Turbos, oil coolers, and oil pressure
 

After searching for hours on this I have not come to a conclusion, there seems to be contradicting information on this everywhere. Also, didn't know which subforum to put this in, so mods feel free to move this if you want.

When I was N/A, my oil pressure at startup was around 60 psi, and any blipping of the throttle would put me close to 90 psi. This is on the stock OP gauge.

I put a turbo on and switched to Rotella and my start up psi is closer to 50, and warm idle is anywhere from 10-20 psi. I don't have an oil temp gauge so I don't know if this is just because my oil is getting super hot now. I have another thread about the head I toasted, cam bearing was destroyed and the cam seized while I was driving to get food, so not hard driving. I'm not sure if this was related to my low oil pressure.

Obviously feeding a turbo oil is going to drop the pressure some, especially if you have a restrictor for those of you with Garretts, etc.

On to oil coolers. I don't really want to track without one, just found myself an FC rx7 oil cooler which I am going to install. After searching I can't see if anyone has actually had a noticeable pressure drop from installing an oil cooler with -10 lines. With my borderline oil pressure at 10-20 psi idle, I don't really want to drop pressure anymore.

tl;dr oil pressure ok with stock oil pump(not shimmed either), turbo with restrictor, and oil cooler with -10 lines?

Also, because I'm making this in an attempt to gather all info on this into one thread...
oil cooler/turbo/oil pressure/oil pumps general.

Cam bearing?

Camshaft seized for lack of oil? no

Fine, cam bore.
Are you saying a lack of oil won't seize a camshaft...dude wat

I think it would most likely break the timing belt or it would jump teeth before it seizes the cams up completely. It probably galled the cam, journal, and cam caps. Would make a horrible noise, but they would still turn. Maybe not my hand, but the engine will still turn them. My .02

I was around 15-18psi warmed up with my FM kit. 40-50psi on start up.

That was with a FM oil filter relocation kit, GT2560R. No oil cooler. So can't really say how much an oil cooler will drop pressure, but I can't imagine it would be a ton.

Nope. The cam seized completely and without any warning. The cap, journal and cam are completely destroyed. Timing belt wasn't broken, bolt that holds the gear onto the cam sheared.

Thats pretty much where I am minus the relocation kit. Nobody seems to have a definitive answer on how much pressure an oil cooler drops with the t-stat open/closed.

If you wait long enough I can tell you lol. But I'm about 6-8 months away.

Ah, see I knew something would have to give for it to completely seize up. I figured the belt would break rather than the cam bolt on the gear. Impressive.

Wix oil filter? If your oil pressure sender is on the turbo's oil feed, don't expect it to read anywhere near accurate.

I have no real numbers on my car for the open thermostat because the factory gauge is a heap of shit. However, it never drops to the left of straight up and down.

I think you need to get a real oil pressure gauge and go from there.

Yep, wix oil filter. My sender is in the stock location, the oil feed for the turbo is on the other side of the block.
I'm thinking if you're on the stock pump with no shims I'm probably ok lol

Block is coming out for some slight refreshing and a possibly tranny swap, I'm putting a pump from another block in with new relief valve parts. Might stick a shim or 2 in there.

Related: Holy shit the FC oil cooler is huge.

Do you made any progress?

Negative, no changes. Trying to track down a noise that I thought might be from the turbo because of a lack of oil but have not found it.

Did your cam look like this? (this is my 1.6L intake cam, sheered between Cyl 3 and 4).

https://www.miataturbo.net/attachmen...ine=1318891259

https://www.miataturbo.net/attachmen...ine=1318891259

This is the same block the cam broke on.

https://www.miataturbo.net/attachmen...ine=1318891259

I replaced the head with one that supposedly had 80k miles on it, cleaned it myself, tried to polish the chambers (did not get far before I gave up on that lol), new OEM HG, ARP studs. Lifter tick rarely an issue now, better oil psi, oil temps never reach hotter than 220 on an 80* SoCal track day, bone stock engine, same oil pump (should have tore into the block, but resources were limited).

The bearing surface was destroyed like that but the cam didn't break when it was in the head. I broke it later for fun lol.

I think the main reason my head went south was because I'm sure at some point before that my oil pump took a shit so I must have been driving with no oil pressure. I had another thread with carnage pics of that. I ended up throwing another pump in with another head and have been driving on that with no issues so far.

Is that 220 with an oil cooler??? That sounds a little too good if you don't have an oil cooler in a SoCal track day.
EDIT: derp just realized you said bone stock. I'm not sure if I'm wiling to track a turbo Miata without an oil cooler. Until someone tells me otherwise.

220 degree no oil cooler at all. bone stock engine (sub 100 hp). i typically switch between 5w30 and 10w40 (currently a mix)... straight 10w40 it seems to tick like crazy even when warm, and 5w30, the oil psi is too low. on a side note, my 180 tstat keeps coolant (automatic radiator) very cool as well, so that may affect oil temps.

Do you have blowby at all ? It will raise oil temp a bunch and thus lower oil press too. Have you tried playing with thicker oil ?