Help Analyzing S52 Dyno Graph

[pazi88]

Yes if the vanos wouldn't work correctly it will throw dtc. But not necessarily if the cam(s) are degreed incorrectly. Non working vanos will cause loss of low end torque. Not high end.

[dude8383]

Did you check the camshaft range of operation with VANOS actuated?

https://www.youtube.com/watch?v=angrrw9TaRc

[ian e30 318is]

Did you check the camshaft range of operation with VANOS actuated?

https://www.youtube.com/watch?v=angrrw9TaRc

I did not, but wow that is ingenious! I’ll have to give that a try ASAP! Thanks for the link.

[ian e30 318is]

Yes if the vanos wouldn't work correctly it will throw dtc. But not necessarily if the cam(s) are degreed incorrectly. Non working vanos will cause loss of low end torque. Not high end.

That makes complete sense. Thanks for the reply.

[dude8383]

I did not, but wow that is ingenious! I’ll have to give that a try ASAP! Thanks for the link.

That's actually how it's supposed to be done according to the manual :up:

[ForcedFirebird]

That's actually how it's supposed to be done according to the manual :up:

Yup. And most Vanos kits no longer come with the fitting. Had a local mobile mechanic borrow my setup and I charged him a $250 deposit. He never brought it back (it was like $400 back then) and the kit I bought to replace it didn't come with the air fitting ftmfl. Good thing I am fairly crafty and own a TIG welder, but it was a pain to have to replicate a tool I had once owned. :(

[dude8383]

Thats exactly why I don't loan out my tools!

[ian e30 318is]

Well after 6 months I finally tested the VANOS unit in the car with a pneumatic fitting and a 12V battery. Once hooked up to compressed air and actuated, the VANOS threw oil everywhere and did not return to the non-advanced position due to lack of oil pressure. A seal was either pinched or not installed correctly when I rebuilt with the Beisans seal kit.

I'm going to purchase and install a Dr. Vanos unit this next week and redyno. Hopefully that resolves the issue. Thanks to ForcedFirebird (John at WOT Tech) for all the help!!

[dude8383]

Thanks for reporting back... now get it done before you chime in again in another 6 months.

[thedentonmare]

Just read the entire thread, a ton of helpful/knowledgeable dudes on here trying to help out! Glad you found what is likely the main culprit to those #s.

[ian e30 318is]

Thanks for reporting back... now get it done before you chime in again in another 6 months.

Hahah do I win a prize if I report back in less than 6 months? ;D

A 2 year old and pregnant wife don't allow for much free time on the side projects.

Another Update:

7/19/19: Installed new Dr. Vanos Stage 1 unit myself and redyno'd the car. Still had a slight dip in horsepower. See graph below.





I was still wondering why the graph dipped, so I did some additional research and found MMW's graphs below (https://www.r3vlimited.com/board/sho...d.php?t=327183). One shows a dip from cam timing and one shows a dip from VSS (Hmmm interesting)





7/27/19: Had a friend of mine who is a BMW technician come by and check timing one more time. Sure enough it was off by a half tooth. Moral of the story: Don't trust the mark on the harmonic balancer...do trust pulling a spark plug and checking actual TDC of piston.

7/29/19: Because of my curiosity, I decided to also check VSS from the differential. The positive side of differential speed sensor to pin 14 (blue/yellow wire for my 318is which apparently can also be a black/white wire) showed continuity.





Next I unplugged the 413 Red ECU and found the proper pin number on wedophones wiring diagram.





Awesome!! Pin 42 is the VSS...Plug in wire to pin 42 of the ECU harness, turn on the auxiliary, and test continuity...



Seems like the VSS is wired to the ECU correctly. Now need to schedule a redyno AGAIN. Will report back will another update (hopefully soon).

[pazi88]

On 413 ecu the vss doesn't affect vanos. On ms41.2 that s52 originally has it affects. And the reason being that m50/m52/s52 vanos is slow so ecu tries to match the vanos switching point where it best matces how fast engine revs up at each gear.

[ian e30 318is]

On 413 ecu the vss doesn't affect vanos. On ms41.2 that s52 originally has it affects. And the reason being that m50/m52/s52 vanos is slow so ecu tries to match the vanos switching point where it best matces how fast engine revs up at each gear.

This is good to know. I was searching for this information.

[moatilliatta]

Put stock injectors, Maf, and chip in and see what it dynos on a dyno jet.

Put the wideband in the an exhaust bung also close to where factory would.

If curious about the vanos make one run with it unplugged, on with it jumped on.

Pictures of intake and exhaust?

[ian e30 318is]

Welp I feel like an idiot. Finally dyno’d the car today. Graph was perfectly smooth and pulled strong. The culprit? Bad timing when installing the VANOS. Make sure the engine is TDC via the piston AND NOT the marking on the engine timing cover and the harmonic balancer.