BMW OEM cam specs
 

I had a lot of trouble finding reference for BMW OEM cam specs. I spent a number of hours researching and figured I'd compile the data into a table. Hopefully this will be useful to more people out there:

Just unformatted text:

M50B20nv // int: 240º(9.7mm) // open:24º close:36º // exh: 228º(8.8mm) // open:38º close:10º
M50B25nv // int: 240º(9.7mm) // open:19º close:41º // exh: 228º(8.8mm) // open:35º close:13º
M50B20tu // int: 228º(9.0mm) // open:3º close:39º // exh: 228º (9.0mm) // open:39º close:9º
M50B25tu // int: 228º(9.0mm) // open:4º close:44º // exh: 228º(9.0mm) // open:35º close:13º
S50B30 // int: 260º(12.0mm) // // exh: 260º(12.0mm)
S50B30US // int: 252º(10.2mm) // // exh: 244º(9.5mm)
S50B32 // int: 256º(9.7mm) // // exh: 240º(9.0mm)
M52B20 // int: 228º(9.0mm) // open:4º close:44º // exh: 228º(9.0mm) // open:39º close:9º
M52B25 // int: 228º(9.0mm) // open:4º close:44º // exh: 228º(9.0mm) // open:39º close:9º
M52B28 // int: 230º(9.0mm) // open:1º close:49º // exh: 228º(9.0mm) // open:39º close:9º
S52 // int: 252º(10.2mm) // // exh: 244º(10.2mm)
M52B20tu // int: 228º(9.0mm) // open:-6º close:54º // exh: 244º(9.0mm) // open:47º close:17º
M52B25tu // int: 228º(9.0mm) // open:-6º close:54º // exh: 244º(9.0mm) // open:47º close:17º
M52B28tu // int: 228º(9.0mm) // open:-6º close:54º // exh: 244º(9.0mm) // open:47º close:17º
M54b25 // int: 228º(9.0mm) // // exh: 244º(9.0mm)
M54b30 // int: 240º(9.7mm) // // exh: 244º(9.0mm)
M54b30ZHP // int: 248º(9.7mm) // // exh: 248º(9.7mm)

Here's a couple versions in .txt and .doc; I hope you find this info valuable. Please let me know if you have verifiable data that differs from this. This data is only as good as I've been able to collect online so far. Thanks in advance for your contribution to this too! Thanks TIem!

-Nic 328ti (z3 swap)

Sweet thanks for posting

John S

I got my M54b30 cams this week. I'll get one setup on my bench and measure it. the intake definitely looks like it's easily got the 240º duration with the way the lobe looks; The lobe is fat and the peak is rounded/fat too. The lift is 9.7mm (as measured with a mic).

The exhaust looks way different. The peak is pretty sharp but with close inspection of the profile it looks like the ramp is way more gradual. That could account for the long advertised duration (244º). With my old school engine builder eye, at face value it looks shorter due to the width of the peak but it could be that this profile is optimized for exhaust and manipulation by the vanos.

I'm planning on adapting both of these cams to the M52b28 I've got. The intake is an easy swap; Most cut the splined cog for this so it's flush with the top of the fastener, around 4-5mm. Since that surface (the outer face of the splined vanos/cam register) is not used, pretty much anybody with a cut-off wheel can cut this as long as they can get close.

One thought I had was to use the M54 vanos hub to build a sort of manually adjustable exhaust advance off the front of the exhaust side. Then I may be able to dial in the exhaust cam advance/retard for optimal power and usability. The challenge there would be to build something that would last. On the other hand, I may just weld it in at roughly neutral and call it good.

Once I get the exhaust cam benched out I'll post the results.

Solid info here

Thanks

Messing with numbers
 

I did measure the cams and they do sort out at the expected duration/lift. The numbers I can't figure out without having them installed is the IO/IC and EO/EC numbers. Here's why that's important:

We just finished building a CHUMP car. Our M50TUB25 makes an advertised 189hp@5900/181lb/ft@3500. The thing is the M52B25 (basically the same concept, single VANOS) makes an advertised 168hp@5500/181lb/ft@3950.

