S55 oil pan on N55 (e82)

hollracing

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Oct 26, 2022
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Just thought I’d share my progress on adapting an s55 oil pan and pumps to fit the n55 in my e82 135i after it all seems to be working normally after initial (road) testing.

Basically I cut the corner where the power steer pump bolts off the original oil pan and stuck it on the s55 one..
 

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houtan

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Nov 2, 2017
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Very cool. I still don’t fully understand what you did. In the fourth picture, where is the bolt you show in the first picture.

Does the oil pan clear the subframe? I thought it hit on the e82.

Finally, I would be great full if you can provide additional details in what is need to do the swap. Maybe a parts list and custom modifications that are required.

Thanks for sharing !
 
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hollracing

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Oct 26, 2022
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Very cool. I still don’t fully understand what you did. In the fourth picture, where is the bolt you show in the first picture.

Does the oil pan clear the subframe? I thought it hit on the e82.

Finally, I would be great full if you can provide additional details in what is need to do the swap. Maybe a parts list and custom modifications that are required.

Thanks for sharing !
Unfortunately I was in a bit of a rush so didn’t take many photos during the process but hopefully what I did should help clarify.


This is a stock e82 135i n55 oil pan. You can see the 3x bolt holes the the power steer pump bolts to (2x at the front and 1x on the side).
IMG_4018.jpeg


This is the corner I cut off the e82 135i n55 oil pan, roughly trimmed up and next to the f80 s55 oil pan.
IMG_4022.jpeg


The side bolt hole didn’t clear this pick up for the s55 suction pump so I had to get rid of it and make a weld on for a stud to thread into. That pick up also fowled on the recess for the power steer pump so I had to modify that.
IMG_4536.jpeg


And this was the design for the weldon.
Sliced front 2d.png


Which then required 7mm to be milled of the face of the powersteer pump bracket that mounts here.
Half modified.png


This is the best photo I have of that bracket and stud.
IMG_4560.jpeg


To make sure it all didn’t warp when welding I had a spare n55 bed plate and had it bolted up to that on my bench. To keep everything located properly I turned down the heads on m8 cap screws so they had a tapper that loacated all of the oil pan holes to the bed plate. And to weld it on the inside of the oil pan I cut out the front bearing cap from the bed plate so I could fit my hand through.
None of which I have photos of..

It clears the factory steering rack bolts and everything else fine. I had read that somewhere to but was not even close to being a problem in my instance.
The undertray even fits without modification, although it does touch the bottom of the sump. The sump does sit slightly lower than the subframe but its not lower than the jacking point directly in front of it.

As a bonus the f8x dct thermostat bolts to the s55 sump as per factory and I’m running an fittings and hose from it to a 1m auxiliary radiator…
IMG_4616.jpeg

IMG_4613.jpeg
 

hollracing

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Oct 26, 2022
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As for parts list, you need:

S55 oil pan (later aluminium version)
S55 oil pump
S55 suction pump
S55 oil pick up
S55 oil pan bolts set
S55 oil pump bolt set
The 2x bolts that bolt the tensioner and chain guide bracket to the oil pump
Weldon for stud
M10 stud
Sump gasket

If you are single turbo you will need to block of the rear port on the suction pump.
IMG_4546.jpeg


The hole in the chain guide and tensioner bracket that the snout of the oil pump goes through needs to be enlarged as the snout on the s55 oil pump is larger.

You would also ideally want a n/s55 bed plate to hack up and weld on.
And many turned down m8 cap screws with a taper to locate both bits of oil pan.
 
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CalvinNismo

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Nov 1, 2020
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Fantastic information, thank you for sharing! Does the S55 front turbo oil drain pipe mate up perfectly on the N55? I guess the N55 M2 setup must do the same as what you’ve done.

I don’t know if you tried out of curiosity, but does the E-Series N55 pan fit over the S55 sump assembly? The front intake pipe would still have to be modified as you have done I imagine.

Your engine bay is also very clean, nice!

S55 Engine Document

BMW M2 Document
 

wheela

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Jun 4, 2021
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This is the info from the technical training on the s55 oiling system that sold me on the idea to do the conversion.
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This is awesome! But I'm confused about their ratings? They say up to 0.61g longitudinal acceleration, or -1.2g negative longitudinal (deceleration). Is longitudinal acceleration straight up going forward? Only 0.61g in longitudinal accelaration? Surely that can't be right? I hit over 1g acceleration per dragy, surely we're not starving our bearings going fast in a staight line?
 

