worf928

I have one 'extra' right-side (passenger-side for LHD) duct for the plastic undertray for '87+. One of my clients does too.

Anybody out there have two left-side (driver-side) ducts?

We could do a trade and each have a complete set.

Or maybe someone has an orphaned left-side duct and a buck or five would lever it out of your hands?

Adamant1971

No extras, but I need a right. Name your price.

ROG100

I have plenty for $395 the pair - brand new factory parts.

Alan

Man with 2 right side hen's teeth seeks someone with 2 left side hens teeth...

it may be a long shot

Alan

worf928

And are riveted to a plastic undertray which you get for free

2 right hen's teeth are better than one or none.

Let's see if there are any left ones hanging out.

Alan

Dave - Indeed but its a small club.

I started out with a right side hen's tooth riveted to half a plastic undertray (so exactly half of what Roger offers...). Bill Ball helped me out with the remaining one - so its possible to get lucky.

They are now both safely riveted to a 928Intl aluminum undertray tray so they won't decide to go 'walkabout' again.

You planning the same?

Alan

worf928

From my perspective, my client (chart928s4) has a Schrödinger Under Tray. I do know that he has a right duct.

I have a right duct from another client's car still riveted to a mostly-dead discarded plastic tray.

If a loose left duct can be procured, I predict an aluminum under tray in his future. If not, it'll be a $395 duct and we'll still have two right one's between us.

I suspect Adam's rooting for the latter

FredR

I am in the "have not got one" club. I do have one of Carl's aluminium undertrays and remain well pleased with that after about 5 years of service and as I am convinced it provides a lot of extra protection compared to nothing.

Needless to say such trays are sold on the basis of relocating one's stock vents to the new piece- fine if you have them. My sub query [hopefully Dave does not mind] is whether someone can post a photo of what the vents actually look like with a 1 foot ruler next to them to give some scale.

As I understand these things allegedly act to funnel some "cooling air" to the motor mounts- whether there is any quantitative evidence to support this notion remains to be seen. I wondered if one could jury rig some of that hose that carries cooling air to the alternator to do the same thing.

Alan

Fred - don't have one with a ruler but this is what they look like.

IMO Hose is not going to work. BTW as you can see they are a part of the structural mounting support for the under-tray.

This may actually make them more likely to get fractured off the tray!.

Note the left & right vents are actually quite different.

Alan

FredR

Alan,

Thanks for posting the pics. Tends to support my last memory of them some 12 years ago just before my late S4 got trashed. Never thought to recover the assemblies as the under tray was trashed along with the a/c compressor in the wreck.

Not sure I understand your comment that they are part of the under tray structure support. My theory on the hose is that with a mounting adapter it might improve cooler air flow into the general area.

If my motor mounts take a dump within the next 5 years [they are currently about 5 years old] I will then know for sure they were needed!

Alan

See these - these are mounting points and the aligned holes in the trays are the access ports for the mount bolts.

On a stock panel having these solidly mounted makes a heavy impact on the under-tray there locally likely to fracture at the rivet mounts. On an aluminum tray the whole tray is much stronger. The mount points do at least keep the vents positioned correctly wrt motor mounts - again more of an issue with the plastic tray.

You can see on the face of the panel that the ports are a sort of NACA scoop inlet - and part of the scoop is in fact the vent. I think you'd need to create at least a port to rivet in that was a bit like this to feed your hose - then the hose section would be so short that you may as well just form a metal 'tube' section all the way to the mounts...

Porsche made these asymmetrically and not matching side to side and in very complex shapes - there is certainly a reason for this - I don't know what is is though

I'm trusting that Porsche knew what they were doing to spend a good deal of development time & effort and some incremental product cost $ to make these & the tray like this...

Alan

worf928

My personal opinion - no serious data here - is that lack of ducts accelerates the onset of "two-piece motor mount syndrome" (2PMMS for (not-really) short.)

https://rennlist.com/forums/928-foru...t-shields.html

FredR

Alan,

Thanks for that. On the stock plastic tray it probably needs all the support it can get- the aluminium tray is pretty solid and the two central bolts seem man enough yet alone the counter supports at each end.

It is reasonable to assume that Porsche knew what they were doing and why but I have found a number of things they did were quirky to say the least and these days if I see something that does not make sense at face value I tend to challenge it to the extent I can given we have an excellent community and lots of combined experience to make meaningful evaluations.

ROG100

OK I have to ask 8>)
Not long ago some where willing to sign up for the ducts at circa $600 a pair.
The OP is willing to offer $150 for a used left duct.
Me thinks that $395 for a brand new pair is not a bad price. $197.50 each

worf928

Re-read. OP made no such offer. $100 for a matching pair of loose ducts + $295 (IIRC) for the alOOminEEum pan = $395 for the OE plastic pan with ducts.

Thus, $50 per loose duct - assuming any specific duct requires no remedial work - seems to be a starting point, unless the preponderance of right ducts is statistically significant over a large sample of loose ducts in which case left and right side ducts may have different supply and demand curves.