Re: Thanks marc.

Hello fair Porsche people,

I'm adding oil pressure and temperature to my street-legal track car.

I have VDO analog gauges.
Are there convenient places to either piggy-back on existing senders, or add new ones?

next - any pointers to a 2 or 3-hole blank plastic mounting plate for the radio opening in a 2000 986?

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Quote
grant
Hello fair Porsche people,

I'm adding oil pressure and temperature to my street-legal track car.

I have VDO analog gauges.
Are there convenient places to either piggy-back on existing senders, or add new ones?

next - any pointers to a 2 or 3-hole blank plastic mounting plate for the radio opening in a 2000 986?

Grant

When I installed an oil pressure gage in my Datsun 510 I tapped (so to speak) into where the factory oil pressure sensor was located. I used brass T to retain the factory pressure sensor and to connect the fitting from the gage. The hole for the factory pressure sensor was a standard pipe thread and was in the main oil galley.

The Boxster oil pressure sensor I think is up at one of the camshaft covers. That's where I'd get the oil pressure for a gage probably using a T fitting to retain the factory pressure sensor.

For oil temperature the factory gets this from the oil level sensor which is a tube that extends down from above the crankcase down into the oil sump. I really don't see how you can utliize this sensor or its location for temperature. In the past the oil pan was drilled and an adapter fitted to allow a temperature sensor to be used right in the oil sump.

Of course with the Boxster this is not as straightforward as it would have been in the past.

Based on my memory of the Boxster engine block and given the engine's integrated oil sump the only path you have into this is from underneath via the sump plate. This is not the end of the world but you need a sensor then that sticks out as little as possible.

Another possible "solution" would be a spacer between the engine block and the factory sump plate. This would lower the sump plate and increase oil volume -- the oil pick up tube would need to be extended! -- and the spacer could be tapped for an oil temperature sensor. The sensor could be mounted on the back side and thus shielded from damage from road debris.

I haven't kept up to speed on this technology but aren't there devices that plug into the OBD2 port and communicate via Bluetooth with a smart phone running an app that can display selected engine telemetry? Thus you could have oil pressure and temperature.

By the way, i already have a spacer between my block and sump - its part of most deep sump kits, including Pedro's.

The ODB2 idea is interesting - i wondered about that too, and am curious if anyone has practical experience "buy this, it works"

I need to ask Gene (engine builder who finished the job while i was in France working and drinking, generally in that order) what senders he installed - One question is "why can't the factory pressure sender drive two gauges?" Ditto for the temperature.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

Quote
grant
By the way, i already have a spacer between my block and sump - its part of most deep sump kits, including Pedro's.

The ODB2 idea is interesting - i wondered about that too, and am curious if anyone has practical experience "buy this, it works"

I need to ask Gene (engine builder who finished the job while i was in France working and drinking, generally in that order) what senders he installed - One question is "why can't the factory pressure sender drive two gauges?" Ditto for the temperature.

Grant

The pressure and temperature sensor each supply an analog voltage signal to the DME and its AD converter which converts the voltage levels into digitial values, say something between 0 and 255. (The temperature sensor digital value might require an offset, say -40 (C) so a zero reading would be interpreted as "-40C".) This digital value then can be packaged up in a CAN message and sent to the cluster controller which converts the value back into a voltage level which then drives a gage.

With the proper electronics this info could be used to feed any number of gages with the info.

In the Boxster, at least in my Boxster, the oil pressure is just used to know the oil pressure is not too low which keeps the low oil pressure light off. I'm not sure if the DME is responsible for the low oil pressure warning light directly or if the cluster controller handles this. Either the DME sends a CAN message to the cluster controller to turn on the light in the event of low oil pressure or it sends the actual oil pressure -- in digitial format -- and the cluster controller then processes this to know if the oil pressure is ok or not. At the cluster this provides a relatively painless way to make this low oil pressure level threshold a value that can be rather easily changed vs. having to flash a change to the DME.

The temperature sensor value may only be used internally by the DME to compensate/adjust the oil level reading though by my observation over the years with my Boxster the oil level varies with temperature. Because I park in the same spot at home I can check the oil level in the AM with the engine cold and note the level. After a drive that gets the oil fully up to temperature I park the car in the same spot. Sometimes I return to the car with the engine still warm even hot and check the oil level and it is up by 1 to 2 bars depending upon how cold it is in the AM.

I haven't delved too deeply into what's available on the CAN bus. My automotive test tool work was focused on generic data that was well documented and available from all OBD2/EOBD/JOBD compliant vehicles.

It doesn't help matters at all that Porsche does not provide any details on what bus traffic is present or how to perhaps navigate through any gateways to obtain this info. (It is obtainable after a fashion by other means. For instance, when I had my new 2008 Cayman S in to get the service light extinquished I captured all the bus traffic that arose from the Porsche diagnostics computer doing this. I had plans for doing a Porsche specific OBD2 data logger but shortly after I captured this bus traffic the Cayman was destroyed in an accident and I lost all enthusiasm for doing anything more in this area.)

I think the easiest path is simply a 2nd wire on the oil temp sender that I *believe* is installed ( i saw two terminals, one used) and to put a T on the pressure feed.

What i have heard of, but not seen or had any meaningful discussions, on, are products (for porsche and others) that plug into the OBD2 port and drive a digital head-end. I believe the head-end can be configured to display different sets of data. But the former is "I read somewhere once" and the latter speculation :-)

I'll report back when i figure out a solution and like it. But one way or the other i want to see both in real-time, with some degree of accuracy. An idiot light and nothing leaves me wanting.

heck, i have much better on my station wagon. I know what those temps got to on track (250-260F).

I also learned how much oil lagged water, both on heat-up and cool down.

G

Grant

gee-lenahan-at-gee-mail-dot-com

I've heard of it being used on several cars. No idea if P-car.

Grant

gee-lenahan-at-gee-mail-dot-com

Here's one offered by Actron( Bosch). A quick scan over the info has me intrigued enough to think about getting one just for grins.

[www.actron.com]

i need to understand how much more the model-specific data is :

"Note: You must purchase Powertrain Enhanced Data and/ or ABS DTCs and Definitions, and/or Airbag DTCs and Definitions to access respective CodeConnect coverage for manufacture specific Powertrain, ABS warning lights, and Airbag warning lights."

I may get one too, just to go exploring, and learning.

Thanks,

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

via a "standard" OBD2 PID if your car's DME supports PID $5C. This is "engine oil temperature". It is a 1 byte value: $0 to $FF and is the oil temperature in 1C per bit with a -40C offset. Thus $00 is -40C while $FF is 215C.

Oil temperature might be obtained another way using a Service $9 Request Vehicle Information if the DME supports providing oil temperature in one of the Infotypes. I sort of think it does because a Porsche tech did some kind of a data log dump of my Boxster's DME using a PST2 diagnostics computer and oil temperature was present. However research would need to be done -- using say Vehicle Spy -- to construct the proper queries to first determine what InfoTypes the DME suppors then query for them and try to work out what they are. With Vehicle Spy one could set up a number of queries and do these every so often and look for values that go up at some steady rate as the cold engine idles which would probably be coolant temperature and probably oil temperature. (Engine run time counters -- if present in the data (and they could be) -- would go up too but these would go up by 1 every second and I think they could eventually be id'd and eliminated/ignored.)