The chip contributes to that but the cam timing also changed. This would be pretty much invisible if you just compared the duration numbers because they both run 228º/228º cams. BUT the timing is different:

The M50TUB25 works out like this:

Intake Duration is 228.00 degrees.
Exhaust Duration is 228.00 degrees.
Installed Intake Centerline is 110.00 degrees ATDC.
Installed Exhaust Centerline is 101.00 degrees BTDC.
LSA is 105.5 degrees
Overlap is 17.00 degrees.


The M52B25 looks like this:

Intake Duration is 228.00 degrees.
Exhaust Duration is 228.00 degrees.
Installed Intake Centerline is 110.00 degrees ATDC.
Installed Exhaust Centerline is 105.00 degrees BTDC.
LSA is 107.5 degrees
Overlap is 13.00 degrees.

You can see that the exhaust timing is phased for a much more sportier 105 LSA and an extra 4º of overlap as the base numbers. It would be interesting to see what the HP differences would be with a cam swap from M50 to M52...

I was also considering trying an intake cam swap from the M50TUB20 (Installed Intake Centerline is 105º vs. 110º) into the M50TUB25, effectively advancing the intake timing;

M50TUB20 Intake, M50TUB25 Exhaust:

Intake Duration is 228.00 degrees.
Exhaust Duration is 228.00 degrees.
Installed Intake Centerline is 105.00 degrees ATDC.
Installed Exhaust Centerline is 101.00 degrees BTDC.
LSA is 103.0 degrees
Overlap is 22.00 degrees.

Even sportier 103º LSA and a massive overlap difference (to the stock M52). Not great for street but it would be interesting to see how this might feel on track at high RPM and whether it would effect our lap times... This would be a viable stock sanctioned swap because the base numbers of 228º/228º @ 9mm lift is identical for all of these cams only the cam timing is different.

I've found the timing for the M54B30 cams:

M54b30 // int: 240º(9.7mm) // open:-6º close:66º // exh: 244º(9.0mm) // open:47º close:17º

That works out to these specs:

Intake Duration is 240.00 degrees.
Exhaust Duration is 244.00 degrees.
Installed Intake Centerline is 126.00 degrees ATDC.
Installed Exhaust Centerline is 105.00 degrees BTDC.
LSA is 115.5 degrees
Overlap is 11.00 degrees

I may look into advancing the intake cam somehow to improve performance a bit, and compensate for the lack of a VANOS on the exhaust cam.

I did the swap this past week.

I swapped in both intake and exhaust from the M54b30 into my M52b28.
I'll start a new thread to outline a couple interesting points.

One thing I got confirmation on was the exhaust cam. I found conflicting references online about whether the 3.0 exhaust cam was indeed 244º dur or 228º.

I was able to confirm that the duration is longer than 228º by measuring my existing cam from the M52b28 (228º) and the M54b30 cam. I didn't have a degree wheel so I won't bother posting any specific measurements but I was able to check that the angle of rotation on the M54b30 was longer than my M52b28 because the angles were different. Again that was observed angles on the cam, not angles based on crank position.

Another interesting point about the cam profile is worth mentioning:

The opening side of the cam slope has a more gradual curve. I'm not sure what this does but I did notice that the exhaust note is markedly quieter and deeper despite the significant change in duration. Here's a pic to show what I mean:

http://www.318ti.org/forum/attachmen...1&d=1502369258

Hello,

The information on the m54b30 ZHP cams is incorrect.

I had a set of ZHP cams measured by a performance cam shop and they measure as follows:

Intake: 246 degree duration, 10.0 mm lift
Exhaust: 237 degree duration, 9.4 mm lift

The ZHP cams are NOT the same as the Schrick 248/248 set.

Thanks so much for the info! I'll edit the numbers in a bit to reflect this info. I don't suppose they got open/close angles did they?

Sorry, no, they didn't get the open/close angles.

Thank you!

Hi, can someone help me if is possible fit M50 intake cam on a M52 exhaust side? And how to do it?
It easier fit a S50 exhaust cam?

My plan for my m52b28 swap is m54b30 intake cam, b25nv intake as exhaust, m50 manifold and tune while I delete EWS. Has anyone run this before? I'm thinking it might only be worth it if I do the m54b30 bottom end swap also now. Btw I already had the manifold and nv cams, so the intake cam is only cost to me.

Sent from my Pixel 3 using Tapatalk