FormulaRX

Has anyone really tested to see if removing this makes a real world improvement in cooling?

Derek911

I think the main reason for taking it off is maintenance. Part of maintaining these cars is a regular visual inspection. I am fortunate not to have any leaks, but I still like to look everyone time I check the oil. I rather catch a leak when it develops rather than a tray holding it until the engine is covered in oil. Some cars weep rather than drip. You will never see a drip but there will still be oil. With the tray off you can monitor it and keep it clean. If you have a daily driver and drive on salty winter roads, then the tray may serve a purpose. As far as aerodynamics, how many of us is pushing it hard enough to worry about lift?

kos11-12

In Germany there is little speed limits on motorways , Italy too
If you track your car you see often 130 + depending on track

C4inLA

Took a tuneup class back in 96' with Jerry Woods and Bruce Anderson. They mentioned noticing excessive and early exhaust valve guide wear when doing teardown and agreed with suggestion to leave tray off. The question I would have is who has proved it makes a difference? Mine has been hugging a wall since then.

porscheandy

Took a tuneup class back in 96' with Jerry Woods and Bruce Anderson.
Sorry for the Noob question, but as an aspiring wrench, where do you take classes like that?

cscrogham

You won't be taking classes with Bruce, he passed a few years ago. His manuals and teaching notes are available online by Googling his name, or his widow Stephanie who has an ad in pano. Not sure if Jerry is doing those any more, that was pretty much Brice's thing. I did a few on the east coast myself, then decided to put the engine assembly piece into book form for iPad or hardcopy. 911 Engine Handbook.

g60pops

I run with the undertray and plan on keeping it on.

Porschenut_Lee

This is good because someone needs to keep the engine rebuilding guys busy.

Goughary

Every guy on rennlist, since its inception, that opens and rebuilds 911 motors for a living, has said to leave the engine tray off due to damage done by heat buildup. Every one.

There are 1006 pages on rennlist if it's sorted with 50 threads per page. Go back and find one. Just one. Where anyone that actually builds or rebuilds these motors for a living, where he said the opposite.

And then put you tray on your car and pray you don't get stuck in traffic on a hot summer day. Sharks have to keep moving or they don't get oxygen (air)....911s w engine trays are the same. If you stop moving, you don't have enough convection to suck enough air up through for cooling. When you are moving, if you have removed the sound deadening material, you'll be ok...

C4inLA

Well said. Maybe I'll nic name my car Sharky maybe not ... It does make you wonder why the engineers didn't pick up on this ....