whitegst97 said:

Guys im having similar problems, i installed my t04b and i had smoking problems at wot, now i added the restrictor and saw the opening was too small, so i drilled it out to 1/8". The smoking problem now comes at idle, and only when idling for more than like 2 mins or so, otherwise, no smoking neither wot or idle, but when it sits for a while then reved or taking off it puffs burned oil. Also my spool up sometimes is at 4800 and sometimes it gets full boost (15psi) at 4k. I know is not too much oil cuasing the slow spool because this happened without the restrictor and with the original tiny(nondrilled)restrictor, and has continued after restrictor being drilled to 1/8". I have my PCV to the stock location and crankcase vent line to the intake with a filter in between. Any help please, this thing is driving me insane i hate that smoke!!! Thanks

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Check the filter you have installed from the vc and make sure it isnt clogged with oil. If it is or beginning to get clogged, it will cause smoking at idle.

I've tested it, the filter is pretty new, i've blown through both sides and the air comes out perfectly through the opposite side. I got a new pcv valve today, don't know what else. The smoking at idle isn't constant, it happens when the car sits, idles for about two minutes, not regular stop and go. Thanks

Hi Guys- I am currently on my 3rd turbo (GT35 non-ball-bearing center) from PTE because of this reason! - my first setup was a straight 4an line from the filter housing & blew oil from the turbine side. second setup I used a 4an line + earls 4an filter from the head & it leaked from the compressor side. The engine is rebuilt with new seals & guildes & no balance shafts, I use a 5/8" return line & stock PCV valve to an oil catch can (with breather) together with the valve cover vent. I have the third turbo ready to install & I dont want to blow this one! is the non-ballbearing GT bearing section the same as a t sries? I plan to run a restrictor from the filter housing but dont know what size to use? should the oil catch can be lower than the pcv/valve cover vent?

Guys please HELP!

SuperTalon said:

I plan to run a restrictor from the filter housing but dont know what size to use?

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A .078 nitrous jet should work just fine.
http://www.dsmtuners.com/forums/showthread.php?t=171317

99gst_racer said:

A .078 nitrous jet should work just fine.
http://www.dsmtuners.com/forums/showthread.php?t=171317

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i have a .078 nitrous restrictor setup for a -4an line if you need it

Burnett03 said:

i have a .078 nitrous restrictor setup for a -4an line if you need it

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No thanks- I already have a restrictor fitting from ATP Turbo- its for a ballbearing turbo (.035) they suggested .065 for a t series turbo? I am going to have to whip out my fluid dynamics book & look up the formulas for fluid pressure changes in relation to changes in orifice- then again the numbers will change with change in oil viscocity. I believe .078 translates to 5/64" drill bit- the never ending quest continues...

Hey Guys- got some results from my setup (check out my gallery for pics of the Turbo oil pressure gauge setup)- I installed the .078 NOS flare restrictor & got 15 psi at idle & a little over 60 psi at 5K rpm- this is a little more than what Garrett suggests (12-15 psi at idle & 50-55 psi at 5K rpm) I have a .075 & .065 NOS flare restrictor to try next-

NOTE- at engine startup the gauge jumps to 70 psi !!! (with .078 restrictor) & once it warms up it gradually drops to 15 psi at 190 deg. of coolant temp- this shows that before jumping to full boost- the engine should be thoroughly warmed up!

I hope this helps someone out there!

SuperTalon - If your oil pressure gauge is mounted under the hood, how do you monitor pressure at 5K under load?

99gst_racer said:

SuperTalon - If your oil pressure gauge is mounted under the hood, how do you monitor pressure at 5K under load?

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just a thought, but maybe he has a friend sit in the car and rev to 5k while he monitors the guage. but if you do it while under heavy boost, then i have no idea how he monitors that unless he has his hood off and hangs out the window while boosting!

