Just though I'd share some information I've found in the last few weeks on my track car.

Some information about the setup.

2.5L block with Wiesco pistons.
Stock bearing clearances.
WRX heads with Kelford cams, stock valves, no porting
Stock WRX oil pump. (no shims)

Oil cooler setup.
MOCAL sandwich adapter with built in thermostat.
13 row half width cooler
3 quart accusump.
All plumbed with -8 fittings.


Warm idle oil pressures on this setup were about 35 psi. Noticed on the track that the car only made 65psi of pressure at redline. Went home after the track day and swapped the pump with a 12mm that I had in the drawer. Went back out the next track day. No change in oil pressure.

Removed the sandwich adapter, to include the oil cooler and accusump. Still had the 12mm pump in. Motor now makes 80psi at redline. Ran the car for about 30 minutes at a local autocross setup up and down until the oil temps got close to the level I see at the track. No change in oil pressure.

My conclusion is that the -8 (1/2 ID) lines are simply too small, causing a restriction. I'm going to re-plumb the setup with -10 (5/8 ID) and see if that fixes the issue.

Anybody else have some similar experiences, advice, criticism, etc....

Duncan

65psi at redline isn't all that bad - the general rule is you want 10# for every 1000rpm. More pressure isn't necessarily better.

The setup on my Mustang is -10AN, but that's a bigger cooler (25 row full width Mocal), 357W with BIG main bearings, etc etc.

While I agree that 65psi isn't terrible for a redline pressure, I'm running the motor to 7200 in some cases and would like a little cushion. Unless I'm mis-interpreting the results of my experiment, I think that the -8 lines were definitely a restriction.

Duncan

Just curious... but don't all the other companies all supply -8AN equivalent lines with their oil coolers? I'm thinking Greddy, Process West, B-line, etc etc. They all have -8 lines, and i've never read of anyone complaining about the pressure being lower than before.. in fact, they all seemed to report higher oil pressure, and cooler oil temps :confused:

It could be the plate. If you can easily do so (not sure if you can with the mocal) you might want to try pulling the thermostat out of it.

Just curious... but don't all the other companies all supply -8AN equivalent lines with their oil coolers? I'm thinking Greddy, Process West, B-line, etc etc. They all have -8 lines, and i've never read of anyone complaining about the pressure being lower than before.. in fact, they all seemed to report higher oil pressure, and cooler oil temps :confused:
I've seen an awful lot of cars, even track-prepped cars, that rely on the factory gauges and nothing else. It honestly wouldn't surprise me if the overwhelming majority of guys that have the GReddy/B-line/etc oil coolers simply don't have the gauges to detect the drop in oil pressure.

It could be the plate. If you can easily do so (not sure if you can with the mocal) you might want to try pulling the thermostat out of it.
I have the Mocal sandwich adapter w/built-in t-stat on my Mustang. When the oil temp is up and the t-stat is open it shouldn't restrict flow from what I can remember. You can kind of get an idea of how it's setup here - http://64.202.180.37/files/sp1t.pdf. It does appear you can remove the t-stat function so that it allows full flow all the time - might not hurt to give that a shot.

Pat

When you add a sandwich adapter and additional plumbing it is like making the oil gallery from the pump to the bearings that long. As in many feet longer. To draw and example when you are using a paint spray gun with a 3/8 id hose you will run more pressure through the hose with a adj. regulator at the gun to set the spray pressure. A 50 foot hose makes a huge difference. I have already posted all of this awhile back.

The oil galleries in the motor are about .550 to .600 id. In order to have the 72 lbs pressure at the bearings when you increase the length plus reduce the id with the small hose you reduce the pressure and volume. The 12 mm has so much volume it might make up for the restriction.

The oil sender put at the front of the driver head before the restricter in the head is a good place to monitor the pressure at the far end of the oiling circuit. It's where the sti oil feeds the acvs.

I also posted that I bought a pretty expensive cooler setup and decided not to use it because of the 1/2 lines. I'm not sure but I think I remember replacing just the lines won't fix the 1/2 cooler id.

so my original guess of pumping losses was to blame with the oil pressure issue in your car...cool, except for wasted time and cost =/

fewer degrees of bend, less tubing lenght and larger diamter tubing are your easiest fixes, outside of shimming it...

When you add a sandwich adapter and additional plumbing it is like making the oil gallery from the pump to the bearings that long. As in many feet longer. To draw and example when you are using a paint spray gun with a 3/8 id hose you will run more pressure through the hose with a adj. regulator at the gun to set the spray pressure. A 50 foot hose makes a huge difference. I have already posted all of this awhile back.

