Oil pressure regulator to turbo
 

So I am curious as to what most of you guys are using to regulate the oil pressure to the turbo. At idle I have 130psi oil pressure and this is far too much for my triple ball bearing turbo. Its a -3an line to the turbo and on first start up it was way to much pressure so we added a simple inline -3 regulator but its also still pushing too much into the turbo. I need to regulate this thing down a lot to at least 40psi. Ive searched some threads but no one really shows how they are reducing that much pressure down to what the ball bearing would like to see. Any help is very greatly appreciated

This is the only thing I can find that makes the most sense turbosmart oil pressure regulator ts-0801-1003. Has anyone used this? because if it works great I'm thinking of maybe draining it back into the old rear turbo oil return as I also have an oil catch can I wouldn't mind feeding back into the pan as well. I know I have the rear return blocked off right now but I could either tap into that block off plate or else purchase a fitting for there. Is it the same style as the front? (if someone knows)

most use a restrictor

you could try this: no return needed: Turbo Oil Regulator - Freelance Motorsports LLC

On my built FC I put the Mazda Factory Race rotor oil cooling jets in to drop idle oil pressure.

They flow more oil than the (closed at idle) stock jets with check balls and flow less at high rpm so the rotor bearings have more oil.

But yeah, thats kind of a "well, next engine" solution...

Think there was someone here in the last 18mths~2 years who has run the turbosmart reg, with a pic even!

Still a bit bemused how a restrictor reduces pressure, implication being, if you stacked restrictors on end, you could reduce what's seen at the turbo to zero.

130psi at idle seems excessively high, no? Wouldn't the OP want to identify and address the cause of that first and foremost?

Orifice flow is proportional to the square root of pressure, it desensitised flow to pressure restricting it effectively to a low level relative to the resistance of the drain/core, noone is saying if you dead head the line it won't build pressure, it is a dynamic system. Your argument basically suggests fuel pressure line loss, intercooler pressure differential etc is non existent in a dynamic application which is clearly not true.

You can totally restrict the line which I have done but at 130psi at cold start this causes just a smaller line but flow is still at 130psi. I like the idea of the turbosmart piece because it will keep the pressure at the turbo at 40psi no matter what the pressure or flow is at. It dumps the rest of the oil back to the pan so this keeps the flow the same. It sucks as its more of a pain to install but now im thinking of using the rear oil return on the 13b to feed back into there with both the turbo smart piece as well as my oil catch can (this way I dont have to empty it regularly). Has anyone done this and is the rear return an ok spot? My front one is so tight to the turbo drain that I dont think ill be able to add anything more to it.

The restrictor reduces both pressure and flow at the CHRA inlet. The pressure will be 130psi BEFORE the restrictor but it will be significantly reduced after the restrictor.

Garrett recommends a 0.040" restrictor for BB turbos.

Turbosmart's regulator works very well if you either don't have a restrictor or do and need even more of a drop, however, the only time I've seen that much oil pressure at idle is when I received an engine that had both the front cover bypass blocked off and the rear regulator was locked out as well. Effectively oil pressure was determined by oil pump clearance. This is not the way to do it and is a recipe for a shorn oil pump shaft.

When I had the engine done the builder had asked if I wanted the oil pump upgrade and such. Original quote from his email:

"I would also spend a couple hours porting the oil pump scavenge side and
pressure side of the cast iron,more volume to help keep the rotors cool at
500 hp
the rotor combustion chambers are cooled by two oil jets on the eccentric
shaft which we get rid of the oem oil jets and go competition,more flow to
chambers."

Now that 130psi is on a cold start and Im sure if I was able to get the car more up to temp before the turbo starts spewing oil it would drop a bit. Im hoping there is no issues inside the motor but I knew I was going to have higher oil pressure. As of right now I have a 0.035 restrictor on the feed line and I can fill a 6 ounce glass with the oil in about 20 seconds so its still moving far too much. This is why I've been now looking at this regulator so that it can just feed the turbo with 40psi no matter what pressure and it will dump the rest in the oil pan.

