E9X N55E Speedtech 6266 Build

sk8

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Aug 31, 2022
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It's been a while since I posted an update. I gave up on chasing 26psi, as anything over ~22 psi makes my ecu think it's misfiring in 4th@5500rpm.

Had the chance to get a few runs one the Dyno at a local car show, and ran into some issues.

Even with TC fully turned off and the newest xHP DCT update, the car didn't want to get out of 2nd gear on the Dyno. I had to drive it on the Dyno for a few minutes in auto mode until it decided to shift out of 2nd by itself. After that it let me shift.

Second problem was the Dyno not loading the car up enough to build boost. All 3 runs were done in 4th gear. You can see the difference between a street run and the Dyno.
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Logs from the Dyno: https://datazap.me/u/sk8/dyno?log=1&data=4-20

The result was 530hp. I don't think the TQ numbers are accurate since the RPM reading was off too.
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For comparison, a newer Mustang GT with unknown mods before me put down 380hp, and a FBO supra on e50 made 516hp. Not sure if it's worth my time going back next month to try the runs in 5th gear. Open to suggestions on how I can get the car to load up more on the Dyno.
 

houtan

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Nov 2, 2017
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135i N55 DCT; PS2
Frustrating you couldn’t load up the car for normal spool but nice result.

Have you emailed MHD? If not, please do and tell them you’re having the issue regarding misfire for no reason on a E-series N55DCT car. I’ve been patiently waiting over a year and they keep telling me they’re too busy, but I am probably the only one telling them we have this issue. Maybe if other people start emailing them about the same issue, they will make time to help us.
 
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sk8

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Aug 31, 2022
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Haven't emailed MHD, but the misfire still seems to be flywheel related. Before the S55 flywheel upgrade, my misfires would happen at 18psi. So I don't think there's anything MHD can do outside of disabling knock detection.

Also forgot to mention, looking at the Dyno logs looks like I only hit 18.5psi.
 

houtan

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Nov 2, 2017
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That was different. The n54 DCT doesn’t have this issue with the s55 flywheel, nor the MT e series N55, or any f series n55. I think we are hitting another torque limiter.

I have even disabled all torque monitors in my tune and they still occur. So something isn’t implemented correctly.

I don’t think disabling knock detection will do anything. my logs have zero timing corrections and I will get a misfire in 4 5 or 6 the second I get near 600whp.
 
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sk8

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I'll hit up MHD to see if they have any info, but I doubt we will get much. It would be nice if there was a standalone ECU that could drive the DI injectors for our cars.
 
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houtan

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Nov 2, 2017
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Haven't emailed MHD, but the misfire still seems to be flywheel related. Before the S55 flywheel upgrade, my misfires would happen at 18psi. So I don't think there's anything MHD can do outside of disabling knock detection.

Also forgot to mention, looking at the Dyno logs looks like I only hit 18.5psi.
finally got to a computer. datazap is not phone freindly.

sucks you didnt get a full pull in. looks like your car is shifting at 5k.

hard to draw good information from the logs as well. but it looks like you hit up to 30psi. not sure what pull corresponds to what log though.

also, typically DCT does pulls in 5th. thats what i recommend you use if you go to another dyno.
 

sk8

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The Dyno graph rpm is off, the datalog shows the car hitting 6.9k rpm, but yeah didn't really get a full pull since the car didn't have a chance to build more boost. There wasn't much load on the car so it revved up super quickly.

I don't run a BOV, so thats why you see psi spikes in the logs after throttle closure. Seemed like all 3 runs in the log were ~18.5psi.

Here's a video someone took in the crowd, you can hear how quick the 2.5k -> 6.9k pull was.
 
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wheela

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Jun 4, 2021
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Frustrating you couldn’t load up the car for normal spool but nice result.

Have you emailed MHD? If not, please do and tell them you’re having the issue regarding misfire for no reason on a E-series N55DCT car. I’ve been patiently waiting over a year and they keep telling me they’re too busy, but I am probably the only one telling them we have this issue. Maybe if other people start emailing them about the same issue, they will make time to help us.
You'd think they'd know, I'm not DCT and I know because it's all over the forum's!

