7M-GTE track oil pressure to low?

[blackmk3]

Hey guys so just finished a track day on Friday in my supra and got a question about the oil pressure.

The engine specs are
Rebuilt motor (not sure of clearances re builder did it). Oil squirters, full flow relocation setup with a 19row oil cooler and a 86c oil tstat
New toyota oil pump shimmed 6mm
Hard pipe oil pump mod thinge (no banjo setup)
Custom winged and gated sump 9 liters capacity

When on the track the oil temps got up to 120c
I'm running a penrite 5w-30 oil full synthetic that's pao based racing spec high zinc etc etc
But what I noticed is that at 4000rpms it was making 300kpa oil pressure 43psi and by redline 6200rpms it had only increased to around 320kpa 46psi

I have a Greddy gauge that's a digital stepper motor and very sensitive, the pressure at cold startup shoots to 500kpa 72psi then the relief must open it causes pressure to instantly drop back to 420kpa 60psi which is normal when cold pressure?

At normal oil temps around the streets the temperature sits around 80c the pressure is prefect and rises around 10psi per 1000rpms and has done ever since the the engine was first started.

Its just when the oil is at track temp 120C that the pressure wasn't getting as high. I understand how the viscosity changes at temperature and even more so at race temp, i wanted to know if that pressure around 40-45odd psi is enough when at the track? or do i need to step up to a thicker grade?
So my question really is at track temps is the 5w-30 that im running that's making 45psi of pressure enough to protect my 7M-GTE?


Thanks!

[Flannelman]

I don't think the (insert brand) oil is up to the task.

As you now have data regarding temps, do some research as to what can maintain the pressure at that temperature.

Oils are much like anything. All are built to a standard, but some exceed this better than others. It may be found a specific brand may be required rather than changing the weight. (eg, royal purple/brad penn)

[blackmk3]

I did suspect there could be some difference here so i did abit of looking the CST limits for a oil to be called a 30grade is 9.3 to 12.1 at 100c

The penrite im using is 10.0
Castrol Edge 5w-30 is 9.7
Royal purple XPR racing 5w-30 is 11.6

At 120C this can all be out the window tho who knows what csts there at then as the manufactures don't measure and provide that data

[KinLoud]

Hi
Where is the oil temp sensor? Sump, filter?
The "oil pressure rule" of 10 psi per 1000rpm is misleading - required oil pressure depends on bearing width/area, clearances etc.
no use shimming the oil pressure bypass valve spring to up the pressure without checking the engine specs and clearances.
What's the toyota oil pressure specs?

[blackmk3]

Temp sensor is in the sump away from the turbo oil return to.
Yeah i understand the 10psi 1000rpm isnt correct, more of a guideline ive been treating it that way

Shimming the oil relief spring is quite a common mod in 7M circles just to get a bit more pressure in those upper rpms

The toyota specs are at idle 4.3psi 29kpa
And at 3000rpms 36-71psi 245-490kpa

It dosent mention testing on a hot or cold engine so im guessing this is the reason for the very wide OK areas of pressure. Which my engine certainly exceeds
Its just at 120c i had concerns. Sustained rpms high load etc etc

[Ninja25t]

I have found my oil pressure gauge (digital numeric type) almost impossible to read on track. Fortunately it is capable of data logging. When I logged my standard 4age blacktop sump setup (viewtopic.php?f=3&t=92794&p=961466&hilit=4age+oil+pressure#p961466) the pressures were all over the place due to surge. Could you be seeing the same sort of effects and you are just not seeing the peaks while glancing at it on track?

I'm not sure which track you are on but maybe have a look what is happening towards the end of the main straight(s) where any surge should be minimised?

That said, data I collected once I had installed a the baffle in my sump showed a range of only 5-10 psi in pressure with temps into the 130's. I was running a similar Penrite product of 10W-40 grade (can't remember exactly which one). This range compares to more like 20-25 psi at normal operating temperature. So perhaps it is a combination of reduced viscosity and surge in your case?

I have installed an oil cooler but haven't had a chance to data log it yet.

[Mr Ree]

Hi mate, just out of interest, how is your oil cooler orientated? Could there be an air lock causing the core to perform sub optimally? Ideally you want it mounted vertically, with the feed line entering the bottom port. Also, is it ducted?

Going up to a thicker oil will reduce flow so unfortunately that wont help reduce your temps.

Are you still running the same power level? I think that with as much power as you use to have, there is only so much you can hope to achieve with a small cooler, so perhaps you need a larger one?

Also, what are your water temps at the track?

[blackmk3]

Thanks Ninja25t im pretty sure that its not oil surge that im experiencing, the reason the motor was rebuilt in the first place as it ran a big end bearing because all of the oil was racing forward and exposing the pick up under braking. So i spent quite abit of time making a new sump for it with all the gates and wing dings!
sure it could be better with a windage tray but it seems to be doing the job, that center area holds 2liters of oil and will have oil racing in from any direction at the track



Hey Reith the oil cooler is mounted vertically so the fittings to the top, im running a permacool thermostat which from the spec sheet when oil temp is below 82C it runs in 90/10 mode so 90% of the oil bypasses the cooler and goes straight for the engine, the 10% is there to just keep the oil moving in the cooler, i guess like you say to prevent air locks and to pre warm the oil for when the tstat opens.

Its not ducted currently and sits behind the intercooler. I have noticed it takes along time to drop oil temps and low speed, when stopped the hand test on the oil cooler certainly confirms its dam hot! there's definitely room for improvement here which will happen.
Water temps are really good i run the factory radiator and factory viscus fan and the hottest ive seen it get was 92C. which is around the same times as the oils at 120c which is 5laps into the race or whatever

Powercruise next weekend i guess it will be another good test and some time to monitor everything