When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
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.
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.
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!
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.
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.
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.
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.
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
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.
09-28-2021, 11:59 AM
0
