetres from the turbo exit with the´gasflow in a 100,000rpm vortex.
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> No cooling duct on an ur-quattro - that's a Type 44 issue.
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> I'm buying another Type 44 next week with a cracked manifold, and I'll
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> probably put a one-part on even though officially it should have a two-part.
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> I know the engine mount is gone.
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> > Do they not have problems after that?  Assuming a good engine mount. I
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> know Aelred can't say the same - I've got the proof.
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> Never seen a problem - never had a customer come back.
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> > In that regard, not that I would want to let the mount go bad and
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> > transmit those shocks, the cryogenic treatment would help prevent the
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> > cracking due to relieving stresses and increasing strength.  I "was"
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> > thinking mostly heat expansion at different rates was causing the
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> > cracking, not so much shock.  But now I can see where both are
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> > potential problems.
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> The quick test is a piece of paper.  Get under the car and see if you can
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> slip it round on top of the subframe.  If it gets stuck, the engine is on
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> the subframe.  With practice, you can spot it from the front of the car by
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> the shape of the sump protrusion - a couple of years ago I spotted about
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> fifteen in an hour when we brought 240-odd ur-quattros together at
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> Silverstone - I think all also had cracked manifolds  I keep meaning to
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> take a 'good' and 'bad' front picture - if the car is cresting a slight rise
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> it's incredibly easy to see.