My current theory is this is due to crank shaft twist, and the different mass of the M4 flywheel is enough to change the harmonics to not trip misfire detection, which comes from the crank shaft rotation speed, which picks up each power stroke. Seems to me excessive crankshaft twist could throw this detection off.
 
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houtan

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Nov 2, 2017
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135i N55 DCT; PS2
The Dyno graph rpm is off, the datalog shows the car hitting 6.9k rpm, but yeah didn't really get a full pull since the car didn't have a chance to build more boost. There wasn't much load on the car so it revved up super quickly.

I don't run a BOV, so thats why you see psi spikes in the logs after throttle closure. Seemed like all 3 runs in the log were ~18.5psi.

Here's a video someone took in the crowd, you can hear how quick the 2.5k -> 6.9k pull was.
Wow. That’s really odd. Was the Dyno broken? It seems like any car that would go on there would have the same issue.
 

houtan

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Nov 2, 2017
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You'd think they'd know, I'm not DCT and I know because it's all over the forum's!

My current theory is this is due to crank shaft twist, and the different mass of the M4 flywheel is enough to change the harmonics to not trip misfire detection, which comes from the crank shaft rotation speed, which picks up each power stroke. Seems to me excessive crankshaft twist could throw this detection off.
Well, if I can find a way to disable it to test I will! Right now I’m stuck.
 
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wheela

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Jun 4, 2021
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Well, if I can find a way to disable it to test I will! Right now I’m stuck.
I imagine there is a way? I know knock detection can be disabled, and adjusted, but I don't recall ever seeing anybody talk about adjusting or disabling misfire detection? There must be table that define misfire detection too, but perhaps nobody had defined them, or not thought to use them?
 

houtan

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That’s ok. At least I’m not the only one letting them know. And maybe it will help them take it more seriously once they do have free time. I email them every couple months just to see if Time is available.

Thanks for taking the time to reach out to them!
 
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wheela

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Jun 4, 2021
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@sk8 Any updates on your misfire issue? Also, I re-read your post about the rpm's being off on the dyno - that would defintaley skew your hp numbers lower. And plus 1 on what houton said about running on 5th gear on the dyno with DCT👍
 

sk8

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Aug 31, 2022
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@sk8 Any updates on your misfire issue? Also, I re-read your post about the rpm's being off on the dyno - that would defintaley skew your hp numbers lower. And plus 1 on what houton said about running on 5th gear on the dyno with DCT👍
No updates, just leaving it at ~22psi on the street. I gave up trying to push it harder. Waiting on MHD to hopefully release MHD+ for the N55E platform, or until a decent standalone ECU option pops up.
 
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sk8

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Update, decided to move on from this build and bring the car back to stock.

Selling the following parts, hit me up if you are interested.
PR Stage 3 bucketed LPFP
NXM B58 coil kit (Can include OEM B58 coils)
Dorch stage 1 HPFP
BMP Port injection with 750cc injectors
3.5 bar boost sensor (N20)
Speedtech Gen 2 Precision 6266 kit

Less than 3k miles on all of the parts.
 

wheela

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Jun 4, 2021
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Twin Cities, MN
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2015 e84 X1 35i Msport
Update, decided to move on from this build and bring the car back to stock.

Selling the following parts, hit me up if you are interested.
PR Stage 3 bucketed LPFP
NXM B58 coil kit (Can include OEM B58 coils)
Dorch stage 1 HPFP
BMP Port injection with 750cc injectors
3.5 bar boost sensor (N20)
Speedtech Gen 2 Precision 6266 kit

Less than 3k miles on all of the parts.
Sorry to hear this. Assuming you weren't able to resolve the misfire?
 

sk8

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Aug 31, 2022
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That is one of the reasons, although I was able to get 26psi and as long as I tapered it down to 22 by 5.5k I had no issues. Trying to move over to a b58.
 

houtan

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Nov 2, 2017
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135i N55 DCT; PS2
sorry to see you go! we have disabled misfire detection which allows us to run high boost. its not perfect but it works so far.
 
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SLOWESTN54

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Feb 9, 2021
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That is one of the reasons, although I was able to get 26psi and as long as I tapered it down to 22 by 5.5k I had no issues. Trying to move over to a b58.
B58 is good, just has way more support overall as a platform over N5X
 
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