EFR 6758 leaking into compressor housing
 

I have around 2000 miles on my kraken 6758 setup, maybe 500 miles on the forged engine on a previous setup. Photo below. Most of this driving was done with a stock PCV setup, although after noticing the oil, I cleaned the charge piping and deleted the PCV. Stock breathers in the valve cover, PCV open to atmo. As you can see, that’s a temp setup while I wait for the proper fitting from radium, all the hoses are ready once that shows up.

I let it idle like this long enough for the thermostat to open (~10+ min) after wiping the turbo clean. After sitting, theres a small build up of oil below the compressor wheel, you can see similar oil in the pic of the compressor housing.

Oil feed is -4 from VVT housing, goes through a Turbosmart turbo oil filter, pressure at it's source (the block) reads around 45psi cold, 17psi hot, usually 45-60psi when driving. Running Total 5-30 synthetic. Exhaust breather has always just been open, never seen any evidence of oil in it to cause concern, although I may put a small catch can on it for fun. Leak down was 3-4% when I checked it a few weeks ago. It is an aluminum super core, looks like the compressor housing was built in 2020, super core in 2016.

Any idea what could be causing it? I'm hesitant to blame the super core after reading up on this thread:
https://www.miataturbo.net/engine-pe...-please-90835/
and this one:
https://www.miataturbo.net/build-thr...1/#post1276378

There is some shaft play I'll post a video of, but only when hot. Cold there's barely any, similar to what @psyber_0ptix describes in his thread.

https://cimg4.ibsrv.net/gimg/www.mia...c563c39cd.jpeg
excuse the mess, heater core sprung a leak, waiting on catch can fittings, and a few things were ziptied out of the way for compressor housingless running.
https://cimg7.ibsrv.net/gimg/www.mia...aa1fa3471.jpeg

Here's the promised video. I had to use a rag it was so hot, prissy mechanic hands. I start by rocking up/down, end of the video I'm pushing in/out.


I'll also say I've done most of my driving lately at 18psi, which is a little north of 325hp. 30+ miles round trip commute to work, usually with multiple pulls to red line. RIP 6-speed.

It's enough oil that the BOV is coating my sway bar below it.

Pic and specs on drain?

Sadly don't have much that comes to mind that might help. I couldn't find any shaft play specs but I think you're justified in thinking if it's tight while cold you're probably fine. It's not much help, but from my reading of this guy it looks like the nominal behavior (under some load at least) would be boost blowing by into the cartridge and not the other way around: https://www.borgwarner.com/docs/defa...ining_book.pdf . That said if the oil accumulation is only at idle there would be an expectation of sooome oil leakage, but certainly not coating your sway bar amounts. Maybe there's thinning due to something like fuel contamination? How old is the oil/were you using a thicker weight previously? Only other thing that would come to mind is an oil drain restriction (or drain clocking angle so drain location is higher than bottom of the oil seal)?

https://cimg8.ibsrv.net/gimg/www.mia...aecbebd5c2.png
https://cimg9.ibsrv.net/gimg/www.mia...afe2848212.png
https://cimg6.ibsrv.net/gimg/www.mia...cca5eff48c.png

Ah, yes. It’s a -10 off of fullrace’s EFR adapter. I believe it’s 1/2npt, but I’ll get a pic

From your second link in the first post it seems that your drain is too small. I'm not sure why they tapped the oil drain in the cartridge but I think I read somewhere that if you use the tapered threads you absolutely have to use a scavenge pump. I bet fullrace adapter isn't any better...

https://www.miataturbo.net/diy-turbo...l-drain-93944/

There's the scavenge pump post.

I think AN on the drain is a hell of a lot more trouble than it's worth.

Good link deezums.

