BNR s4 smoking/bad turbo?

So, I’ve recently upgraded my Speed3 with the BNRs4, along with JMF manifold, CNT exhaust manifold, DM 3.5” intake, FMIC, has a Tial BOV, and the rest of the supporting modifications.

Turbo has less than 1500 miles. Compression test and cylinder leak test were performed approx 2 weeks ago, results for compressions were 210, 190, 210, 185 left to right. Cylinder leak down was all green.

Additionally, performed at combustion leak test (3x) and it passed.

Attached is a photo of the bottom of the turbo and a video of the car at idle. The smoke is rough and gets worse after the car starts to move. While driving it’s not apparent or as noticeable. Only at idle and first acceleration.

https://youtube.com/shorts/pBY0HFEd7YQ?si=yAbjkt3IGLzVVVd8

Video is of the car at idle.

What do you guys think? Brand new turbo purchased less than 2 months ago, less than 1500 miles.

Thank you all, happy holidays and happy new year!

-Kas

 

Who's your tuner?
What, exactly, changed just before the smoking started?

 

Will @ Purple Drank.

Nothing has changed, no new modifications since the turbo went in. I’ve changed the oil, found a couple vacuum leaks(MAF o-ring, pcv connection), but the ONLY thing that has been done since the turbo went in is tuning, no further modifications have been made or done since.

Modifications same day as turbo:
JmF manifold
Replace KR sensor
Replace thermostat
Replace temperature sensor
DM intake
Exhaust manifold gasket
3 Bar MAP sensor
Vacuum lines to JmF manifold
51r battery and box
Cobb EBCS

Everything else was done prior to and I had the K04, I was chasing a KR issue but found several items were lose. Engine compression and cylinder test were always good which lead to think something was loose.

Note: first couple tuning revisions there was no KR so that issue was revolved. Car was running very well, until the smoking started.

 

The presence of oil suggests that you might have some blowby issues. I suggest capping all vacuum ports related to PCV and seeing how much flow is coming out at idle; if it's a ton, you probably have ringland issues.

Also please define combustion leak test; if that's not the same as a "leakdown" test, I suggest running the leakdown test too.

 

Combustion leak test is the test to check to see if there is combustion gases in the coolant reservoir tank. Testing to see if there was a head gasket failure. The fluid was blue at start and blue at the end. Did not change colors.

The last time I did a cylinder leak down test, all four cylinders were in the “green” portion of the tester. I don’t recall the percentages. This was about 2 months ago.

I’ll be back at the shop tomorrow, you said block all ports related to PCV? So temporarily remove the OCC from the system?

 

That's what I figured you meant, but wanted to make sure. These cars rarely have head gasket failures, especially on stock turbo or sub-500WHP.

Alot can change in 2 months. Did you have a prior tuner before Will and the big turbo?

You can leave the OCC in play if it isn't VTA, but you want all the crankcase gasses to come out of one hose so you can get an idea of how much blowby you have. Vice-grips to pinch closed some of the other hoses is fine, as is capping them. You don't want any gasses going into the intake or intake manifold, though.

 

No, I had acquired the car and it was tuned by Freektune. I had reached out via email and Facebook to get any information about the car, but never got a response. The previous owner was, well, I’ll be nice..he didn’t know much about it. So, my first actions were compression, cylinder leak down, oil change, coolant flush, transmission fluid change. I worked it up and down, in addition to the fuel injectors, new seals, sensors, etc. I had to piece together everything but was very thorough with the car. Had some help and insight from [mention]Raider [/mention]who happens to be local.

I only have one OCC. goes from PCV valve (new as October 2023) to the occ (it is vented) and then back to the intake manifold (with a check valve between the can and manifold)

I’ll try and get another cylinder leak down done tomorrow when I am back at the shop just to confirm. But, my compression results from just last week or so, if there was a ringland issue, wouldn’t that show on the compression or not so much?

By the way, haven’t said it yet, but thank you [mention]Enki [/mention] for your help and support.

 

IIRC, compression and leakdown don't actually check the same things. Leakdown should be your absolute source of truth regarding engine health, if memory serves.

There might be other reasons besides ringland issues, but between that and simply too much oil going to the turbo (does the S4 require a restrictor?), there's not much else I can think of. The blowby at idle test is something relatively simple and quick to check and has bit me in the ass troubleshooting wise in the past.

