ST Pump Map vs ST e85 TS Map

[Stormshadow335]

Guys I have an 08 335i N54 with a single turbo Doc Race kit. For some reason, the JB4 BEF for the IJEOS doesn’t have a twin scroll (TS) pump gas file for my DME, but there is an e85 TS file.

I compared the two files by looking at the sections I thought would be important, and/or different due to e85 TS vs non-TS pump and listed where I found differences below.

If anyone knows the differences with TS and non-TS file I’d much rather just alter the pump file to be TS, rather than alter the e85 file to be pump.

Of the sections that I compared, I listed where I found differences below.

Boost Control
- Spool mode max rpm – different

Fueling
- Fuel (Bank 1 & 2) - small difference where AFRs are slightly higher on the e85 map in higher RPMs.
- Fuel Scaler (bank 1 & 2) – e85 1.30, pump 1.10
- Warm-up Enrichment Factor – Different
- Fuel start - Different

Ignition - All ignition maps are the same. Quite surprised.
Load – all the same
Functions
- All the same except below.
- Disable Lean Spool – Different
Knock – All the same. Another surprise.
Overboost - Load Adder – all the same
Spark Dwell – All the same
Anti-lag – All the same

Any insight? Please no guesses as to what it might be.

Thnx!

 

[KClemente]

Twin scroll vs single scroll will mostly be affected by vanos (citation needed lol). There's really no data public for basically any manifold out there so you'll mostly have to play around. For any turbo setup, my preference is usually keeping lean spool on (ethanol only) and changing every spool map to count for the spool mode max rpm table. I like to keep timing lower than stock to introduce more heat and fuel into the turbine housing

It really takes a lot of gas and time spent to get your spool dialed in and I suggest creating a bunch of different tunes and load em up on the side of the highway.

 

[Stormshadow335]

Thanks for the info. This is definitely helpful.

I'm a bit of a noob, so I wanna make sure I'm unpacking what you meant when you said lowering timing to introduce more heat and fuel into the turbine housing. This is to run higher boost levels that would require more fuel for the increased air as well as cooling purposes? I'm also guessing that the increased heat is related to the larger combustion and not the decreased timing, right?

Thnx!

 

[KClemente]

Thanks for the info. This is definitely helpful.

I'm a bit of a noob, so I wanna make sure I'm unpacking what you meant when you said lowering timing to introduce more heat and fuel into the turbine housing. This is to run higher boost levels that would require more fuel for the increased air as well as cooling purposes? I'm also guessing that the increased heat is related to the larger combustion and not the decreased timing, right?

Thnx!

We all start somewhere. What I meant about lowering timing and enabling lean spool, is that in order to get the fastest spool possible, you'd want to introduce more heat (EGT) into the turbine housing only during spool. I usually set "spool mode max rpm" to just under 4000 rpm.

On your normal timing/fueling maps, you want lower EGT's and that can be handled by making the afr mixture richer. Ethanol does wonders with its cooling capabilities because of the alcohol present.

And finally, increased heat is due to timing being retarded and combusting late in the cycle (and running lean).

I recommend starting off with the jb4 backend flash and tweaking things like the spool maps. A tune isn't completed if you aren't using the designated spool (timing, fuel, vanos) tables. Also, don't forget to rescale your spool tables, usually the last RPM row, and blend them in with your main table. Or else you might get some jerkiness when transitioning from spool mode to regular mode.

Until you get the hang of it, you can look at other peoples successful logs and compare them to yours. Just make sure you don't compare a pump gas log to one with an ethanol concentrate. Get your wastegate only boost pressure completely dialed in before jumping in the deep end. Also do your best not hitting 34% stft (50 trims if jb4). That's where motors get sent to the moon

 

[Stormshadow335]

We all start somewhere. What I meant about lowering timing and enabling lean spool, is that in order to get the fastest spool possible, you'd want to introduce more heat (EGT) into the turbine housing only during spool. I usually set "spool mode max rpm" to just under 4000 rpm.

On your normal timing/fueling maps, you want lower EGT's and that can be handled by making the afr mixture richer. Ethanol does wonders with its cooling capabilities because of the alcohol present.

And finally, increased heat is due to timing being retarded and combusting late in the cycle (and running lean).

I recommend starting off with the jb4 backend flash and tweaking things like the spool maps. A tune isn't completed if you aren't using the designated spool (timing, fuel, vanos) tables. Also, don't forget to rescale your spool tables, usually the last RPM row, and blend them in with your main table. Or else you might get some jerkiness when transitioning from spool mode to regular mode.

Until you get the hang of it, you can look at other peoples successful logs and compare them to yours. Just make sure you don't compare a pump gas log to one with an ethanol concentrate. Get your wastegate only boost pressure completely dialed in before jumping in the deep end. Also do your best not hitting 34% stft (50 trims if jb4). That's where motors get sent to the moon

lol at sending the motor to the moon Definitely not trying to do that. I really appreciate the details. I have a much better understanding of the spool process now.

I’m running around 14 psi on a precision 6062 and I’m getting random timing drops across some cylinders. I was throwing more fuel at it under the assumption that the BEF timing was fairly conservative, but it looks like I might need to back off a little timing under spool like you said, and maybe in the normal timing/fueling maps as well.

I’ll have to research the vanos maps before I start messing with those.

I’m running the stock coils, and I’m thinking this might have something to do with the timing drops. I heard they’re good to around 550 hp.

The BEF comes with WG pressure, 17 psi and 20 psi maps. Do you think the 17 and 20 psi boost targets are attainable on pump gas w/o meth or e85? I have a meth kit that I’ve never used before. But like you suggested, I wanted to sort out the pump gas tune before I tried throwing another variable in the mix. The 14 psi is my WG pressure. Not ideal, but those WG’s are a pain to get to under the car.

Thanks!

 

[Jake@MHD]

Never enable "lean spool" as you will not have control over the lambda target during spool then. If you meant "spool mode" then that is different (and fine to use), which references the spool mode set of tables used at WOT under the spool mode max rpm.

 

[Stormshadow335]

Never enable "lean spool" as you will not have control over the lambda target during spool then. If you meant "spool mode" then that is different (and fine to use), which references the spool mode set of tables used at WOT under the spool mode max rpm.

Thnx for the clarification. I'll be holding off on any of the more technical changes until I have a better grasp of how those changes might impact the safety of the tune.