Oil cooler, is it really required for my 34GTT

[Murray_Calavera]

21 minutes ago, YD34GTT said:

Ahhhh ok so getting an oil cooler without the taarks oil block and getting these sandwich plate attachments is what you're suggesting ?

Yep. The Taarks block deletes the factory oil warmer/cooler. 

The sandwich plate I linked attaches to the factory oil warmer/cool (where your oil filter is now) then the oil filter attaches to the sandwich plate. I run the sandwich plate option, I don't have any issues with access to the oil filter. 

The above kits are good if you want to relocate your oil filter. 

[Butters]

Adding another view for your consideration. 

 

The factory water to oil heat exchanger does make the car run warmer(not hot) but it does also make the water warm up quicker(which is nice, specially in cold countries). 

After removing mine, water temps go from mid 80s to mid 70s, basically sits on the thermostat opening  temp of 76 degrees.

It is a solid 10 degree ECT drop. Which I really like personally  and being in a place geographically that never sees sub 20c water temp start,  the slower warm up is no issue. 

Your car must be tuned for this lower water temp though. 

 

You then need to control oil temp and adding an air oil cooler solves that. 

 

[YD34GTT]

1 hour ago, Dose Pipe Sutututu said:

Another way to do it, is to use the Greedy relocation blocks, then make up your own lines and mount your oil cooler where you want it.

Alternatively just buy their kit, although it comes with a small-ish oil cooler, which would be plenty for your usage anyhow.

Is this the same as a sandwich plate that was mentioned earlier ?

[Dose Pipe Sutututu]

28 minutes ago, YD34GTT said:

Is this the same as a sandwich plate that was mentioned earlier ?

A bit different 

[joshuaho96]

1 hour ago, Butters said:

Adding another view for your consideration. 

 

The factory water to oil heat exchanger does make the car run warmer(not hot) but it does also make the water warm up quicker(which is nice, specially in cold countries). 

After removing mine, water temps go from mid 80s to mid 70s, basically sits on the thermostat opening  temp of 76 degrees.

It is a solid 10 degree ECT drop. Which I really like personally  and being in a place geographically that never sees sub 20c water temp start,  the slower warm up is no issue. 

Your car must be tuned for this lower water temp though. 

 

You then need to control oil temp and adding an air oil cooler solves that. 

 

You really don't need to drop operating temps below the 80C that an RB already operates at normally. Thermostats don't change the cooling capacity of the radiator/fan/pump, they just change when that system is used. Worst case for a thermostat that determines what the crack temp should be is if you floor it with the thermostat closed how rapidly it responds and opens up before the engine overheats. In modern cars the ECU uses a heater on the thermostat wax so the moment you floor it despite the engine running at 95C before they can almost instantly pop open the thermostat and drop temperatures down to 80C with almost no overshoot past 100C. Most RBs are already running relatively cold for a "modern" engine so there's no need for such fancy tricks or really any effort to drop coolant temps.

1 hour ago, YD34GTT said:

Is this the same as a sandwich plate that was mentioned earlier ?

Sandwich plates don't relocate the oil filter, so it's slightly different. The relocation block is functionally equivalent for oil coolers, it just allows you to move the oil filter somewhere less annoying than the factory location.

[YD34GTT]

23 minutes ago, joshuaho96 said:

You really don't need to drop operating temps below the 80C that an RB already operates at normally. Thermostats don't change the cooling capacity of the radiator/fan/pump, they just change when that system is used. Worst case for a thermostat that determines what the crack temp should be is if you floor it with the thermostat closed how rapidly it responds and opens up before the engine overheats. In modern cars the ECU uses a heater on the thermostat wax so the moment you floor it despite the engine running at 95C before they can almost instantly pop open the thermostat and drop temperatures down to 80C with almost no overshoot past 100C. Most RBs are already running relatively cold for a "modern" engine so there's no need for such fancy tricks or really any effort to drop coolant temps.

