barney55

I've read all of the posts about heat,BUT our engines are surely situated lower

than any other car on the market that i can think of.

Imagine with the cover off, and hitting a rock/piece of wood,any old piece of road

furniture at 80mph on the highway,if that gets flicked up in the engine area,it

could puncture a Cat ($2000 thanks) smash a heat shield or rocker cover etc.

My take on the cover is this:

1. Protect engine bay.

2. Catch oil drips.

3. Aid aerodynamics at high speed (germany only i would guess).

4.Sound deadening.

And maybe others.

Mr.Alex

Well if you avoid flying debris you won't have that fear, and I think that if anything of that magnitude makes its way under you it will unsettle the car and give you worse problems.

But other than that, I'd rather know where my oil drips are than having the cover catch them, and nobody I know wants sound deadening on that aircooled engine. If anything its the reason so many people get the car in the first place. But to each their own.

dhc905

Perfect world. Also have fun going over speedbumps worrying whether you're going to ding the case.

There was a post here recently about a 964 (maybe 993) and a Boxster that hit a pothole around a corner and the guy hit his case pretty good. The boxster ruptured a bunch of oil tubes.

If you feel 11lbs of sprung weight at the lowest point of your car, or believe in the la-la-land story about it messing your valves, have at it.

Ken D

None of the previous 911 road models - from 1963 through 1989 - had an undertray. For that matter, neither did its predecessor (the 356) from 1948 through 1965. How many instances of engine damage are you aware of due to the lack of an undertray? You can even include the cars that ride stupid low.

As has been made clear in prior posts, the undertray was not installed for protection. It was to allow the 911 to meet European noise regulations.

dhc905

In my post for one. I read it in the last few weeks, I'm sure you can search for it. Better question is how many cars DO NOT have an engine tray. The exist on all Porsche's since 1989 and non-Porsche for a lot longer.

Just like airbags. And other innovations for safety, comfort, and design. Don't think saying all the old ones don't have it is good logic for taking it off.

Tmistry

I think this debate is feeling circular. I don't use the tray just because it's a pain to remove and I don't want added weight or extra heat, regardless of how small.

On my 997, I installed a lightweight engine cover plate for protection. I liked it and it may have even acted as a heat sink. Anything like that available for our 964s?

Ken D

The incident you refer to with resulting damage was on a very low Boxster, and not a 911 (the thread is in the 993 forum and was posted by Foxman).

Did the Boxster suffer the damage with its engine tray intact?

So hundreds of thousands of 911s have been produced without engine trays, and you can point to one incident, and it was a Boxster, which in the absence of contradictory evidence, most likely had its undertray installed.

It's clear that there is not some epidemic of engine damage in 911s or 356s (or millions upon millions of other vehicles, for that matter) due to the lack of an undertray.

Again, the undertray is not a safety device. If it makes you feel safer to run with one, that's your business.

Moving on from this thread now.

Duck

Seems like major concern is heat, unless your car is super low. So it also seems that we could put this to rest if we knew factually whether the tray elevates heat at the cylinder heads. I still think someone could do a simple test with a scantool, PDT-999, KTS301, etc. to read actual head temp. Run the car without tray until operating temp, then idle say for 5 min, measure temps, and then do the same with the tray on. Need to have same relative outside temp and humidity, but since the tray is easy to remove, could do it on same day with fairly stable temp. Again someone more knowledgeable could suggest a better test procedure in terms of running the engine and when to take temp readings. I would do it, but since my engine is missing right now, my results would not be very accurate.

Otherwise, we should all do whatever we want. And even after the experiment is completed, we should all do whatever we want - at least more informed with data.

Earlydays

...if everyone believed the "experts" like Bruce Anderson, no one would have bought the 964 in the early days!

deadendd9009

Anyone claiming the undertray protects anything...its made of plastic, not going to save much!

I took mine off because of accumulated heat as there is not enough ventilation with it on.

dlpalumbo

Everyone's concerned about overheating, but my car (90 C4) doesn't warm up sufficiently in Winter. I live in SE VA, temps aren't that cold here. Once the cold weather does set in the car rarely opens the thermostat. This causes condensation accumulation in the oil system. I get a good bit of water draining when I change oil in spring. This bugs me.

I actually sourced an engine tray with the thought of putting it on in Winter so the card would warm up on the way to work. What stopped me was the abundant oil leaks. I go in for a reseal next week to stem the flow.

Only time will tell if I'm motivated to put tray on in December. From this discussion, and considering how much colder it is in Germany, I suspect the water accumulation is common and not an issue.

Dan

DobermanDad

Could you drill a few drainage holes in it?

Mines off and staying all. I also remove all the brackets I could that it mounted to. Much cleaner and less fuss to work on. I also, only drive mine in the summer / fall.

Duck

I believe dlpalumbo is referring to the oil condensation in the oil tank. When the car does not run enough at temp in cool, humid climates, water will condense in the oil tank. When you go to do an oil change, a rush of water comes out with oil. I have definitely seen it with mine in the winter.

Does sound like a plausible reason to run the tray in the winter especially if the drives are not very long.

dhc905

Thanks. Found it.

Do not know, but they stuck a 997 engine in the boxster, so it very likely lost the engine tray.

Well, read what he said: Well yes, it does. You may never have played baseball with a cup, but I like to protect (even with plastic) my important parts.

abarthguy

I should point out the instance I had bottoming the case out on a severe dip in the road. Quite a loud bang on the case !!

No under tray, no damage.

The reason it bottomed was the blown out motor mounts and original shocks with 128,000 miles on them.

New mounts and Bilstein shocks made all well.

These cars are made for a wide variety of road conditions without the tray.