I just got my track car dynotuned, but I feel that something is not quite right.
Here are my mods: Dinan CAI, 3.5" MAF, M50 manifold, BBTB (not sure of brand - riot?), 24lb injectors, fan delete, Turner under drive pulleys, Turner shorty headers, traction control delete boot, cat removed, and Ebay exhaust.
This is the final dyno run (SAE corrected). As you can see, around 5200 rpm, hp flat-lines. Also power seems to be dying off rather quickly with M50 manifold. My tuner tried to smooth it out around 5200 rpm, but he was unable to do so with Vanos settings. Any idea? We were thinking possibly Vanos is not working as it should. I believe that the previous owner already repaired the Vanos with Beisan seal kit less than 10k miles ago.
Can you post the dyno? Make sure you don't have any vacuum leaks, but if your hp does actually flat line, then you have a serious issue, even without VANOS working. Did the dyno continue to track RPM too? Did the car feel like it was running flat? What happened to the torque curve?
1997 Arctic Silver/Black M3
CES Stage IV (651rwhp/615rwtq @ 24 psi)
1999 Techno Violet/Dove M3
Auto/Convertible and staying stock!
Can't see the dyno? Weird... I can see it in the original post. If you still can't see it, I will post a direct link.
Also, I should have said it flat lines from 5200 rpm to 5400rpm or so then jumps up. Torque dips around 5200rpm and that's causing the momentary flat line.
You can't post an image from imgur here, they banned image linking from bimmerforums.
Next time, you can use the built in image upload (attachments) feature on the forums.
You are able to see it, because the image is in your browser's cache.
Car goes pretty rich above 5,000 RPM, probably why you have that dip. Cam sensor, misstimed cams, vacuum leak, or just a bad tune can cause that.
See thread here, most cars with a dip like that have something wrong with them:
https://www.r3vlimited.com/board/sho...d.php?t=327183
Last edited by earthwormjim; 05-15-2018 at 09:47 AM.
Ah. Didn't know imgur doesn't work.
I have looked through the dynos in the link. It appears that the drop off after 6k rpm is typical with Turner shorty header. Shorty headers increase the mid but lose a little at the top.
As for the torque dip, it is not significant and I may dismiss it. I am losing about 6 hp in that area which is not a lot. We went up in AFR but didnt gain anything so we decided to keep it a little rich. I have done smoke tests and I believe that there is no vacuum leak. I am talking to my tuner and seeing if he has some comments to add.
Last edited by AlpineM345; 05-15-2018 at 03:55 PM.
I agree something is off. The car is seriously modded and power is peaking at 5900 and there is a giant dip around the vanos retard point. I’d guess cam timing. I don’t see the turner headers costing that much power. I have actually read they are pretty good. Bavauto shorty headers took a modded canned car to 265 rwhp — adding 5 rwhp over stock. I’d guess the turner and bavauto were comparable, but don’t know for sure.
We went another 0.5 point leaner, and it didn't make any significant changes. At that point, we called it good for AFR. Wonder if we should have gone even more leaner.
final vs leaner.JPG
Now... This could have happened when the headgasket was replaced about 30k miles ago. I will have to take a look at it this winter.
I still think it makes pretty good power. It doesn't have aftermarket cams so it is in line with other similarly modded S52. The peak is indeed somewhat earlier in rpm than I thought it would be...
Last edited by AlpineM345; 05-15-2018 at 11:17 PM.
I don't think adjusting your tune is necessarily the solution. Your AFR is dropping, probably because something is off on your cams (timing or sensing) right around when Vanos starts altering timing. Engine is not getting enough air in that area.
Headers wouldn't cause a dip like that, something which changes with respect to RPM would.
Last edited by earthwormjim; 05-16-2018 at 12:35 AM.
If it does not have cams your power is about right. But it does seem odd peak is lower than stock. Also seems odd torque equals power. Usually with mods you improve power more than torque. Here you improved torque more than power, which makes me think maybe the power and got shifted down through cam advance.
Hm... I will check the cam timing and update this thread later. Thank you all for the help!
Doesn't this dyno graph resemble yours?
It's from an S52 with incorrectly timed cams. https://www.r3vlimited.com/board/sho...66&postcount=1
Well... you guys were both correct. My timing is definitely off... The exhaust cam is timed correctly, but the intake cam is off. I guess I will be re-timing my cams.
Last edited by AlpineM345; 01-05-2019 at 02:03 PM.
Before tearing it all apart, perhaps the VANOS when being timed wasn't catching the very first mesh? Make sure it should slide in and catch immediately.
https://youtu.be/8ACzOE7nV6g?t=916
Last edited by Hova; 01-05-2019 at 09:52 PM.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
I think you might be right. The exhaust cam primary gear was set incorrectly anyways so it didn't hurt to disassemble everything. Plus, I can sleep at night knowing that everything is torqued and installed correctly.
Hopefully fixing this issue won't require another dynotune session...
Roger that. I mentioned the VANOS teeth because I believe it's around 4.2-4.5k that the VANOS solenoid fires (depends on load), and it seems like it dies right after that in your dyno. Obviously, if the timing blocks don't line up as in your photo however, there's a problem.
Best of luck.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
Note: hand turning the loose exhaust sprocket to finalize the VANOS install is not the correct way to go about it.
Use the proper vanos air tools for this process before locking the four etorx on the exhaust cam.
Can you elaborate or point me to the right thread about this? I did it by hand when I did my head gasket forever ago, but I've been getting closer to finally getting cams and so I've been thinking a lot about this again. I imagine it's something along the lines of using air to activate the vanos and turn the exhaust sprocket the correct amount vs just doing it by hand?
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
http://www.autotoolworld.com/Sir-Too..._p_205510.html
It replaces the oil banjo on the vanos solenoid. Plug in your air compressor, then cycle the solenoid on the vanos unit with 12v (be careful, it's polar sensitive, if you reverse the power and neutral you can damage the solenoid)
The Bentley says 2 bar to 8 bar max (around 115 psi) but usually it moves just fine around 60 psi. I would NOT put 115psi into the unit, that just sounds dangerous.
Brett recommends testing the unit with air because it simulates the actual VANOS actuation. With similar air/oil pressure and electrical signal, you can replicate real world conditions instead of you turning it by hand. Def the better way to do it. If it won't fully turn with 60 psi of air (similar PSI to what the oil pump produces at the RPM when VANOS engages), there is something wrong, where you will likely exert more than that pressure with the VANOS wrench and your hand and the problem will go unnoticed.
"Be who you are and say what you feel because those who mind don't matter and those who matter don't mind."
-Dr. Seuss
DIY BMW Tools. Charlie For President
Check out these links as well.
https://www.youtube.com/watch?v=0GUHUkiDe9Q
https://www.youtube.com/watch?v=angrrw9TaRc
Good advice you guys - thanks.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
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