Ultra short turbo drain line
 

What are your suggestions for building a very short turbo drain line? The forged 45* AN fittings I just got in hopes of building something that isn't terrible are too long. Running the ARTech low mount manifold with a 2560 and trying to use the stock MSM drain location.

In this picture the bottom NPT-AN adapter is finger tight, a little room will be gained by snugging it up but not even close to what I need.
https://www.miataturbo.net/attachmen...ine=1456453032

In this picture the NPT-AN adapter is removed and the 45* AN fitting held flush against the flange. Enough room there is not.
https://www.miataturbo.net/attachmen...ine=1456453032

For the past year I ran a 45* socketless adapter on the turbo side to a hose barb on the pan side. It kind of worked, the hose is partially kinked and has collapsed on itself creating a massive restriction that I believe causes the turbo seals to leak at idle when the PCV vent doesn't route to the intake. Or in other words, the turbo seals leak oil at idle unless the crankcase has a vacuum. This condition has hidden just how poorly the turbo drains.

Swapping the NPT flanges out for male AN flanges will buy a small amount of room and look something like #2 above. There won't be much room for flex in a 1/4" long piece of hose.

Replace the turbo side 45 with a straight fitting and hope the hose doesn't kink? Braided hose has a better bend radius than the socketless I was using.

Hose barbs on both ends with some high temp hose?

Man up and drill the pan in a better spot?

If the hose is too short (and that looks like it definitely qualifies), then it won't flex enough to allow you to install it when the turbo is installed.

--Ian

If it did, I'd ask a local hydraulic shop to lend you a couple crimp on fittings, I bet they have a shorter profile.

Buy 2 straight barbed NPT fittings and 2 barbed 45* NPT fittings. And a foot of oil-safe rubber line. This way you have some options at hand when you go to "fabricate" the solution. And even with those fittings you might not need, you will still be at half the cost of one of those AN components.

bit of thread jack, but what npt adapter is that on your msm pan? A generic t25 flange?

The three barbed fittings is an interesting idea. Where are you guys getting high temp hose from? Only good option I found at Mcmaster is $20/ft.

Yes, t25 flange. If I end up drilling the pan and moving the return you can have it.

The advantage to the AN lines is that you can take them off and put them back on again. Rubber hose on barbs that's baked in turbo heat for a while usually requires a knife to come off.

--Ian

I had this same problem see my build thread (at the beginning). Push-loc fittings are quite a bit shorter, I'll find pics tomorrow.

Tried that initially, think you suggested that in my build thread. They don't fit either and are longer than the ones pictured.

If the drain wasn't spaced an inch out from the pan wall this wouldn't be a problem. I think that will get capped and a new hole drilled.

What about an NPT-pushloc 45* fitting? fitting

I welded an AN fitting onto my pan. You could do the same to that flanged NPT fitting or make your own flange to eliminate the adapter. Will using a barb at the CHRA then give you a reasonable length of hose to make the curve to the 45 at the pan? That's the place to use the barb since oil is not flowing into the face of the barb end. I used one there and never had it leak. Might consider using another metal than aluminum for the fittings with a hose section that short/rigid.
https://www.miataturbo.net/attachmen...ine=1456495679

I keep looking at that first picture, and thinking that as much as I dislike press-fit hose in general, that it's the easy solution here without having to re-drill the pan, and it's not like it's going to be under pressure.

Remove the AN adapter from the turbo, and replace it with a straight hose barb. Or better yet, unscrew the flange from the turbo and replace it with one that has an integral barb fitting, such as this: http://www.treadstoneperformance.com...+5%2F8%22+Barb

Remove the AN adapter from the plate on the pan, and replace it with a 45° barb.

Find some reinforced hose rated for use with hot oil (example, or example) and install it between the two.

For anyone who doesn't like puch-loc, you should try them out one day. I used it for my fuel system on my car. Looked into it, they are tested at 3x their rated pressure and can not leak/burst at that pressure. The stuff I used was rated at 350 PSI, meaning it can hold 1,000+ without a leak or burst. Good enough for me. Also once you install the hose onto the fitting (which is a huge pain BTW, like trying to put a 1/4" hose on a 3/8" barb...) it will never come off without a knife. You'd rip the hose before it slide off the hose barb.

I also used pushloc/Socketless Aeroquip AQP hoses and love them.

I'm just not too convinced yet for e85 fuel applications.

I'd probably use the barb/silicone drain hose method versus AN. You will have far less radiant heat issues than mine, as my drain passes right next to a long runner manifold. Never had an issue.

Rated for oil at 150°C, looks like good stuff.

Available at local hydraulic shops, I assume? How is it for flexibility compared to reinforced silicone?

I've had it on my car for a year now on E85. I run 60 PSI base pressure, 1:1 regulator, twin pumps, all the boost, no leaks, no problems. Why are you not convinced?

For OP, I'd use barb fittings/hose, and throw some fire sleeve over it for protection if needed.

I bought mine from SummitRacing when I bought all the fittings too from them. It's as flexible as regular fuel hose, with 6AN you can make a bend with a 1.5" radius no problem. Silicone would colapse compared to this stuff.

I've seen push loc fail. I would never use it for anything that is pressurized. So basically vent lines to a a catch can is the only thing I would ever use it for...

If barbed fittings and hose was kind of working before, then just get an appropriate sized spring and put it inside the hose. No more kinks.

An oil drain sees no more pressure than a crankcase vent lol.

Yes I know, you kind of misinterpreted my post, I guess I should have added in "like" before "vent lines". I said anything non pressurized and just meant catch can lines as an example.