Track driving oil pressure 20XE

[Iain]

I've had issues with oil pressure on trackdays since the very beginning, been through various iterations and it's still causing me a bit of grief.

Water temp sits reasonably stable at about 90C, oil temperature now seems to sit stable at 110C ish when out there but the pressure continually drops while I have my foot down hard. If I back off, coast around a bit of drive on part throttle the pressure will sit comfortably at over 50psi, if I'm giving it some it'll drop down to near 30-35psi on the gauge under acceleration.

Set up is:
20XE, high compression, Kent cams, standard injection/inlet but with higher rev limit (don't go above 7k often)
Valvoline 15w50 oil
GM thermostat sandwich plate, 16 row 235mm oil cooler mounted up front, fully exposed with no grille fitted

Suggestions?

[millworm]

Baffled sump?

[8valve-craig]

Doesnt sound like a baffled sump would help here. How many miles has the pump done? and have you had a look at the pickup pipe recently?

[Iain]

I don't think it's surge issues as there's no immediate low pressure point, although I do have a baffled sump on there.

It's a used XE pump not sure on condition now but I must have been happy with it when I fitted it 3+ years ago.

Pickup pipe was checked for blockages when I fitted the baffled sump not that long ago.

For some reason I've overlooked the core component of the oil pump lol ZLET pump upgrade maybe?

[Stuart]

The internals of the oil pump could be cavitating at higher speeds/loads causing the pressure to drop.

The oil temp sounds 5-10deg too high especially as you have the cooler too, but 110 isnt something to worry about...much more (120) and you might want to rethink the oil system too.

[turbo-boy]

check your relief valve in the pump its probabliy scored and sticking at times which ajusts your pressure, get a sbd nylon one

[Iain]

Didn't seem like a sticking relief valve to me as it's reproducable quite consistently with 10 minutes of hard driving.

ZLET pump looks a doable upgrade.

Oil temps used to rise up to 120C before the cooler upgrades so it must be doing something. I could possibly get a different thermostat so it opens earlier than the OE one?

[Stuart]

opening earlier wont lower the temps (much like a lower temp coolant stat wont stop how hot the car gets, yet mongs still fit them), a bigger cooler would help, but as you are 'down' to 110 then youre doing something right.

Does sound like the pump is tired, maybe shoving oil round the cooler is just too much for the poor thing as 10mins is about the right time frame for the oil to get hot enough.

[turbo-boy]

try adjusting the spring on the relirf valve

[Iain]

Washer underneath the spring to increase pressure?

[Johnny A]

If I saw any pressure variance at revs I would **** myself!!

In your situation a Z20LET pump and pickup is a wise choice

[Stuart]

I recall driving a Ford V6 Morgan (newish one back in 2006) and once hot the oil was so thin that the at idle the oil pressure was zero on the gauge :s some revs saw it come back up but still it was hugely lower than when cold. The engine was fine though....

[turbojolt]

Remove gauge . Problem solved

[Iain]

That doesn't involve the fun of spending money though? lol

Looking at about £330 for a modified pickup and new GM ZLET pump, hmmm

[turbojolt]

Pay me 300 quid to rip it off the dash lol