nycgps

iTrader: (1)

I use 20w50 and I never seen 110 psi. I bypass around stock pressure which is 85 +/- 5 psi.

You got your car used right? maybe the previous owner did something to the regulator ? cuz no way a stock Rx-8 will have 110 psi.

tofu_box

no idea, the regulator looked like the stock one, cous i am actually holding the Mazmart mod in a box infront of me.

I have no idea what is going on, but the previous owner was a older lady, so i really doult she will be installing oil pressure mod?

There was a engine swap done by dealers, maybe they did something then?

DarkBrew

Maybe you have a restriction somewhere? And still the pressure regulators should release the pressure

Mazurfer

10W30 right now.
I will probably take a more detail run later on today or note in on the way to work in the AM, but I've been in the garage all day changing the install a little bit as I didn't like how it was fiiting onto the RB adapter. Had a bit of a weep I wanted gone!


Not the same weep, but here's why no numbers yet! https://www.rx8club.com/showthread.p...97#post3744697

I've been busy!

Mazurfer

Ash,

Not sure if you went and looked at the other thread yet, but.............this is what I am seeing at the moment.

Oil right now is 10W30
Cold start..........looks like 50psi
Warm idle.........anytime sits about 16-18psi

After warm up:

Ambient = 82 degrees
Water temp = 190 F
Oil temp = ~205-210 F
Oil pressure at 3k rpm's in 2nd = 60psi
Oil pressure at 3k rpm's in 3rd = 60psi
Oil pressure at 3k rpm's in 4th = 60psi
Oil pressure at 8k rpm's in 3rd = 80psi (Not real sure about this one, I need to check this tomorrow as I only did it once as might be explained in the other thread. I was being super cautious).


Now..............having said that, I'm a little bewildered as a lot of people seem to read 50psi at 3k rpm's. There is a chance that it has to do with the way I grounded everything. The oil pressure and oil temp sensor separate grounds are run over to the grounding point(bolt) on the drivers side in the engine bay by the master cylinder on the side wall. From there, one solid ground wire runs through the firewall(with the other two sensor wires). That one big ground wire is then tied into the grounding point(bolt) located by the interior fuse box where it joins all other ground including those coming from PLX sensor boxes and the PLX power sensor grounds are also tied there along with the two power grounds from the PLX OLED display boxes.

See attached for grounding scheme.

Mazurfer

Confirmed these numbers again today. Think I might adjust the grounding scheme slightly and see what happens. Anyone fell this is abby normal and something I should really be concerned about.

I figure once you set some sort of a baseline, the most important thing to observe is if you see a significant change in what you normally do.

Comments?

ASH8

Interesting Dave..

The Factory Stats with 5W20 Oil is 50.8 PSI @3000 RPM, Oil Temp 212F(100C)~~(Series 2 72.5 PSI).

I am thinking that perhaps your 10W30 being slightly heavier in Viscosity is the reason for your higher numbers...plus perhaps different meter calibrations/quality??

IMO with 5W20 oil use S1 OP should be higher, hence the Mazmart upgrade.

What do you think?

9krpmrx8

iTrader: (46)

I have not seen a difference in OP despite which oil I use. I am now using 5W-40 and the pressures are the same as when I was using 10W-30.

ASH8

Well it must be owners dial, meter and equipment quality and calibration.

It can't be much else, because everything else is identical...except maybe the brand of gauge, and installation as Dave hinted?

The Mazda made oil pumps for rotaries are very reliable, and as I have said it is a 1985 FC RX-7 Oil Pump anyway in S1 RX-8's.

9krpmrx8

iTrader: (46)

Yeah I am actually going with a different oil pressure gauge soon so we will see if there are any significant
differences.


Question, do you think adding a "T" where the factory oil pressure sending unit would work? You could still retain the factory sending unit and add the sender for the gauge there.

Mazurfer

Well.......for the sake of argument, this is what I'm using. One for the oil pressure and one for the oil temp. They are both located on this page and if you click on Tech Specs it say accurate to within ~1psi. But I know that's all relative.
http://www.plxdevices.com/sensormodules.html

I'm going to look over the grounding scheme this weekend and maybe move it around a bit and see what happens. First thing I'm going to do is jumper across the two sensors right at the plate and see what happens. Maybe I have somewhat of a ground loop going on?
Maybe I will seperate the sensor grounds and power grounds for the boxes and see. Or maybe my oil pump is strong like Ox?
Oh, and sorry for the crappy grounding diagram, I didn't take the time to make it look all nice!

Here's the actual sensor box manual.

DarkBrew

Just got my RB gauges up and running today
After about 15-20 min driving steady 100km/h... 5W30 Castrol GTX
9C ambient
72C oil temp
84C water temp
4.8kg/cm2 oil pressure

120km/h cruise the oil temp rose to 76C

Booting around up to 8K RPM temp rose to 85C

For those who are non metric
F = C*9/5 + 32
PSI = kg/cm2 * 14.2

Edit: more data from this morning
Cold start, Ambient 8C
2K RPM fast idle
4kg/cm2 oil pressure
No reading for WT or OT

1150 RPM
63C WT
<60C OT
1.7kg/cm2 OP

1K RPM
80C WT
62C OT
1.8kg/cm2 OP

3K RPM cruise
85C WT
72C OT
4.2kg/cm2 OP

850 RPM
83C WT
72C OT
1.5kg/cm2 OP