Arjan B.

I plan to do the Heat gun test on track next Saturday.

We have planned a few rounds on the Nurburgring next Saturday [16]. The weather will be warm, so I want to do the test once more WITH undertray.

I will not remove it on track, so I was hoping that somebody will join my test on Saturay.
I believe that JW Hubbers will be there too, so I hope he has no undertray and that I can write down the data and bring it on Rennlist.

This is the last I can do and the last I will do on this issue.

Have a nice day,

Arjan
964 C2C 1992 Black

Arjan B.

I notice that no one did response on the question to test with me on the Ring without undertray.

I will see who is there tomorrow..............

Data coming up a s a p

Nice weekend to all of you!

Arjan
964 C2C 1992 Black

Arjan B.

O.k.

I promised to give te date which are measured yesterday on the Nurburgring.

I did a 2x 5 lap session, and here are the data, after both sessions:

Oudside temp: 25 Degr. Celc.

OIL TANK 90,5/91,0
ENIGINE NEAR OIL DRAIN PLUG 103/104
VALVE HEAD COVER LOW ONES 118/119
VALVE HEAD COVERS ENGINE BAY 115/117
CILINDER HEADS 125/129
OIL COOLER 70/74

All temps are in degrees Celcius.
All temps are measured WITH undertray!

Oil brand = Mobil 1 / 0 W 40
oil pressure on track max 5
oil pressure at idle coming in after session, 1.2

I wanted to colect data without a undertray, so I was hoping that JW Hubbers would be there and would have no tray under his car, but when we left the track and drove home, he passed us near the BP gas station, so I think he will take his rouds today...............

I hope that the data is interesting for some people. I did my best the get as accurate as possible data.

Have a nice Sunday!

[I have to clean the Porsche from brake dust and rubber/insect spots and wax the car completely today...]

Arjan B.
964 C2C 1992 Black

Trader220

Arjan,

I have a couple of questions but who knows what nice things people will say about me if A) they're too simple or B) they were answered already. So I guess I better ask privately.

Christer

how about C) too sarcastic?

John Boggiano

Arjan B.

May be that everyone is sick of my topic about the undertray thing.
I can understand that. I am a perfectionist, so I go on till I know everything about it.

I did the testing to share information with people who are interested in it.
When no one is interested, bad luck.

I hope that in the future people does look for the data, and need it.

If the replies stay out, the topic will lower every day, that means that the interest was low. I had my fun doing it.

Greetings,

Arjan
964 C2 C 1992 Black.

Adrian

Dear Arjan,
The figures you have presented speak for themselves. No further comment is required. The reason this thread is not getting longer is that you have ended the debate. Your figures are very similar to the original tests you did. 10 laps at the ring and no massive cylinder head temperatures. Story over somebody has to go find another excuse now.
There is no point debating when you have provided the answer. You have been thanked on another thread for your efforts.
I for one can take yes for an answer. Yes there is no evidence to support the argument that the fitted rear engine cover of the 964 raises cylinder head temperatures into a range which will cause an increase in valve guide wear or "premature valve guide wear" whatever that is. Removal of the rear engine cover will reduce temperatures by a few degrees but not to any level which could be argued that even normal valve guide wear rates are reduced. Arguments for removal of the rear engine cover are based on cosmetic and weight issues and not that keeping it installed will damage the engine. By the way the original argument seems to have started in 1987 with the Carrera 3.2. This engine and installation was not designed for a rear engine cover, the 964 was. Comparisons of the 3.2 to the 3.6 are also invalid.
Ciao and thanks,
Adrian
964C4

robmug

Arjan

This IS great info. 4 of us met yesterday in Wales and we ALL had our undertrays on (ooh-err!)

There should be no criticism of what you've done; except from those who didn't get the data they wanted to prove their cause!

As Adrian said earlier, this is the first time that data has been used in the undertray argument and it is certainly udeful now and will be in the future.

Regards

Speedraser

Arjan,

Although I recently removed my (993) undertray, I really appreciate the effort you put into this heavily discussed issue, and the results.

Arjan B.

Thanks Guys,

I did the testing with pleasure, no thanks.

I always try to prove things I say. Technical things I change, should be tested before doing it. That's my way of thinking. As somebody said before, 'Are we smarter then Porsche engineers?'............Don't forget that years of testing should be take serious by car owners. Multi million Dollars are invested in the test work in deserts and snow/ice areas.
This to look for a compromise in use of the car.

OT: Speedraser: Long Island is a nice area, I was there last year, stayed in Cental Iselip for a few days in a hotel with freinds.

Have a nice day all of you.

Arjan B.
964 C2C 1992 Black

john thompson

HI,

My thoughts......It would seem to me that just measureing the oil temp would provide the best evidence to heat loss or gain. Of course you would have to run it long enough to evidence any changes and correct for any changes in outside heat and temp.

Thanks,
John

Christer

John, whether you are a undertray off or on person, I think we all agree that the undertray doesn't affect the oil temp itself, but rather the temps of engine parts around the engine bay. Even if it is by only a few degrees which was borne out by Arjan's research. The oil temp will be unaffected or as good as.

Adrian

There is another important point here which Christers post reminded me to make.
Cylinder head temperature is monitored by the cylinder head temperature sensor. The input of this sensor to the DME affects the timing. IF cylinder head temperature gets too high the timing will be retarded. If the sensor is detected failed the default setting used by the DME in the calculations is 120C. It is clear by Arjans experiments that the rear engine cover is not causing massive deviations of temperature even from the failed sensor default condition. I do not have the figures of the maximum permitted cylinder head temperature of the 964 engine but based on design requirements and reliability requirements it would be at least 50% higher than nominal and for the sake of argument I would suggest nominal is 120C.
Ciao,
Adrian
964C4

JW Hubbers

Yes, I was at the Ring too last weekend. I didn't spot you, though

It would have been fun to measure some temperatures, but as I run with the engine in place it won't have mattered too much.

I did get a chance to test my new rear brakes (upgraded to 4-pots), new discs, new pads (Pagid Orange) and new brake distribution valve (55bar) and liked the results very much. More on that later

Cheers,

JW