RomRaider

pretty much thats it, i just bought the crank an rods for first iteration, maf was stock b20, now i have b28 maf but not a must.
be aware of the alignment problem (keyways) with the M51 crank (pictures in first post)

Update: new cams
Intake-Cam from S52B32
Exhaust-Cam from M50B20NV int with mod (Installed at 1,1mm lift at TDC)

Can anyone share some experiences with optimal timing for the modded ex-cam?

result so far (Vanos retuned):

Am i running out of MAF now?

...Reving to 7300

You should check airflow values in kg/h and check your MAF linearisation or simply check MAF voltage.

thanks, jup seems like MAF is maxed.

Its hitting 2nd highest cell in the MAF-map. Log shows the limit at 573 and Maf-map is max 578. So its @4.98V i guess.

I did rescale the MAF-Map when i switched from small B20 Maf to B28 Maf. To Equal the loadcurve before/after.
The B28 Maf i got was a cheaper one. (I was expecting the load to be the same when just switching to the bigger MAF)

My conclusion is that my cheap B28 Maf must be reading way off, because in no way my stroker is maxing out a real B28 Maf (i only dream that it would )

Does my suspicion sound realistic?

Any recomendations for affordable but working new MAF?

you can use your b20 maf sensor inner assmbly in b28 casing. if your b20 one is bmw branded.

Interesting! So the Hot-Wire element is the same Thanks for the idea! I have two B20 Mafs laying around.

i got the 82.8 crank from 525tds e39 now im insure about using it to stroke the my e39 m52b20 which is a daily driver and for family use or use the tds crank in my e30 m50b25 non vanos !!!
for the m52b20 the stroker is clear
for the m50b25 :
- 82.8 tds crank
- stock rods
- M50B25 VANOS pistons , not b28 or your CR will be low ( this is usefull for boosting )
actualy this is the same combination that ALPINA use for their M50B28
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but i need to know what other modification should i do ?? the front end i think ?? any photo or info on what i should exactly do ???

what do you mean exactly?

i want to know which mod i have to do for the tds crank to fit m50/52

have you checked the first page with the sketch of the different crank stubs?

important: i use the front dampener for my crank position signal (MS41.0). The crank and dampener are held by the one woodruff key of the m51 crank. no issue here.

how the sprocket is held on the crank is different! No more woodruff key. check S55 etc. newer engines for reference.

What i did: i put some weld in the chamfer of the sprocket and filed it to fit. Now there is a little bit of material grabbing the woodruff key (not necessary in hindsight). The orientation of the sprocket doesnt matter for timing.

Also i used a punch to create 4 highpoints where the axial pressure is touching the dampener flange (that is locked to the crank by the one woodruff key). Reason is to make these parts bite into each other. This i would also do again as extra safety!

Further i calculated the torque that would be necessary (from cam drive and oilpump drive) to move the sprocket against the crank if there were just the pressure from the crankbolt holding it:
M18x1.5 torqued to 410Nm (oiled) = ca. 120kN of preload with coefficient of friction 0.12-0.14 (conservative)
Surface pressure from dampener hub to crank sprocket and crank sprocket to crank then is ca. 177 MPa

(Coefficient of friction used is 0.1)
Torque to move the sprocket against the crank ca. 228Nm
Torque to move the sprocket against the dampener hub is also ca. 228Nm
Combined well over 400 Nm. But the chains cant put this much load on the sprocket before they just break. ->just vibrations to worry about.
Here i can spreak from experience: over 20.000km with no issue regarding moved timing.
Make shure you tighten the crank-bolt to spec! And oil it slightly for some extra preload.

thank you very much bro

Update: Changed the original BMW B20 MAF-element into the noname B28 housing and retuned fuel roughly. Thanks for the idea!

I assume the current MAF setup is way more precise, but iam wondering about the load and Airflow numbers.
They seem to good to be true, especially ca. 610 Airflow up top? Where would a B25 or stock B28 typically land?

Attached a WOT pull and the current tune for anyone interested.

I have B25 with B20 head and reground cams and load values are almost identical to yours - max load ~550 @5500rpm and taper out to 490 @7000rpm. Stock B25 values are lower.

Thanks for your response!

Interesting that you are running the B20 head on the bigger bore.
I was worried in the beginning that the ports will limit power quite a bit, but it seems its not that big of a deal.

Stock head and M52 intake manifold also? What are your cams specs?

Do you mind sharing more of your setup?