Also has anyone used the oil return on the rear of the motor? I am curious if its a viable spot to return the regulator and my oil catch can. I can only seem to find info on blocking it off, not reusing it

Crispy I think used the rear turbo oil return on the rear iron as a drain for his recirculated oil catch can on his track FD.

I noticed the oil pressure on my new FD motor from Mazda ('99 high power part #) is really hyper. Anything over 2,000rpm even warmed up using 20w-50 and its 130psi.

My 70,000 mile twins arent loving it...

My race engines I built were never this hyper even with full oil mods and MFR regulator and shimmed relief.

I think its the new Mazda tight bearing clearances plus some oil pressure regulator change over the '93-95 USA low power spec. My race engine ofc used the largest bearing sizes available and further flapped out for clearance, so thats going to drop pressure.

I'd be very interested to see what pressure drop you'd see over the 3 odd mm of a restrictor drilling. I could see a volume decrease.

In regards to the Garretts, this is from a local distributor who has been selling them for close to 40 years

Fact: Garrett ball bearing turbochargers all have oil restrictors internally. Normally 0.8 mm
Fact: Garrett ball bearing turbochargers do not need an additional restrictor.

Perfectly ok to use the rear drain. Usually blocked because oil drains from turbos are best as near vertical as possible and downpipes and wastegate plumbing get in the way usually.

Taken directly from Garrett's Turbo System Optimization page:

https://www.garrettmotion.com/racing...-optimization/

https://cimg8.ibsrv.net/gimg/www.rx7...6172f13d46.png

You guys have been awesome. I decided to place the order on the turbosmart piece and we will see how long it will last. I noticed after purchase it doesnt want to see much above 160psi but I would much rather destroy it then this irreplaceable turbo. I think that is also where a little of my issue lies as well. This turbo is off a 2006 Champ Car and there is absolutely zero reducers in it so I really have to get this thing down to 40psi consistently.

Last question im hoping someone knows before I keep trying to find the answer. Is the rear oil return the same size as the front? I need to order the flange and fitting or I can always take the block off plate off and maybe have someone weld a tube to it.

Why not use the front return? It's a shorter/more direct path. That rear return is a good location to add a second vent to the pan for an oil catch can.

Also, it really seems like you're slapping a baindaid over a wound to fix arterial bleeding. 130psi at idle is likely to cause some pretty significant issues beyond a turbo. If it were me I'd be hounding that engine builder to fix it.

Also (x2), no turbo should be "irreplaceable," it's ultimately a wear item. Just because it used to be on a racecar doesn't mean it's somehow elevated above what's widely available 🤷‍♂️

Front return is being used already for the turbo oil drain. I want to use the rear for my oil catch can and the oil regulator. As for the psi yes some have said this is high but at the same point many people are getting high oil pressure from what ive been reading. Im sure at warm ill be closer to 100-110psi. Sadly the builder has passed away a year or so ago so I cant go bugging him so Im in high hopes there is no motor issues. As for the turbo it is kinda irreplacable as its not made anymore nor could it have ever been purchased by a consumer. Its an IHI RX8 turbo and the consumer grade is the RX6. The whole monster turbo weighs a whopping 12.5 pounds and runs a triple ball bearing center cartridge. Granted I have a spare center cartridge so this can go kinda wrong once lol

What oil weight are you running? Maybe you can try lower viscosity along with the regulator.

This is actually a good idea. I am running a decently thick weight but also I'm in canada and these starts have been at either 0celcius or lower so that will also account in some really high pressure for the first minute. Haven't been able to run the car longer yet

I can see why they mightn't have run anything on the champ car. Oil pressure, if it was carried through by Cosworth from the early V8s was only around 50psi after originally being 110 back in the very beginning.

Front and rear drains are the same, if there's any way to run even a partial hardline for the turbo drain, a -4 weld-on, also on that tube would probably be more expedient than trying to plumb and heat shield to the rear.

The regulator should show up today and ill start sorting out the return. I still think the rear will be a little easier compared to what has already been built on the front one for the turbo. I was just going to use some heat sleeve to slide the lines in. shouldnt need to actually build a heat shield...I hope. At this point its unplanned fixing lol