[PearlyN55]

Can’t figure out why I’m getting misfire on a WOT mods list and datazap below

Current Mods:
Pure Stage 2
TurboSmart VR9 BOV (Dualport)
Pure Turbo inlet
VRSF FMIC 7.5"
VRSF DP and Cat Back Exhaust
BMS Intake
COBB Charge Pipe
N20 TMAP 3.5 Bar
N20 Plugs gapped to 0.021
93 Octane

https://datazap.me/u/pearlyn55/3rd-g...og=0&data=4-15

[wheela]

I looked at one of your logs in your other post (the link here doesn't seem to work for me?). Your rail pressure drops down to 1600-ish at 4500 rpm, slightly recovers, and drops again to 1500-ish 5300 rpm. From what i've read, around 1700 psi is the point where n55 will start misfiring at WOT if rail pressure drops below that point. I suspect rail pressure is your issue; your moving enough air that your HPFP can no longer keep up.

[PearlyN55]

Originally Posted by wheela

I looked at one of your logs in your other post (the link here doesn't seem to work for me?). Your rail pressure drops down to 1600-ish at 4500 rpm, slightly recovers, and drops again to 1500-ish 5300 rpm. From what i've read, around 1700 psi is the point where n55 will start misfiring at WOT if rail pressure drops below that point. I suspect rail pressure is your issue; your moving enough air that your HPFP can no longer keep up.

hey man updated the link if you wanted to look over that specific 3rd gear pull i made lmk if you see the same hpfp issue there or if something else doesn't look right

[wheela]

Yeah, it's time for a bigger hpfp. I did some rough calculations at the points your rail pressure drops:

4500rpm point
MAF: 275 g/sec
AFR: 12.8
Fuel demand: 22 g/sec
Stock pump capacity @ 4500rpm: 18g/sec

5300 rpm point:
MAF: 327 g/sec
AFR: 12.5
Fuel demand: 26 g/sec
Stock pump capacity @ 5300rpm: 21 g/sec

At both points it looks to me that your fuel demand is just beyond what the stock hpfp can supply at those rpm's.

[PearlyN55]

Originally Posted by wheela

Yeah, it's time for a bigger hpfp. I did some rough calculations at the points your rail pressure drops:

4500rpm point
MAF: 275 g/sec
AFR: 12.8
Fuel demand: 22 g/sec
Stock pump capacity @ 4500rpm: 18g/sec

5300 rpm point:
MAF: 327 g/sec
AFR: 12.5
Fuel demand: 26 g/sec
Stock pump capacity @ 5300rpm: 21 g/sec

At both points it looks to me that your fuel demand is just beyond what the stock hpfp can supply at those rpm's.

Well that sucks... go big or go home i guess

[wheela]

Heck yeah brother! Good excuse for some new toys!

[whyzee125]

Being a 2013, you have the newer style HPFP that flows less but is more easily upgraded. That's likely your issue BUT I'd also look at plug gap. I'm N54, but I'll misfire up top at .021 too. Gapped to 0.18, it runs like a champ. I'd try that first, it's cheaper than an upgraded HPFP!

[PearlyN55]

Originally Posted by whyzee125

Being a 2013, you have the newer style HPFP that flows less but is more easily upgraded. That's likely your issue BUT I'd also look at plug gap. I'm N54, but I'll misfire up top at .021 too. Gapped to 0.18, it runs like a champ. I'd try that first, it's cheaper than an upgraded HPFP!

too late already in crippling debt so i opted for the stage 2 hpfp but will make sure i gap to 0.018" with my new plugs coming in thank you!

[PearlyN55]

Originally Posted by wheela

Heck yeah brother! Good excuse for some new toys!

I appreciate you troubleshooting for me on 2 separate threads dude, you're a legend for that for real

[wheela]

Originally Posted by PearlyN55

too late already in crippling debt so i opted for the stage 2 hpfp but will make sure i gap to 0.018" with my new plugs coming in thank you!

Yeah, good to check this too, multiple things can contribute to misfires. But your're definately low on fuel, so that stage 2 pump will be put to good use.

[wheela]

Originally Posted by PearlyN55

I appreciate you troubleshooting for me on 2 separate threads dude, you're a legend for that for real

No problem, glad to help! I'm living vicariously here until I can get my own turbo upgraded. How are you liking the ps2 so far? Do you notice any difference in response from the stock turbo?