I’ve got a lathe, I can open up my adapter and/or the flange. Chra is easy enough to remove at this point

Pics of drain. line is -10, so .625 ID. The turbo drain is about .575" ID, the steel 3/8NPT to -10 adapter is much smaller, a little over .500" on the -10 side, and .400 on the NPT side. I have access to a lathe, I'll try opening it up and see if it has enough strength to tighten and seal properly. If not, I can weld a -10 bung to the aluminum adapter to skip the NPT portion.

https://cimg9.ibsrv.net/gimg/www.mia...359175ca6.jpeg
https://cimg0.ibsrv.net/gimg/www.mia...3ca635c72.jpeg
https://cimg1.ibsrv.net/gimg/www.mia...84e315cc2.jpeg

Yeah, those threaded adapters are known to be problematic. The pan side fitting looks like a 90 degree too, so that is not recommended. A welded flange fitting is my favorite way to go. I like to extend it enough to clear the compressor housing so I can get a wrench on it.

Edit: pic of 12AN


https://cimg5.ibsrv.net/gimg/www.mia...e6ef76e494.jpg

Location of 1/2NPT bung welded to pan requires a 90 to meet the turbo. I can extend down and maybe make it a 45/45 instead of 90/30 fitting.

That's a better drain than most have. Could be better but hard to believe that's the cause of your issue.

Nothing really stands out to me, but my guesses would be:
1. Excessive shaft play? I think mine too has a tiny bit when hot, but not much.
2. Excessive backpressure? I had to mod my breather on mine as I had way too much backpressure.

Clean looking setup, sir! Hope you get it figured out quick.

I agree with Pat, your drain does already look better than most. The observation that sticks with me is leaking at idle. If you had enough blow-by at idle to cause a problem, I would think it would launch the dipstick at 325hp. I think it would absolutely puke out that ex side port there too.

Did you confirm that you are clear of the pick-up tube where your pan fitting is?

Turbo seals may be the only other reasonable culprit.

Hard to think there would be enough blow-by or back pressure to cause serious oil accumulation with just ~10-15 min of idling? I mean it's not a labyrinth seal or anything, there will always be some leakage, but other than for cooling the ball bearings really don't need much oil to function (hence the tiny built in restrictor from what I can tell). From what I can logic, the difference between something like a 0.5" and 0.6" ID drain in terms of flow restriction should not matter significantly at the pressure/flow rate I'm guestimating BW designed for from reading their docs and the relative size of the supply restriction.

Is the oil pump boundary/shimmed? I know its a no-no according to BW, but two things to try would be a small (magnitude wise, so large orifice wise) restrictor on the oil feed and a test to verify overall flow rate (to make sure you're not reducing the cooling power significantly with the restrictor/see if it's excessive with the current setup). Would it be difficult to blank off the drain on the pan and idle the car (already warm) in the air with the turbo drain going into a small pail for a minute or two? Could measure vol & time to get an idea of what might be going on.

Well, I haven't posted here since I started a build thread way back when and then didn't update it ever, but that's usually how things go for me. A friend pointed me here after seeing some issues I was having with my own 6758 setup, so I thought I'd add in my own experience as another datapoint:

https://cimg5.ibsrv.net/gimg/www.mia...9c08a6d94c.jpg
I got my Kraken high mount manifold installed along with the 6758 from Turbokits and built all the plumbing. Decided to run a -6AN oil line via advice from the BW tech docs saying that runs over 18" should use that size line. Hooked up a drain with a Vibrant bolt-on -10AN flange to the CHRA and a welded-in -10AN bung on the pan.
From the first few days I was running it, I noticed oil collecting in the turbo intake (actually inside the plumbing to the air filter) and got concerned. Did a bunch of research while doing some light tuning and the oil persisted. The intercooler was also collecting oil.

https://cimg0.ibsrv.net/gimg/www.mia...319472ea28.jpghttps://cimg1.ibsrv.net/gimg/www.mia...7edea18609.jpghttps://cimg9.ibsrv.net/gimg/www.mia...6368a32eae.jpg