Hey guys- the oil pump is mechanically connected to the engine- it does not matter if you rev the engine from the throttle body or on the road- you still get the same ammount of oil pressure- I have my wife sit at the wheel & tell me when it hits 5k rpm.

I took the car for a test drive & noticed that the turbo spools much faster and at a lower rpm than the previous turbo (same GT35)- now that the turbo is getting close to optimum oil pressure- its able to do its job more efficiently or because the older turbo with a failed compressor seal (oil all over the compressor wheel) was not able to work properly? dont know for shure. Can high oil pressure cause drag on the turbine shaft rotation?

SuperTalon said:

Can high oil pressure cause drag on the turbine shaft rotation?

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Yes, too much pressure and/or volume can definitely create drag.

http://asciimation.co.nz/turbine/

These guys throttle the turbo down with just 40psi of oil pressure, so I'd say it's a pretty significant effect.

99gst_racer said:

Yes, too much pressure and/or volume can definitely create drag.

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I had this feeling that this is possible! I tried to get in contact with a Honeywell turbo engineer (owners of Garrett turbos) but after three tries they could not transfer me to someone that can tell me the optimum oil pressure for a GT35 non-ballbearing turbo which I am shure is the same as a T series turbo (journal bearings). Well I will try again tomorrow & let you guys know the outcome.

SuperTalon said:

Hey Guys- got some results from my setup (check out my gallery for pics of the Turbo oil pressure gauge setup)- I installed the .078 NOS flare restrictor & got 15 psi at idle & a little over 60 psi at 5K rpm- this is a little more than what Garrett suggests (12-15 psi at idle & 50-55 psi at 5K rpm) I have a .075 & .065 NOS flare restrictor to try next-

NOTE- at engine startup the gauge jumps to 70 psi !!! (with .078 restrictor) & once it warms up it gradually drops to 15 psi at 190 deg. of coolant temp- this shows that before jumping to full boost- the engine should be thoroughly warmed up!

I hope this helps someone out there!

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where are you taking the oil pressure...because if you're taking it at the pump, you may have 15 psi before the restrictor, but after(turbo) would have...I bet like 0

talon_boy69 said:

where are you taking the oil pressure...because if you're taking it at the pump, you may have 15 psi before the restrictor, but after(turbo) would have...I bet like 0

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Look at his gallery - there is pics of the set-up. The gauge is inline and after the restrictor, so it is reading the actual pressure going to the turbo's CHRA.

ohh ok...I looked at the gallery but didn't stare at the gauge

I have not gotten a response from Garrett- I spoke to Brian from Precision turbo & he believes the 1/2" hole in the oil pan for the return line is too small even though I am using a 5/8" line. This restriction might be causing oil to get backed up & sent up the cartridge- I was thinking of using some Home Depot 5/8" nylon line (clear) for a few minutes just to see the flow of oil coming out of the cartrdge into the oil pan (nylon is not high temp or oil resistant- so it can't be used for long periods)

I will be on vacation for the next two weeks so I will try this when I come back- will post results here shortly.

SuperTalon said:

(nylon is not high temp or oil resistant- so it can't be used for long periods).

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Definitely can not withstand extreme temps . . . but isn't nylon tubing used for mechanical oil pressure gauges?

Are there anymore good/bad experiences with using a restrictor to limit oil pressure the the chra? I am having a problem with the turbine side seal leaking and blowing out a lot of smoke at WOT, especially when I first get on it. I have a PTE SCM-3427E.

I have a crankcase evacuation system setup with an electric vacuum pump and catch can. Currently I have it setup with a hobbs boost switch so that it activates at 8 psi of boost or higher. I'm going to change that to a cockpit toggle switch so that I can turn it on/off whenever I need to. I'm thinking that a lot of the smoke is coming right when I get on it so it may be come from not having any evacuation until the turbo pumps to at least 8 psi.

Let me know what you guys think.

