16 replies to this topic

[RallyRed]

Might be something to do with engine clearance opening up at temp as well?

i.e bigger clearances = less back pressure, but still plenty of oil flow.
I remember getting all worried about oil pressure ( see separate thread ) at one stage, ...felt better after asking Old Johnno
who DOES know about these things.
From memory he said it was more about flow than pressure. i.e you can have wonderful pressure and its not necessarily good as
the engine needs the oil FLOW to be lubricated. Pressure is an indication that there should be flow if all is well, but pressure
is not the be all and end all.
Cooling the oil might make it thicker, and therefore make more backpressure as the pump tries to force it thru the engine, but is that what you really want?

Anyway..I'll leave it up to someone who is more schooled in this area.

p.s. 10psi at 3000 does seem a little low??( have you fitted a 2nd gauge even as a test?
I did and it showed the GTR dash gauge was definitely reading low.

Regards

[warrenm]

You mention that you get a blip under hard cornering & braking, this could indicate that the oil pickup is sucking air, which as you know air doesn't lubricate. Have you tried running more oil in the sump, to allow for oil that may be in the top of the motor, I'd run a litre more than the std dip stick "Full" mark as a trial. What type of pickup is in the sump? 

[Dave6179]

Why no baffles? I had the lil red light come on with heavy braking years ago. New (second hand) race engine (from an actual race car) had a baffled sump... no more red lights. I've also gone back to 20/50 oil, from 15/40. The lighter oil let the engine 'rumble' at cold idle, not there with the thicker oil.

[ckblock]

I had the same thing in one of my xu1,s when you came in off the track.I tried lots of things pump mods etc but the thing that worked was as simple as running MOTUL 300V competition 15W50 and over filling.I wont run anything else in the race cars now as it raised the idle pressure by 8 to 10 psi

[rexy]

You mention that you get a blip under hard cornering & braking, this could indicate that the oil pickup is sucking air, which as you know air doesn't lubricate. Have you tried running more oil in the sump, to allow for oil that may be in the top of the motor, I'd run a litre more than the std dip stick "Full" mark as a trial. What type of pickup is in the sump? 

This is the same advice I followed with success.
I used to get the oil warning light flickering with hard braking after a hard run up through the gears.

[rodomo]

I run 6 litres in the Grease Slapper sump.

[N/A-PWR]

That's great Info Rob.

 

I run 6 litres in the Grease Slapper sump.

[Litre8]

I think all modern engine oils are designed to cope with temperatures over 100c.  I understand a good mineral based oil should safely handle to around 115c and a synthetic to about 140c.  

[N/A-PWR]

In the past,

 

I noticed that engine oil plays a part in keeping the engine cool too, as when the oil is at the low mark on the dip stick,

 

 the motor has a higher temperature, because the oil is hotter having less oil, like wise on a hotter day the oil gets hotter quick and stays there.

 

 

 

So I can imagine an oil cooler to be switched on or off as needed would be handy.

 

 

 

I wonder what coolers the dry sump motors use?

[N/A-PWR]

Just looked up Dry Sumps, and is heaps of information there, including Images:-

[warrenm]

In the past,

 

I noticed that engine oil plays a part in keeping the engine cool too, as when the oil is at the low mark on the dip stick,

 

 the motor has a higher temperature, because the oil is hotter having less oil, like wise on a hotter day the oil gets hotter quick and stays there.

 

 

 

So I can imagine an oil cooler to be switched on or off as needed would be handy.

 

 

 

I wonder what coolers the dry sump motors use?

I can't remember the exact figure, but the oil does the majority of the "cooling" & the water takes care of the rest.

[N/A-PWR]

That makes a lot of sense Warren.

 

I can't remember the exact figure, but the oil does the majority of the "cooling" & the water takes care of the rest.

 

Like Button for You. 

[Litre8]

Yes, Litre8 was at one stage running a 202 (208 actually) with an upgraded NGM Strata VI kit . More details under the General -> History tab on the Litre8 website.

It was featured in the July-Aug 1986 Street Machine.Magazine (and running 16"x9" Simmons way back then)

[ozyozyozy]

From my experience, if your going to the track and doing more than say 5 laps at a time an oil cooler is needed.
I find the type of oil affects pressure good synthetic oils recover faster when hot and also handle higher temps but not always good for flat tapper cams.
It's not uncommon for the pressure to drop when hot.
There is a few mods that are required internally that will help with pressure too.
10 psi at 3000rpm on the track is bad.
A good sump for the track is an absolute must, DO NOT skimp or you will suffer.
To be really honest if your going to see the track with a 308, after all the issue some friends and myself have had I see only 1 option dry sump.
In the time I have had mine fitted I would have rebuilt my wet sump motor 3 times by now.
The other point people don't think too much about with dry sumps are they are generally filtered more and due to the design of the oil tank there much better at separating oil from air which is a big deal in engines.
End of the day there is no 1 single main fix, there will be a number of small things that are required to be done.