Addressing N5x oiling and spun rod bearings (Accusump installed)

[Asbjorn]

So the M2 has the solution of the "dual oil pump" system with a baffle. One feeding the other. Great solution.

For the N54 actually i figured ppl sharing only the VAC baffle option.

What i cannot find and am planning to do somehow is to check the bolt pattern from the N55 Oil Pan and the N55 Bead Plate.

It may be a bigger DIY project but connecting the second oil pump to the n54 primary pump should be doable. Maybe even the M2 solution fits to the N54 bead plate?

The M2 Oil Pan has everything needed for that and with some hole adjustments it should be possible to fit the Pan to the N54.

Has anyone ever compared these component against each other?

S55:

N55:

What we know

• N55 features lower overall oil pressure compared to the N54. And unlike the N54, the N55 measures the oil pressure and runs an oil pump with flow control. The S55 oil pump is similar but flows up to 18% more than the N55. The pickup design is also quite different between N54, N55 and S55.
• Dips in oil pressure happen more frequently on N55 (non M), ie both on right and left hand turns, and the dips seem to be deeper than N54 (ie sometimes below idle pressure). N54 seems to only have a problem with left hand turns according to the data I have shared. This data has yet to be confirmed by others though.
• The VAC baffle does not seem to help at all. My baffle doesn't seem to work, and we have at least one case of a spun rod bearing on a car running the baffle.
• No track data has been provided from N55 M or S55 engines in here, but BMW says they can handle G forces of up to 1.4g depending on oil amount used. As you described, M has solved the N54/N55 problem by returning oil from the front of the pan with a pump and added a baffle. I have tried to copy this solution, but my results are not great. Either my electric pump doesn't flow enough oil, or the baffle doesn't support the oil pickup location well enough.
• Finally, AFAIK we are not aware of any cases of turbos failing due oil not being able flow back from the turbos, but the M versions have pumps that help extract oil from the turbos.

N54 and n55 share the same oil pan IRC. The one issue though is the m2 uses an electronic power steering pump whereas the n54 and e-n55 use a hydraulic power steering pump which mounts on the oil pan.

I know a Z4 or two that might disagree with this statement.

Overall I am pretty glad I traded in my m235i for my m2, alot less headaches to deal with when building it for the track.

Nope you're incorrect, I just checked and the oil level sensor itself is the same P/N as used on all the S55 and N55 motors: https://www.realoem.com/bmw/enUS/pa..._GTS&mg=11&sg=10&diagId=11_5919&q=12618638755

It is the oil pan that is different:

RealOEM.com - Part Search

Yes I stand corrected. If the sensor is the same, maybe they modified the oil pan so that the position of the sensor in the sump is raised?

Fun fact: The GT4 S55 uses a dip stick instead.

 

[F87Source]

S55:

View attachment 34121

N55:

View attachment 34120


What we know

• N55 features lower overall oil pressure compared to the N54. And unlike the N54, the N55 measures the oil pressure and runs an oil pump with flow control. The S55 oil pump is similar but flows up to 18% more than the N55. The pickup design is also quite different between N54, N55 and S55.
• Dips in oil pressure happen more frequently on N55 (non M), ie both on right and left hand turns, and the dips seem to be deeper than N54 (ie sometimes below idle pressure). N54 seems to only have a problem with left hand turns according to the data I have shared. This data has yet to be confirmed by others though.
• The VAC baffle does not seem to help at all. My baffle doesn't seem to work, and we have at least one case of a spun rod bearing on a car running the baffle.
• No track data has been provided from N55 M or S55 engines in here, but BMW says they can handle G forces of up to 1.4g depending on oil amount used. As you described, M has solved the N54/N55 problem by returning oil from the front of the pan with a pump and added a baffle. I have tried to copy this solution, but my results are not great. Either my electric pump doesn't flow enough oil, or the baffle doesn't support the oil pickup location well enough.
• Finally, AFAIK we are not aware of any cases of turbos failing due oil not being able flow back from the turbos, but the M versions have pumps that help extract oil from the turbos.

