Garrett & Holset Turbo Users - Your Oil Drain May Be Too Small!

[JusMX141]

So my turbo was smoking and I thought the seals were blown. I put a new turbo on and it seems to still be smoking.

The smoke doesn't disappear immediately- it can take up to 500 miles depending on how much oil was in the exhaust and whether your car has a cat or not.

If your turbo was dumping oil, the exhaust is probably full. Think of how long a valve cover gasket that drips on the manifold will smoke from just a few drops of oil.

 

[Raymos24]

Yea thats what I was hoping too. But wouldn't it smoke all the time if there was oil in the exhaust? I definitely know theres oil because my tailpipe is full. I would expect it to smoke at all times though as it gets rid of it instead of the same smoke after WOT?

 

[LiquidX]

This is the drain flange you want Turbo Flanges & Gaskets, T6 / S400 Oil Drain Flange, RPS-T6ODF | RacePartSolutions.com

You'll also need a weld in bung for the pan and 3/4" NPT adapter fitting to thread into the flange. The -AN fittings are your choice.

 

[Raymos24]

Can you point out where I can get the 3/4" NPT adapter fitting? So would it be bad if that adapter fitting tapered down to a -10AN fitting?

 

[LiquidX]

You can get the fitting on the website I posted or on Ebay. Any place that sells fittings for -AN lines will/should have it available.

I'm guessing you want to taper it down to a -10 so you don't have to weld in a -12 on your pan? Yes you can reduce it down but it's best if you go -12.

 

[Raymos24]

Oh ok. Yea I don't have a problem welding the new one to the pan. It is just that right now I am running a -10an braided line on this return line so I wanted to see what I could retain.

 

[Raymos24]

So I am building a -12an return line and I have a question about the fitting I will be welding to the oil pan and the male to female adapter fitting from the turbo flange. I see that everyone uses a flared end. Is there a reason why? I found some that are not flare on one end but instead the same diameter on both sides. Wouldn't a fitting that isn't flared be less restrictive than one that is flared because the flared end has a smaller opening than the 3/4" end. I will add pics at the end to compare. So should I use the one that is flared or the straight fitting?

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The first is the straight fitting while the second has the flared end.

Ignore that last post. I just got a lesson on fittings from -red97rum- .

 

[Gamble97]

So I am thinking of holset now. What is the ID of a 12an fitting? The inlet maybe big but the "neck" seems much smaller. I would like to go 14an with mine. Can someone tell me who has the least expensive fittings?
And this fitting where can I find this? I saw the link for the flange but I do not like using the female to female adapters. I was thinking this flange with a short straight piece just until it clears the compressor cover then going 14an.
And with this turbo do you need to dent the water pipe? I will be using a fp manifold.

I can't find anything for 14an fittings. Do they even make them? I rather not go 12.

 

[dsm-onster]

the inside diameter of 12 fittings is 19mm, which is within spec per the holset repair manual. . . ? ? ? ? ?

 

[99gst_racer]

I can't find anything for 14an fittings. Do they even make them? I rather not go 12.

No -14's. They jump from -12 to -16.

-12 is plenty big enough.

 

[Gamble97]

Yes but the neck of the 12an is probably smaller than 19mm correct? Are we measuring the 12an inlet or did someone cut the swivel off and measure it there?

 

[talon1979]

So I am thinking of holset now. What is the ID of a 12an fitting? The inlet maybe big but the "neck" seems much smaller. I would like to go 14an with mine. Can someone tell me who has the least expensive fittings?
And this fitting where can I find this? I saw the link for the flange but I do not like using the female to female adapters. I was thinking this flange with a short straight piece just until it clears the compressor cover then going 14an.
And with this turbo do you need to dent the water pipe? I will be using a fp manifold.

I can't find anything for 14an fittings. Do they even make them? I rather not go 12.

On the thread "Holset turbo's pt 8," pg 15 there are some pics posted by a member named Calan which is the best setup I have seen. I spent the money on adapters & -12 an fittings and if I did it again I would mimic what Calan did. It appears he purchased flanges & welded tubing onto them. My -12 fittings w/ adapters are more restrictive then they look.

I thought I would share my oil pressure readings. I do understand that different engine's will have different results. For the record, My car is a 1990 with about 160k miles on the original 6-bolt. My oil pump has not been modified. My front balance shaft was left in place and my rear balance shaft has been replaced with a stub shaft. I am of course not running a balance shaft belt. I am running a -3 oil feed strait from the OFH unrestricted. This was done on 10w30 oil when the engine was warm. When the engine was cold I know the oil pressure was much higher. I'm also running a -12 oil return line that is welded to the oil pan.

Here were my warm oil pressure readings directly at the turbo after the -3 feed hose.