Sandwich plates don't relocate the oil filter, so it's slightly different. The relocation block is functionally equivalent for oil coolers, it just allows you to move the oil filter somewhere less annoying than the factory location.

Thanks heaps for clearing it up, have a good direction now as to what I'll be doing

[MBS206]

2 hours ago, Butters said:

Adding another view for your consideration. 

 

The factory water to oil heat exchanger does make the car run warmer(not hot) but it does also make the water warm up quicker(which is nice, specially in cold countries). 

After removing mine, water temps go from mid 80s to mid 70s, basically sits on the thermostat opening  temp of 76 degrees.

It is a solid 10 degree ECT drop. Which I really like personally  and being in a place geographically that never sees sub 20c water temp start,  the slower warm up is no issue. 

Your car must be tuned for this lower water temp though. 

 

You then need to control oil temp and adding an air oil cooler solves that. 

 

This comes back to something I've said in another thread.

 

It really seems to me, the water flow in the block/head isn't working 100% in the engine how we all think it is (slower flow in the back), that quite possibly, the oil is stripping excess heat from areas of the engine, and then using the factory oil/heat exchanger to move that heat into the coolant.

 

This is likely why so many high powered cars that have the oil/coolant exchanger removed, end up needing to run an oil cooler when being used for more than basic driving.

Also possibly why engines with it removed and no oil cooler still have issues later on with bearings/oil.

 

Again, this is just my hypothesis. But if you're saying coolant temps have dropped by removing it, then that heat has to be staying somewhere, likely in your oil, so you really do want an oil cooler. But it also means another area of your engine is too cold now as coolant is now 10 degrees cooler than designed to run.

[joshuaho96]

15 minutes ago, MBS206 said:

This comes back to something I've said in another thread.

 

It really seems to me, the water flow in the block/head isn't working 100% in the engine how we all think it is (slower flow in the back), that quite possibly, the oil is stripping excess heat from areas of the engine, and then using the factory oil/heat exchanger to move that heat into the coolant.

 

This is likely why so many high powered cars that have the oil/coolant exchanger removed, end up needing to run an oil cooler when being used for more than basic driving.

Also possibly why engines with it removed and no oil cooler still have issues later on with bearings/oil.

 

Again, this is just my hypothesis. But if you're saying coolant temps have dropped by removing it, then that heat has to be staying somewhere, likely in your oil, so you really do want an oil cooler. But it also means another area of your engine is too cold now as coolant is now 10 degrees cooler than designed to run.

Yep, hence why you want both the oil/coolant heat exchanger and dedicated fluid to air heat exchangers for both coolant and oil. Coolant heats up faster than oil so during cold start you want to send that heat into the oil. Once you're at operating temp engine oil temps tend to get out of hand due to all the bearings, windage, and engines like the RB26 cool the pistons with oil so now the coolant is the one absorbing heat. Even with a dedicated air to oil cooler the coolant radiator dominates the front area of the engine and you really want all the dissipation capacity you can get. For a really serious track car probably both driver and passenger side under the headlights you want the biggest core that will fit and appropriate ducting to suit. You can shove more into the car but those are the lowest compromise options.

[soviet_merlin]

21 hours ago, joshuaho96 said:

Look for this round thing stuck to your oil filter housing with two coolant hoses coming off of it. Basically every modern remotely high performance engine uses one to help regulate oil temps

Thank you! So it should sit between the oil filter and the engine block? Oil travels through the heat exchanger and then through the oil filter? Coolant is piped through the heat exchanger around the oil. If the oil is cold it'll pick up heat from the coolant, otherwise the coolant will leach off heat from the oil?

// edit: You guys just just explained this. Makes sense.

 

Looks like I don't have one on my setup. The oil filter sits on a sandwich plate with oil temp and coolant sensor and that goes straight into the block. Must have been disappeared at some point.

The result: the coolant temp is solid. It sits around 90°C and doesn't budge seemingly regardless of how hard the car is driven. But oil temp creeps. Give it what feels like 30 minutes in the twisties and it it'll start creeping above 115°C and I have to take it easy.

