Accusump; foggettaboudit or hellayeah cuz?

This is my low pressure light:


It is an LED combined read/brake light for a trailer.
I was a bit surprised of the size when it arrived, but hey, can't beat it for "un-missability".

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Brgrds
Brian

Quote
wildert
This is my low pressure light:


It is an LED combined read/brake light for a trailer.
I was a bit surprised of the size when it arrived, but hey, can't beat it for "un-missability".

What pressure does it light up at?

So many OEM switch the light ON at maybe 0,4 bar-0,45bar and with the oil pump I use in the old mighty V4 Saab, it makes 0,4bar pressure even after I have spat the rod bearings out into the bottom of the sump for cylinder 1, and 1mm clearance on cylinder 3..
True story, bro.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Audi has 2, 0.35 Bar and 1.8 Bar - (the 1.8 Bar rings a buzzer) - I'll be using the 1.8 Bar switch

The allstar performance ones are 20psi not sure how many bar that is? $13 for a light and the sensor. 235 degree water temp light. Those are the only 2 after market guages I have in the car and there not even guages.

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First rally 2013
Rally car type AWD subaru
Total rallies as driver 6
Total rally cars built 2
Total rally cars caged 3
Total rally cars repaired from offs 4
Total years racing exp other then rally 19 yrs
Like 31motorsports on FB!
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Not precise, but a way to remember is bar = barometric pressure = about 14psi or so, so a 20psi is a 1.5 or 1.4 bar switch.

Look at fuel pressures, most EFI systems are 42-43psi base pressure which is 3 bar, except for a bunch of GMs with the weird central injection which are 58psi minimum which is 4 bar, and CIS which is best not thought about....

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.



Edited 1 time(s). Last edit at 12/08/2014 12:54PM by Pete.

Quote
john vanlandingham
What pressure does it light up at?

So many OEM switch the light ON at maybe 0,4 bar-0,45bar and with the oil pump I use in the old mighty V4 Saab, it makes 0,4bar pressure even after I have spat the rod bearings out into the bottom of the sump for cylinder 1, and 1mm clearance on cylinder 3..
True story, bro.

Hm - you do have quite a point - I actually don't remember.
The VW has the same 0.4 and 1.8 dual setup that Vittorio mentions for the Audi - but that is long gone.

I THINK I have the 0.4 switch - but it is in the head though - and there is quite a difference in pressure from just after the filter, to the cylinder head. Way back when, I used to run a single gauge with two sensors and a switch. The difference was pretty significant, and I seem to recall that I went for the 0.4 in the head for that reason.

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Brgrds
Brian

A 5 psi low oil light is to low oil pressure to save any thing in my opionion. Good idea to maybe have it cut out at 5psi and just signal at 20 psi.

The water temp light saved me at Snodrift this year. We Sno banked and plugged radiator solid. With out the light im sure i would not have know it was hot till it was to late.

---

First rally 2013
Rally car type AWD subaru
Total rallies as driver 6
Total rally cars built 2
Total rally cars caged 3
Total rally cars repaired from offs 4
Total years racing exp other then rally 19 yrs
Like 31motorsports on FB!
Check out 31motor sales on ebay for used Subaru parts

Quote
Reamer
A 5 psi low oil light is to low oil pressure to save any thing in my opionion. Good idea to maybe have it cut out at 5psi and just signal at 20 psi.

The water temp light saved me at Snodrift this year. We Sno banked and plugged radiator solid. With out the light im sure i would not have know it was hot till it was to late.

Speaking from own experience TWICE: 20-25 psi switch is too low if you look and the low oil pressure and don't do anything---except say "DOH!" when it finally pops..

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Damn Subies run around 20 psi at idle! Light will be on at idle if any more then 25 psi. My 20 psi oil light flickers at stop signs when the engine is warm. The old oval track saying was 10psi for every 1000 rpm. So if your reving at 8k with cheap oil and 20 psi chances of scorring a bearing are going to be pretty good. Not sure how much higher then 25 psi you would want before you start ignoring the light at lower rpm's? at least on a subie.

---

First rally 2013
Rally car type AWD subaru
Total rallies as driver 6
Total rally cars built 2
Total rally cars caged 3
Total rally cars repaired from offs 4
Total years racing exp other then rally 19 yrs
Like 31motorsports on FB!
Check out 31motor sales on ebay for used Subaru parts

Quote
Reamer
Damn Subies run around 20 psi at idle! Light will be on at idle if any more then 25 psi. My 20 psi oil light flickers at stop signs when the engine is warm. The old oval track saying was 10psi for every 1000 rpm. So if your reving at 8k with cheap oil and 20 psi chances of scorring a bearing are going to be pretty good. Not sure how much higher then 25 psi you would want before you start ignoring the light at lower rpm's? at least on a subie.

That's more than some cars. Fiats old twin cam motors no more than 6psi at idle was completely normal!! ACK!

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

And my Volvo's light comes on at 14psi and in the owner's manual it says it is normal for the oil light to come on at idle if you've been driving the car hard, so hold the idle speed up a bit until the engine cools off.

I think the VW system of two different switches is RPM dependent somehow. Like, it's okay if you have 10psi oil pressure at idle because who cares, you're at idle, but if you have under 25psi at higher RPM then you're killing your rod bearings even faster than normal (only applies to 136mm rod engines).

I think. Anyway, on the ones I've paid attention to, both switches are screwed into the same oil gallery two inches apart.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

Quote
Pete
I think the VW system of two different switches is RPM dependent somehow. Like, it's okay if you have 10psi oil pressure at idle because who cares, you're at idle, but if you have under 25psi at higher RPM then you're killing your rod bearings even faster than normal (only applies to 136mm rod engines).

It is. The 1.8 bar switch is only "monitored" if the revs are over 2000 rpm. It is also linked to a buzzer, so if you have under 1.8 bar @ over 2000 rpm, the oil light will flash (not be lit - but flash AFAIR).

Quote

I think. Anyway, on the ones I've paid attention to, both switches are screwed into the same oil gallery two inches apart.

That is very likely - I can't really remember. I changed that layout years ago when making room for an oil pressure transducer for the pressure gauge, as well as a temperature sensor.

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Brgrds
Brian