I know a Z4 or two that might disagree with this statement.



View attachment 34119



Yes I stand corrected. If the sensor is the same, maybe they modified the oil pan so that the position of the sensor in the sump is raised?

View attachment 34118

Fun fact: The GT4 S55 uses a dip stick instead.

Real oem could be wrong, I've seen mistakes on it before.

However I have also seen on eBay an image of the CS/GTS oil pan and it does indeed have a different p/n stamped into it, so it means the pan is different. Whether that means the pan is physically larger or a different mounting hole is used to position the sensor higher, remains unconfirmed until someone with a gts pan measures.

 

[Bnks334]

The only areas where n55 oil pressure is lower is in the midrange. The n55 engine pdf has a comparison of how the oil control valve works vs n54. I think you might see much higher pressure because of the location of your sensor? It's roughly 40psi at idle and 70psi under load for the n55. Not low by any means amd I thought we established that people had posted very similar numbers for the n54 in the past when using the stock sensor location.

I cant speak for all chassis but for the 135i the n54 and n55 pan are the same. I was referring to the m2/m235i oil pan being fitted to an n55 or n54 135i. Cant speak on a z4 as the car is different in a lot of ways including the subframe, right? More to it than just the bolt pattern.

N54 oil pickup tube sits in the same spot as the n55. Just slight variances in the pickup tube diameter and style. I cant see that changing much of anything to say one car sees different oil pressure drops than another and that the pickup has anything to do with it. But now were getting chassis specific with the z4 vs 135i thing so maybe you're talking about a z4 difference in the pan? Not something I care to catalog every little detail of for every single chassis. Fact of the matter is the pan sucks on all these cars lol

If you could fit a m4 pan with more capacity from the s55 then that would be great. S55 is supposed to share the same block with the n55 according to the BMW pdf. Maybe that's reading it too literally though and they only meant it's based off it because we do know it's closed deck so it's not actually the same exact block.

This is kind of chasing your tail too since an s55 oil pan and the whole oil pump setup is rare to come across and expensive! It's not exactly a feasible solution and just about any actual sanctioned "race" event would probably prohibit the swap. The fact that it might have a larger oil pump is kind of moot too, right? The n54 and n55 oil pumps are not a bottleneck. They can provide much higher volume than bypass pressure. N55 in emergency mode produces 60psi at idle and 100psi+ under load. The overhead is there. More volume and or oil pressure does not really solve anything. Too much oil pressure can be just as bad as too little.

So where does that leave us? Aftermarket oil pans with deeper sumps? Longer pickup tubes to match? Mimic the s55 setup like being done above? Better baffles? I'm sticking with the accusump for now and I'll probably replace my rod bearings at the 2 year mark as preventative maintenace like they do on the s65 and s85 engines. Not holding my breadth we'll ever get any aftermarket solutions outside of maybe a one off product with a small group run at a high expense.

 

[F87Source]

Yeah it's unfortunate BMWs get so little aftermarket support for track racing guys, it's due to our community being so small to begin with and most of that community only cares about straight line performance, even though BMWs are motor sports orientated cars not really drag orientated.


On a side note, for those that want to retro fit the 1.4 g capable increased volume sump make sure you get the GTS/CS version otherwise you'll just get the standard s55 sump which is only capable of 1.2 g. This makes it even harder to find because GTS/CS models are even rarer, albeit there is one on eBay right now but the caviot is that it's $700 and has a huge gaping hole in it from damage to the vehicle underside. So if anyone is brave enough to buy and repair it and install it that would be awesome to see the diy, and maybe even dimesions of the pan too.

 

[Bnks334]

Yeah it's unfortunate BMWs get so little aftermarket support for track racing guys, it's due to our community being so small to begin with and most of that community only cares about straight line performance, even though BMWs are motor sports orientated cars not really drag orientated.