After reading a lot about oil drains and how critical they were, I decided to change from the Vibrant flange (which admittedly was a little on the small side) to the flange Kraken provided in their plumbing kit (welded pipe to a wide open flange bore). At the same time I switched from the braided line I'd been using to the Kraken-provided line, still into a 90-degree bend into the pan. I measured the diameter of the AN fitting, and it was .485", which seems to be large enough compared to other similar setups.
https://cimg5.ibsrv.net/gimg/www.mia...f51c51d4cb.jpg
I pulled the compressor housing and it had oil in it, but I didn't start and idle it without the compressor housing installed as earlier in this thread, so not sure if it was leaking at idle. I'd guess it may be acting similar though.
Since I had to pull the CHRA to swap over the flange, I took a look at the turbine. It didn't appear to me that there was any oil leakage from that side, but I'm not very experienced in the ways of turbos, so not sure if the dark soot in the sealing area is from oil or just rich burning that hasn't gotten hot enough to burn off.

https://cimg4.ibsrv.net/gimg/www.mia...bdd7c3d135.jpg
After changing my oil drain out, I still had the same amount of oil gathering in the air filter and also in the intake piping, and so decided that either the changes I'd made to the oil drain hadn't worked, or that wasn't the source of the issue.

I saw Ryan_G's build thread, in which he was having similar issues with an EFR leaking oil out of the compressor side: https://www.miataturbo.net/build-thr...5/#post1382850
I'm unsure if it was ever resolved, as I think the car ended up getting sold after the CHRA was rebuilt.

A couple days ago I resolved to try changing my oil feed out from -6AN to -4AN to act as a bit of a restrictor (without actually installing a restrictor) and I found that it actually worked somewhat.
Oil in the filter has been reduced to several drops instead of pouring out. There's still oil getting through though, which leads me to believe that it may still be over-oiled. The next option would be to put an even larger oil drain in, but I'm not sure about going to a 3/4" as Ryan_G had done in an effort to exhaust every available option. It seems extreme, but if it's what's required, then I'll pull the engine and put another hole in the pan.

More info not included in the saga above:
Running a BE VVT pump with 70 PSI shims
Current line routing Block -> BSP to NPT adapter -> NPT to -4AN adapter -> -4AN line (18" length) -> -4AN to Turbo adapter
My oil pressure gauge is out of the loop while I test this smaller line to see what effect it has.
Watching the oil pressures on the -6AN line, pressure would hit 60-80 PSI on cold start, but during warmup to running it would drop back down, and the turbo wouldn't be fed over 40 PSI warm.
I have some shaft play while cold, i can push the shaft around maybe 0.25 to 0.5mm, nothing much but just noticeable. I haven't tested while hot.
I have a genuine Mazda GTX PCV valve in there (from the dealer) and that's routed appropriately, and this is a fresh rebuild, so there shouldn't be much blowby, though it's possible.



The next steps for me are to test with a Turbosmart oil pressure regulator I have, and then move to a larger drain line. I have a feeling after seeing the pressures it was being fed with, the regulator would do little more than act as another restriction in the system and possibly provide lower flow (and may mask the actual issue by reducing oil flow). Drilling a bigger drain hole in the pan may help too, but that's a significant effort, especially at that size (I'd be worried about getting chips in the pan, so I'd probably pull the engine to do it).
I'm a bit hesitant on installing the regulator, as it's a drain-back regulator, and thus would require it's own oil feed-back into the pan. I have plans to do a temporary test setup using a replacement oil cap with a hole drilled/tapped to accommodate the return line.
Maybe I'll try pulling the PCV and running a vent for a short bit to see if that has any effect on the amount of oil to validate if there's crankcase issues as well. Thread a pressure sensor into the oil cap, even!

Interested to see that this issue has happened among a few turbos here, and curious if it's just a single problem or the result of several things (too much oil, too little drain, too much crankcase pressure) all coming together to cause this. I really don't know how much oil usually leaks from turbos, but seems like more than there should be.