[PearlyN55]

Originally Posted by wheela

No problem, glad to help! I'm living vicariously here until I can get my own turbo upgraded. How are you liking the ps2 so far? Do you notice any difference in response from the stock turbo?

Tough to tell specifically what’s making it so much more fun, not having the jerky JB4 anymore or the PS2, or maybe both lol but for it not even being 100% done yet I’m already in love with it. I don’t listen to music anymore. The sheer sounds of the turbo made it worth it for me

[jlegelis]

Also *really* curious how you can run 23PSI on 93 octane? Are you running additional fueling, etc? I have a very similar setup (PS2, HPFP, etc) and get timing corrections at much lower boost levels. Yes I've got fresh plugs and coils.

Here's a log: https://datazap.me/u/jlegelis/ps2-v9...&solo=11-12-24

[wheela]

Originally Posted by PearlyN55

Tough to tell specifically what’s making it so much more fun, not having the jerky JB4 anymore or the PS2, or maybe both lol but for it not even being 100% done yet I’m already in love with it. I don’t listen to music anymore. The sheer sounds of the turbo made it worth it for me

Glad to hear!! I'm really tired of my stock turbo

[wheela]

Originally Posted by jlegelis

Also *really* curious how you can run 23PSI on 93 octane? Are you running additional fueling, etc? I have a very similar setup (PS2, HPFP, etc) and get timing corrections at much lower boost levels. Yes I've got fresh plugs and coils.

Here's a log: https://datazap.me/u/jlegelis/ps2-v9...&solo=11-12-24

I tried to compare similar points between your guys' logs. On the 23 psi log at 4640 rpm, the throttle is closing to keep load on target (around 183%, or MAF of 272 g/sec). On your log at 4690 rpm and 18 psi, your throttle plate is at 100%, and load is around 187% (MAF of 283 g/sec). Load% is just mass airflow (MAF) expressed as a percentage of cylinder fill/engine revolution -100% load is 100% cylinder fill). I believe the BMW documentation refers to load% as cylinder stuffing factor. So despite the different boost levels, both your engine are consuming very similar amounts of air, and are therefore probably at very similar power level (barring differences due to timing, afr, and vanos).

[jlegelis]

wheela, appreciate the insights. What would cause tuners to use different 'strategies' to accomplish the same HP results? Is there some qualitative difference in the two approaches? 'Inquiring minds wanna know...'

[PearlyN55]

Originally Posted by jlegelis

wheela, appreciate the insights. What would cause tuners to use different 'strategies' to accomplish the same HP results? Is there some qualitative difference in the two approaches? 'Inquiring minds wanna know...'

It would be the same concept as tuning an NA car which gets much more timing adjustments vs a turbo car getting more boost to achieve the same hp, it’s when you maximize results by tuning both without maxing any of the 2 systems which comes with the reliability aspect. So my tune is more boost with less timing adjustments and yours is less boost with more timing adjustments. Ultimately it would depend on what the tuner has more experience with. My guess is that WedgePerformance is well known for tuning PS2 N55s really well so they most likely found more boost might be the more reliable way to go. I’m no expert by any stretch of the imagination, maybe wheela can tell me if I’m horribly wrong or if that sounds about right haha

[jlegelis]

PearlyN55 Interesting since my tuner is also Wedge... not sure why ours are so different.

[wheela]

Originally Posted by jlegelis

PearlyN55 Interesting since my tuner is also Wedge... not sure why ours are so different.

Pearlyn55, your tune is still in process, correct? I imagine by the time it's done, he'll have it set up so that your throttle plate isn't closed when you're WOT as on the log I screen-shotted above. Not sure if that means you'll run less boost, or if he'll tweak other parameters to run 23 psi with the throttle plate wide open - that may be asking a lot from 93 octane though? If you guys have really similar mods and run similar fuel, I'd guess that by the time Pearlyn55's tune is done your tunes may look pretty similar to eachother?

I'm definately not a tuner, but as far as differences, I think some customers will tolerate the risk of more aggressive tunes than others. Also, two identical engines usually will perform slighlty differently, which is why OTS tunes usually leave a lot on the table. So the tuner may be going for the same perfornance on different cars, but some may start running into knock sooner than others, so they won't be able to push all cars to the same level.

