2ndof2

Agree that this is the best engine tray thread of all time! No argument on the reduced drag and minor ground effect advantages with it on....at high speeds. Newer 911s don't have em, 993 factory racecars didn't have em, and my car doesn't have one. If someone can prove having one on will keep things cooler under the typical driving conditions I experience then I'd put it back on (that is if I hadn't thrown it and the rear attachment bracket in the trash!). Since I don't plan on testing the engine temperature theory for MY driving conditions it's staying off. If I ever need more downforce I'll go ten an RS tail.

How many posts are we at now gents? Keep it going!

Ps was it an airplane, us missle, or foreign missle launched off the Cali coast several days ago? Experts saying airplane...yeah, and that airplane flew out of my *** then out over the ocean. Who dunnit?

Wilder

Ahhhh. Good'ol Rennlist...

rsr91128

Why would you buy another one, it is already there. Just get a diagnostic scanner and you can monitor CHT in real time. Here is a sample of a cold start with a few sensors chosen at random using an old style Durametric cable and software on my early 95.





To insult the likes of Steve W., Bruce A. and many others by using the term "so-called gurus" makes you sound like a condescending know it all.

They have years (even lifetimes) of experience with these cars and engines and they share their real world experience with shade tree's like me. I hope that they will continue to share their experience based opinions.




As for the "PROVEN DISADVANTAGES" of running without a tray mentioned earlier. They are the result of improperly adjusted heater flapper boxes. If the owners would have taken the time (apx 2 minutes) to properly re-adjust the boxes no damage would have occured to the boxes. I have drug muffler tips, rear bumper lip and scraped a heat exchanger without any damage to the boxes. Properly adjusted they are at or above the heat exchangers.


My car has 93,000 miles is aero stable to 145 mph, uses no oil and the oil temp stays in the 8 o'clock position without a tray. Results are good enough for me.

DO WHAT YOU WANT IT IS YOUR CAR!

IXLR8

Shouldn't someone have proven that taking it off makes things run cooler or makes valve guides last longer?

I sometimes wonder how these ideas start up. The same thing happened on the BMW motorcycle forum where BMW NA via someone started a belief that only a BMW battery charger could keep a BMW battery charged.

IXLR8

It hasn't been assembled yet...a winter project. Is the one on the car resistive or a thermocouple? Furthermore, so that there is no doubt, I'd want to calibrate it.

Whoever came up with the idea should back it up with something. If I made a statement like that, I would only do so based on measurement data and if someone asked, I would not get bent out of shape being questioned. Till now, nobody has done so. I know its so taboo to question anything these days.

BTW, your voltage is low.

rsr91128

Looks resistive to me.

The DME uses it to adjust the engine so as long as it is consistent if it is off .2 c it will not matter for an engine tray test.

Wilder

+1

Why does anyone need to prove anything to you or anyone else? There is no negotiation going on here. This is a discussion. As futile as arguing which car is faster between a guy who quotes performance stats, a guy who drag races and a guy who tracks.

I'm no engineer but my logic would be to put my money on those engineers who have spent years learning about and working on these engines...like the "so-called gurus" on this forum. But hey...we all have the option to choose what flavor of koolaid we want to drink.

IXLR8

Cripes...and I have the factory manuals. I have to remember to use them for stuff like this.

Certainly not worried about 0.2C or even 2C, but I'd have to check it. That is what calibration is all about.

IXLR8

You're absolutely right. But then I don't have to believe them either. I'd at least state "why" and "look at what I discovered" before making a statement.

Porsche has no engineers?

I would guess we work in different environments...I work in labs, so we don't just assume everything. We take measurements and collect data. When I used to work on aircraft, I just didn't assume everything was fine and hand it to some poor owner. I'd test fly it myself to make sure everything was OK and then hand it over.

Next summer, we...well at least I, will know the mystery of the engine undertray. Should be fun...looking forward to it.

DaveM993

...

Greg Lab

IXLR8 you are legend! Thank you!

Wilder

Exactly. They're just opinions and we're all welcome to do with them as we wish. But I'm not quite sure it's anyone's place to define how people should contribute their opinions.

No need for sarcasm. Yes, they have engineers. The same engineers responsible for weak valve guides and SAI ports that clog up, among a number of other brilliant designs. However, since these cars were designed 16+ years ago, those engineers are probably not around to answer our questions regarding the engine tray. However, there are several techs who have worked on these cars during that 16-year period who are probably better qualified than the original engineers in opining about what actually works and what doesn't on these cars.

Yes, we do. I work in business and I'm concerned with being practical. I don't have the time or inclination to run tests, take measurements, collect data or get lost in paralysis-analysis over an engine tray. I don't make assumptions but I do make educated decisions by listening to people I consider to be experts in their field just like everybody else who is not an engineer, owns a Porsche and doesn't have time to burn. People like Steve W. who has a long history on and off this board and Mike J. who is an engineer, has rebuilt his own engine and I consider to be a good authority on these cars, have made good arguments on this subject over the years and that's good enough for me. I think he still has one or two of my engine trays at his shop.

And please don't get me wrong, I applaud your inclination and approach. I think it's great that you're going to take your time to investigate and attempt to quantify this age old dilemma. This board used to have an abundance of technical posts. I don't find that to be the case anymore. So I too look forward to your findings.

IamSMC

When Porsche engineers, or any manufacturer's engineers, design parts that evenutally amount to making of an entire car, they run "test beds" to see if the part actually works as designed. If the part works as designed, it enters into production.

Upon cars being sold, sometimes parts as designed don't stand up to real world use as designed and a recall is issued, or at the very least a service bullentin is issued, so that a defective part can be replaced by a better designed part or a recommended procedure advised (ie: remove engine tray).

In regard to the engine tray, has this happened?

Irrespective of that, it appears we have persons here onboard that have real world experience and have issued advice based on that. So removing the engine tray based on that is fine if other persons have experienced the same thing or just being cautious.

But on the flip side, if IXLR8 wants actual proof, then that's fine too. No need to undermine his desire to obtain proof because it has been expressed that there are a number of "factors" that could lead to issues on the engine with the engine tray in place but not necessary directly linked only to the engine tray in place.

Bottom line, its your car, do as you please.

IamSMC

I've seen this "argument" repeated several times. But how is comparing a "racing" 993 to a "street" 993 a valid argument?

The "leverage" may have been faster access to the engine during a race if a "racing" 993 needed service on the engine.

Cemoto

"Ps was it an airplane, us missle, or foreign missle launched off the Cali coast several days ago? Experts saying airplane...yeah, and that airplane flew out of my *** then out over the ocean. Who dunnit?" (2ndof2)

IMHO - Chinese or NK missile launch from a sub.