Oil cooler = pressure drop??

[Chevy1925]

This isnt in the diesel section because its not going on a diesel and frankly i never seen it as an issue with them but this might be different...

Project:
my 2000 "grand tracker" 2.5 v6 has a t3/t4 china turbo on it. Ive already killed one engine due to low oil pressure which i attribute to 250k miles, pulling oil pressure for turbo off the mains, and running hot oil temps. Like, it would kick the oil pressure light on at idle after a highway cruise from work to my house in the summer . The fix was to just ignore it till it something sounded bad. Well that took about 1.5 years and finally killed a rod lol. Anyhow, the new engine has 160k on it, resealed, new oil pump, shimmed pressure relief, and turbo now gets its oil from the head/cam oil galley. No inditication of low oil pressure but also has no gauge. i would have put a high volume pump on but they dont make one for them. This will be the new engines first summer so im really thinking about putting a oil cooler on it. it will see alot of highway time to and from trails with hills running at 3-6 lbs of boost contantly to hold 75mph (wish this engine had oil squirters!)

My thoughts:
So i struggle with this in my head. Lets say this thing runs the bare min of 10psi of oil pressure to every 1000rpm. not likely but lets play that game. In my mind, its simple hydraulics. if the engine oil cooler is not a restriction on oil flow, i should not see a pressure drop from running one, correct? The cooler will be fed oil from the oil filter port using an adapter so mechanical pump is being used and its dumping oil back in before mains/rods/etc. I cant quite put a finger on why i feel it can still see a pressure drop but my gut is telling me it can/could still happen. I feel the oiling system on this rig is already taxed due to the additional turbo (i even have a restrictor in the turbo). food for thought, i used an allison 6speed trans cooler as an oil cooler on my samurai when i turboed it but i also blew up more engines from lack of tuning skills than oil pressure (no gauge there and no signs of it after each new more lol).

Question:
Do you think ill be pushing my already taxed oiling system beyond its capabilites by adding an oil cooler? it wont be huge but i want it to do its job too. ill be keeping it as close to the filter head as possible but its still going to have about 4 to 5ft of 1/2 hose it has to push through plus cooler.

 

[JoshH]

There will always be some restriction and loss in any system. The question is how much, and do the benefits of the cooler outweigh the negatives? My gut reaction is to say they would, especially on a properly built system like I'm sure you would put together.

 

[1FastBrick]

Back in the day, The STS rear mount turbo systems used an Auxiliary pump to pump oil to the turbo's.

Have you considered something like that to circulate the oil through a cooler???

 

[1FastBrick]

A scavenge pump. That's what they called it.

I don't know the exact brand they used but something like this. https://www.amazon.com/Heavy-Duty-Mount-Scavenge-Replace/dp/B01L26DCT6

 

[Chevy1925]

yeah but its not really useful in my situation. im not dealing with a turbo that is trying to get oil to drain back to the oil pan to keep it from backing up into the turbo. If i were to add an electric pump, it would either need to be flow through so if it doesnt keep up in high rpm's, the mechanical pump can push through it or the pump its self needs to be able to flow more than the mechanical. they do make kits for that but they aint cheap and its mainly just a helper pump.

ive been thinking the same, Josh but i figured it wouldnt hurt to grab some more opinions. I guess worse case, this more dies an untimely death, its time to finally do the honda K or J swap in it

 

[2004LB7]

I think he was implying the use of an auxiliary pump just to supply oil to the turbo taking the load off the engine oil pump

 

[Chevy1925]

I think he was implying the use of an auxiliary pump just to supply oil to the turbo taking the load off the engine oil pump

na, now we are getting into possible starvation issues from the factory pan/pickup that i dont want to mess with.

 

[Chevy1925]

So i ordered a cooler. aint a big ass one but a 9x9 stacked plate with a 300cfm fan on it. its probably going to have to get mounted more rearward on the tracker looking at things under there. In the mean time, im going to pop a glowshit sensor in where my oil pressure light trigger is and just plug my fuel pressure gauge into it. they use the same sensors between gauges, just different names on the gauges. That way i can see what actual oil pressure is cold and hot prior to the cooler and see if it will be able to handle it. Then i can do a test after its installed and make sure all is good. it wont be apples to apples because i should really have a sensor after the cooler too to see what the pressure drop is and i may do that if the initial oil pressure prior to me adding a cooler is on the low side but we shall see.

 

[1FastBrick]

Just K-swap it and be done with it... Lol

 

[Chevy1925]

Eventually . It needs the ttb swap done first. That already requires a trans swap, tcase swap, and whole front end swap.


So pressures before cooler were about 10 psi to every 1000rpm. That’s hot hot after the 1000ft climb from phx to my house (20 miles). Cold it’s hitting over 100psi with 15w-40 and the shimmed prv, yikes. That’s just at 1500rpm lol.

So before changing too many things at once, I put the cooler in and also changed oil to 5w-30 full syn. Hoping to knock down cold pressure. Didn’t really change it that much but it was better cold. On the road, it was holding 85psi at 3k rpm and over 100 at 4800. Red line is 6k.

Made the decision to drop the upper and lower oil pan and take some shims out of the oil pump. I had .110 worth in there. Took .070 out and tried again. Now I’m seeing 70-75psi at 3k and 90psi at 4800 with very little increase in pressure as rpm climbs. I think it just touches over 100 at 6k. Higher than I want but not worth dropping the pan again. It’s also not 110* out yet. Pressure will get lower when those temps hit

BUT the main thing is this cooler made a massive difference in pressure. That oil must have been getting pretty fricken hot before!

 

[2004LB7]

Do you think it could have made a bigger difference with an oil to water cooler, And used the coolant to cool the oil like often done for the transmission ?