bd32322

Hi,

I have been tracking my car a decent amount recently and noticed the low oil pressure light come on while there still being plenty of oil as shown by the dipstick (1 dot below full mark). The low oil pressure only comes on when I come off the track and drive slowly in the paddock. My naive theory is that the oil is too hot and thin and I haven't done enough of a cool down on track. After a bit of idling around the pressure light goes away.

Anyway my oil coolers are 15 years old now and I am thinking of getting an upgrade for reliability reasons.

Can anyone provide me information about their setrab cooler setup? What dimension and what type of setrab cooler to buy? I have the racing beat stainless steel oil hoses (oem oil line connectors rusted out in north east usa road salt conditions). I was hoping to maybe just have to change the connectors on the hoses and mate them to the setrabs or in the worst case get new hoses.

Thanks,
Bodi

NotAPreppie

What year is your car? Are you sure it's oil pressure and not oil level? The oil pressure is indicated by the fake gauge fed by a switch on the driver side of the motor. The oil level is the little oil can light and that is fed by a switch in the oil pan.

Earlier RX-8's had an issue where the oil level switch would falsely report low oil level when it was fine.

TeamRX8

iTrader: (25)

You shouldn’t be tracking your car without an oil temp and oil pressure gauge for starters. If you can’t afford them then why are you on a track in the first place? Do you understand what a new engine will cost?

Just take the factory thermostats out and use an aftermarket one instead for 185F. It’s been proven that the OE t-stat is the issue. The bypass temp is too high and they leak hot oil past the coolers. You could also try to remove just one of the OE t-stats and block the bypass hole so one cooler runs at max cooling all the time. You might have to block that one off in the winter time if you drive the car on the street too. If you do that the eliminate the one on the LH/driver side so then other one can bypass after it if the temp is too low. Oil flows from the front of the engine to the LH cooler, then RH cooler, then to the oil filter pedestal and then to both the engine and rear pressure regulator.

myself and a few other people had our OE coolers refurbished here. They charged me $125 each and they came back looking like new. Being 15 yo doesn’t mean anything. Unless they’re significantly damaged in some way they should still function fine

Bob Randle
Customer Service Manager
AMERICAN COOLER SERVICE, INC.
919 W. Mayfield Rd.
Arlington, Texas 76015
(P) 817-419-8008
(F) 817-419-8118
bobby@americancooler.us


you also have the option of just replacing the OE t-stats with cooler ones, but I don’t recommend it because imo it’s a halfway fix. They will still likely leak past the coolers at some point.

https://rotaryperformance.com/produc...ler-thermostat

those are your options besides an entire new kit

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bd32322

Its a 2005 rx8. I am sorry its oil level and not pressure. The oil pressure gauge stays uselessly in the middle. I am in the process of setting up a obd2 reader and display.
Regardless I would like to upgrade the oil coolers because my current ones have small leaks in them. And I also want higher cooling efficiency - e.g. for hot days on the track.

TeamRX8

iTrader: (25)

You don’t understand the situation properly, but most people don’t. The info is all on the forum, but most people still haven’t figured out how to connect all the dots. Let me just point out that racers who pulled the OE t-stats completely out couldn’t get their oil up to temp on the track. What that means is the OE cooler isn’t the issue when it will obviously over cool the oil when unregulated. But it’s your money and time. Good luck.

kevink0000

Team,

Isn't the first cooler (hottest) on the LH side as you drive the car?

TeamRX8

iTrader: (25)

Thank you. That was my bad memory. Corrected.

bd32322

So anyone have a setrab setup they can send me info on - part numbers or dimensions of the cooler, hose lengths etc?

TeamRX8

iTrader: (25)

best response ever;

ktec

iTrader: (2)

To keep this thread relevant and clear up some questions,
1) Why you think only the oil cooler thermostats are not a good fix? If total oil cooler capacity is plenty, it just needs to be regulated properly right? 165F seems a little too low to open (100% @ 175F according to the graph for the RP oil thermostats).
2) Lately it's been cold here, 35-45F at times when driving my RX. I feel the oil never gets hot enough, coolant slowly gets to 185F and will hardly move up. Makes me think the oil is below the quoted 220F stock oil-T opening; yet when I get out to check the oil coolers, they are warm maybe 140-170F. So how are they getting hot oil if the stock oil-thermostat opens at 220F?

TeamRX8

iTrader: (25)

1. They’re not a positive shutoff like a good bypass and are prone to leaking hot oil past the cooler. It depends on a lot of variables. From the factory perspective they‘re less expensive and effective enough. It you really study the difference between how they function and how a well designed bypass functions the difference is obvious, but there is both a cost and effort that has to be made for doing that rather than just swapping out the OE parts.

2. They’re also not a 100% bypass either. It simply opens the bypass; which the majority of oil will follow the path of least resistance, but the cooler itself is still open to oil flow. The aftermarket ones are the same in that regard. Some oil is always going through the cooler even in bypass mode. The bypass will also cycle open/closed in low temp situations. So flow is not consistently going through the cooler, but will be diverted back and forth between the cooler and bypass flow paths. Ideally you’d need to measure oil temp pre and post bypass to fully understand how the system is functioning. You can’t do that on the OE system though because the bypass is tied in directly with the cooler outlet.


High-Flow Engine Oil Cooler Thermostat FSM

which you can also get same with integral oil filter pedestal and along with a oil filter pedestal eliminator manifold relocate the oil filter to a more easily accessible location. I really hate where the RX8 oil filter is located.

https://www.rx8club.com/rx-8-racing-...7/#post4898759


the t-stat deal has all been discussed/done before. 9krpmrx8 has some threads and posts worth reading on his experience on both the bypass and alternate oil coolers.

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kevink0000

Ktec,

The coolant should be at 185 with a 185 degree thermostat.

When it is greater than that for more than 30 seconds to a minute,(waiting for thermostat to respond) that means your cooling system is unregulated, and the only limits to temperature are power output and air temp/flow. You have what amounts to an air-cooled engine at that point.

185 is very good.It should be that way 100% of the time in my opinion, at all power levels/ambient temps, after warmup of course.

Seek ways to keep it at 185 all the time, and your engine will be much happier, longer. Stable, well regulated temps are what any engine need, especially this one with so much built-in temperature differentials and different metals and plating composition in its design.

I am not as concerned as some about the 175 degree open temps of the RP kit. My car at the engine output to the coolers gives 190-195 oil temps unless the cooling system gets overtaxed in the summer here in Arizona.It seems to regulate quite well. A week ago I drove to work in 28 degree weather and I saw oil temps level out at 190 within 15 minutes of a cold start with car outside. And with 20w50.