[V8bait]

Originally Posted by 135Pats

How does JB4 scale fuel trims? I honestly don’t know…obviously it’s not +/- 34

Don't think it shows negative. But 50 denotes maxed out STFT's.

FOL is how much it's lying about fuel pressure to get trims into range... 0 is an honest jb4, 100 is a dirty liar and maxed out. You want it at zero or low ideally (by adjusting your scalar), that way if you want to run more E85 and don't want to flash you can raise it to keep trims good.

OP's car needs a backend and who knows what else if he intends to use E85.

[waterbottle1]

Originally Posted by AK 335i

Single turbo backend flash tweaked from terry.

up to full e85


aem v2 standalone meth kit
Vargas modified HPFP and rail
inline 255

wow, nice

just did a quick wot in 2nd,
u rekon at 15.1 @ 4000rpm then 14.8 @ 4400rpm and drops to 13.6 5500rpm and then 12.9 at around 6000rpm.. seems okay ?
just seeems still high in mid rpm range at WOT......

This is after update terry told me to do
and probably %20 e85 now.. coz i added more 93 in due high afr

[V8bait]

That's because it is still lean at all mentioned points. In map 4 what are your afr's?

[Jeff@TopGearSolutions]

Originally Posted by waterbottle1

wow, nice

just did a quick wot in 2nd,
u rekon at 15.1 @ 4000rpm then 14.8 @ 4400rpm and drops to 13.6 5500rpm and then 12.9 at around 6000rpm.. seems okay ?
just seeems still high in mid rpm range at WOT......

This is after update terry told me to do
and probably %20 e85 now.. coz i added more 93 in due high afr

Still lean and it's going to be hard to get the fueling capacity with a piggyback only down in the mid-range.

I'd like to see AFR, especially in the meat of the torque at 12-13 AFR across the board.

[waterbottle1]

Originally Posted by V8bait

That's because it is still lean at all mentioned points. In map 4 what are your afr's?

im not to sure, have not done this yet

[waterbottle1]

Originally Posted by Jeff@TopGearSolutions

Still lean and it's going to be hard to get the fueling capacity with a piggyback only down in the mid-range.

I'd like to see AFR, especially in the meat of the torque at 12-13 AFR across the board.

yep, i went to dyno and asked the dude there, and he said its "very dangerous lean to be above 14-15 at high rpm.." (although he is an evo tuner not bmw, not sure if have same limits)
he really disliked piggyback ... also said due to being piggyback, the afr will always be jumpy and kept telling me the safer option would be flash the ecu instead, or using something like cobb.

Just did more WOTS' after new update and less ethanol%, still lean... but less than original..


high rpm, but just to see AFR


second wot,



AFR will do 15-14-13-12.9
(as going up from 2000 - 6000rpm)
i think im gonna go no ethanol and see my figures again ...

[135Pats]

@waterbottle1 the DME is refined to a degree that EVOs will never be, so we can get away with piggys. JB4 is very good, just doesn't manage fuel well.

[V8bait]

Find somebody local to install the bms backend flash for you. Problem solved for free. Nobody has an excuse for these shenanigans anymore.

[Jeff@TopGearSolutions]

Originally Posted by waterbottle1

yep, i went to dyno and asked the dude there, and he said its "very dangerous lean to be above 14-15 at high rpm.." (although he is an evo tuner not bmw, not sure if have same limits)
he really disliked piggyback ... also said due to being piggyback, the afr will always be jumpy and kept telling me the safer option would be flash the ecu instead, or using something like cobb.

Just did more WOTS' after new update and less ethanol%, still lean... but less than original..


high rpm, but just to see AFR
Attachment 1009193

second wot,

Attachment 1009194

AFR will do 15-14-13-12.9
(as going up from 2000 - 6000rpm)
i think im gonna go no ethanol and see my figures again ...

The JB4 is ok for a typical bolt on car or typical FBO with meth car.

However, once you start playing with E85 you really need to run two tunes piggy back and flash, that's just the nature of this platform.

There are a couple of tuning changes that can be made to support about 30% E85 in the tune but I leave those remarks to the tuner as I never had access to e85 so I never played around with those settings.

An EVO is not direct injection therefore they must target richer AFR targets. Usually 11 to 11.5 max AFR for them and most other port injection fuel vehicles.

Since the N54 is direct injection, meaning the fuel is sprayed in the combustion chamber, you can get away with slightly leaner AFR and still be safe. However, 14-15 and WOT is not really safe. 14.7AFR is what every vehicle should target at idle. So by no accident a 14-15 AFR is not adequate for any car at wide open throttle.

