R34 GT-T Low Oil Pressure?

[Gw2]

So i have a 98 r34 gt-t, recently fit in an greddy oil cooler with a built in thermostat sandwich plate.

When you start the car when complety cold, the factory oil pressure guage reads correctly, about 4-5 bar at idle. When the oil gets to proper temp the pressure then sits on 2 bars at idle, will go to 3 bars when at 2,000rpm, and 4 bars when at 3,000rpm.

If i were to turn the car off, and then start it again, the oil pressure will now read about 1-1.5 bars, 2 bars at 2,000rpm and 3 bars at 4,000rpm. 

Sometimes the needle will jump up and down and then revert back to reading 2 bars at idle, sometimes it doesnt. 

Today it was reading correctly, drove it for an hour, guage was reading 2 bars turned it off and started it, guage read about 1.7-1.9 bar, after about 15 or so mins or driving, while sitting at about 3 bars of pressure, i saw the needle drop back down to 1.9bars, i was in 5th gear doing 80kph, about 2,000rpm or so. At idle it would now sit at about 1 - 1.5 bar. 

I dont get it, is this normal? Is my oil pressure guage faulty? Is the oil cooler and or sandwich plate somehow affecting my oil pressure readings? 

Also my stock boost guage sometimes completly stops reading and then will randomly go back to reading, so i am hoping its got something to do with faulty guages and not engine related.

Any help appreciated thank you!

[thebe]

The stock gauges often have a life of their own. Mine started showing correctly after I removed and cleaned it (and fitted to another block). If you are worried about your oil pressure I would fit a good quality aftermarket gauge for a peace of mind

[GTSBoy]

I second the above statements.  I would, however, caution that the behaviour you describe does sound like it might have something to do with the installation of the external pipework.. Not swearing by it, just suggesting it - if it didn't used to happen and is only doing it since.  Perhaps take the sandwich plate off and put the filter direct back onto the engine.  See if the problem goes away or stays.

See recent thread by Dose Pipe where similar shenanigans are reported.

The electrical problem possibility is also strong.  Take the dash out and check the happiness of the various connectors on the back.  Wiggle the instruments' fuse in the fusebox.

[Gw2]

54 minutes ago, GTSBoy said:

I second the above statements.  I would, however, caution that the behaviour you describe does sound like it might have something to do with the installation of the external pipework.. Not swearing by it, just suggesting it - if it didn't used to happen and is only doing it since.  Perhaps take the sandwich plate off and put the filter direct back onto the engine.  See if the problem goes away or stays.

See recent thread by Dose Pipe where similar shenanigans are reported.

The electrical problem possibility is also strong.  Take the dash out and check the happiness of the various connectors on the back.  Wiggle the instruments' fuse in the fusebox.

Yeah i think i might have to give that a go. Also not sure if this important or not, but the oil filter the car used to use before the oil cooler install, was a fairly bulky one, which is the standard one for the s1 r34s. When i installed the oil cooler and sandwich plate, the sandwich plate wouldn't fit the stock s1 oil filter as it was too large, so i had to use the smaller one from the series 2 r34s. I don't know if this would cause a random drop in pressure but thought i might aswell bring it up.

[KiwiRS4T]

Won't be the filter. If you are worried get the Nismo ones which are smaller but allegedly more efficient.

[Sam62391]

As for your boost gauge, replace or fix the boost sensor. Small black module in front of the VIN plate. 

[7amooda.007]

Mine reads around 4 constant when warmed, higher than 5 when cold.
However oil used is 20w50 from previous owner, thats why.

Will change to fully synthetic 15w50 in the coming days.

What surprised me also, the owner uses a 2jz oil filter.

[KiwiRS4T]

Nothing wrong with your oil pressure ...I would try something like 10W 40.

Many filters will fit - try to buy quality ones - get Nismos if you can get them at a reasonable price.

[niZmO_Man]

What's so special about Nismo oil filters?

[KiwiRS4T]

7 hours ago, niZmO_Man said:

What's so special about Nismo oil filters?

They are not special but guaranteed quality. Someone in SDU actually did the research on filters cutting them open to check how they are built and the best value for money turned out to be one used on aircraft engines (he worked in that industry).

So the only reason to buy a Nismo filter is that it will do the job (and its a bit smaller than OEM if room is a factor) but of course if you can find a good one for less then that's the way to go.

[niZmO_Man]

Ah yes, the quality should always be there. But I'm concerned about the price.

I'll stick to Ryco Z442