SO I tried to find some info on this have not found much but if there is any additional info please round house kit me to the face and point me to it.. thanks.
I got an 2005 RX8 MT.
just got your basic bolt on mods. header, Aem intake, Exhaust, BHR ignition.

Oil mods.
Mazmart oil pressure regulator
Prosport evo Oil pressure gauge, Oil Temp gauge, Water temp gauge..

I have noticed NO performance issues at all. Just changed out my spark plugs the other day and car feels really good and pulls hard with no stumbling or poor idle. Oil Temps and Water Temps stay normal around 180 degrees for the most part on water and 180-195 degrees on oil temp. (depending on how hot the day and traffic conditions)

When I drive I get 50~80 psi over 4000 rpm cruising at 3500 ~ 4000 range its about 40 ~ 55 psi range everything looks good as I am driving. but when car is warned up and I'm at a light it drops out to 0 psi. On start up (Cold) psi is high about 50 - 70 psi and as the car warms up at idle it slowly eventually drops out to 0 psi. When I bring my rpm's up to about 1500 - 2000 the psi shoots up to about 17-20 psi.

I remember when I first put on the gauge it was always around 17-20 psi at Idle and to be honest I do not know how long its been going to 0 at idle I look at the gauge Mostly when I'm driving to make sure its not dropped out or too low when i am on throttle. I do remember old RX7 engines having this problem due to a front O ring but I'm not sure if its the same issue on the RX8 engine. Any info on this what to look for??

 

If you really didn't have any oil pressure, even at idle, then your engine would be seized. I suspect a problem with your wiring or sender.

 

hahaha I saw that ... good job.. thanks for the info..

 

Most likely the pressure transducer.....electronic pressure gauges are prone to have issues with the sender after a while. Likely need a new one if you can get them by themselves

 

Sorry for reviving such an old thread. @WreakLoosE if you're still around, did you ever fix that issue? I am having the same problem on my newly rebuilt engine, noticed this while breaking it in (break-in not yet completed). Plenty of pressure at cold idle and through the rpms. But after taking the car for a short drive I get next to no pressure at idle. I'm not sure if it is "no" pressure at all, but it is definitely close. I attached a mechanical gauge in the stock pressure switch location and it is reading below 5 psi at hot idle.

Here's a background on what has already been done to get to where I am:

Before noticing issue:
- Engine just rebuilt by reputable builder. Oil mods, race clearanced rotors, cnc street port, 1/2" studs
- Engine re-installed in car
- Complete oil flush of the system (no old oil left in coolers or lines)
- 10w40 oil

After noticing issue (not in a particular order):
- Tested oil pump by loosening oil filter while engine was running by loosening the oil filter and oil came out
- Inspected chain
- connected mechanical oil pressure gauge to stock pressure switch location
- switched to 20w50 oil (now back to 10w40 after the 20w50 had no effect on the issue)
- Tried a few different oil filters including the oem series 2 oil filter (will be trying oem stock s1 oil filter tonight)
- Just installed re-medy oil pressure regulator and shims - https://mazmartstore.mybigcommerce.c...kit-2004-2008/
- Checked for leaks, no leaks

I am trying to rule out everything besides the engine build itself. Have I missed anything?

Thank you!
Kush

 

Have you checked oil pickup tube and seal?

My car currently has a stock renesis with a FD oil pressure regulator, shimmed the front, I get 20-25 psi hot at 750 RPMs with 20w-50.

 

I just checked that the bolts were tight but didn’t remove it or check the seal. I’ll see if I can source a seal, drop the oil pan again and replace it (can’t have the car sit on hoist at the shop) anything else? Thank you!

 

Maybe as things heat up and expand the seal gives out or maybe a crack in the pickup? Did you use a new oil pump? While the oil pan if off I'd check the oil pump chain as well.

Atkins made their own oil pickup seal, I'm not sure if its better than OEM or not:
https://www.atkinsrotary.com/Oil-Sys...4-V28-ARE.html

OEM S1 (I'm guessing that's what you have):
Pickup: https://www.atkinsrotary.com/Oil-Sys...1-14-240A.html
Seal: https://www.atkinsrotary.com/Oil-Sys...H1-14-V28.html

 

Same issue

 

The car is still not back from the shop yet but I’m hoping this would help

 

If you’re still around please chip in.