The Piggyback were never good at the mid-range fueling capacity, however, like most tuning it's also theoretical and there really haven't been any failures because of these lean mid-range areas yet.

Keeping that in mind I still wouldn't ignore it, so get a back end flash to control fueling and you can enjoy your car without worrying.

[blbrchnk]

Still have to have a Bav Tech cable to do the backend flash correct?

[135Pats]

Originally Posted by blbrchnk

Still have to have a Bav Tech cable to do the backend flash correct?

yes.

[V8bait]

It doesn't have to be your bt cable, any bt cables the right bt cable.

[waterbottle1]

Originally Posted by Jeff@TopGearSolutions

The JB4 is ok for a typical bolt on car or typical FBO with meth car.

However, once you start playing with E85 you really need to run two tunes piggy back and flash, that's just the nature of this platform.

There are a couple of tuning changes that can be made to support about 30% E85 in the tune but I leave those remarks to the tuner as I never had access to e85 so I never played around with those settings.

An EVO is not direct injection therefore they must target richer AFR targets. Usually 11 to 11.5 max AFR for them and most other port injection fuel vehicles.

Since the N54 is direct injection, meaning the fuel is sprayed in the combustion chamber, you can get away with slightly leaner AFR and still be safe. However, 14-15 and WOT is not really safe. 14.7AFR is what every vehicle should target at idle. So by no accident a 14-15 AFR is not adequate for any car at wide open throttle.

The Piggyback were never good at the mid-range fueling capacity, however, like most tuning it's also theoretical and there really haven't been any failures because of these lean mid-range areas yet.

Keeping that in mind I still wouldn't ignore it, so get a back end flash to control fueling and you can enjoy your car without worrying.

wow, good info!
yep, im going to go back to 93 or what we call 98 in australia,
then buy the BT cable , walbro 255 and flash it!

cheers

[RagingE93]

Sorry to revive an old thread but it’s on the same subject I’m having so no point in making a new thread.

I’m having issues with my AFR. The car runs fine but my afr is around 15-13 at wot and it’s like that all the way to redline. I’m FBO on jb4 with e30 mix. I’m looking into the MHD BEF pump flash and wondering if that will help with getting my AfR down to 12. If anyone can chime in on my issue that would be great. Debating if I should go full MHD flash and ditch the jb4 or keep the jb4 and load a BEF.

[Paanzerfaust]

Originally Posted by RagingE93

Sorry to revive an old thread but it’s on the same subject I’m having so no point in making a new thread.

I’m having issues with my AFR. The car runs fine but my afr is around 15-13 at wot and it’s like that all the way to redline. I’m FBO on jb4 with e30 mix. I’m looking into the MHD BEF pump flash and wondering if that will help with getting my AfR down to 12. If anyone can chime in on my issue that would be great. Debating if I should go full MHD flash and ditch the jb4 or keep the jb4 and load a BEF.

Like it was said in this thread and a handful of others, the JB4 just isn't good at adjusting fuel delivery which is key to a good AFR and especially so for e blends. An MHD flash is absolutely necessary for you at that point, and if you wanna keep going with e blends then maybe (probably) replacing at least your lpfp.

The jb4 was great and convenient when it was one of the only options we had for this platform but personally I ditched it completely for MHD and couldn't be happier. If you aren't using the 2-step, no lift shift or other jb-dependant feature then about all a jb4 is useful for nowadays is a boost controller which we have better options for now anyway, but each person has different goals, opinions and wants for their car so YMMV. If you're happy with the jb4 and don't want to run ethanol or use the fancy new features of MHD then leave it in and stick to 93oct, if you like your e85 blends then at least do a BEF so MHD can manage your fuel efficiently, but I'll always personally vouch for the 100% flash route for various reasons.

[RagingE93]

Originally Posted by Paanzerfaust

Like it was said in this thread and a handful of others, the JB4 just isn't good at adjusting fuel delivery which is key to a good AFR and especially so for e blends. An MHD flash is absolutely necessary for you at that point, and if you wanna keep going with e blends then maybe (probably) replacing at least your lpfp.

The jb4 was great and convenient when it was one of the only options we had for this platform but personally I ditched it completely for MHD and couldn't be happier. If you aren't using the 2-step, no lift shift or other jb-dependant feature then about all a jb4 is useful for nowadays is a boost controller which we have better options for now anyway, but each person has different goals, opinions and wants for their car so YMMV. If you're happy with the jb4 and don't want to run ethanol or use the fancy new features of MHD then leave it in and stick to 93oct, if you like your e85 blends then at least do a BEF so MHD can manage your fuel efficiently, but I'll always personally vouch for the 100% flash route for various reasons.

Thanks. I like the jb4 functions so I think the MHD backend flask is my option.