N54 335i Single Turbo Tune Help

Hi guys. I have a 2008 335i with a Doc Race single turbo upgrade. I’m running the Precision 6062 gen 2 turbo with the following upgrades: 3.5" exhaust, FMIC, charge pipe, low pressure fuel pump. FYI - the coils are stock.

I’m currently tuning a base map to optimize my pump gas tune, and have a few observation/questions that I’ve listed below related to the attached log of runs.

What might be accounting for varying ignition timing across cylinders? I assume this isn’t normal.

Every so often the AFR raises to 12 under WOT at higher RPMs. Is this a function of load, or something else? In one run the AFR went from 11.1 to 12.1 at around 6,600 RPM. I’m assuming that higher AFR’s near redline aren’t desirable.

When I switch gears at WOT, there’s a significant ignition/timing drop off. What changes can I make to resolve this issue?

This is my 1st attempt at tuning, so any observations of anything that can be improved would be greatly appreciated.

Thanks.

Hi, I have an N54 as well, E82 with upgraded Twins. From the logs it looks like you aren't hitting target boost either but as for timing drops the stock Bosch coils aren't very good. Delphi are the N55 coils and Eldor are the S55 coils, either ones are OEM upgrades and worth considering. I run Eldor coils and put down 620hp/680tq last time i was on the dyno at 30 psi with about 8 degrees of timing up top and target about 12.3 AFR on an E60 blend, spark plugs are NGK 97506 and gapped to .019.

On 93 pump gas i wasn't able to push much timing without running into serious timing drops and from what i've read online MBT for the n54 is around 14 - 14.5 but you'll need Ethanol or some other higher octane fuel. Hope that helps.

FYI - don't watch the 17 psi. I'm running map 1 on the BEF, so it's targeting the wastegate spring pressure, not the 17 psi target shown in the log.

I'm actually running Delphi coils that I got from FCP Euro. I didn't know they were really from the N55 and considered upgrades. I need to look into how much power those can make.

The logs I posted, I dropped the ignition by .5 degrees in the high load range and the timing looks much better than before. I guess I have to factor in that the boost is low, but the turbo is big so the power output might be pushing the max I can make on pump gas.

Yesterday I increased my FOL from 88 to 92. Took it for a ride today and the logs look a little better at a glance. But looks like my HPFP was a little low early in a couple runs. I've highlighted in red wear I think I might have problems, and green where I think the logs look good.

oh ok, i didn't spend too much time with my JB4.

Your HPFP doesn't look that bad 6 ~ 900 psi and thats as low as you want it to go, AFRs look fairly consistent from bank to bank. There are a few tricks to help increase rail pressure, you can drill the main rail supply hole slightly larger - there's some info and DIY's floating around and some people remove the inline filter inside the HPFP but that has it's own considerations. The target rail pressure is adjustable and there are pid tables for it as well. I don't know if they've been added to the Github repository but they've been uploaded on some of the forums.

You'll be fine with delphi coils, i ran them for 4 years with no issues.

As for all your timing drops I would pull more timing if i were you, the computer is pulling timing in the middle of a run on multiple cylinders. If the plugs/coils are all in good condition then maybe you're just finding the knock threshold, you can try adding a small amount of ethanol and see what happens. The fuel system can handle small amounts - anything more you'll need to upgrade a lot of the fueling.

Thanks for taking the time to review the logs. And yeah, the JB4 boost target thing is just weird lol. They could’ve set that up better.

I actually have a Helix Overdrive kit for the HPFP. I’m waiting for the support bracket to come back in stock before I install it though. I also need to figure out how to incorporate the calibrations to the tune for the kit. I’ll definitely look up the threads related to raising the target pressure in the meantime.

I have a meth kit installed for about three years now that I never used. Guess now that I’m bold enough to try my hand at tuning, I have the stones to run a little meth lol. A 50/50 mix should help with cooling in addition to raising the octane right?

On N54 Tech, in the logging notes section, they mentioned the timing have a U shaped curve, starting high, dipping before hitting the heavy load area and raising towards redline. Based on that, I figured the dip and then rise of the timing was normal. I’ll take your advice and drop it a bit more though. I definitely wanna be on the safe side.

I actually have a meth kit installed for about three years now that I never used. Guess now that I’m bold enough to try my hand at tuning, I have the stones to run a little meth lol. A 50/50 mix should help with cooling in addition to raising the octane right?