On a side note, for those that want to retro fit the 1.4 g capable increased volume sump make sure you get the GTS/CS version otherwise you'll just get the standard s55 sump which is only capable of 1.2 g. This makes it even harder to find because GTS/CS models are even rarer, albeit there is one on eBay right now but the caviot is that it's $700 and has a huge gaping hole in it from damage to the vehicle underside. So if anyone is brave enough to buy and repair it and install it that would be awesome to see the diy, and maybe even dimesions of the pan too.

I was watching an hptuners webcast and they were talking about frs or BRZ race cars over in Australia running the moving oil pickup tube. I thought it wasnt really feasible to do something like that but apparently those cars suffer from oil starvation too and the moving pickup was a solution that kept the car within the street class rule set. Accusump on top as a safety net. Who can design us a moving pickup lol? At an affordable price too of course. Oil sloshes and the pickup tube moves with it. That doesnt really solve the braking and turning issue though if that's what happens.

 

[F87Source]

I was watching an hptuners webcast and they were talking about frs or BRZ race cars over in Australia running the moving oil pickup tube. I thought it wasnt really feasible to do something like that but apparently those cars suffer from oil starvation too and the moving pickup was a solution that kept the car within the street class rule set. Accusump on top as a safety net. Who can design us a moving pickup lol? At an affordable price too of course. Oil sloshes and the pickup tube moves with it. That doesnt really solve the braking and turning issue though if that's what happens.

Interesting, Australia imo has been leading the performance sector for all Japanese cars because folks down there don't mind spending money on good parts, wheras here in North America all I hear is "max performance" for as little money as possible and people going for power mods before supporting mods.... People even don't want to get protunes here, that's how cheap they are.

 

[Bnks334]

Interesting, Australia imo has been leading the performance sector for all Japanese cars because folks down there don't mind spending money on good parts, wheras here in North America all I hear is "max performance" for as little money as possible and people going for power mods before supporting mods.... People even don't want to get protunes here, that's how cheap they are.

I dont know if the race team actually marketed the pickup tube. I cant find a link. It was a webinar about oiling.

Here is another one they did recently. So much in there and it's almost like its paraphrased from some of the stuff said in this thread lol they have experience dealing with issues like this on almost every popular tuning engine. It's not an "n5x" thing by any means.

227 | Improving oil supply

Lubrication related failures are one of the leading causes of engine failures, particularly in engines that are making more power and revving higher than the stock rpm limit. In this webinar we’ll cover some subtle changes that we can make during the engine building process that can pay big...

www.hpacademy.com

 

[F87Source]

I dont know if the race team actually marketed the pickup tube. I cant find a link. It was a webinar about oiling.

Here is another one they did recently. So much in there and it's almost like its paraphrased from some of the stuff said in this thread lol they have experience dealing with issues like this on almost every popular tuning engine. It's not an "n5x" thing by any means.

227 | Improving oil supply

Lubrication related failures are one of the leading causes of engine failures, particularly in engines that are making more power and revving higher than the stock rpm limit. In this webinar we’ll cover some subtle changes that we can make during the engine building process that can pay big...

www.hpacademy.com

If someone made an oil windage tray for the n5x motors, and I mean a really good one that doesn't let oil splash up and hit the crank like killerbee does for the sti then we can probably get away with putting in another 500 mL of oil like the m4 gts allowing an increase in the amount of G force the car can take. But like you said no one is willing to invest any kind of money into these cars especially since they're getting old now and the fact that every one in the BMW community only wants to go fast.


There maybe some hope in Europe though, those guys over there still build BMWs for track usage and their aftermarket still cares about building parts to support that type of driving. However their parts cost a lot of money and since so few companies are working on parts development is slow, low amount of interest also inhibit product development.

 

[Bnks334]

If someone made an oil windage tray for the n5x motors, and I mean a really good one that doesn't let oil splash up and hit the crank like killerbee does for the sti then we can probably get away with putting in another 500 mL of oil like the m4 gts allowing an increase in the amount of G force the car can take. But like you said no one is willing to invest any kind of money into these cars especially since they're getting old now and the fact that every one in the BMW community only wants to go fast.