As far as strategy, for a given load and rpm point, the biggest levers for making power are probably timing, AFR, and vanos (i'm not very familiar with vanos adjustments...). All things must be balanced, but in general advance timing until either 1) you stop making more torque, or 2) you start running into knock. With really rich AFR, you can generally advance the timing more before running into knock (extra fuel helps cool things down, making it less prone to knock). But a "leaner" rich mixture (closer to stoich, but still rich) will make more power than a really rich AFR. With a turbo you obviously can increase the load with higher pressure, but the higher load will need less timing (or more octane) to avoid knock. As the timing gets lower, you make less power, and if you go far enough, Exaust Gas Temp (EGT) will really start to rise. Where's the sweet spot? I don't know, but that's where a good tuner comes in. Looking at logs, it seems a lot of people on this platform run around 12.5 AFR at WOT, give or take. Probably richer as load goes higher. I'm sure all these things find new balance spots once you start throwing vanos adjustments into the mix. The principals are pretty much the same across all internal combustion engines, but each platform has its idiosyncrasies.

[PearlyN55]

https://datazap.me/u/pearlyn55/check...log=0&data=3-9

Originally Posted by wheela

Pearlyn55, your tune is still in process, correct? I imagine by the time it's done, he'll have it set up so that your throttle plate isn't closed when you're WOT as on the log I screen-shotted above. Not sure if that means you'll run less boost, or if he'll tweak other parameters to run 23 psi with the throttle plate wide open - that may be asking a lot from 93 octane though? If you guys have really similar mods and run similar fuel, I'd guess that by the time Pearlyn55's tune is done your tunes may look pretty similar to eachother?

I'm definately not a tuner, but as far as differences, I think some customers will tolerate the risk of more aggressive tunes than others. Also, two identical engines usually will perform slighlty differently, which is why OTS tunes usually leave a lot on the table. So the tuner may be going for the same perfornance on different cars, but some may start running into knock sooner than others, so they won't be able to push all cars to the same level.

As far as strategy, for a given load and rpm point, the biggest levers for making power are probably timing, AFR, and vanos (i'm not very familiar with vanos adjustments...). All things must be balanced, but in general advance timing until either 1) you stop making more torque, or 2) you start running into knock. With really rich AFR, you can generally advance the timing more before running into knock (extra fuel helps cool things down, making it less prone to knock). But a "leaner" rich mixture (closer to stoich, but still rich) will make more power than a really rich AFR. With a turbo you obviously can increase the load with higher pressure, but the higher load will need less timing (or more octane) to avoid knock. As the timing gets lower, you make less power, and if you go far enough, Exaust Gas Temp (EGT) will really start to rise. Where's the sweet spot? I don't know, but that's where a good tuner comes in. Looking at logs, it seems a lot of people on this platform run around 12.5 AFR at WOT, give or take. Probably richer as load goes higher. I'm sure all these things find new balance spots once you start throwing vanos adjustments into the mix. The principals are pretty much the same across all internal combustion engines, but each platform has its idiosyncrasies.

Hey brotha mind checking these logs out? I upgraded the HPFP and did a adaptation reset but I’m getting a few codes on the top end that I’m not too sure what could be causing them
https://datazap.me/u/pearlyn55/check...log=0&data=3-9

[wheela]

Rail pressure is fixed! I took a look at the log, but only a couple parameters were available? It would be good to have throttle plate position, boost request, load request, load actual, cyl 1 timing, all cylinder corrections, ltft, stft, torque actual, and the torque limiters, MAF, and lamda target.

Are you still having misfires? Can you post a screenshot of your codes?

[PearlyN55]

Originally Posted by wheela

Rail pressure is fixed! I took a look at the log, but only a couple parameters were available? It would be good to have throttle plate position, boost request, load request, load actual, cyl 1 timing, all cylinder corrections, ltft, stft, torque actual, and the torque limiters, MAF, and lamda target.

Are you still having misfires? Can you post a screenshot of your codes?

Got an iPad mini for my set up and I goofed it by taking logs with no parameters checked on but I do have a list of the codes I got

3rd Gear Pull Codes: 2C53,2C83
4th Gear Pull Codes: 2C58, 2C83, 2EE0, 2EF4, 2EFE, 2F04