Has anybody measured the oil pressure in a feed line connected to a Garrett ball-bearing turbo?

This is off the FAQ section of the Garrett website:
http://www.turbobygarrett.com/turbob.../faqs.html#t16

My GT42R has what looks like a restrictor in the oil inlet, but I'm not certain of what it is. If it is a restrictor, I assume all GTXXR turbos have them and the recommended psi quoted above is measured before the the restrictor.

 

bump! I'm thinking about running one of these on my new 500R. Comments, input?

http://www.atpturbo.com/Merchant2/me...egory_Code=OIL

 

The oil restrictor in the inlet of the GT42R is actually for restricting oil and keeping the ball bearing cartridge from moving/rotating. It is infact true that you need less oil pressure as the stock system gives it. The more oil pressure the higher chance of compressor and turbine oil seal leak.

 

Well, I think I answered my own question. Just spent some time searching and it seems the .035 ATP restrictor is too small for a rotary. Howard blew a turbo that way......JD recommended no smaller than a .05 or so. I plan to vent my crankcase, and if needed (smoking) pull vacuum from between the turbo and the filter.

 

What are you guys basing all this on. Links, data -please share.

 

Chris, I just performed a search for 'oil restrictor' in this section (single turbo) and found a couple informative threads.

 

Kick ***, now quote what you found here or don't bother posting at all

 

I answered your question, you belligerent little peckerhead

We're in the same boat. Go up and read my post up above......although none of the links I found referenced your almighty 20b, I'd assume the 42r and the 35r are equivalent for this purpose at least.

 

My question is, what is the oil feed line pressure with a GT series turbo without a restrictor. You didn't answer my question; you told me Howard and JD answered my question -and to go search for their answer.

I already searched (as I always do before posting a question) and didn't find any data on this. Since you seem to have done a better job at it than I did, it would be nice if you posted the links to exactly what you found.

I'm not going to put a restrictor on my oil line simply based on someone-anyone's opinion. This isn't art it's engineering. Only data will do. :smiley_12 .

 

https://www.rx7club.com/showthread.p...oil+restrictor

https://www.rx7club.com/showthread.p...oil+restrictor

https://www.rx7club.com/showthread.p...oil+restrictor

 

Still no data on this. When I get my car up and running I plan on taking some pressure readings on the feed line with a couple different restrictors. Of course by the time that happens there may not be any oil left to run through the lines :p

 

I spoke to Alex over at Gotham at length about this. He told me that with a ball bearing turbo he measured oil pressure between the block and the feed line and found that with the common -4 oil feed line a restrictor is needed.

With the smaller -3 line, supposedly a restrictor isn't necessary, but there are logistical problems with running a -3 line....the fitting into the block is around an M14 by 1.5, and evidently that's impossible to find if you want it to screw into a -3 line. Plus, price is quite a bit higher and they're harder to find. Most hydaulic shops stock -4 but -3 is a special order.

He found that by using a restrictor (carb jet) sized around 0.060, the oil pressure at idle was around 60 psi, which is on the upper end of what's acceptable but he said he has had zero problems with all the single turbo kits installed since using these restrictors.

Take all of this with a grain of salt b/c it's second hand, and some of the figures Alex wasn't 100% sure he was remembering correctly.

Based on Chris' quote from the Garrett site in the opening post, I plan to try out one of the restrictors I liked to in post #2 up above and measure oil pressure to see what it's at, both at idle and on the dyno at redline.

 

Instead of doing a hack and trying to regulate PRESSURE by limiting flow with a restriction why not regulate oil pressure at the turbo inlet?

You could put a "Y" fitting at the turbo oil inlet and have your regular oil supply line on one side and a checkvalve w/ adjustable "cracking" pressure on the other side of the "Y" fitting. Now route the outlet of the checkvalve right into your turbo oil drain tube.

I know Swagelok sells some nice adjustable opening pressure check valves that we use at my work. Very high quality ss and ~4" long.

Then you will have the same pressure at the turbo inlet as long as engine oil pressure does not drop below set turbo pressure!

If by some small chance the checkvalve gets coked up and fails you will simply be back at square one w/ too high oil pressure...

 

^^I'm having a hard time envisioning what you're describing. Any pictures?

 

Here is a pic and stats on a Swagelok adj pressure check valve. This one has a Kalrez O-ring so it should be good for a bit over 300 deg C.

Unfortunately, I can only find them w/ 8mm or 1/4" tube fittings instead of NPT connections (that is you fit a bare tube in them and tighten them up).

3-50psi release check valve

So, what I am saying is you would put a "Y" or a "T" fitting in your turbo oil feed line where it enters the turbo.

Two ports are taken up by the previously existing oil supply line and the turbo oil inlet.

On the 3rd port you place the check valve.

Attach a tube from the other end of the check valve to the turbo oil drain line.

Now you have an adjustable pressure regulator for your turbo oil pressure.

