oil pressure

[Synthesis5]

ok, i just ordered my autometer phantom series 0-100 psi oil pressure gauge, and i was just wondering whats the normal pressure reading on a p5?




oh yea i ordered the gauge from summitracing, and the gauge comes with 1/8 in. electric sender and 1/4 in. NPT fitting. Is this all im going to be needing for the installation?

 

[LittleRedWagon5]

I have a an Auto Meter Electric O/P guage and I show around 75 to 100 PSI when the engine is cold. And keep in mind its been like low teens outside around here for weeks so thats just winter startup pressure. But when it warms up the idle O/P pressure is around 15 to 20 PSI and around 4500 RPM it maxs out at about 65 PSI. I try to keep the revs down when the engine is cold cause theres just something about 100 PSI of O/P thats disturbing. After about 5 to 8 mins it settles in at the normal operating temperature range.

As far as the fitting, the threads in the block are metric. your gonna need an adapter from autometer it converts from sae to metric thread. its like 8 bucks.

 

[Synthesis5]

ok, i gotta a couple more questions.....

-where exactly is the sender suppose to hook up too and what are the exact measurements and size of the adapter that i need???

-for the ground(-) wires i know where i'm gunna hook them up, but where would be a good place(or wire to tap into ) to hook up the 12v(+) for the voltmeter???

-where exactly is the ignition switch(wire) that i need to hook up the rest of the oil pressure gauge???

-will i need to drain the engine oil before i unscrew the stock sender unit or can i just unscrew w/o drain'n???

thanks so much for any info

 

[Hawkeye]

The sender can attach one of two ways. First is to thread it into the stock sender hole. This is to the left of the oil filter when you're looking up from below. You'll never get it out without first removing the filter, so it looks like you'll be doing an oil change.

Another option is an adapter that goes between the engine and the oil filter. I got one off of eBay for $45. I attached my oil temp and oil pressure senders to it. Worked like a charm!

As for the wiring, I actually re-wired my ignition system some time ago for keyless/push-button starting, so I just tapped the existing relay for the 12v power for the gauge. For the lighting, I installed another relay that closes when the parking/headlights come on.

 

[Little Beavis]

Oil pressure is going to be dependent upon the oil you use to an extent.

I run Mobil 1 and only see oil pressure of about 40 - 50 psi when I start the car, but then it will drop to 15 psi and below when hot (I was always worried that it dropped so low, so it is nice to see that someone else gets those readings. . .but I never get anywhwere near 100 psi. . .sorry.)

A 1/8" BPT nipple will go right into the block where the oil sensor already is. Get a 1/8" NPT "T" and and make a little setup and go on your way.

 

[Hawkeye]

That's funny, I run Mobil1 5w-30 w/ Mobil1 filter and I get 75psi on start and 85+ on cold revs.

 

[Little Beavis]

Holy crap. . .
Actually I should say that I have my gauge after a restrictor for the turbo, so now that you mention it, I shouldn't have posted those numbers. That is not the oil pressure at the engine. Sorry for any confusion.

Does your pressure drop big time when it gets real hot (after a couple good runs)? Very curious about that. . .mine drops big time.

 

[Hawkeye]

Yeah, once it warms up it falls considerably. At idle, once it's fully warmed up, the needle's around 5-12 psi.

 

[twilightprotege]

gee seams to me that the oil pressure people are getting is quite varied. has anyone had a chat to mazda as to what it should be?

 

[Little Beavis]

I'd like to know what it "should be" as well, but I feel A LOT better than others are getting real "low" reading after it warms up. I was a little worried, but since I never got an oil idiot light, I figured I was okay yet.

 

[mopiko]

Just want to chip in on my reading....

50psi summer cold start (75F - 90F)
65psi cold start (50F - 70F)

15-20psi Warmed up Idle

55psi 3200rpm / 120kmh

humm..... hope this helps...

 

[Maxx Mazda]

The shop manual says minumum 57psi hot above 3000, RPM, but think. THose of us who are turbo are running the pressure sender T'd into our oil feed line, so the pressure reading is inaccurate. The oil is only flowing past the sender, and not into it and stopping. My hot idle pressure is only liek 15psi after some hard runs. Cold start is like 55 psi. Before my turbo I was at around 75 cold, and 25 hot idle.

 

[magnumP5]

The shop manual says minumum 57psi hot above 3000, RPM, but think. THose of us who are turbo are running the pressure sender T'd into our oil feed line, so the pressure reading is inaccurate. The oil is only flowing past the sender, and not into it and stopping. My hot idle pressure is only liek 15psi after some hard runs. Cold start is like 55 psi. Before my turbo I was at around 75 cold, and 25 hot idle.

Reading this has made me feel a lot better. Cold start, I sit around 55 psi but it drops pretty quickly as the engine warms up. After full warmup and some driving my idle oil pressure if barely noticeable but I know for a fact I'm not leaking oil and it is not low. I think I might invest in a full sweep electric gauge from autometer for some more accurate readings...