roland has me thinking re:964 engine pan

[Planter91C2]

i have come to believe that roland kunz really knows his stuff. two weeks ago i removed my C2 engine pan. now i'm confused by this posting from roland. i always thought that porsche would not design something faulty.

in addition i find it hard to believe that they would design a restrictive air filter box to decrease performance in relation to their other offerings.

here it is:

Hello

Sorry Iīm "impressed" how many people do think that Porsche would make a silly thing and stupid design.

Porsche just wasnīt very good in the story telling ( say sales ) department and many things Porsche even will not mention are worth making a book about high technology on other car brands. To understand this is very simple. Porsche is saleeing highest technolgy in there Weissach Branch to all others.

Just look at the costumers there.

The ( old ) 911 or 928 ( Well even the "cheap" beetle, 356, 914, 924, ) was allways the showpiece for the Weissach branch. Every engineer in the other car companys was waiting to get one and look what they made how and how they handled that problem those people hadnīt a solution or one the clerks/bookkeepers would like to see.

Now the new Porsche comes in and following happens.

Porsche showes a working soulution and those guys can follow the path.

Porsche was developing the complete structure including the manufacturing into a complete ( turnkey ) technology. This brake trough was done, the tooling ready and the normal companys knew that it is doable. Also there was nothing to spend in research anymore and the price for the units went down.

IF Porsche would have hang there progress out to much all there costumers would have had bad engineered cars in the puplic. So it was unvisible to the puplic but all the engineers from the other companys knew it and gave jobs to the company who proved to handle it with working solutions.

Also many costumers ( competitors ) could say:

"Hey this is a ultra expensive Sportscar, loud, uncomfortable, only for fast driving. Mother you drive a simple car and why should you have brakes like a sportcar. Sitting in your SUV castle and some airbags is much safer..........and costs only 50% of that. And lady, real world driving is stop & go and parking the car 23 hours a day. But if you wish to blast down like in a Porsche we also have a super sportscar for the same money. That car is even faster then a Porsche as we skiped all that useless grap and so that car is better. If you buy a Porsche they sale you useless overhead or as we say overengineered."

Thats the backround from Porsche engineering: Overkill. Or in my wordgame: "Overskill"

As a simple stupid light skilled mechanic I can find following reasons why Porsche used the pan by just thinking over and use my finger to count down.

Basically everything is physic and form follows function is spelled has a Name: Porsche

1.) One was just to stop droping oil on the driveways from the rich and weahlty. If they would have seen then a drop it was then the BMW, Jaguar or Ferrari ..........

2.) The pan helped to generate high speed downforce. But it also helped pulling out the air by using the ventury effect. If you look from underneath the car you well see a very smoth bootom, everything covered even the trany. This all works together. If I would say remove the rearspoiler as this will increase topspeed or makes the car lighter everyone would say: "This guy is stupid as it will hurt downforce and make the car handle bad at higher speed". But well when do you guys exeed that speed where the spoiler cuts in ?

On the other side if that thing is under the car it is useless, just hanging around there to kill the engine and make a poor handling. So thats an improvment to remove the part as we will never hit that speed ?

Very clever and very ingenius.

3.) The pan should also isolate the heat inside the enginebay. This had following reasons:

The warm up time was improved especially if you drove in intervalls. Helped on emisions and fuel economy.

Due the slower heat down they avoided cold spot heat warping.

This was done as Porsche had many failures caused by that subject. Starting in the 70īs with the 2,7 R cases that pulled the studs later the dilavar disease.

Just remember that ticking noise when your engine cools down ? Thats the killing field.

Porsche investet some Millions in research about those things.

The uneven cool down will make the now much thiner cylinders slightly unround. Those cylinders are not machinded bores like the average car has.

Those cylinders have a special two dimensional orientatet bore. They are unround and they have different bores depending on where you messure them. This helps power and lowers oil consumption. However heating up the cylinder with the piston is a very important step as there the most wear will ocur.

If you remove the pan and drive, the air will foil into different areas and generate uneven heat disapation. Some cylinders might stay colder then others while the pistons heat up even inside the engine.

If this happens the cylinders will stay longer unround and small while the rest is expanding. Exactly this is to avoid as this will generate the oilsipping. The heat itself isnīt a problem as the complete construction will work even and the directional cooling air and the oil will try to cool down the complete unit, not just some spots.

If this wouldnīt be important Porsche could have made the engine tinware much simpler and cool only the right side as the fan will force more air to that side.

heat follows physical laws. Hot air is warmer and therfore lighter then cool air. So even if you remove the pan the heat will stay inside the engine like before. Only geting out on the upside trough the intake duct.

Now if you remove the pan there will not be to much difference ?

Well yes and no. The air getting out by heat will be the same but it will not stream as before. The pan made the stream follow a path and like mentioned before to spread the cooling into the right areas.

Now look up what can you see in the direct sight of the slots ? The covered cylinderfins. How does this fit into my theory. I said the cylinders will not like to get coold spots. Well the cylinders are not only cylinders they have the main heating area in the engine via the cooling fins. Now if you have cooling fins upright into a channel and the hot air streams up it will generate a underpressure. The hot air will pump the cooler air inside ( In german: Kamineffect ).

As the cylindes are coverd with guiding channels the air has to stream a known way and the amount of the air streaming by is easy to calculate and then to control.

Now without that pan it looks a bit different as you shorten the hight of that channel.

Also without pan the cold air will be affectet more by blowing by wind

Everyone claimes that removing the pan will help cooling sdown but it does the oppesite in standing and while driving.