 

Thanks for posting that up. It's too bad that I didn't know about that from the beginning, I would have been interested in integrating that into my setup. The lack of NPT connections coupled with having to hack into my s/s return line makes it not an attractive choice unfortunately. Definitely something to look into though......

 

Great idea! Thank you!

 

I have found out of the tons of GT-R series turbo's we've done. Few have needed restriction maybe one in ten. They are internally restricted and once cut open you can see just how small it actually gets. That said if you are wanting to feel safe run a restrictor at up to roughly double or .060-.070 of ATP's, I wouldn't go any smaller as you will have issues with lack of oil. You can also run a inline oil filter on the feed and that will help as well. Just make sure to check the filter regularly.

-S-

 

I have data on this. Tested it myself before putting a restrictor on (and after.)
This is by memory.

Test Goal:
Test oil pressure on the turbo supply line, at the turbo, compare to Garret specifications

Secondary Goal:
Influence pressure at turbo to within Garret prescribed range.

System setup:
1 female NPT "t" fitting,
1 male/male NPT to AN-04,
1 male/male NPT to NPT,
3rd leg used an Autometer adapter for its pressure gauge,
GT40R Turbo
1994 Large street ported engine with modifications to "oil pill" on the eccentric shaft and porting to oil system internals,
Autometer oil pressure gauge,
Mobil1 10w40,
Garret "documentation" on prescribed operating oil pressure of Gt40r turbo.
Note: I can not produce this last piece of data right now or quickly.

Test case 1:
Baseline test at 1000, 2500, and 4000rpm.

Test case 2:
Test setup with ATP .060 (1.48mm) restrictor and test at 1000, 2500, and 4000rpm.
Note: Since test I have changed to integrated oil restrictor and flange of same size.
http://www.function-7.com/a0-turbo.html

Observed Test results 1 (abbreviated):
Test pressure at oil inlet of turbo and from stock gauge "roughly matched" at 1000rpm, 2500rpm, and 4000rpm.
Note: unless this test is preformed with digital oil pressure gauges and logged there is a lack of precision on "sweep" gauges and "eyeball" observations.

Oil pressure at 2500rpm and higher showed greater than 60psi.
Note: This is outside the Garret prescribed range.

Observed Test results 2 (abbreviated):
Oil pressure at 2500rpm and 4000rpm were below 60psi measure at the turbo.
Note: Measured with the .060 restrictor the observed oil pressure is within Garret prescribed range.

Conclusion: For the turbo and motor combination tested, a .060 oil restrictor influences observed oil pressures at the turbo inlet LOWER and within Garret prescribed ranges.

Note: "abbreviated" test results mean that I am too lazy and impatient to find the recorded actual test results.

 

This supports my thinking that the problem is engine/oil/system specific. If you have a stock oil supply system within the car, I don't think it is as big of an issue if you have ported, de-pilled, modified system. And then within that, there is enough room for variation I am sure.

All I know is that about every problem that can happen, has happened to my systems!

Tony

 

I pulled my turbo to replace my wastegate and noticed that there was oil dripping from the bottom of the compressor housing. Pulled the filter and found some more oil. My oil system was modifed, can't remember if it was ported or de-pilled. I am leaning towards de-pilled because I'm running upwards of 115 psi of oil pressure at high rpms. I'm wondering if my turbo oil feed line is restrictive enough. Only have about 5k on the non ball bearing Garrett unit. Guess its time for a rebuild. Hmmmm...gonna have to check into it.

 

Might not need to be rebuilt yet. Do you have a catch can setup with oil NOT being pulled back into the intake track (like stock with the PCV).

You running the PCV or routing any of that back into the intake track? Is so, that could be a source of oil in the compressor housing.

I see upwards of 100psi at 5K rpms too.
Tony

 

I'm running a catch can with one end going to the oil filler neck and the other end vented to atmosphere. I don't notice any smoke on acceleration and decel. But I did notice a bit more shaft play then normal. Sent it off to Majestic Turbo lets see what they say. Tony

 

i just did an oil pressure mod but this is on a t2 so the oil pressure is lower stock than third gens. I never had any problems before, but im worried now . should i use a restricter and where can i buy one, anything local or does it have to be a turbo shop
john

 

You can do it the way I did, I ordered the M14 x 1.5 to -4 AN Adapter (Earl's PN 9919BFH) and a -4 AN Adapter to -3 AN Hose End (Earl's PN 600143). This allows you to run -3 line from the M14 x 1.5 to -4 AN adapter without special ordering anything. Just make sure you get a crush washer or O-Ring for under the Metric Adapter, failing to do so will leave you leaking oil like a Sieve... ask me how I know. I have been running this setup with a friend's turbo for a few weeks, and will be until I swap the GT3574 in, and it seems to be working like a champ. The downside is the hose end is only available in stainless, so it won't match the other hose ends.

Here's an installed pic from before the motor was put back in: