S475 Turbo T4 Oil Feed Fitting Nitrous Jet Restriction

darknezz7 · May 12, 2022

So with the t25 it had a 1.5mm restrictor that threaded directly into the turbo, then a swivel 90* feeding 4an from the OFH.

With the 20g journal bearing this fitting does not thread into the turbo, but the 20g came with a new feed line kit and some fittings. This was a cheap turbo kit though and I dont trust they know what is best, half the bolts were coarse thread and didn't even fit the turbo.

Heres what I have, 1.5mm restrictor on the right, banjo fitting that came with 20g on the left, 90* swivel in middle.

Now obviously the banjo on the left is smaller than the 4an, but the 1.5mm restrictor is super tiny!

I feel the banjo on the left will restrict the oil enough to not blow the turbo, but want to make sure. If it needs something more I will have to buy an inline, if so what size should I get?

No balance shafts, head oil port mod, OFH ported, 15-20psi at idle, 60 cold idle, 60 cruise, 110 peak

Let me know what you guys think thanks.

Oh heres where I am at today, lots more to do still, mostly small stuff though. Hope to have it running this weekend.

GST with PSI · 2,696 1,435 Jul 27, 2005 San Diego, California

Is that a bastard 20G? Why not just feed it from the head via the OEM hardline?

ec17pse · 5,522 2,829 Nov 1, 2008 London, UK, Europe

I could be wrong here but im sure it should still be fed from the ofh and use the .075" restrictor! Im going to be running a .080" on my 16g as thats still safe but if in doubt drill it out with a 2mm bit and that makes it a .078" so within safe limits i would think,

GST with PSI · 2,696 1,435 Jul 27, 2005 San Diego, California

IIRC, most MHI journal bearing turbos typically used on the DSM use a .075" restrictor from the factory, so that's what I'd stick with regardless of where it's fed from. You may get more volume from the OFH, but I've successfully used the head to supply half a dozen 16Gs on my various cars over the years.

Ideally, you'd want to measure the pressure, and go from there.

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

Its some kind of bastard I'm sure

Do not have or want to feed it from the head.

So the banjo bolt on the left is too big?

I still have the issue that the restrictor does not thread into the 20g like it did the t25!

ec17pse · 5,522 2,829 Nov 1, 2008 London, UK, Europe

The restrictor wont as that is a imperial thread on the t25! The 16g is metric! So thats why it wont fit!

As for the banjo i dont know the size unless you measure it for us and tell us its hole size! Try a 2mm drill bit and if it goes in and wiggles then its too big. Other then that you can buy a 1.5mm banjo bolt from kinugawa and then drill it out or go to rtm racing and by there inline restrictor https://www.rtmracing.com/xcart/home.php?cat=1786

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

Oh I remember that thread difference now, I swear the first kit I got came with an adapter for the bigger turbos, have to see if I can find that.

The banjo on the left is more like 7/64 (.11")
Too big then? It would blow the seal?

A 5/64 bit would be .078"

I think I will drill out the 1.5mm restrictor I have and try to adapt it

synthetek · 1,658 83 Dec 13, 2005 La palma, California

That looks like an EBay turbo so its probably M10 x 1.5 at the oil feed an MHI would be normally be M12 x 1.25 the T25 is 7/16 x 24

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

I've read that ".100" restrictor for full flow journal bearing turbos."

That is about what the banjo is. Sure it wont be ok?

darknezz7 · May 12, 2022

Well I just ran into another problem... Apparently the throttle body I got is for a "lancer EVO 4 5 6" so the TPS doesn't fit, its too big.

I only hope I can get the right sensor and adapt it in....
Now to find which sensor I need

I really want to get this going this weekend, if I have to buy another restrict or that wont happen...

ec17pse · 5,522 2,829 Nov 1, 2008 London, UK, Europe

I just looked into the feed side ofbthe 16g chra and its all ready has a restrictor! Its drilled to .075" anyway! So another restrictoe wont be needed really, did not know this till i just looked myself.

GST with PSI · 2,696 1,435 Jul 27, 2005 San Diego, California

I just looked into the feed side ofbthe 16g chra and its all ready has a restrictor! Its drilled to .075" anyway! So another restrictoe wont be needed really, did not know this till i just looked myself.

Nope. Not to mention, if that's an Ebay knockoff bearing housing, who knows if there's even a "restrictor" there, or what size it is.

If I'm correct, weren't the 14b/16g CHRA's fitted with a restrictor already? I looked in 14b and there is only a small pin hole

Nope. These turbos all had a restrictor in the factory feed line.

And also:

Buy a factory 1G oil supply line from the head and be done with it. This is what Curt Brown used on the 499awhp / 10.33 Evo III 16G setup he ran a few years ago; I can't see how anyone's 16G could ever need more oil than what his turbo needed.
Even the factory 1G line from the head has a restrictor built into the banjo end at the turbo.

At head:

At turbo:

If I were you I'd ask myself why feeding a 16G unrestricted from the filter housing with roughly three times the pressure and volume that the turbo requires is the right thing to do.

OP, I think you're making this much more complicated than it needs to be. Keep it simple and do what works, rather than jumping through hoops to find fittings and restrictors. If the factory banjo fittings won't even fit your knockoff cartridge, you've got bigger issues, IMO.

Every one of the threads linked below are a good reads:
http://www.dsmtuners.com/members/jusmx141.60709/
http://www.dsmtuners.com/threads/tr...strictor-do-i-need-one.453337/#post-153156779
http://www.dsmtuners.com/threads/will-this-feed-line-work-from-the-head.386725/#post-152390316
http://www.dsmtuners.com/threads/oil-feed-in-line-reducer.382183/#post-152331215

P.S. Your engine bay looks pristine!

donniekak · 5,622 970 Mar 23, 2008 Surprise, Arizona

The eBay 20g's have a larger shaft and bearings than a Mhi unit. I'd feed it unrestricted from the oil housing.

I've been feeding all my jb turbos from the oil filter housing unrestricted for years, with no issues. The main issues with having to restrict oil because of smoking is either a bad drain setup, or excessive crankcase pressure.

My last jb turbo setup was an fp red. I ran it everyday at 28 psi for a year and a half, unrestricted -4an from the filter housing. The turbo has as much shaft play when I removed it as new, and the turbine wheel also looked new, with zero burnt oil on it.

GST with PSI · 2,696 1,435 Jul 27, 2005 San Diego, California

My chra is a genuine mhi unit. I tried to plug it with a 2mm and it did not fit so its not .078" i tried a 1.5mm and it moved so it does seem to be close to the .075" as stock in the ofh locaton! I even confirmed this with my 2nd mhi chra unit aswell, both have the same sized hole in the oil feed side! It cannot be anything but a drilled restrictor from the factory!

I was referring to the OPs CHRA as being a knockoff, not yours.

The small port you see on your CHRA may act as a restrictor, but I wouldn't solely rely on it, just as Mitsubishi didn't. Telling people to do so is contrary to what's been know for years about proper oil supply to the standard JB MHI cartridge.

As far as feeding MHI JB units form the OFH unrestricted; sure, it can be done. If you have the correct pressure and volume, the turbo can be fed from anywhere you want. The key is correct pressure and volume, which you determine by measuring. There's no blanket scenario where one oil source is always optimal over the other. The optimal oil source for ANY turbo is the one that provides the correct pressure and volume according to the turbo's specifications and requirements.

There's no arguing that...

ec17pse · 5,522 2,829 Nov 1, 2008 London, UK, Europe

I thought you was on about mine i checked! Sorry i didnt know you ment the OP's chra.

Yes not trusting it is safer then doing do but as the oem t25 was not and mitsubishi added it but think about it thats a garrett unit! No wonder why mitsu added a built in one on the ofh! The the 16g is mitsu's own unit so it would make sense if they did build it in.

At least thats how i think about it. I myself will be running a .078" restrictor just like i have recommended above. I agree with the pressure and placement of course and i am no turbo expert but from what i found and ZERO mention of this built in hole anywhere on here it means i wont trust this hole alone.

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

The eBay 20g's have a larger shaft and bearings than a Mhi unit. I'd feed it unrestricted from the oil housing.
I've been feeding all my jb turbos from the oil filter housing unrestricted for years, with no issues. The main issues with having to restrict oil because of smoking is either a bad drain setup, or excessive crankcase pressure.

My last jb turbo setup was an fp red. I ran it everyday at 28 psi for a year and a half, unrestricted -4an from the filter housing. The turbo has as much shaft play when I removed it as new, and the turbine wheel also looked new, with zero burnt oil on it.

This is what I've researched too, yes this is a ebay 20g. I believe the oil feed kit that came with it and the .1" banjo bolt will be fine for it.

My drain is an 8an(I believe, its big anyway) Nice and straight.

I have the block breather and good pcv catch can breather setup, should be no cc pressure

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

Thanks everyone for all the good info and help!

boost97gst · 3,033 133 Apr 2, 2012 st jacob, Illinois

The eBay 20g's have a larger shaft and bearings than a Mhi unit. I'd feed it unrestricted from the oil housing.
I've been feeding all my jb turbos from the oil filter housing unrestricted for years, with no issues. The main issues with having to restrict oil because of smoking is either a bad drain setup, or excessive crankcase pressure.

My last jb turbo setup was an fp red. I ran it everyday at 28 psi for a year and a half, unrestricted -4an from the filter housing. The turbo has as much shaft play when I removed it as new, and the turbine wheel also looked new, with zero burnt oil on it.

This, JB is JB. Big drain, plenty of flow, fed from ofh......you nailed it.

JusMX141 · 15,095 1,145 Dec 13, 2005 Greensburg, Pennsylvania

OEM turbos at OEM boost levels = OEM oil source. This includes a 16G up to 18 or 20psi because Evo VIII/IX turbos are fed from the head despite running 17-19psi of boost from the factory.

If you want the turbo to last at high boost, or if any component has been changed for something designed to pass more oil (larger journal bearing oiling bores, larger/more holes in the thrust plate) then a filter housing feed may be mandatory. Always oil the turbo in accordance to the manufacturer of the unit to protect the warranty....for instance FP uses big-bore journal bearings and a steel coated thrust plate with three giant oiling holes instead of one tiny oiling hole like the factory thrust plate. This is why a 14B can last hundreds of thousands of miles when fed at the head but a FP Red may fail before 1k.

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

Good info.

So not that it will surprise anyone but the ebay 20g has a cracked center housing, water pours out the oil drain...

So thats getting returned and refunded and never again ebay parts.

Purchasing a real MHI EVO 3 16g from a member here.

So I'm still going have the restrictor problem. I can drill mine out to .078" then Can I get an imperial to metric adapter locally for it? I just need to know the size to ask for.

jed344 · 1,177 282 Jan 10, 2008 Waterville, Iowa

I have ran a 14b, 16g, 20g all off head with no restrictor with no issues.

darknezz7 · 571 79 Mar 30, 2014 Eugene, Oregon

Yes but we are talking about running from the oil housing, on modified engines.

Waiting to get the real evo 3 16g so I can figure out what thread it is and find a restrictor fitting

Janesfam · 103 43 Jul 9, 2021 Milwaukie, Oregon

So did you find the 16g .075 restrictor? If so where did you buy it from?

S475 Turbo T4 Oil Feed Fitting Nitrous Jet Restriction

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