Engine undertray
11-08-2010, 11:38 PM
#136
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I do firmly believe after reading and from your info that the tray is a very big intricate part of the 993's aerodynamics. I think a lot of people would agree. Even though we agree, the engine tray "myth" came about because it supposedly caused premature valve wear and most were told at the expense of losing some of the aerodynamics and ground effects. Here lies the main questions. The tray is indeed for stability. Does it actually retain engine heat and cause valve wear? If it does then what is more important to people? I'm going to cut mine in half and put half of it on. I don't know what to do yet. Until I do I'll just keep it nearby ready o bolt back on
Let’s all get real ... do we all think that car manufacturers go to the expense of adding an undertray’s for the sake of extra cost to themselves (to think this or to try and prove otherwise would simply be ridicules) - I really do hope that this clears up this matter otherwise we might as well start a thread stating " Porsche were/are a bunch of jokers for adding an undertray" as are the rest
Do not worry about your engine “this, that, and the other”, just enjoy your car for what it is = Perfection
11-08-2010, 11:40 PM
#137
Burning Brakes
To be honest with you whether it be for street or track I'd just leave the undertray on as Porsche and all other car manufacturers designed and intended.
Let’s all get real ... do we all think that car manufacturers go to the expense of adding an undertray’s for the sake of extra cost to themselves (to think this or to try and prove otherwise would simply be ridicules) - I really do hope that this clears up this matter otherwise we might as well start a thread stating " Porsche were/are a bunch of jokers for adding an undertray" as are the rest
Do not worry about your engine “this, that, and the other”, just enjoy your car for what it is = Perfection
Let’s all get real ... do we all think that car manufacturers go to the expense of adding an undertray’s for the sake of extra cost to themselves (to think this or to try and prove otherwise would simply be ridicules) - I really do hope that this clears up this matter otherwise we might as well start a thread stating " Porsche were/are a bunch of jokers for adding an undertray" as are the rest
Do not worry about your engine “this, that, and the other”, just enjoy your car for what it is = Perfection
11-08-2010, 11:54 PM
#138
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If anyone is looking for an engine undertray, I know of a couple 993 and 993 turbos ones that are just sitting around that the owner would sell if he got an offer.
11-09-2010, 12:00 AM
#139
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^ Evan ... engine undertrays just doubled in value on eBay 
Mate did you finally sell you 993 race car? we might just be interested if you could PM me
Mate did you finally sell you 993 race car? we might just be interested if you could PM me
11-09-2010, 12:22 AM
#140
Rennlist Member
imagine if there were a sports car manufacturer that would use inferior valve guide materials... and an SAI system that can clog is less than 50k miles!
Ludicrous!
Ludicrous!
11-09-2010, 12:42 AM
#141
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11-09-2010, 12:56 AM
#142
Here is Steve W's post on the topic from a few years back. I've asked this question of 4 other mechanics since picking up my car 18 months ago, all agreed.
Hi:
I'd strongly concur with Mark & Edward.
That undertray was installed for noise suppression only and all it does is accelerate engine upper end wear and oil leaks. Please keep in mind that one of the most common sources of oil leaks on these are the through-bolt O-rings that require removal of the cylinders to access & replace.
It seems particularly silly to to me for someone to shell out $ 4-5K for the engine job to change 10 bucks worth of O-rings. Keeping that tray in your garage is excellent preventative medicine.
911 motors did just fine without them from 65-89 (Carrera 3.2) and its not really needed for "protection",....
Just my opinion, though. Ultimately, its YOUR engine.
I'd strongly concur with Mark & Edward.
That undertray was installed for noise suppression only and all it does is accelerate engine upper end wear and oil leaks. Please keep in mind that one of the most common sources of oil leaks on these are the through-bolt O-rings that require removal of the cylinders to access & replace.
It seems particularly silly to to me for someone to shell out $ 4-5K for the engine job to change 10 bucks worth of O-rings. Keeping that tray in your garage is excellent preventative medicine.
911 motors did just fine without them from 65-89 (Carrera 3.2) and its not really needed for "protection",....
Just my opinion, though. Ultimately, its YOUR engine.
11-09-2010, 01:33 AM
#143
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So what is the downside of taking the cover off? A bit reduced downforce at high speeds, and that is about it? I am with Steve's old comments, it was fine for the older cars (some of which had really long lasting engines), so it should be fine for my 993.
Besides that, given I tossed all five covers I had in storage here, I do not feel like scrounging one up.
If I remember right, both the 996 and 997 do not have these? Given they are quieter engines, is that the sole reason Porsche elected not to add them?