750 about 10psi
1k 15psi
2k 28psi
3k 48psi
4k 55psi
5k 59psi
5250 rpm was also 59psi

I couldn't rev higher due to my launch RPM. When I get more time in about a week I'll raise my launch RPM and update the oil pressure at higher RPM's. It almost looked to me like things were topping out at about 59psi since there was no change from 5k to 5250rpm when there was such a dramatic rise in the lower RPM. I'm guessing the curve was peaking at around 60psi, but I won't know for sure until I can test at a higher RPM.

I'm sure readings directly from the OFH would have been higher, especially without reading in a line that had a return in it.

My hx40 spins incredibly easy. If I start spinning it with my finger it continues to spin for several seconds after I release my finger.

 

[LiquidX]

Have some pictures of my -12 drain setup. More like 2 versions of it. The first couple pictures are the old style and it was using 2 45* swivel push lock fittings. So many issues with them and had to do a lot of cutting and was worried about leaks.

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How it looked pre cutting which was way too long. (NOT ribbed for your pleasure)

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Recently got back from the garage for some other issues and had the drain reworked. 45* fitting on the pan was reused but up top it was changed to a straight NPT to Hose Barb fitting.

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[kicker91laser]

Here are a few pics of the -12 line setup I did for the truck today, running an hx35 on it.

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[Gamble97]

I'm going to order my parts later in the week, so I think I have this correct.
This flange
Turbo Flanges & Gaskets, T6 / S400 Oil Drain Flange, RPS-T6ODF | RacePartSolutions.com
This fitting
Summit Racing SUM-220247 - Summit Racing® AN to NPT Adapter Fittings - Overview - SummitRacing.com
12an SS Hose (probably go with black lightweight hose)
and 1 straight and 1 45* fitting or would I be better with 2 45* fittings?

 

[kicker91laser]

Gamble, the flange and npt/-an fitting is correct, I cannot comment on the hose ends since my setup is on a rwd.

 

[Gamble97]

Who else sells that oil drain flange, I'm not going to pay $26 for it after shipping.

 

[kicker91laser]

Who else sells that oil drain flange, I'm not going to pay $26 for it after shipping.

https://turbodaves.com/Accessories.html

 

[Gamble97]

Thanks, my stuff is now coming for the oil drain. I still need an oil feed, What size is everyone using? Or does it not matter with the restrictor? I got the restrictor from Justin when he rebuilt it. And how long does it need to be?

 

[JusMX141]

Restriction is generally .075"-.095" for Holset users depending on the amount of pressure. If you're running a -12AN drain, you have a sufficient drain setup....focus on giving the turbo as much oil volume as possible without going over 75psi or so at wide-open throttle.

Keep in mind the Holsets on Dodge trucks are fed with a -6AN feed, but both the supply pressure and drain size are within spec. If your drain is ample and you have the correct pressure at the feed, the volume of oil you give is literally up to you.

 

[Gamble97]

Restriction is generally .075"-.095" for Holset users depending on the amount of pressure. If you're running a -12AN drain, you have a sufficient drain setup....focus on giving the turbo as much oil volulme as possible without going over 75psi or so at wide-open throttle.

I am running a 12an oil drain. Still waiting for them to come in the mail, and still waiting on my stage8 bolts to bolt up the turbo.
My friend sent you the turbo and you rebuilt it and I bought it from him so I am not sure exactly what size restriction fitting is in there, but I trust you.
Just not sure what my oil pressure is since the motor is a fresh build and still not in the car. 3an or 4an. hmmm

 

[JusMX141]

The HX40 DSM record-holder is currently using a restrictor I drilled to 3/32" which is around the same size as a -3AN line's I.D. He's also using a -10AN drain which I "funneled" the top of the turbo's drain flange to match the outlet of the Holset cartridge. The drain itself consists of two 45* fittings with a short piece of braided line in between.

He now has a full season of racing as well as some street driving on the HX40, and a full season of racing and driving the previous year using the same feed and drain setup on a HX35....both turbos are as tight as the day I rebuilt them.

 

[Gamble97]

So 3an with no restrictor or 4an with a restrictor is what you are saying. Ok.

 

[El Cuervo]

Gamble97. Regardless of restrictor size. On cold starts, I believe 80psi is permitted. Only on cold starts. When fully warmed up, at your set idle, it cannot be less than 10psi and at your rev limit at wot, it cannot be more than 75psi. A restrictor of .075 is a good average starting point. Meassure the oil pressure at before the turbo oil inlet with what size restrictor or with whatever you have. If it checks out within spec, then use what you have. If not, then drill it bigger or get a smaller one. I have the .075 and its perfect. But I also have a 16an to 20mm id custom oil drain. Though a lot of people are having good luck with the 12an oil drain, I personally don't trust it. Since its not a true 19mm of id. Which is what holset requires as the min. But that's probably just my paranoia taking over. Lol

 

[red_devil]

So 3an with no restrictor or 4an with a restrictor is what you are saying. Ok.

I run a -3an feed and modified stock drain, no issues in over a year and 10k miles. Turbo has 0 play and spools great.