Turbosmart OPR with a VVT actuator feed , restrictor, and -4 lines

https://cimg9.ibsrv.net/gimg/www.mia...0c32cb8802.jpg

That's really clever, using the VVT actuator and welding the opr flange to the valve cover. Much cleaner than how I did mine. I ran hardlines from the oil pressure switch and a softline to the pan. I wish I thought of doing it your way.

https://cimg2.ibsrv.net/gimg/www.mia...240dca5ba4.jpg
https://cimg3.ibsrv.net/gimg/www.mia...6a977c2fd7.jpg

I do have a -6 bung welded to the pan for a catch can drain, un used currently. Could easily use that for a opr return.

ted, that’s where I source my oil too, but I took the housing off/apart, and put a NPT tap into it, same thread pitch as BSPT, no need to drill it. Less fittings for you.

to be clear, I am not advocating for the OPR. I have several iterations on my design, early versions suffered from compressor side oil leaks, hence the giant in-manufacturer specification drain and the OPR. I also did quite a bit of work on the valve cover and actively monitor both crankcase pressure and turbo oil pressure. Suffice to say, I no longer have oil leaks from the turbo.

There are many builds out there that don't have reports of compressor side oil leaks, so I have to think the OPR is not necessary. I also don't know of any other -12 drains.

If you do decide to go OPR from the VVT actuator, I recommend a moderate restrictor, as it allows the VVT mechanism to get the stock oil pressures.

Honestly, my first step would be to get rid of the pan side 90 degree if possible and ditch the AN-NPT adapter flange (or bore to 0.5"). This assumes you confirmed that the pan drain port isn't blocked by the pick-up tube.

P.S. you don't want the stuff that comes out of a catch can going back to the sump anyway, it is very polluted.

PPS (Edit) - The fittings at the actuator facilitate the restrictor

For sure, I opened up the NPT portion of the adapter today, took the ID from .400" to .490". Sounds small, but that's almost a 50% gain in area. It was free and fairly easy, I'll give that a try before anything else drastic. And to clarify on the pan fitting, it was meant for an AOS drain back before I got a free radium catch can from a friend.

The -10 fitting at the pan was a 90* fitting, I opened it up a bit, and I haven't leaked any oil from the car sitting with the line off, so it's well above the oil level. The 1/2NPT bung was welded at a very slight upwards angle

I have fuel and oil pressure sensors wired into the MS, I could easily repopulate one for some sort of crank case pressure monitor temporarily, I had already thought of doing that when this issue popped up. Can you explain your tests any more and what you found? Although, looking back, I see the sensor on your valve cover now.

On the first iteration of the design, I was working on an un-opened stock block. With a M45 at ~170 uncorrected whp I would see 1-2psi at WOT. When I went with the compound V1 on that block those numbers jumped to 2-5psi and oil came out of everywhere on the motor, including the turbo seals (225wph uncorrected). A turbo rebuild did not fix the issue. The VC was modified for improved flow and the crankcase pressures dropped to 2-3psi, but the turbo and RMS still leaked. For the V2 I used a fresh built block with the hooks shown in the images above. The output from the CAMcover sensor is periodically monitored for changes in average pressure over the entire operational range as a motor health check. Maximum pressures don't exceed 1.5psi. 400whp/400wtq corrected. No Leaks. I have seen a change in ~0.5psi average over the operational range (800-7250 RPM, 12kpa - 265kpa) from the 0-mile motor to now, 24+ months down the road (mileage not tracked, DD when convenient and weather conditions allow).

I think as a diagnostic tool the crankcase sensor adds value, not sure it adds enough value to go as far with it as I did. As a spot check, if there are concerns, crankcase pressure can be really informative.

Took an hour to reinstall my supercore with the enlarged drain adapter, I’ll drive it for a few days to see if it looks better. If not, I’ll install a 1/8npt bung on the valve cover, and monitor that for a pull or two. If that checks out, I’ll try a welded drain with at least .600” ID.
https://cimg0.ibsrv.net/gimg/www.mia...2d2538ebc.jpeg

This is the drain fitting I used on mine to avoid the 'to-AN' adaptor at the turbo:

https://franklinperformance.nz/colle...n-adaptor-38mm

@curly did that fix the issue? I’m looking at going with an EFR turbo and just want to plan ahead if I need a big bunghole.