There maybe some hope in Europe though, those guys over there still build BMWs for track usage and their aftermarket still cares about building parts to support that type of driving. However their parts cost a lot of money and since so few companies are working on parts development is slow, low amount of interest also inhibit product development.

I wasnt inferring people are unwilling to spend money lol I was thinking more along the lines of a lack of knowledgeable people who have the means and experience to developed some of this stuff for market rather than say for their dedicated race car (like Turner). I cant imagine it's really all that hard to "develop" a 1/2" deeper oil pan. Give me access to the software and connections to some manufacturers lol

We do get a little trickle down from people like VAC, bimmerworld, and Turner. Prices should also be reasonable though and they almost never are.

Look up some of the costs for the parts you're talking about. Killer B specifically charges pretty reasonable prices. $500 for deeper oil pans with integrated baffles. $100 for upgraded pickup tubes. Look at the pricing on moreso oil pans.. $100-500 for just about any car you can think of lol this is hot soemthing that would (or should) cost a fortune... Someone comes out with something like this for an n5x and it's going to be $1500 and it will be crap to boot lol so yeah I think there is a lot of hate on "cheap people" for absolutely no reason when they are just pointing out what is actually much more reaosnable most of the time.

 

[Asbjorn]

Just wanted to add another data point below.

Went to the track with @CNM135i today to collect some data from his M135 running stg0, cup2 tires and 0w40 on the same track I did my data. We were not able to spot a single instance of oil pressure dropping below 50psi during right hand turns pulling up to 1 lateral G. However it did drop below 30psi during the same left hand turn that my car struggles with, and on top of that the oil pressure would also drop below 30psi consistently when braking hard in a straight line.

I correlated the MHD log with data from my AiM GPS also sitting in the car:

In below log, braking hits almost 1 longitudinal G for half a second, then the car turns left, pulling 1 lateral G for 3 seconds. Oil pressure drops below 30psi.

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In this log oil pressure goes below 30psi while braking hard pulling 1 longitudinal G for almost 2s in a straight line.

datazap.me | Asbjoern | M135i at GIC

datazap.me

 

[Bnks334]

Just wanted to add another data point below.

Went to the track with @CNM135i today to collect some data from his M135 running stg0, cup2 tires and 0w40 on the same track I did my data. We were not able to spot a single instance of oil pressure dropping below 50psi during right hand turns pulling up to 1 lateral G. However it did drop below 30psi during the same left hand turn that my car struggles with, and on top of that the oil pressure would also drop below 30psi consistently when braking hard in a straight line.

I correlated the MHD log with data from my AiM GPS also sitting in the car:

In below log, braking hits almost 1 longitudinal G for half a second, then the car turns left, pulling 1 lateral G for 3 seconds. Oil pressure drops below 30psi.

Hide legend Reset zoom

In this log oil pressure goes below 30psi while braking hard pulling 1 longitudinal G for almost 2s in a straight line.

datazap.me | Asbjoern | M135i at GIC

datazap.me

M135i is an n55, right?

Being down to 20psi is below even normal idle pressure of about 38psi. Could some of the pressure drop we are seeing also be related to the response of the oil pump? Rpms and load to drive the oil pump is dropping more rapidly than intended when you're braking at 1g?

 

[Asbjorn]

M135i is an n55, right?

Being down to 20psi is below even normal idle pressure of about 38psi. Could some of the pressure drop we are seeing also be related to the response of the oil pump? Rpms and load to drive the oil pump is dropping more rapidly than intended when you're braking at 1g?

Yes, it is the higher powered N55 with forged internals and without the M sump.

I found one instance in the log where the oil pressure still dropped below 38psi although rpm was kept up by downshifting rapidly. However the braking duration wasn't long enough to cause the oil pressure to go below 30psi.

datazap.me | Asbjoern | M135i at GIC

datazap.me

I do not know if this answers your question, but it seems the drop is directly related to braking force and duration and unrelated to changes in rpm. As soon as brake pressure is reduced, oil pressure returns.