Example:
Shit like this is bad:
https://www.youtube.com/shorts/QelaFZHM1Kw

Do *NOT* test it this way on a first gen car unless you run a second gen valve cover and/or have an upgraded oil block plate mounted to the valve cover. If you remove the oil cap and can see chain, you don't have this. Failure to abide will result in your oil being flung up on the hood of your car.

 

I ran the same oil restrictor bolt that I had bought for the K04 when I acquired the car, just used new crush washers that were provided with the s4.

Additionally, I’ll get my TDC kit before I head out tomorrow and do a cylinder leak down test tomorrow and post the results for you, just to rule that out or be devastated and disappointed.

Also, can you run me through exactly what you meant for the blow by test at idle? Just slightly confused on how to perform that once if there’s no vacuum from the intake?

Noted! I do not have a gen 2 valve cover, yet. I want to get one but I need to get this all under control first.

 

OP you say cylinder leak down was all green but what were the actual percentages of leak down.

The reason I ask is I was in the green also on a known good Snap On leak down tester. If I recall correctly 30% was still in the green. However 25%-30% leak down is not a good result at all.

@Enki I would agree with you on the statement that leak down is a better indicator of overall engine health. I had great compression results but my leak down was for shit.

OP I had 142,000 on my OEM motor and I was using a qt every 500 miles. No smoke out the exhaust that I could see beyond what's fairly normal at WOT. I had clogged oil control rings and worn valve guides.

 

Basically just make sure the valve cover outlet, oil fill cap and pcv port on the intake / intake mani are blocked off. You want the only place that gasses can escape the crankcase to be the PCV port on the side of the block (the one on the valve cover is pretty restrictive).



Also, the vented OCC might be hurting you here unless it also has a checkvalve built into the vent.

 

Rgr. I will do just that. Additionally, there is a check valve in the VTA line before the filter. I made sure of that as not to introduce a vacuum leak. Only excess crank pressure exits, nothing is pulled in. How should I guesstimate the amount coming from the PCV? Video and post?

[mention]Mtnbker3531 [/mention] I don’t recall, I apologize. But I will be doing the test again tomorrow hopefully before my time’s up and I leave town for holiday. I will post my results and findings, however good or bad.

 

If you can blow lines of coke off a mirror, it's not great. No flow at all is preferred, but unrealistic. SOMETHING will be coming out, just hope it's not as bad as in the video I posted earlier.

 

Noted! [emoji1787][emoji23]single best response to-date. Thank you for the laugh. I’ll be in touch!

 

The bnr does not need an oil restrictor bolt and neither does the stock ko4

 

Wonder if seals are gone on turbo from oil starvation with the restrictor bolt? Although I know people put them in frequently because they use them as a bandaid on the k04...you know when they really just needed to fix their crank case pressures issues.

Oil on the bottom of turbo could be a bad drain or feed line connection too

 

Surely hope not because that would void the warranty and when I last spoke with Brian a while back about the turbo, I had told him I had a restrictor bolt from DM on it and he said it was fine.

 

So on the note of oil restrictor bolts and such....



You might find that interesting. Not saying that's the cause of your issues.

When you had the intake manifold off did you see any evidence of oil in the manifold?

 

No sir. The OE manifold was relatively clean from what I can remember. I’m currently at the shop doing some work. I have the intake pipe off and the inlet side of the turbo is dry and clean. No sign of oil.

 

When I bought a S3 they recommended a oil line/filter.
https://bnrsupercars.wpcomstaging.com/mazdaspeed-36-custom-oil-supply-line-built-engines-only/
I had a problem with a small oil leak from the turbo area hotside housing flange bolts.
I called to ask if I could add a restriction on oil line.
Here's the response from BNR.

"Sorry for the long delay on the reply. Best to call! I wouldn't go any less than .075". Id also check the crank case ventilation and make sure that CC is getting as much vacuum as possible"

Bryan Nickell
Owner of BNR Supercars LLC
(205)640-1193
www.BNRsupercars.com

Here's where I bought my filter set up. I just bought a brass AN fitting and drilled a 0.125 hole.
https://www.graveyardperformance.co...83802&pr_ref_pid=4185569853476&pr_seq=uniform