Oil Surge

[Gareth87]

I'm curious to know a bit about oil surge. I run an external single stage wet sump pump and a custom 7.5 liter sump, with baffles and windage tray to go with it. I was told to run the oil level around half way up the dip stick but when i went for a spin up the hills the other night and went through some tight hairpins quick, i noticed a momentary drop on the oil pressure gauge. It dropped fast to around 40psi but quickly came straight back up again once i straightened up.

I added another liter of oil to take it just over the full mark on the stick which seems to have stopped it, however, there is one really tight uphill off camber corner that i seem to note the slightest drop on. I really turned in hard to see if i could make it surge on purpose to test it but its hard to be sure if its the revs dropping or a slight surge (its hard to tell because watching the gauge and driving it pretty tricky obviously)

I know oil surge is definitely not a good thing but im curious to know if anyone else experiences these problems under high cornering load and how much a problem a slight surge is. I hear GTRs have a pretty big problem with this.

Any info?

Thanks,

G

[T04GTR]

it is a problem. its not just dropping oil pressure, but rather pumping foamed up oil instead. you may want to get a better sump design.

its a very common problem., in a stock gtr, with the oil on the full mark. just accelerating in 1st gear to redline on a flat straight road, it surges. i know this because i tested mine.

just like fuel surge, if left for to long it will cause damage.

[MBS206]

It makes things start knocking.

Do everything you can to avoid it, and don't try and "test" to see if it's cured... It's expensive if it isn't.

[Gareth87]

It makes things start knocking.

Do everything you can to avoid it, and don't try and "test" to see if it's cured... It's expensive if it isn't.

No i dont plan to keep testing it. But i didnt realise how common it is. That really surprises me with the GTR. Ive moved my oil pressure gauge to straight in front of me so i can really keep an eye on it. Ill have a look into the sump design, but without going dry sump, its about as serious as i can go.

Cheers for the heads up though, if anyone has any more info, i would love to hear a little more about it.

How about in drift cars and track cars without a dry sump... you wouldnt be able to completely remove oil surge would you?

G

[MBS206]

No i dont plan to keep testing it. But i didnt realise how common it is. That really surprises me with the GTR. Ive moved my oil pressure gauge to straight in front of me so i can really keep an eye on it. Ill have a look into the sump design, but without going dry sump, its about as serious as i can go.

Cheers for the heads up though, if anyone has any more info, i would love to hear a little more about it.

How about in drift cars and track cars without a dry sump... you wouldnt be able to completely remove oil surge would you?

G

Where is your oil pick up?

You say external pump, but is the external pump still using the stock pick up? If it is, is the sump gated and baffled?

[Gareth87]

No, its not using the internal standard pickup. The standard oil pump and pickup has been removed. It is a baffled and gated sump with a pickup that runs horizontal across the bottom of the pan. Its like a slotted tube from memory.

G