The oil galleries in the motor are about .550 to .600 id. In order to have the 72 lbs pressure at the bearings when you increase the length plus reduce the id with the small hose you reduce the pressure and volume. The 12 mm has so much volume it might make up for the restriction.

The oil sender put at the front of the driver head before the restricter in the head is a good place to monitor the pressure at the far end of the oiling circuit. It's where the sti oil feeds the acvs.

I also posted that I bought a pretty expensive cooler setup and decided not to use it because of the 1/2 lines. I'm not sure but I think I remember replacing just the lines won't fix the 1/2 cooler id.

Some great points. Can you elaborate where on the head you're suggesting tapping for oil pressure. I have a gauge with two sending units right now, one is in the forward oil galley where the factory switch was, and the other is in the back of the drivers side head.

I've ordered a new oil cooler that has a 5/8 inlet instead of the 1/2 one. We'll see how it goes.

thanks

Duncan

aside from boring the oil galleries, you can also open up the #3 main feed a bit...

you want the highest pressure in the oil system to be at the entrance of the bearing. we all know this isn't possible due to bends and pipe losses but having no bottlenecks prior to that point will greatly help achieve it.

-10 or -12 for external oil lines IMO as they usually will have sharp 90+ AN fittings and losses through a cooler. We ran -10's on all of our formula cars and they were just dry sumped crotch rocket engines.

The head restricters are in the front of the passenger head and the rear of the driver head, they reduce the volume of oil to the head. The rear of the driver head is AFTER the head restricter that means it is being measured after going through the head restricter to reduce the flow in the head. The fitting on the front of the driver head is where the acvs is plumbed from on the sti or any acvs motor that is BEFORE the restricter. I made a tee out of a ph 1 turbo fitting (just like the one to the wrx turbo called a banjo fitting) and brazed a tee to the top of it to go to the acvs and to hold a sender. The sender is close to the oil filler and the air cond. compressor lines but it fits.
I drilled the old line out of the banjo and actually silversoldered, brazing will work but it is much hotter, the line in then soldered the tee on the line. I also added a metal brace that goes to a bolt close by to help support it.
On the wrx it's a lot easier as all you need to do is cut the line off of the banjo flush at the banjo and tap the banjo with a 1/8 npt tap and screw a short nipple in it and screw the sender on the nipple. I also made a short dog leg bracket to slip over the banjo where it is threaded and it bolts to the same bolt that holds the dip stick in. The banjo will need to be angled over toward the head for the sender to fit good in the space and the bracket formed after the spot is selected to get the angles right. I welded the bracket to the banjo after it all got lined up. You can loosten the inner timing cover up and get the plug out of the gallery and work the banjo, it's bolt and the sealing washers in.

Yes, you want -10 lines. -8 is quite small for oil.

Here's my setup. -10 AN lines, 3qt High Pressure Accusump. Thermostatic sandwich plate, biggish oil cooler. I get 85psi with this setup.

http://forums.nasioc.com/forums/showthread.php?p=22173515#post22173515

Did all of mine with -10 fittings and lines.
I run a remote oil filter with a chev sb sized oil filter (cheaper to buy), large oil cooler.
I had to move the oil filter from the original position as my large oil pan doesnt give access to that area any more.
Total oil capacity is close to 8.5 litres (entire system not just the oil pan).

Yes, you want -10 lines. -8 is quite small for oil.

Here's my setup. -10 AN lines, 3qt High Pressure Accusump. Thermostatic sandwich plate, biggish oil cooler. I get 85psi with this setup.

http://forums.nasioc.com/forums/showthread.php?p=22173515#post22173515

Can you comment on that Earl's check valve. What made you pick the 120 dollar Earls valve vs the 20 dollar Accusump valve.

thanks

Duncan

Did all of mine with -10 fittings and lines.
I run a remote oil filter with a chev sb sized oil filter (cheaper to buy), large oil cooler.
I had to move the oil filter from the original position as my large oil pan doesnt give access to that area any more.
Total oil capacity is close to 8.5 litres (entire system not just the oil pan).

Are you using the brass check valve?

Duncan

Can you comment on that Earl's check valve. What made you pick the 120 dollar Earls valve vs the 20 dollar Accusump valve.

thanks

Duncan
When I received the Accusump kit with the brass check valve, I looked at it and thought that it seemed pretty restrictive. With the oil pressure issues I'd had, I didn't want to take any chances, so I used every opportunity to improve oil pressure.

I found the Earls full flow valve for under $100 here:
http://www.anplumbing.com/shop/index.php?shop=Accessories&dept=Check!_Valve

Still expensive, but it sure flows nicely.

Russ

Thanks for the link, ended up ordering one for my redo.

Duncan