Hi Natedogg- I have not had a problem with my restrictor setup yet- but I have only logged about 250K miles since I installed it.
Do you have a good sized return line? The guys at Precision Turbo hinted at me that the stock return line @ 1/2" is to small- I am working on a true 5/8" setp with a welded fitting at the oil pan- I will report any pressure changes on this thread if noted.

Try doing the turbo pressure gauge setup I have (check my gallery) this is the only way to find out what oil presssure is going into the turbo- the pressure should be high at startup since the oil is cold but when the temps reaches 190deg. from the throttle body- try a 5K rpm pull (have a friend sit on the car & call it) & check the oil pressure reading at that RPM if its past 70 PSI its to high. I am still trying to get to someone at Honeywell or Garrett performance to give me a stright answer on the oil pressure limits for a t series & GT series turbo. What I heard from other sources is that at idle the turbo should se no more than 10 to 20 PSI & 50 to 60 PSI at full throttle but dont quote me on this- that is why I want to talk to an engineer from Garrett.

You are the first person I have heard with a vacumm pump on a dsm- maybe its doing its job but not enough to eliminate the high pressure oil that the turbo cha is seeing? maybe with a restrictor setup & right size return line- you wont need that pump anymore?
I would hate to see anyone go through three turbos like I have!

Im not sure why PTE loves to blame oil returns, but from what ive seen, a 1/2" line is plenty, especially when you are regulating the oil pressure with a restrictor. Unless there is a blockage, 1/2" should be plenty.

Thanks for the feedback guys. I tried the cockpit switch for the vacuum pump and it seems to help some, but she still smokes quite a bit at WOT. I went ahead and ordered a restrictor for the feed line. Still waiting on it. I actually do have a 5/8" return line, but I haven't checked it for blockages yet. That'll be the next thing I check as soon as I can find time to get in the garage.

The vacuum pump also serves to keep excess crank case pressure from adding to overall oil pressure. It also helps the rings seal and allows the pistons to move more freely because they don't have to fight against as much crank case pressure on a down stroke.

Well, I finally got the restrictor on yesterday. Using a .078 orifice. It helped a lot. Instead of a huge cloud of smoke coming out the tailpipe I have a small puff that I can't even see while driving. This thread was a huge help.

I can believe it- the turbo seals went out again Monday morning I start the car to go to work & I go back in the house for a few minutes & when I go back to the garage there it is that dreaded heavy smoke coming from the tailpipe! heart broken I turned the talon off & took my daily driver to work. I was soo pissed off that I just wanted to part out the whole car!!! I have run out of patience & money for this project- it has been 3 years since I started this project & I have yet to enjoy one pass down the track! well enough rambling that was two days ago- I spoke to a trusted friend & he said that I should try a turbo from a different company & that I should not part out the whole car because of a bad turbo. Honestly I am lost & I am open for any suggestions guys- thanks for your input in advance!

SuperTalon said:

Honestly I am lost & I am open for any suggestions guys- thanks for your input in advance!

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First off your car/engine is the cleanest 1990 I've seen in a long time, good work

Just a few things off the top of my head:

1.) Are you sure you used the correct oil feed fitting on the 1990 filter housing? One feeds pre-filtered oil and the other filtered?


2.) The turbo oil return is a combination of low pressure and gravity. Is your oil return line perfectly free of kinks/restrictions (even when engine torks side-side) and has no spots lower than the oilpan inlet?

3.) Building on #2, if your crankcase pressure is high, this acts against the freeflow of oil returning to the pan. Try gutting your PCV and running to ATM and/or reattach your valvecover vent to a (-) pressure intake source with oil separator or vacume pump.

4.) What weight motor oil do you use? Have you tried a lower viscosity motor oil?

5.) Not sure if this has been tried, but wonder if you can tap into the oil cooler return fitting (less initial surge of pressure, cooler oil).

6.) If all else fails, pick up a new/used FP3065 as you already have the Tial40mm, the BB oil feed line/filter/restrictor and it feeds from the head