 

[Bnks334]

Yes, it is the higher powered N55 with forged internals and without the M sump.

I found one instance in the log where the oil pressure still dropped below 38psi although rpm was kept up by downshifting rapidly. However the braking duration wasn't long enough to cause the oil pressure to go below 30psi.

datazap.me | Asbjoern | M135i at GIC

datazap.me

I do not know if this answers your question, but it seems the drop is directly related to braking force and duration and unrelated to changes in rpm. As soon as brake pressure is reduced, oil pressure returns.

Yeah I've seen the correlation in my logs too. Makes sense I'm just covering different angles. So it seems like to some degree that what you have done to your car appears to be helping compared to this M135i?

 

[CNM135i]

Oil level after the trackday. I'll try to device a test measuring the effects of this current mid-level, then max and 0.5 liter overfilled.

 

[F87Source]

Oil level after the trackday. I'll try to device a test measuring the effects of this current mid-level, then max and 0.5 liter overfilled.

View attachment 34141

Careful overfilling it because that can cause windage which does more harm than good.

 

[Asbjorn]

The only areas where n55 oil pressure is lower is in the midrange. The n55 engine pdf has a comparison of how the oil control valve works vs n54. I think you might see much higher pressure because of the location of your sensor? It's roughly 40psi at idle and 70psi under load for the n55. Not low by any means amd I thought we established that people had posted very similar numbers for the n54 in the past when using the stock sensor location.

Here's an overview of the data I was able to collect. More info here.

N54	VTT, no oil cooler	Asbjorn, baffle + pump	Dzenno	Drunkenup, baffle
Hot idle	40psi	38psi	22psi	23psi
Cold idle	80-100psi	90-100psi	70psi	N/A
WOT	60psi	95-100psi	65psi	70-80psi
Measured where?	VTT adapter kit	Oil cooler feed line	Similar to VTT, LeatherZ gauge kit	Similar to VTT
Pressure drops below idle during braking or turning?	N/A	No	N/A	Yes, trail braking into left handers, 10-20psi

N55	@CNM135i	@Bnks334
Hot idle	43psi	38psi
Cold idle	N/A	+90psi
WOT	86psi	70-90psi
Pressure drops below idle during braking or turning?	Yes, trail braking into left handers, 20-30psi Yes, braking hard, 20-30psi	Yes, left handers 20-30psi Yes, right handers 20-30psi Yes, ~10psi oil pressure under heavy braking

 

[Asbjorn]

Yeah I've seen the correlation in my logs too. Makes sense I'm just covering different angles. So it seems like to some degree that what you have done to your car appears to be helping compared to this M135i?

Yes, it seems that a baffle does help in terms of preventing oil pressure drop during braking. But we do not have any data points from any unbaffled N54s to confirm 100%.

 

[Bnks334]

Oil level after the trackday. I'll try to device a test measuring the effects of this current mid-level, then max and 0.5 liter overfilled.

View attachment 34141

Yeah I am usually down 1/2qt of oil after an HPDE. Sometimes takes a day or two for the oil level sensor to "normalize" and pick up on it though.

 

[CNM135i]

Here are some "data points" from me.

Emergency straight line braking:

Oil level at medium according iDrive (as shown on the picture above) 23psi
Oil level at medium according iDrive (+0.5 liter) 25psi
Oil level at max according iDrive (+ another 0.5 liter) 25psi

See attached logs with Medium level and Max level (+1 liter). I wanted to measure accurately in mm but I could not find the function in ISTA...

After seeing this I am starting to wonder if this a problem at all? BMW did not design a car that self-destroy during emergency braking - I hope haha Track driving is another beast ofcourse as documented earlier.

Medium

Hide legend Reset zoom

 

[CNM135i]

Max (+1 liter compared to Medium)

Hide legend Reset zoom