I still seem to be getting oil out of my downward facing BOV, I need to pull all my piping, properly clean the them and the intercooler (bumper off for me), to really know if it fixed it. So I won’t really have an answer until I’m no longer lazy.

I believe the question of whether or not you should err on the side of ‘large’ for the drain on an EFR is settled.

Make sure your crank case ventilation is also adequate.

Still working on this. Dealt with it for the rest of 2022, but in 2023 I started having random couplers blow off, 2 or 3 of them, seemingly all related to too much oil in the system. Between a full time job, racing other miatas and BMWs, and 3 busy kids, the car doesn't get driven too much.

Tore it down end of 2023 and ordered a new 6758. Cleaned the intercooler, piping, welded the old BOV port shut, cut the radiator brackets some that were digging into my couplers, and a couple other random project. Radium split flow ethanol sensor, fuel pump hanger, blah blah. And after all that....still no new EFR. While I was waiting on the next batch with the rest of the internet, I decided I'd put it all back together and do some testing on the dyno, which finally happened today.

I drilled and tapped a random oil fill cap for 1/8, and screwed in our dyno's MAP sensor. I did about 10 pulls, but below is an example of three, at about 300, 320, and 330hp, just increasing boost pressure and seeing how the crankcase pressure reacts.

Saw about .4psi at 300hp, creeping up to half a psi, and a noticeable increase by a tenth or so at 330hp, graph below.

Is this enough to cause oil drain issues? Maybe. It's a -14-45psi MAP sensor, so it's not the most accurate at these pressures, but its pretty clear that it's connected to boost pressure.

In other new, the new 6758 showed up, and now I'm even more unsure as to whether or not I actually have a turbo issue.

SCIENCE!
https://cimg5.ibsrv.net/gimg/www.mia...d67464b58a.png

For reference, valve cover is completely stock, the exhaust side is open and never had any oil in it, PCV side has a 323 valve, and is 3/8 hose to a Radium catch can, then 3/8 hose to intake manifold with one of Radium's check valves in line.

Oof, sorry you are going through this man... so frustrating

You are certain that "new" oil is making into the piping as opposed to old oil moving around?

I didn't go back through the entire thread, but did you confirm the passage into the pan didn't have a blockage by the windage or the pickup tube?

0.5 psi sounds reasonable to me. You can/will pull vac if you route the hotside to the turbo intake through an air/oil separator.

Guess I hadn’t thought about that, pcv side for vacuum off throttle, intake side for vacuum while in boost. I also don’t think .5psi is out of the ordinary, if it was 1+psi I was going to leave the turbo on and work on block venting. But it’s right in the area where I’m unsure what to do.

Here is a 20psi pull showing ~-5kpa at 6800RPM. Moroso AOS, large K&N, all the VC things.

https://cimg6.ibsrv.net/gimg/www.mia...175f88a2c3.jpg

I will be the dissenting voice and say that half a pound of pressure in a crankcase that is designed to be at atmospheric pressure is a problem.

EFRs HATE centerhousing backpressure according to the BW expert we dealt with on RyanG's issues.

I do not use an EFR. However, at 300whp it was beneficial to use much larger fittings and hoses from both sides of the valve cover to a vented catch can, open interior passages, and add some mesh material to collect the oil vapor out of the gasses.

I opened my catch can drain yesterday which was not drained since MATG and there was only a few drops of water inside. Track days yield similar results now.

I think I'll swap to two of these:
https://www.radiumauto.com/10AN-Male...d-In-P940.aspx
Especially since i have a spare valve cover to mess with. I've got a TIG welder and lathe at work to make these fit it. Current ID of the exhaust side is .315", so .500" is a small increase, but at .5psi, that may be all I need.

Rewatching your video from 2021, and having checked my own EFR turbo since my last post, your turbo has probably 3 or 4x the amount of radial play mine does. I'd say now, you have a turbo problem causing the oiling.

