DIY tuning

Jun 12, 2017
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#2
yessir, theres a few of us that tune our own stuff and others that need help. welcome to the club.
 

[email protected]

Lieutenant
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Nov 14, 2016
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North Wilkesboro
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#3
Once a get some free time, I'll help out by making an actual document describing tables and what correlates with them. Some of the tables really aren't self-explanatory. you have to play with them to understand them.
 

Sbrach

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Oct 2, 2017
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#5
Well, I mixed filled up with E30 yesterday but shortly after my alternator died so I only got one 2nd gear pull logged. Started with JB4 BEF fuel tables as a starting point but STFT peaked sharply from around 5% at 3k to 16% at 5800rpm then dropped to zero. I assume because it went open loop. Is this because trim was too far off or is it normal to go open loop at high RPM due to sensor resolution or something like that? AFR stayed in the 12s. Plan to start tweaking the scalar table once I get my new alt installed. On the plus side I had zero timing corrections on E30.
 

Sbrach

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Oct 2, 2017
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#6
Alright, replaced the alt, updated my map with the fuel scalar table from the N5X tuning guide spreadsheet that was posted. I used the E50 table which is obviously too rich but I figured it was safer to start too rich and work my way leaner than the other way around.. Now tonight i'll dig through the logs I got today and try to get the scalar table closer.

2500-6500rpm 3rd gear pull
https://datazap.me/u/sbrach/log-1508368148?log=0&data=9-12-14

4000rpm 2nd to 6500rpm 3rd

https://datazap.me/u/sbrach/log-1508368786?log=0&data=9-12-14

Obviously have a lot of work to do on the fuel scalar.
 
Jun 12, 2017
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#7
Not bad. Boost comes on nice and smooth. One thing I would caution you on is your IAT. You saw temps of 140*. The car pulled a bit of timing once it got hot. Definitely want to look at upgrading the intercooler some time soon.
 

Sbrach

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Oct 2, 2017
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#8
Yeah for sure, doesn't help being in AZ with ambient still in the mid 90's. I was planning on ordering the VRSF 7" HD intercooler but the alternator put a bit of a dent in my wallet this week so I will probably wait a couple weeks. I do get one good pull though after the car sits for a while, I usually waste it on the way to the "test track" though so all my logs tend to be with a heat soaked intercooler. Oh well, if I had self control I probably wouldn't have this car.

Also, FYI, turns out the N54 Bosch alternator fits and works in place of the Denso N55 alt and is significantly cheaper. Harness connection is a little short but it reaches.
 
Jun 12, 2017
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#9
I know how you feel. Its hot here in florida. The only benefit is that we're closer to sea level.
I would take a look at the ambient thermal management intercooler or the wagner evo2. The VRSF 7.5 race isnt bad either. They'll give you a bit more room to grow than the standard 7 hd.
 

Sbrach

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Oct 2, 2017
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#10
Thanks, i'll check those out.

How does my AFR look? Safe?
 

Sbrach

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Oct 2, 2017
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#11
https://datazap.me/u/sbrach/log-1508977783?log=0&data=12-16-22-23-24-25-26-27

Still pulling timing even on E30. In this log I also misfired post shift, looks like due to rail pressure dropping. I remember reading this has been an issue on DCT cars but so far I have only had it happen the one time. Rescaled the Fuel Tables and Scalar Table last night so I will need to get some more logs to see how I am making progress on trims.
 

Sbrach

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Oct 2, 2017
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#12
New log 3rd, 4th, 5th.

https://datazap.me/u/sbrach/log-1509...30-31-32-33-34

Obviously I need a freaking intercooler and to figure out why its so rich WOT around 5k-6k. Fuel table doesn't reflect that at all.

Big corrections on Cyl 5 which is where I normally see corrections. Coils are brand new delphis and plugs are NGK 95770s gapped to .022. Really seems like it pulls timing to limit load, not because of knock, at least until IATs get high and it starts pulling timing on all cylinders.
 

Sbrach

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Oct 2, 2017
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#14
N55 will get there. For what it's worth I'll keep posting my progress. I don't think N55 will ever reach the levels that N54 is at but it's a good engine with a lot of potential especially in an E82 with DCT.
 

doublespaces

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Oct 18, 2016
6,558
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AZ
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#15
N55 will get there. For what it's worth I'll keep posting my progress. I don't think N55 will ever reach the levels that N54 is at but it's a good engine with a lot of potential especially in an E82 with DCT.
Stock for stock, probably not. The rods on the N55 from what I've seen are ever so slightly less meaty and because just how long and how many N54's were produced, I think development will last until B58 tuning becomes more popular and yes N55 will be a bit overshadowed. I am envious of the DCT however, I think the N55 sound fantastic.

Its been so long since I've really looked at stock boost curves I actually am surprised by how much you have to taper off the boost.
 

Sbrach

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Oct 2, 2017
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#16
I haven't really done much to the WGDC table yet so hopefully I can improve that. Really need to get fueling dialed in and an intercooler before I go much further.
 

doublespaces

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Oct 18, 2016
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#17
Any reason you don't just tune for E54, or is that coming? You're in AZ right?
 

Sbrach

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Oct 2, 2017
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#18
Yup, I'm in AZ.

I was told that N55 can't run E50 even with a LPFP upgrade because the solenoid injectors can't handle the low rail pressure like the piezos. But JB4 guys are running straight E54 so IDK, maybe at lower boost. Once I get my AFR table solid and scalars dialed in a bit I will experiment with E40 then E54. Even if I have to run less boost it may be worth it for the octane and convenience.

I think I may have the issue with misfiring post shift figured out. It doesn't do it everytime but everytime it has done it the DME calculated tq value has been over 600nm and I believe the DCT has a 600nm limit. So I will lower the load to tq values slightly for the highest load row and see if I see that post shift misfire again.
 

doublespaces

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Oct 18, 2016
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#19
I think I may have the issue with misfiring post shift figured out. It doesn't do it everytime but everytime it has done it the DME calculated tq value has been over 600nm and I believe the DCT has a 600nm limit. So I will lower the load to tq values slightly for the highest load row and see if I see that post shift misfire again.
Yeah, be careful with those DCTs and the line pressures etc. I don't know jack about tuning but I've heard some people's clutches going bye bye by treating the DCT like an AT.
 

Sbrach

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Oct 2, 2017
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#20
I think most people who have slipped a DCT were running JB4 without a BEF so the DME was under reporting tq. The DCT in the 135i/335is is the same hardware that's used in the M3, 458 Italia, SLS, etc but with different software so from what I've seen it can handle a lot of torque.
 

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