" Yes, I think there is this common misconception that fuel trims have something to do with fueling capacity. Not sure where it came from. But, it's not accurate. Fuel trims are just a function of the scalar value entered in the flash and whatever biasing the piggyback is doing. Nothing to do with fueling capacity. Fuel PRESSURE is the measure you need to keep an eye on. "

" Looks like the JB4 is working nicely out of the box. Let's get the back end flash loaded to tide you over until we can do single turbo boost control on the JB4 end. "

" The flash and piggyback tuning need to both be modified to work together. "

" Jason reads this forum so it won't take long. Best thing you can do to protest the censorship is to just not post over there. Sooner or later membership will dwindle and those who are looking for more exciting conversation will turn elsewhere. Same thing is happening to the N54 section there now. BB has become the first forum most check in the AM followed by e90post if nothing is going on over here. "

" Basically what you want won't work. Or at least I can't offer you any help with it. Once the DME is not seeing actual boost levels everything on the tuning end must be accommodated via the piggyback for proper engine management. The closer to actual boost the DME sees the less has to be done. But scalar values, biasing, etc, all must be manipulated to make it work. "

" You need to wait for us to write single turbo boost control algorithms for the JB4 for it to work properly. "

" He's not running meth currently (see IAT) but I agree. It masks all these fueling issues. But has its own headaches from time to time. "

" I have one of your dyno logs handy. I've been using the conversion factor of 1 unit per 150psi so in this log high pressure drops to ~1350psi. Those road logs where it's dropping to 6 / 900psi are a killer. Hopefully between our current R&D and Garth's we can figure something out. I noticed in those road runs IAT was lower so much more actual power is being generated which puts that much more stress on the fueling. "

" Load 200 all across would be some sort of wacky boost curve between 16-20psi depending on RPM & air intake temperature. What the JB4 would do would depend entirely on what actual boost was doing vs. the DME target via whatever was controlling it. "

" lol the JB4 does all this stuff. We put lots of extra I/O on it. "

" With meth it's no problem. And without one option is to just run it super lean Vishnu style. Drop me a current log and we can check it out. I'm experimenting with a new fuel pump approach that seems better than in the tank options for boosting lower RPM fueling in early testing. "

" Busy day. Broke down twice driving around due to a fuel line popping off. First time luckily close to the office and second time luckily close to home. So I was able to walk a bit, grab tools/jack, and repair both times. Finally took it apart at home again and realized there was an assembly flaw. The quick connect fitting I was using to mate to the OEM line was not long enough. Found a FRAM F65217 fuel filter at Pep Boys and used that as a joiner. Seems solid now and so far so good. Back in business.

The pump is controlled by the JB4 and turns on at ~8psi. When it kicks on map goes to 20 in the log, and low fuel pressure tilts at 87psi. Based on the last round of testing I'm guessing fuel pressure is around 100psi.

Still slowly building confidence up with the install so didn't venture too far from home tonight but I did grab a few short logs. I can see PWM is maxing out around 60% even when fuel pressure dives. That must just be the maximum. I noticed a bit of inconsistency in how/when it drops. So I'll try to narrow it down so I have a good repeatable test, and then I'll program the JB4 to add a bit of duty cycle to the mass control valve in a situation where fuel pressure has been dropping just to see what happens. "

" Dealers are fairly worthless. If you're bored borrow someones JB4 ISO and do a log or two on that, and then I'd be happy to give you my opinion on what is going on with the car. "

" If you go in and zero out the o2 bias & fp bias, zero out cps or don't install the wires, and remove the solenoid connections so it can't control boost, then the JB4 will report actual boost to the DME up until the factory boost target at which point the JB4 will clamp the boost signal at that level, unless actual boost goes over the JB4 target, in which case the JB4 will start to report higher than actual target back to the DME for throttle management. A few guys run the JB4 with an external controller but they just run a fixed boost level across the board and enter that value both in the JB4 and their external controller so boost hovers around the JB4 target. Sloppy but workable short term.

Generally speaking, for it to work right the JB4 needs to be controlling boost. Some day soon we'll offer that functionality. Until then I don't think there are any good options. The procede in theory is setup for external wategate control for FFTEC's kit but I don't know if that would work with another kit or whether or not they would share the firmware. You'd have to check with them. "

" Went by Pep Boys this morning to pick up some clamps and noticed some asshole has copied your trademarked character and made him in to a headphone jack. "

" What you want won't work. But the JB4 ISO was designed to control an external wastegate. I've just yet to finalize the software. Some day someone will drop off a single turbo car (or we're add one to our stable), and we'll write that part of the code. Once written you can use the JB4 for boost, fuel, and cps (timing), for boost only along with your flash of choice, or boost & fuel along with the BMS flash as we do now for RB cars. "

" lol.. threw him a pos rep also. "

" The 135i happens to have two bolts there to accept a pump bracket. I can't say whether the 335i has the same bolts. "

" Basically same thing. It actually doesn't run full duty full time though. I made a video a long time ago, let me see if I can find it...

Found it. lol @ old CMGS.

https://www.youtube.com/watch?v=ujgOsmzwSek "

" Based on the first set I learned the sensor tilts out at 87psi, throws a shadow 29F3 code, and the pump then switches over to a default duty cycle curve that is basically 100% duty at full throttle. So for now I won't bother with it. I'm going to program the JB4 to kick the pump on at 100% duty cycle at 12psi and see how it does in general compared to the Walbro in tank. "