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Hey Sean, I have no doubt the harness will perform well! Exact fit and connections, and built better then OEM, thanks for getting it out to me in such a prudent manner.
I did try various assembly options with the adapter. It just wasn't going to happen and the VDO sender has a taller profile then the one pictured.
I think there would be an option to take some threads off the top of the adapter, it's really close, a few mm would get you there.
I just didn't have the patience to spend more time on it.
Below is the current set up, I gotta get kids to a few events and then circle back home and see what the readings will be.
For future folks finding this thread (Crumpler, you probably already know this):
You should get >5 bar cold idle pressure on your gauge (maybe as high as 8)
As the oil warms the idle pressure should drop. Once the oil is at operating temp, idle pressure should be 1.5 to 2 bar. With throttle, pressure should increase to ~5 bar by ~2800 rpm.
Why didn't the engineers make a cluster gauge that would read cold oil pressure in our cars?
Why not just read up to 8-10 bar, instead of capping it at five?
LOL. I'll phrase my mildy- to wildly-speculative answers in terms of multiple choice. Choose one or all:
a) 99% of the engine's operating time is when the oil is at operating temp. As the oil heats it becomes less viscous and therefore the pumping pressure will decrease. A gauge that offers better resolution in the operating regime is better than a gauge where ~50% of the resolution is useful 1% of the time.
b) Porsche's accountants _finally_ reined-in 928 engineers and told them that they couldn't spend 10s-of-thousands of DMarks designing a bespoke 928 pressure gauge and sender when an off-the-shelf 5 bar system would work 99% of the time.
c) Porsche's engineers didn't really know how much oil needed to be in the heads at high rpm, (and in 1972 it was effectively impossible to calculate it) so they just got as much as they could up there. The 5 bar gauge hides their ignorance.
a) 99% of the engine's operating time is when the oil is at operating temp. As the oil heats it becomes less viscous and therefore the pumping pressure will decrease. A gauge that offers better resolution in the operating regime is better than a gauge where ~50% of the resolution is useful 1% of the time.
This is going to sound like Nigel Tufner's Amplifier going to eleven....
Why didn't the engineers make a cluster gauge that would read cold oil pressure in our cars?
Why not just read up to 8-10 bar, instead of capping it at five?
One possibility is the following: People like to see the oil pressure at the max. Otherwise, they'll call the dealer and complain. Porsche doesn't want to get those calls, so they set the oil pressure gauge to peg out at 5 bar.
The whole oil pressure gauge on a show-room stock car is kind of silly marketing thing. If it were up to engineers, I'd guess they'd have a table from the ECU what's the minimum acceptable oil pressure in each operating condition. Then if the engine produces significant errors (oil pressure deficit * time spent at that deficit is high), there's a visual and audio error message and some severely restrictive limp home mode. But the marketing department is going to tell the engineering that since it's a sports car marketed to enthusiasts, it absolutely has to have an oil pressure gauge instead of just a warning light. But it has to be mostly non-informative, because we don't want to get those calls from the idiot owners. And you're allowed to also put in the warning light.
09-23-2017, 02:39 PM
