Flat6 Innovations

Go buy a 79 dollar VDO oil temp gauge with sensor. Place the sender in the sump and then compare that to the OBDII data.

I trust nothing that the OBD delivers other than simple fault codes, the problems that we work with can't be solved with a computer cable and some software. Practical application development has taught us things that words cannot describe.

My assembly guide touches on this, but volume II will illustrate it.

San Rensho

So I shouldn't trust the Durametric cam deviation values or the O2 sensor values or the air mass sensor values?

spare tire

I think what Jake was saying was; When your 02, or mass airflow sensor goes bad you can replace them with a new sensor. Thermo couple oil temp sensor can not be replaced when it goes bad because there is not one sitting in the oil.

spare tire

[QUOTE=eric523;9958511], increased bearing clearances, Carillo rods, Mobil1 Racing 0-50. Scary low oil pressure on the banking of Cal Speedway at full throttle (160mph+), under cornering, under braking etc. Still alive so far, but can't believe it lives with those oil pressure numbers.


Eric, What is scary low 50 lbs, 60 lbs.?? 32lbs at idle

Macster

I cut apart an oil level sensor (the long plastic tube that is located in the oil sump) and there's an oil temp sensor (thermistor) at the bottom of the tube. There is a bare wire that is the oil level "sensor" as well in the tube.

In the case of my Boxster this oil temp reading is not brought out to the dash and is not readable via a standard OBD2 code reader/data viewer.

But the dealer tech was able read the temp using the Porsche diagnostics computer.

Also in my 02 Boxster there is no real oil pressure sensor at least one that can provide a real time oil pressure reading. There is something like an oil pressure switch that is closed when oil pressure is sufficient which extinguishes the low oil pressure warning light.

Sincerely,

Macster.

J richard

I'm in the spiral of ever increasing stickiness on the boxster. I am looking to run my yoko cup scrubs on it and of course concerned with this issue. I don't have a lot of history with these motors so please forgive my ignorance to a degree...

Directly to the OPs point: Jake you are saying that it is thermal overloading and breakdown of the oil that is the demise of these motors in high G applications?

We faced these same issues in the spec944 crowd. Water temps would be fine but motors failed, factory guages read fine but motors failed, connecting mechanical gauges to the factory sender locations in the block read similar to the factory gauges. However drilling and installing the sensor in the pan where oil was being scavenged showed localized and simultaneous spikes of oil temps to 300+ where block mounted oil and water gauges would be 50+ degrees cooler. A higher grade oil and more cooling was added but in my own case the localized temps were something that when you saw them spike you were ok but if they did not drop on the straight you had to back out to save the motor.

If the oil is being superheated in the "working" components (piston and bearing assemblies) it would seem that supplemental cooling would be helpful but not solve the problem. The old air-cooled solution would be larger squirters, which I don't know if the WC motors can accommodate...

thoughts?

San Rensho

So there is a thermistor in the tube. So are you saying the durametric cannot read the value, only the dealer diagnostic can?

Flat6 Innovations

With the durametric, PIWIS pr PST2 attached disconnect the "thermistor" and watch what happens to the oil temp value. Thats all.

Macster

When I got the tube cut open and was able to see what it contained -- if I can find the time I'll post pics later today -- I asked some EE's and was told the blob of ceramic in the wire at the base of the tube was a thermister used to measure/report temperature.

I do not see in the full list of OBD2 Mode 1 Pids (parameter IDs) and Pid available for reading oil temperature.

Yet oil temperature was read by the diagnostics computer used by the tech. Briefly this is done during a full scan of the car's electronic systems. The diagnostic computer has a menu selection to start this process and the scan takes minutes. There may be a way a to navigate through the menus to get right at oil temp but either the tech didn't know how, or didn't have the time or wasn't willing to give me the time.

Since the Boxster scan was being done at no charge to me I was not willing to ask for more of the tech's time.

Also, while I have the ability to monitor/capture OBD2 bus traffic and log this to my laptop I did not have this connected when the oil temp (among a lot of other things) was obtained from my 02 Boxster. The data comes through after a pretty long scan, I should say at some point during a pretty long scan/read of the various controllers in the car, and I was not able to be there when this was done.

(Now I did manage to be there when my Cayman S was scanned when it was in for a bad radio/stereo while under warranty and captured a lot of bus traffic.)

Now this oil temp could have been obtained via some less direct method perhaps from the instrument cluster controller or perhaps as a message sent from the DME to the instrument cluster over the Komfort bus (CAN bus at least in the newer models).

Anyhow, I do know just how the oil temp was obtained.

(My line of work has me focused on the public OBD2 bus traffic. All cars since '96 have this. But there are manufacturer specific buses and bus traffic that carry a lot of other data/info from seat belt status to oil temp and everything in between. While some automakers publish how to obtain this, interpret this, others do not. At the very top (or bottom) of this list, is Porsche. It is as tight lipped about this as any company could be.)

I have never used a Durametric and do not know what it is capable of. Based on what I have read about it I believe it has some ability to obtain/interact with the DME and other controllers in a Porsche proprietary way.

But it is not an aftermarket 100% identical duplication of the the Porsche diagnostics computer system.

It is a pretty good tool though.

(Porsche does not share the info to produce one of these with the public not even to those of us in the test equipment business although it obviously shared this info with at least one company, the company that produced/produces the Porsche diagnostic computers.)

Sincerely,

Macster.

eric523

[quote=spare tire;9968543]More like under 25 PSI at 6000-7000 RPM under full load on the banking. Even lower numbers like 12-20 in hard braking zones and quick transitions after braking, but not as high of load or RPM. Usually a very quick drop, but it sets off the oil pressure alarms on my Motec dash so regularly during a session that I had to mostly disable them. We download the data after every session and inspect...and cringe.

insite

wow, eric...that is REALLY low. ever try a different oil (i.e. not 0W base stock)?

eric523

Yeah, it's ridiculous. With that data I'd have to say that oil pressure is a problem with slicks. It was bad before with my Boxster Spec car when I used Hoosier R6's as well. The new Yoko slicks, aero upgrades, and power upgrades have made it worse.

I used the 0-50 Mobil 1 Racing oil that is over $15 a quart for the increased film strength when running that low. That oil should hold up to the higher oil temps pretty well also.

Marc Shaw

So to Jake: what is the best way of cooling the oil directly?

I know you sell a block-off plate but do you recommend or sell an external oil cooler kit that we can attach it to?

Marc

Macster

The oil would have to be pretty hot to suffer that much oil pressure loss.

So, I'm thinking your engine is experiencing the effects of aerated oil.

I recall that in some USA engines (big V8s) power at high rpms would drop off and the cause was found to be air in the oil that was causing the hydraulic valve lifters to get mushy/spongy and thus not follow the cam lobe profile accurately. The main/rod bearings were apparently unaffected by this for the engines did not come apart due to oiling failure at any point in the engine.

Better swirl pots coupled with perhaps even runing a low detergent oil (less likely to aerate at high rpms) might be called for. A racing oil with lower detergents then could be the better choice. Sludge build up is not a real concern given the usuage of the engine and the frequency of the oil changes.

insite

i know pressure isn't the only thing that matters, but FWIW, my oil pressure went up substantially when i switched to 20W-50. there is a power penalty there, but i feel a lot better when i know everything is being fed.