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hollracing

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This is awesome! But I'm confused about their ratings? They say up to 0.61g longitudinal acceleration, or -1.2g negative longitudinal (deceleration). Is longitudinal acceleration straight up going forward? Only 0.61g in longitudinal accelaration? Surely that can't be right? I hit over 1g acceleration per dragy, surely we're not starving our bearings going fast in a staight line?
These figures are constant eg. if you spent all day going around in a constant circle you would be good for oil supply up to around 1.2g lateral acceleration before you ran into issues.

Remember to this system is whats used on: m235i racing, m2cs racing, m4 gt4.. without issue. Albeit with 1L ish extra oil than what this document was referencing. BMW fist did this I think with the M4 GTS and then all cars got the extra oil capacity. Theres 2x different oil level sensors the early ones got basically an n55 sensor (im still using my original e82 135i n55 sensor) and the later ones got a much taller sensor and a spacer to bring it to the correct level. I will eventually investigate this further but for now im good with only running stock 135i size michelin ss.
 
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hollracing

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Oct 26, 2022
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Fantastic information, thank you for sharing! Does the S55 front turbo oil drain pipe mate up perfectly on the N55? I guess the N55 M2 setup must do the same as what you’ve done.

I don’t know if you tried out of curiosity, but does the E-Series N55 pan fit over the S55 sump assembly? The front intake pipe would still have to be modified as you have done I imagine.

Your engine bay is also very clean, nice!

S55 Engine Document

BMW M2 Document
Yes, front turbo drain is in the same place. The n55 bed plate has the provision for the rear turbo drain in the casting its just not machined (alpina n55 is twin turbo).
The n55 m2 runs the same as what I've done, with the rear port on the suction pump blocked off.

I didn’t try as my s55 sump arrived before all the other bits so it was already cut up by the time they did. But it would fowl in the same area and you would need to get rid of the rear mounting point for the power steer pump. It would also be missing the 2x areas where the suction pump collects oil from the front of the sump. The main oil pickup would be to long and the e8/9x oil pan has no baffle plate thing like the s55.
And I would guess it wouldn’t clear the suction pump…
 

houtan

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Nov 2, 2017
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@hollracing, thank you!!

This is awesome information so thanks for sharing.

Just curious, did you happen to make a few more modified s55 pans?
 

wheela

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Jun 4, 2021
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Twin Cities, MN
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These figures are constant eg. if you spent all day going around in a constant circle you would be good for oil supply up to around 1.2g lateral acceleration before you ran into issues.

Remember to this system is whats used on: m235i racing, m2cs racing, m4 gt4.. without issue. Albeit with 1L ish extra oil than what this document was referencing. BMW fist did this I think with the M4 GTS and then all cars got the extra oil capacity. Theres 2x different oil level sensors the early ones got basically an n55 sensor (im still using my original e82 135i n55 sensor) and the later ones got a much taller sensor and a spacer to bring it to the correct level. I will eventually investigate this further but for now im good with only running stock 135i size michelin ss.
But what about longitudinal at 0.61, is that a typo? Longitudinal is straight, right? Is it supposed to be 1.61🤷‍♂️. Or maybe I'm missing something obvious?
 

houtan

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Nov 2, 2017
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Long shot but have to ask, did you make any additional modified s55 pans?
 

Szczypiorek

New Member
Nov 7, 2023
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Hi all,
Very valuable knowledge has been shared here, thank you for that.

Does anyone know if I can do the same mod for my E92 335i N55 RWD?
I've read here that there might be not enough room between s55 oil pan and E92 front subframe.
Can someone clarify that?
 

hollracing

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Oct 26, 2022
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Hi all,
Very valuable knowledge has been shared here, thank you for that.

Does anyone know if I can do the same mod for my E92 335i N55 RWD?
I've read here that there might be not enough room between s55 oil pan and E92 front subframe.
Can someone clarify that?
135i and 335i n55 rwd are the same…
Definitely enough room between subframe, from memory someone somewhere had stated it might fowl on the bolts for the steering rack but its not the case.
 

Szczypiorek

New Member
Nov 7, 2023
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Guess I'll have to try it and find out myself :)

img_4616-jpeg.jpg

@hollracing
Did you manage to put engine plastic cover over the oil pan? It looks like it sticks out too much?
 

hollracing

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Oct 26, 2022
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Guess I'll have to try it and find out myself :)

View attachment 87973
@hollracing
Did you manage to put engine plastic cover over the oil pan? It looks like it sticks out too much?
It fits without modification. It does touch the oil pan but fits fine.

The bottom surface of the undertray normally sits level with the bottom of the jacking point and the oil pan sits about 5mm higher than the jacking point.