No one has made deeper thoughts or asked in Weissach. Some have seen that race cars do not have the part:

Well the reason is very simple. Like I said it is to risky and if you have a race situation you like to look under the car to se if everything is all right or from where the oil comes. Also races cars have other exhausts that will not clear tha pan and last not least the typicall racedriver cares siht about the cooling demands from his engine. If it wears out in 20 000 km and not have a brake down then he is strongly staisfied.

However would like to have a race car can remove the pan to stisfy the speed needs. However like to drive a street Porsche can leave it on.

OH yes that pan does lower the sound emission. I know that emmision is something no one in the staates cares. Itīs a waste land. A Porsche stands for the oppesite.

And yes the wight of that part is a bad thing but if you look close the deeper the wight the better and Porsche used to ad wight on there racecars ( f.e: 934 & 935 ) and on the production cars too ) to make them handle better.

If it is a race car the thing would have been different.

And yes I had the opportunity to drive Cars flat out with and without pan and if you are not used to the car or very sensetive you will not feel a difference.

However I do feel it as I feel the difference in tire pressure. Even if i didn#t looked under the car and had the pressures checked and drive "my streets" I can feel the absence at moderate fast ( Well 120 mph ) Autobahncurves. ( Adrian do you remeber the old Leonberg swep down from Heilbronn to Munich ? ) especially if they have slight hills, that lifts out the car, you will have that nervous feeling in your stomac.

If you wold like to have a similar feeling in your own 964 at slow speeds then lower the rear tirepressure to 2,5 bar. ( just a guess, be carfull as this will change the complete behavior off the car at higher speeds to )

SO thats it for now.

I know I hit some nerves here........

Just like W.S.Burroughs said: "And.....Guns...open fire...."


so, i think he is saying to keep the pan on, and i respect his opinion. what do the rest of you think?


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Daryl 964 Targa

[Planter91C2]

p.s. sorry for this long post, but in all my research on this topic i never found this type of explanation and i wanted to share it with you guys.

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Daryl 964 Targa

[Early_S_Man]

No, Daryl, Roland wasn't saying to leave it on ... he was just pointing out that there were some side effects to the acoustic shield that happened to be beneficial to emmisions testing and output!

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Warren Hall
1973 911S Targa

[Planter91C2]

all that info ant that's all he was saying? i interpreted it differently, though i admit i may be wrong.

it seemed like he was saying that everything porsche developed was for very specific and important reasons. i believe this more as in the latest Christophorus magazine there is an article about how the engineers study how to tune the sound of a boxster engine, and research how women and men hear the sound differently. porsche obviously takes every detail to the extreme. anyways, he also mentions, i think most importantly that the pan allows the engine to cool more slowly and evenly and he thinks that is very important.

i'll admit that sometimes i have a hard time completely deciphering his posts, but here he gives more reasons to leave it on than take it off.

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Daryl 964 Targa

[Roland Kunz]

Hello

I said:

Whoever would like to have a race car can remove the pan.
Whoever like to drive a street Porsche can leave it on.

Neither off the pan on or pan off guys did prove any benefits but i beleive more in the craftmansship from Porsche engeniers. But they suit the car to there needs and Porsche is not interesstet to make a Lamborgini or Lotus. They give up some power to gain economy, met any federal law at the highest level and have a reliabilty. If you cut away those and change the car to suit your needs you have an other opinion about those subjects then Dr. Porsche. But the car will not fall apart as enough reserves are in the construction.

I mean do what you like it, is your car.

I never remove the pan or push people to do it. If a car comes in without it gets highligthtet in bill. In fact carswithout pan are very good for mechanics. You can save 15 min worktime and donīt have to handle that thing. if anything brakes while the waranty Porsche can say the car isnīt equiped as the factory made it and so it is not there problem. ( OK the 964 is to old now ). On the other side Iīm only a small mechanic who can not understand the whole system and have to beleive what the factory claimed to be correct or is approved. Whatever I do i have to keep in mind not to hurt any other person and if I hit the wallet from the car owner.

If the removed pan would cause serious engine problems I would have to bear the responsibilty for that. Also if I use unaproved car parts or not correct ways to repair things. There is allways a border i do have the respect in may work.
They are:
Protect the life and health from the owner and all other people on the road; Saefty for even the worst circumstances.
Protect the value from the owners properity.

As correct said it is not my properity and the owner can do what he want and I will stand on his side and try to give him good advise on his wishes. And if he asks were to hit on the car to destroy it I will show him the weak points and give him the tools.

( Very provacative said )

My database is to small but mostly the panless cars have more trouble then the pancars. The reason is not the pan it is the driver. "Pandriver" do drive fast too but they donīt press the car and respect the mechanics. "Panremover" are mostly guys who are in need for speed and do also other things the other drivertype would never think about.

Just reflecting the computers. Some have slow CPUīs and work on there machines. Others have fasz CPUīs and allways have to patch and fiddle to keep the thing running..


The airfilterdesign is also ingeniuess but in fact it restricts the powr output to pass the emission. But if ypo remove it or cut the top away you will not gain power benefits, vice versa you will loose. But the added sound make the car feel speedier.

Donīt rate on dynometer runs as those are not reflecting real world driving.

Grüsse

Just to understand it a bit more:
http://boards.rennlist.com/cgi-bin/911/911_archive.pl?read=1904 http://boards.rennlist.com/cgi-bin/911/911_archive.pl?read=3874

Grüsse