The restrictors are in the oil cooler lines, not the filter head. The oil cooler is only a bypass type, not full flow. They are there to limit the ammount of oil flow loss from the lubricating system as the cooler dumps oil directly back to the sump. I would not remove them, if you want better oil cooling, fit a proper full flow unit.
Oops my bad - agree its best to run a full flow system. The more correct position appears to be "The stock TT uses a bypass valve to bleed off excess oil pressure to the oil cooler. The only way you'll get full pressure to the cooler is by blocking off the bypass valve using a sandwich adaptor" thanks to aliaZ
Me and Bill worked on the design of this for the past 12 months (along with help from Spec Z). I got the first one which arrived last week - just saving up to start fitting it.
What does it weigh? I've often thought about making an ally sump so I can slap some of the heat sink extrusion I have on the bottom and help dissipate some heat, expensive job though.
Is this why the standard Nissan oil filter doesn't have a relief valve, because its built in the oil tree ? Would this mean if you used an aftermarket oil filter with a bypass relief lower then the filter tree you would have no cooling at all through the stock oil cooler ? IE the filter does the bypass not the tree to the cooler. The relief valve is there so when a pressure drop of approx 10 PSI (this can vary from system to system but generally around 10 PSI) across the oil filter, usually at high flow/rpm, this is probably done to ensure high oil pressure when required and to protect against clogged oil filters and possibly protect the pump. You would have better oil cooling with a dirty oil filter. Logged oil pressure would probably show a bump at the bypass point.
Pressure relieve valve is on the oil pump (called a regulator valve in the manual) The only "valve" fitted to filters is a non return valve.(check valve) The bypass valve for a blocked filter is on the oil filter tree (two of them), unsure of the operating pressure for them but it is low. The pressure required to flow oil to the oil cooler is minimal & I'm pretty sure the valve is there as a temperature control device more than a pressure control, we called them a vernatherm in the aircraft industry - essentially it's a thermostat for oil.
Yes strike pump protection from original post, I was aware of the one in the oil pump and its purpose, just typed too much. That's interesting what you say, do you think it has 2 valves, does that include your suspicion of this "vernatherm" valve ? With the stock oil cooler fitted on a race car at full noise for a lot of the time, oil is unfiltered, and being diverted away from a sandwich plate cooler that probably has a larger more effective cooler. If it was in a situation where the stock oil cooler was blocked of and a stock oil filter with no bypass fitted, that could be a problem too. I don't like this idea of unfiltered oil. It would be really good to work exactly what is going on in the filter tree.
Yes if you pull the filter off you will see two valves, it's a ball in a seat one on each side, you can press the ball up and see how it relieves pressure from the inlet side of the filter to the outlet side if the filter is blocked OR under "extreme" duty - high pressure differential. Then there is the valve for the cooler in the front of the tree by the pressure hose for the cooler, can't confirm if it is pressure or heat or a combination of both that this operates by. Service manual doesn't mention it that I have found & without testing I am just guessing. If you are building a decent race engine the whole filter tree can actually be removed and replace with a couple of AN fittings - most people follow the lazy path others have gone down before them and bolt on a sandwich plate. If fitting a plate the pressure relief valves should be removed and blocked off if remote mounting the filter with a block that already has pressure relief valves in it.
These things we know. What we don't know is exactly how the OEM oil cooler feed works. Nissan, Nismo and Stillen seem to think they way to increase oil cooling on a TT is by increasing the size of the OEM cooler. Interestingly Stillen provides a sandwich plate for his Z32 NA kit for obvious reasons. Would he not have done that for the TT if it was of benefit over the OEM feed setup ?
Just pulled apart a TT Oil Filter Tree ... the Oil to the Oil Cooler is controlled by Pressure, have read else where that pressure is 60psi and only 10% of Oil flow is bypassed through the cooler ... cannot see any advantage in increasing the site a the cooler using the factory setup, "full flow" is the only way to go. Example ... my recent track outing produced a max oil temp. of 70'c ... in actual fact I need to fit a thermostat to get the oil temp up because my "full flow" setup is too efficient.
Those numbers sound familiar LS from when I looked into this in the past, I have no doubt full flow is useful on a race car. 60 PSI is about 3000 RPM so it gets a fair go when the engine is being used on the road. I get the impression that Steve Millen is pretty capable technically. I would say when he put the SMZ package together and would of for due diligence reasons monitored oil temps with the increased power during testing, he spent enough time developing the package to come up with 17" front rims and 18" rear rims, I don't think that decision would of come easily, the point is that I think he would of taken the project very seriously to be honoured with a Nissan factory released limited edition marque and would of been quiet capable of putting a Z32 TT through its paces and as a racer would of been quiet mindful of oil temperatures, and given that he makes a sandwich plate product for the NA as it doesn't have an OEM oil cooler, the point is why not use a sandwich plate for the TT in parallel ? Did Steve Millen make a mistake ? Or did he get it right because there is a reason ? No major stress just putting it out there.
I seriously doubt Steve was the sole brains behind the Stillen Zed project, there would most likely have been a team doing the work as is the case now for all projects they undertake. In fact if I recall correctly there was some input on that project from some other not so well known Kiwis. A bigger cooler works just fine for a road car, Nissan themselves fitted a larger cooler to the stock system for the Euro spec Z32s as they knew the Euro cars would most likely see sustained high speed. Still not convinced about that valve operating based on pressure alone, that is how it would appear to those who haven't studied a Vernatherm & if you were to test it at room temp it would operate at a given pressure BUT if you increase the temp to ~100'c what happens? anyone actually tried that? If it were to operate by pressure alone you would get more cooling when the oil was cool and less when it gets hotter (less pressure) I would be surprised if the factory thought that was a good idea. Cost wouldn't come in to it as the two units are extremely similar, there would be a couple of dollars difference maximum. I know there is flow past the valve from cold at higher pressure but then you would expect this as it will give the valve faster response to the heat in the oil, if it were in a static part of the system it would cause delayed reaction to the engine oil temp. Exactly the same principal as the thermostat for the coolant system just executed differently.
I was pointing out the apparent limitations of the stock block in the real world, where organisations have actually built national road race winning engines and apparently found the stock block inadequate. The 1000hp figure was for qualifying using a custom block etc which is basically a one lap dash, the actual race engines did somewhere around 800hp using similar blocks. Which is why it is hard to accept that a stock blocked VG could handle a genuine SAE standard 1500hp. To put it diplomatically
