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M2 Technical Topics > N55 Engine / Drivetrain / Exhaust / Bolt-ons / Tuning > BM3 stage 2+ e30 log big stumble afr's

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      09-03-2021, 09:48 PM   #1
nismoman
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BM3 stage 2+ e30 log big stumble afr's

Just tried out the e30 log after swapping to a Dorch stage 1 HPFP to go with my
CSF intercooler, EVO racewerks charge pipe, injen intake, evo racewerks catless down pipe. Running 3.5 gallons e85 8 gallons 93.

I've noticed before I tried Ethanol that the map 3 93 octane didn't feel quite right and ended up going back to the stage 2 93 map until tonight. I reflashed and mixed up the fuel and did a 4th gear pull. Everything felt fine and then i had a bog during the run and then it started pulling and then bog again. I stopped the run and returned home. After looking at the logs you can see a big spike of the afr for each bog that happened jumping to 16.x for a second then pulling back down to normal 13.x boost actual is at 21psi which seems high and the actual fuel pressure is higher than the target during both bobbles. the timing started going crazy so I'm wondering if this is a boost cut and thats making the afr read like i'm lifting off or a spark plug failing... which i would think would result in a rich reading. (Spark plugs are the one step colder gapped to whatever BM3 was recommending. Swapped 10k miles ago and not had an issue until this new stage2+ came out with new fuel pump. Again stage 2 93 runs great)

https://www.bootmod3.net/log?id=6132...0b433146aa88af

any help is appreciated as I would like to run this setup but I have topped off with octane booster and will run the normal stage 2 tune until I either get a custom tune done or this can be resolved. super sketchy feeling either way.
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      09-03-2021, 10:57 PM   #2
ZM2
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Do you have a 3.5-bar TMAP installed? If not, I'd do that.

I'd also go ahead and run half E85/half 93 since you have the HPFP to support it.
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      09-04-2021, 11:07 AM   #3
ZM2
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And, lots of guys run this map fine, so I don’t think a custom tune is going to help.

This sounds like a hardware or fuel issue.
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      09-04-2021, 01:21 PM   #4
nismoman
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I still have the stock tmap and have that selected as oem.

Hardware doesn’t seem to be the issue because nothing is out of the ordinary, iat was 70 something, fuel pump was chugging along, boost holding strong and no fault codes, Just a big ass hickup which was weird. I’ll try and get it on a Dyno and pull the plugs just to make sure but seems like it should just work lol
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      09-04-2021, 02:36 PM   #5
ZM2
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It’s hardware.

Read up in some of the other Stg 2+ E30 threads, it’s probably the TMAP. You’re already hitting the stock TMAPs boost read limit, so it needs to be changed anyways. Change it and add more E85, and you’ll be fine.

Separately, I had issues with BM3 recommended plug gap that went away when I went back to stock gap, but those were very tiny intermittent hiccups, not big ones.

Last edited by ZM2; 09-04-2021 at 06:05 PM..
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      09-05-2021, 07:08 AM   #6
nismoman
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Quote:
Originally Posted by ZM2 View Post
It’s hardware.

Read up in some of the other Stg 2+ E30 threads, it’s probably the TMAP. You’re already hitting the stock TMAPs boost read limit, so it needs to be changed anyways. Change it and add more E85, and you’ll be fine.

Separately, I had issues with BM3 recommended plug gap that went away when I went back to stock gap, but those were very tiny intermittent hiccups, not big ones.
Sorry, by hardware I thought you meant the aftermarket parts being faulty. The tmap makes sense. Thanks for the info and time.
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      09-07-2021, 06:59 PM   #7
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Quote:
Originally Posted by ZM2 View Post
Do you have a 3.5-bar TMAP installed? If not, I'd do that.

I'd also go ahead and run half E85/half 93 since you have the HPFP to support it.
Can you run 50(e85)/50( gas) on2+ E30 ots map, and would it improve the power?
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      09-07-2021, 07:48 PM   #8
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Quote:
Originally Posted by Mr_M// View Post
Can you run 50(e85)/50( gas) on2+ E30 ots map, and would it improve the power?
IDK if it will give much more power, but the tune & timing seems to run better with more ethanol than E30. E45-55 seems like the sweet spot, so I just go half E85 & half pump gas.
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      09-07-2021, 08:04 PM   #9
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Quote:
Originally Posted by ZM2 View Post
IDK if it will give much more power, but the tune & timing seems to run better with more ethanol than E30. E45-55 seems like the sweet spot, so I just go half E85 & half pump gas.
Good to know
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