Oil pressure at the track to low?

[Blackmk3]

Hey guys so just finished a track day in my supra today and got a question about the oil pressure.
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 186 farenheight
New toyota oil pump shimmed 6mm
Hard pipe mod thinge (no banjo setup)

But anyways during the race the oil temps got up to 120c 248f
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 62000rpms it had only increased to around 320kpa 46psi

Is this enough/normal pressure for a 30w at that temperature?

Thanks!

 

[black89t]

sounds like a solid setup. you have done everything there is to do to help the 7m's oiling issues. the only factor i can see is your bearing clearances. typically the general rule of thumb is 10psi per 1000rpm will keep an engine happy. if your clearances were closer to .001 on the tighter side id think you'd be seeing more oil pressure. they're prolly on the looser side closer to .002 which is fine but 5w30 isn't the best match for that unless it gets freezing cold where you live and you drive the car then. id play around with a heavier weight oil like 10w40 or even 20w50 and see how it reacts especially if it never gets cold where you live. i know you want flow and blah blah blah but the bearings need pressure especially if you're running the car hard. personally i run 20w50 in my 7m i slapped together for my truck that's been going 4 years strong taking a beating till it got totaled. and that was just a used reman bottom end i scored at the picknpull plus a head i had laying around. I also had a built 7m in my car for a while that had looser clearances and it liked 20w50 better. it rarely gets under 40 where i live so cold starts and stupid high oil pressure isnt a problem.

 

[SeeUSmile]

Oil filter bypass spring kicking in? relief valve ?

 

[Nick M]

But anyways during the race the oil temps got up to 120c 248f

Viscosity (resistance to flow) drops as temperature increases. This is why synthetic is used, as it is not affected as much.

But what I noticed is that at 4000rpms it was making 300kpa oil pressure 43psi and by redline 62000rpms it had only increased to around 320kpa 46psi

Make sure you have enough oil in the crankcase. You tried to push more oil through the same space, so pressure went up.

Is this enough/normal pressure for a 30w at that temperature?

30w?

 

[Blackmk3]

Make sure you have enough oil in the crankcase. You tried to push more oil through the same space, so pressure went up.


30w?

Yeah ive got a custom sump with hinged gates and 4quarts of extra volume, oil level was perfect full on the factory dipstick

And 30W oil, well 5-30w. 30w when up to 100C anyways

 

[Blackmk3]

When the engine is cold the relief system works perfectly, i have a Greddy gauge that's a digital stepper motor and very sensitive, the pressure at 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 temps around the streets oil temperature that sits around 80C 176F the pressure is prefect and rises as mentioned 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 248F 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?
Ive done my oil research thanks to the very informative people on this forum and that's why I am running the grade and oil type that i am to maximize the flow to the bearings rather than just please me with high pressure on the gauge as running a thicker oil would do but not providing enough protection.
My question is is that at track temps is the 5w-30 that im running that's making 45psi of pressure enough to protect my 7M-GTE?

Oh and i live in New Zealand, this particular day the ambient temp would have been 25C 77F. lowest we really get is 0C 32F
No snow or anything like that in winter. Heading into summer now

 

[SeeUSmile]

I wouldn't stress too much over it. So as long as there's flow to keep hydrodynamic lubrication going. I'd be more worried if oil pressure is gradually reading lower at the same temp over time which says alot about it's viscosity index

 

[Nick M]

It is "grade" not weight. Gravity has nothing to do with it. The W by 5 indicates winter.