Also, I've measured backpressure on my setup in the past as I was blowing my dipstick out. Mine was in the 1.5-2.0 psi range of crankcase pressure at either 30 or 40 psi boost. I just crimped the dipstick tube to pinch the dipstick so it wouldn't pop up under boost.

But still, I don't have oil coming out of my turbo at all. My drain is 3/4" hose and fittings I think, but it could be 5/8".

That said, less crankcase pressure is better, and I've since changed my setup to lower crankcase backpressure, but haven't measured it since.

Oh dang, I forgot I posted that, thank you Pat! I can compare that to what it's at currently, and to the new turbo. And I'll probably still add the -10 vents.

I ended up moving everything to -12 plumbing on the drain side and adding a Turbosmart drainless OPR. The -10 fittings and adapters I was using necked down to 0.46" at points I could measure. A tap drill for a 3/8NPT is .57" (drain port size, and minimum ID called for in the EFR manual for gravity drain). It took some time for me to find a drain adapter that had a 1/2NPT oil drain port adapter to put a -12 barb in. Now my minimum drain ID is 0.56" Still a little under 0.57", but there isn't any more oil on the compressor side.

Oil drain port adapater: Oil Drain Flange for EFR GT25 GT28 GT30 and GT35 w/ O-Ring Seal - AGP Turbo

Yeah that’s one step I can take. I’ll try plumbing the valve cover port first. I’ve optimized my -10 drain ID as much as I dare, I think the measurements are somewhere in this thread.

I did whip the compressor housing off yesterday, and up/down play on the compressor wheel is near zero, so the play in the video I posted way earlier probably only happens when hot.

Turned down a random -6 bung and had my co-worker weld it to my intake elbow. Ran a small piece of 3/8" line from valve cover to intake, and did some testing.

https://cimg0.ibsrv.net/gimg/www.mia...67c9b65da.jpeg


I don't have a picture of the dyno graph, but I logged the same MAP sensor placement in the oil cap, and instead of rising to ~.5psi, it went into vacuum, to a little over -.5psi, so it's definitely working!

I've put a little over 40 miles plus a half dozen 5th gear dyno pulls, including two 2nd thru 6th gear pulls, and the intake is still bone dry, I'm not calling it solved until I put more miles on it, but in the past, that's enough to get some oil in the intake. So there may be a NIB 6758 for sale soon!

Edit: proof of dry intake. All the weld seams and coupler used to collect oil fairly quickly
https://cimg4.ibsrv.net/gimg/www.mia...55934c752.jpeg

And yet some tool-box troll neg catted me on this very suggestion above.

Hope your favorable results continue!

I always assume my neg cats were simply a mis-key.

Next step is -10 on VC and intake, and maybe optimize PCV side with Radium valve and again -10 hoses. Will probably combine that with a powder coated valve cover, so it's a larger project I don't wanna undertake right now, since it seems to be working now.

Look into that AOS for the hot side. I don't get a lot over there, but I do get some.

Yeah, that's on my short list. I have Radium's giant catch can on the intake side, barely catches anything. I'd like to swap that out for two of the smaller ones, one for intake side, one for exhaust side. Just need to get them purchased.

I think I'm going to try that AOS for the hot side. I recently rebuilt and have been having my catch can fill up like crazy on track. Previous motor build was basically dry after 3 months. Haven't changed the breather system at all. Stepped the oil drain from kinked -10 AN to new bung and -12 AN.

Repurposing the old 3 bar MAP sensor to measure crankcase pressure and will hopefully have some data tonight once it's wired in

So I am in the same boat in terms of oil pooling in the compressor housing and intake tubes. I do already have -10 an lines from the valve cover to a VTA catch can. If I am understanding this correctly, you used this setup, at least for the turbo side, to help? if so, should I keep my PCV side vented to atmosphere via the breather can used in my current setup and run the turbo side the way the picture is showing to see if that helps?


https://cimg5.ibsrv.net/gimg/www.mia...97572c6e77.png

Yes, that's what I did. Again, very preliminary results, only ~40 miles and a dozen or so dyno pulls. Just spent all weekend at Sonoma, didn't get a chance to put any additional miles on it.

