Engine Undertray
11-23-2013, 07:01 AM
#31
button queen
As with the spoiler, we continue to display our shared ignorance. Could someone please weigh in who really knows something about the aero on this car and the tray and spoiler contributions there??
11-23-2013, 10:42 AM
#33
Beautiful Steve!! And I'm sure it helps keep that cooling tower on the ground at high speeds!!
As with the spoiler, we continue to display our shared ignorance. Could someone please weigh in who really knows something about the aero on this car and the tray and spoiler contributions there??
As with the spoiler, we continue to display our shared ignorance. Could someone please weigh in who really knows something about the aero on this car and the tray and spoiler contributions there??
11-23-2013, 12:33 PM
#34
Nordschleife Master
If you look at high-performance race cars and exotics, the entire underbody is covered to create a flat surface, ostensibly for low-lift racing dynamics (forgive my lack of proper racing vernacular). In principle, I can see the advantages of having a tray for high-speed driving/racing. That said, I don't believe there are any negative effects (or advantages) if your tray is removed, especially for street cars. My car came without the tray and I have no intention of replacing it.
I do not think the 993 tray is designed to create the same effect.
11-23-2013, 04:34 PM
#36
R.I.P
Rennlist Member
Rennlist Member
Every one of the 300,000+ mile 993s on this forum have had the tray on since new, and never had any major engine work done! Lots of lower mileage cars have had the tray off and needed engine rebuilds. Of course if the car sits most of the time in a garage, tray on or off doesn't matter.
11-23-2013, 05:58 PM
#39
Rennlist Member
There were a lot of 911's on the podium at extremely fast tracks like Le Mans, that never needed an engine tray for aero.....
A lot of those ran the "oh-so-crummy" 915 gear box too, figured I'd throw that in for good measure.
A lot of those ran the "oh-so-crummy" 915 gear box too, figured I'd throw that in for good measure.
11-23-2013, 06:12 PM
#40
Drifting
I have been on vacation where I spent the entire day driving (city and highway) at temps over 100. I had my tray on and didn't see any difference with the temp of the engine. I also tried removing it when I first bought it and noticed a "drone" from the engine while on the highway. I plan on keeping mine on.
11-23-2013, 07:40 PM
#41
Rennlist Member
The Service Information Technik Carrera 4 '89 covers the first use of an engine under tray and shows a picture of it titled "Engine Paneling" in Section 1, page 29 with the caption:
"Engine paneling is new. The underside of the car is paneled in plastic in order to reduce the reflection of noise"
Then reading the Service Information Technik Carrera '94 911 Carerra (993) on page 5-12 the Front, Center and Rear Underside Panels are discussed.
The interesting issue here is that the diagram of the panels does not show the engine pan, only the one under the front suspension, the one down the center of car and the one forward of the engine pan under the gearbox. The comments about them of note are:
"The underside (floorpan) is flat paneled for aerodynamic and thermal reasons. The panels also help to prevent the engine compartment from getting too dirty even in bad weather conditions"
"The center underside panels are made of steel panels (St 05) to increase crash protection and to improve torsional stiffeness"
"The rear underside panel...forms the trasition to the sill covers in the jack point/lifting platform support area".
No mention or picture at all of the under engine panel which is called a "protective cover" in PET.
"Engine paneling is new. The underside of the car is paneled in plastic in order to reduce the reflection of noise"
Then reading the Service Information Technik Carrera '94 911 Carerra (993) on page 5-12 the Front, Center and Rear Underside Panels are discussed.
The interesting issue here is that the diagram of the panels does not show the engine pan, only the one under the front suspension, the one down the center of car and the one forward of the engine pan under the gearbox. The comments about them of note are:
"The underside (floorpan) is flat paneled for aerodynamic and thermal reasons. The panels also help to prevent the engine compartment from getting too dirty even in bad weather conditions"
"The center underside panels are made of steel panels (St 05) to increase crash protection and to improve torsional stiffeness"
"The rear underside panel...forms the trasition to the sill covers in the jack point/lifting platform support area".
No mention or picture at all of the under engine panel which is called a "protective cover" in PET.
11-23-2013, 08:22 PM
#42
RL Technical Advisor
11-23-2013, 08:54 PM
#43
Rennlist Member
.
If I lived in the south or tracked my cars I'd probably remove them.
On a hot day when parking it in the garage after a drive, I will often leave the hood open to allow heat to escape. That seems to make sense for some reason.
Regards,
.
11-23-2013, 08:58 PM
#44
Technical Guru
Rennlist Member
Rennlist Member
Originally Posted by Greg Labadie
there was a guy from Canada that was going to do some cylinder head temperature tests with, and without the undertray. Did that ever happen?
11-24-2013, 01:28 AM
#45
Last episode undertray: do a heat gun test on track next Saturday....
https://rennlist.com/forums/964-foru...-saturday.html
https://rennlist.com/forums/964-foru...-saturday.html