I thought I needed an oil cooler. Now I'm thinking it might be worth starting with an OEM heat exchanger and see how it holds up.

[Dose Pipe Sutututu]

@soviet_merlin looks like someone has removed it.

Probably easier to just get a proper oil cooler setup installed with an oil thermostat.

Then send its mum.

[Dose Pipe Sutututu]

2 hours ago, MBS206 said:

This is likely why so many high powered cars that have the oil/coolant exchanger removed

It's more so to remove any risk of the heat exchange failing and turning your oil into a frappuccino.

Most engine builders will delete it for that reason as well as simplification of hoses etc.

Same reason I launched mine too.

[joshuaho96]

2 hours ago, Dose Pipe Sutututu said:

It's more so to remove any risk of the heat exchange failing and turning your oil into a frappuccino.

Most engine builders will delete it for that reason as well as simplification of hoses etc.

Same reason I launched mine too.

This is the most plausible one to me, too much pressure/heat differential/heat cycling and it pops. Now that Nissan restarted production of the cooler I'm tempted to buy a spare in case mine ever fails internally.

[MBS206]

3 hours ago, Dose Pipe Sutututu said:

It's more so to remove any risk of the heat exchange failing and turning your oil into a frappuccino.

Most engine builders will delete it for that reason as well as simplification of hoses etc.

Same reason I launched mine too.

Oh I get WHY people remove it, I'm saying more "when people remove it, this is why we see oil temps increasing more"

 

I'm genuinely curious, with no way for myself to validate it, IF the rear of the engine for example, is getting cooling done a bit more in oils favour, compared to the front (eg, front of engine, 99% of heat control is likely coolant, where as coolant may not be flowing as well in the rear, and hence coolant may now be only contributing to 95% of the heat control in the back of the engine).

 

Hence when you remove the heat exchanger, you see oil temps climb 

 

It would be quite interesting to drill and tap the water galleries front and rear and look at coolant temps through the whole motor. Though there are many reasons why the results on this would be skewed and possibly show nothing, even if my hypothesis is true.

[GTSBoy]

1 hour ago, joshuaho96 said:

too much pressure/heat differential/heat cycling and it pops

Nah, it's more corrosion from not changing the coolant.

[Dose Pipe Sutututu]

5 minutes ago, MBS206 said:

Hence when you remove the heat exchanger, you see oil temps climb 

I just think these shit box motors naturally make heaps of heat and Nissan slapped on the water/oil heat exchanger to keep the oil temps happy.

I would assume without any evidence the water/oil heat exchanger is quite efficient at removing excess heat from the oiling system.

This is why a mild RB shit box with a decent radiator and OEM fan/shroud is able to keep water and oil temperatures quite stable for street/drag/roll racing usage. It's only when the water cooling system is overwhelmed is when shit hits the fan super quick.

I believe @GTSBoy has a better explanation than my broscience lol.

[Kinkstaah]

I'm not entirely sure - I had gauges before I changed any of the OEM oil cooling/radiator setups. They are designed as road cars remember. Coolant was really never an issue. Before or after I replaced the radiator (because I did it when it cracked).

If you go out and track the car with nothing, but you have gauges, the coolant temp will sit at 80-90C as you would expect, and your oil will be 150C in short order. Whatever happens, the temperature is definitely not equalized between the systems, even if they do transfer some element of it.

I think as mentioned it's more likely designed to get things up to efficient temperatures (warm things, warm both things equally) rather than being a radiator. Then again, it does have cooling fins on it and a radiator of some kind...

I mean someone could go out and test it but the effort in doing so is more than simply fitting a cooler and having... better cooling. I saw a teardown recently of a Subaru motor where the oil never got to temp and the engine was running E85. That was quite gory, so getting the oil up to 100C to boil off condensation is also really important.

Almost like fluids are designed to operate in temperature windows and too cold is a problem as much as too hot is!