Someone asked for a picture of my current setup, here it is. Exhaust side will eventually get a small radium catch can. The new ones have built in check valves, I'll probably end using one on each side.
https://cimg0.ibsrv.net/gimg/www.mia...d13a4664d.jpeg

Wow interesting, so relieving crankcase pressure solved your problem with oil getting past the seals.. As someone else said maybe the EFR's don't like any crankcase pressure.

Does that crankcase line from the valve cover to intake pipe have an AOS at all? My concern would be over time it would pull vapors into the intake tract from the crankcase but if it's working that's awesome. I've had discussions with folks where people swear the crankcase needs vacuum on it vs just letting it vent to atmosphere but depending on the car and setup (like on a track car), I'm always worried about oil getting into the intake tract from the crankcase. I know another old school way is a slash cut tube in the exhaust pipe to the crankcase but I'm sure that'd get smelly/messy.

As I've said multiple times, my plan is to add a catch can eventually. Yes, it could suck in oil, but nothing so far, both raw oil from turbine seals, or oil vapor from crankcase.

I’m fairly late to this conversation but I have been following it while trying to rack my brains around my EFR oil issues. I hope that I can add little to someone’s else’s journey!

Quick back story back in 2020 I restored a 1998 NB with the vision of dropping most off my boosted set up from my previous NBFL. Upgrading to a forged engine and EFR setup.

Pretty much since day one after the initial break in and dyno I started to notice oil in the air filter also intercooler/pipework.

First fix, I opened up the drain full bore from the turbo outlet to sump with a continuous fall.

Second fix, drilled out the rocker cover on the hot side similar to how SPS motorsport advise in higher HP applications and fitted 2x 3/4” bore breathers to atmosphere. The cold side is also vented to atmosphere AN8.

Third fix, fitted a Turbosmart V1 OPR.

Fourth fix, utilised a breather on the block i pre drilled during my second rebuild. AN8 hose line to a catch can vented atmosphere.

Fifth fix, fitted an additional oil restrictor (1.8mm).

All of these mods helped the issue but none of them have completely solved it.

I am pretty sure the engine isn’t creating excessive blow by I have done a leak down test in the past along with compression tests. I even rebuilt the engine again (rings, shells, machine shop rehoned, another crank all balanced and new boundary oil pump) after a bad set of injectors from the initial build diluted the fuel somewhat coupled with the extra oil from the BW it wasn’t 💯 so couldn’t rule it out. Still running well but I took the plunge again 😂 I upgraded to ID1050s and replaced the CHRA for the ally version. Again after this it was run in and dynoed with a professional made 352bp at
15psi but the problem persisted!

On reflection;
The greatest fix being the oil restrictor (which I tried to avoid all along as per BW manual)
Nearly stopped the oil leakage but over time it has reappeared slightly and Im still not happy to hit the track!

https://cimg6.ibsrv.net/gimg/www.mia...4f6df2abb.jpeg
https://cimg8.ibsrv.net/gimg/www.mia...d09e5459e.jpeg
https://cimg9.ibsrv.net/gimg/www.mia...59d78aeca.jpeg



@curly I am relieved for you to see your problems have ceased! I am going to try a similar solution just deciding whether to attach the block breather to inlet filter via the catch can. Or bung that and use the hot side via catch can.

I really hope this solves it as this car has been a pain in the arse compared to the first which was beaten hard for 5 years. The original engine still sits there taunting me 🤣

Very clean engine bay. My thought is while 0 crankcase pressure is good, crankcase vacuum is better. In order to create that vacuum, you'll have to plug all but two of your vents. Under boost, my PVC side is check valved closed.

If it's of any value, I have a "catch can" of sorts between my valve cover and turbo intake fitting and have never accumulated much of anything in it.
The stainless mesh medium is even mostly dry.
There are some details in post #103 in my build thread. (from 2016... what happened to the years?)