Cheers,
Mike
Besides that, given I tossed all five covers I had in storage here, I do not feel like scrounging one up.
If I remember right, both the 996 and 997 do not have these? Given they are quieter engines, is that the sole reason Porsche elected not to add them?
Cheers,
Mike
11-09-2010, 10:55 AM
#144
RL Community Team
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Who ever said Porsche never engineers mistakes?
RMS? IMS?
What's a 996 then?
RMS? IMS?
What's a 996 then?
Last edited by Speedyellow993; 11-09-2010 at 11:06 AM. Reason: Update
11-09-2010, 11:06 AM
#145
Rennlist Member
As painful as it's been, I've tried to read all the posts on this thread, yet I haven't seen one that mentioned a) It's a pain to remove for an oil change if you've got a lowered car and want to raise the car from the center of the engine case seam and 2) If you were to have an oil leak with the pan installed, it would take a long time to realize it.
11-09-2010, 11:13 AM
#146
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/\ /\ I have not (and will not) read this whole thread, but the last few pages talked about aero. All I got to say is, if it does improve aero, why don't the race cars have them?
11-09-2010, 11:51 AM
#147
Rennlist Member
yes, it certainly was!
and was intended to be.
To propose that "Porsche designed it therefore it must be right" is a bit of a vague argument. I was only trying to point that out, though a bit sarcastically.
I am looking for real info as to why the engine undertray is important to aero. Porsche themselves say it matters to the tune of 2%.
If there are other reasons, great! Let's hear 'em.
Otherwise, I am still in the "off" camp in warmer climates.
Again, if I were going to do some top speed runs I'd put it on... that extra 2% could come in handy
EDIT: by the way, I'd also bet that the cooling gained (if any!) would be similar to the aero gain. I think we are talking minor gains/losses, tray On or Off. I'd just rather have any additional cooling I can get in warmer climates
and was intended to be.
To propose that "Porsche designed it therefore it must be right" is a bit of a vague argument. I was only trying to point that out, though a bit sarcastically.
I am looking for real info as to why the engine undertray is important to aero. Porsche themselves say it matters to the tune of 2%.
If there are other reasons, great! Let's hear 'em.
Otherwise, I am still in the "off" camp in warmer climates.
Again, if I were going to do some top speed runs I'd put it on... that extra 2% could come in handy
EDIT: by the way, I'd also bet that the cooling gained (if any!) would be similar to the aero gain. I think we are talking minor gains/losses, tray On or Off. I'd just rather have any additional cooling I can get in warmer climates
11-09-2010, 10:01 PM
#149
Rennlist Member
ALL fantastic opinions and points made. SO well, in fact, that the jury is still out.
I am still looking for one for our car but once I get a good condition one, it will go up into the attick with all other stock parts taken off the car. It has been known to get a "little warm" on occasion in the Dirty South..
I am still looking for one for our car but once I get a good condition one, it will go up into the attick with all other stock parts taken off the car. It has been known to get a "little warm" on occasion in the Dirty South..
11-09-2010, 10:39 PM
#150
The PROVEN downsides of running without a tray are mentioned in posts #2 and #10 in this thread.
Mike, I know you probably have forgotten more about Porsche's than I will EVER know, but there ARE REAL downsides to running a car that has been lowewred without an engine tray, especially one that has heater boxes that may droop ever slightly. They are EASILY torn off when catching on, say, a driveway when backing up (ask me how I know). They would NOT be torn off with an engine tray attached.
Part costs alone will set you back a few hundred.
There. That's a real, tangible downside to running without an engine tray.
Aerodynamic theories, turbulence, heat dissipation and the rest can still be argued, but this is a real downside that is proven by more than one person on this thread.
Therefore, we've been able to PROVE that running without an engine tray has a significant downside, on a lowered car anyway.
Has anyone PROVEN (that's the key word here) the advantages of running without one? Or is it all still just conjecture and theory?
Mike, I know you probably have forgotten more about Porsche's than I will EVER know, but there ARE REAL downsides to running a car that has been lowewred without an engine tray, especially one that has heater boxes that may droop ever slightly. They are EASILY torn off when catching on, say, a driveway when backing up (ask me how I know). They would NOT be torn off with an engine tray attached.
Part costs alone will set you back a few hundred.
There. That's a real, tangible downside to running without an engine tray.
Aerodynamic theories, turbulence, heat dissipation and the rest can still be argued, but this is a real downside that is proven by more than one person on this thread.
Therefore, we've been able to PROVE that running without an engine tray has a significant downside, on a lowered car anyway.
Has anyone PROVEN (that's the key word here) the advantages of running without one? Or is it all still just conjecture and theory?