[GTSBoy]

The oil-water heat exchangers are 100% intended to get the oil warmed up and thin as early as possible, for emissions reasons. It's absolutely the same as the timing running retarded from cold in order to throw extra heat into the coolant via the exhaust ports, as well as heat up the cat so that the engine can meet emissions.

The heat exchanger is almost certainly going to do a reasonable job of keeping the oil and coolant at reasonably close temperature to each other, when the car is just streeting about, which as has been said above, is what they are designed for. And if the oil and water are both in the 80-100 window, then they will be working just as intended and everything will be happy.

Push a bit harder and you will start to run out of capacity on one system or the other. the HX is almost certainly too small to move much heat from the oil to the water, especially when the water is already at ~100°C. You need both a delta T between fluids and enough surface area in the HX to move a lot of heat. One way to move more heat is for the temperature of the hotter fluid (being cooled) to climb much higher. Now it has delta T and heat can move. But, it's also too hot, in this case.

The ideal system would have the HX and a suitable air cooler, and use both, and be able to bypass either thermostatically, as and when it made sense. ie, bypass the air cooler when the oil is cold, bypass the water HX when the oil is hot.

[Duncan]

The other reason to remove these is simply that if you lunch a motor, you really can't clean out the internal oil passages properly (like all oil coolers) so you need to bin the one you have. Then you find out they are a gaziliion dollars from nissan and decide you can live without it

[joshuaho96]

1 hour ago, Duncan said:

The other reason to remove these is simply that if you lunch a motor, you really can't clean out the internal oil passages properly (like all oil coolers) so you need to bin the one you have. Then you find out they are a gaziliion dollars from nissan and decide you can live without it

Surprisingly they restarted production on those things seemingly and Nissan USA will sell you one for ~240 USD MSRP. Most online sellers will give you a discount over that too. P/N is 21305-21U2A. When I refurbed the oil filter housing it was far more expensive to get new so I sent it off to a government-certified facility for aircraft oil cooler refurb. I figure if it's good enough for the notoriously conservative FAA it should be fine for my car. I might pick one up just to have spares if mine ever starts intermixing fluids.

[MBS206]

On 4/10/2023 at 1:02 PM, GTSBoy said:

The oil-water heat exchangers are 100% intended to get the oil warmed up and thin as early as possible, for emissions reasons. It's absolutely the same as the timing running retarded from cold in order to throw extra heat into the coolant via the exhaust ports, as well as heat up the cat so that the engine can meet emissions.

The heat exchanger is almost certainly going to do a reasonable job of keeping the oil and coolant at reasonably close temperature to each other, when the car is just streeting about, which as has been said above, is what they are designed for. And if the oil and water are both in the 80-100 window, then they will be working just as intended and everything will be happy.

Push a bit harder and you will start to run out of capacity on one system or the other. the HX is almost certainly too small to move much heat from the oil to the water, especially when the water is already at ~100°C. You need both a delta T between fluids and enough surface area in the HX to move a lot of heat. One way to move more heat is for the temperature of the hotter fluid (being cooled) to climb much higher. Now it has delta T and heat can move. But, it's also too hot, in this case.

The ideal system would have the HX and a suitable air cooler, and use both, and be able to bypass either thermostatically, as and when it made sense. ie, bypass the air cooler when the oil is cold, bypass the water HX when the oil is hot.

Interestingly, I would have thought the oil would be warming the coolant up to begin with, and then the coolant keeping oil temps down.

 

From memory oil runs at around 2.6kj/degc, while water is around 4.7

Water capacity from memory is nearly 10L vs 5L for oil.

 

In my tired ass state, coolant would need to be seeing 4x more heat energy than the oil (which is quite possible, this is an aspect I have NFI on, and does seem very plausible).

 

It would be interesting if anyone has oil temp logging and coolant temp (coolant in the block, not the rad hose) with the stock heat exchanger in place.

But I'm guessing most people logging that sort of data these days are running aftermarket coolers and no exchanger.