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Old 02-24-2012, 06:29 AM   #21
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There is nothing wrong with the gauge...

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Originally Posted by Jittsl View Post
Pedro, I would suggest that there was something wrong with the engine's oil pressure gauge long before it failed. Is that what you normally see? I also have an oil pressure gauge that I can see in my video and I have never seen it dropping under brakes (let alone around right hand corners) the way yours does. It doesn't appear as if the car is pushing particularily hard and yet any movement away from dead flat and the pressure drops - and that's with an accusump!

If that was typical I doubt these motors would last five minutes. I would be interested to see your next video after you make repairs to the wiring and (might I suggest) you swap the inputs to the two gauges to see if the response is still the same. I am taking it as a given that the oil level was correct. Just for the record, where did you attach your oil pressure sender?
... the reason it stopped working was because I didn't give the wire enough slack and it was a solid core wire (not stranded), hence it broke.
I don't see any oil pressure drop under braking, just under lateral acceleration.
Most of the turns at Sebring reach or surpass 1G lateral (with racing tires).
My engine's oil sender is located on the left bank port just under the left intake plenum and fuel injector bar.
Why would left hand turns be different than right hand turns as far as oil pressure is concerned?
The Accusump doesn't change the way the engine oil pressure behaves. That depends on the baffles and sump itself and how the oil reacts to the lateral forces.
It only opens up once the engine's pressure drops bellow 35 psi (or whatever other setting you desire). Once the pressure drops to that threshold the valve on the Accusump opens and oil under pressure is injected back into the engine.
Happy Boxstering,
Pedro

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Old 02-24-2012, 09:19 AM   #22
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OK..... I just watched it again and every time you brake (or even slow down) the oil pressure drops. What aren't you seeing?

Right or left is different for some reason or another and typically these cars starve for oil under extreme left hand turns - or right hand if the engine is in backwards such as a 996. No idea why, just quoting what I have heard and what I have observed. Just for the record this does require in excess of 1g for sustained periods. Doesn't look like you would be even approaching 1g in the video you displayed and none of them look particularily sustained.

Brad, you would know better than me - does the behavior of Pedro's oil pressure gauge look right to you?

In my car whilst on the track the pressure reads 80-100 lbs (varying by temperature only) all the time if I am anything above idle. In your film your car is constantly dropping if you do anything other than drive straight and flat. Only three possible explanations that I can think of - the car is starving for oil because it is too low, there is something wrong with the oiling system and it cannot deliver the required pressure the minute the revs drop (such as braking or turning) OR there is something wrong with the gauge. Since it is a noname gauge with a dubious wiring setup I would be inclined to believe the later.

Laurie

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Old 02-24-2012, 09:31 AM   #23
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So, after highjacking my own thread and turning it into the "Is Pedro's oil pressure gauge broken" thread ;-) I'd still like to get a few more opinions on my original question, which was:

So I wanted to collect a few opinions what's the best oil level for the track

Thesis A) fill it up to the brim to avoid oil starvation in high g-force turns (I also have a LN engineering oil sump extension for that)

Thesis B) make it only half full to avoid flooding the AOS in high g-force long sweeping left turns

So what's your formula?
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Old 02-24-2012, 10:17 AM   #24
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Quote:
Originally Posted by san rensho View Post
Exactly. How can a car that has all its oil on the undersides of the car (from oil leaks) have oil pressure?
its been a terrible day....but I am laughing out loud!

er em back to the survery:

Deep sump: (1,5 L extra) with windage tray; extended pick up; slightly over filled stock AOS (now has a film of oil all over the top section); very little smoke

-pilot sports, PS2s

-currently car is run on a high speed type circut and and a tight technical track
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Old 02-24-2012, 05:32 PM   #25
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The other option is ...

.... my particular gauges are electrically operated.
The sensor sends a signal to the gauge which has a servo motor so it reacts to every change of pressure quickly and accurately.
Many analog gauges are. Very slow to react do it seems that the pressure is steady when it's actually not.
Again, there is nothing wrong with my gauges.
What you may see as a pressure drop under braking is just the normal pressure drop from decelerating the engine's RPMs.
On the track the oil temp is much higher than normal and therefore less viscous do it also allows for a quicker drop in pressure than you'd normally see.
The video may not look it but almost every turn generates close to 1G lateral.
Happy Boxstering
Pedro
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Old 02-24-2012, 08:34 PM   #26
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I fill it up to the brim to avoid oil starvation in high g-force turns and have an EBS Racing baffle installed in the oil pan. I'll be back at AutoClub Speedway on Sunday on R-comps and don't expect any problems with the oil pressure.
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Old 02-24-2012, 10:20 PM   #27
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I've always just made sure it was full or reasonably close to full. It never swamped the AOS.

(When I had the oil cloud problem with the car last year, the AOS was a prime suspect at first and I found that the oil level had an effect on the problem (less oil, fewer clouds), which supported the AOS theory. But it turned out be rings, not AOS, and the compression test proved it. And Brad visually confirmed the rings were the problem when he finally laid his eyes on them.)
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Old 02-25-2012, 12:14 AM   #28
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Chris, Sorry for accommodating your own hijack of your own thread and back to the question at hand - I run an X51 sump and keep the oil at the recommended max. Oil (Royal purple 10-40 - I think) is changed evey second weekend and I have a new (last season) AO thingy and no issues so far. Neither smokes nor has ever shown any signs of starvation. Car has run a variety of tracks in race conditions.

Pedro, (sorry Chris I just can't let it go) My car also runs an electric gauge. In my limited experience, if that was what my oil pressure was doing with a known good gauge, I would send the engine back to Brad, tell him he sold me a dud and that he should fix it. Just my 2c.

Laurie

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