03-27-2014, 02:56 AM #1
Throttle closures and boost overshoot. Input needed.
Hey guys. Lately I have been having some issues with boost overshoots resulting in throttle closures. I donít really feel this and it doesnít seem to affect the power of the car. The car pulls strong and did 427/443 on a dynojet this weekend. I talked with Terry and he thought it was because my FF was higher than my PWM. Looking back at my old logs, this has always been the case and I really donít see a difference between now and then.
I have used multiple variations of backend flashes with partial and full writes. I have thrown up a log done on the street and recent dyno. Since then I did 1-7 on the JB4 to reset adaptations. The idle and start was noticeably smoother. The logs still show some closure but I am assuming it may be adapting? Not sure. Just looking for some more input and open to suggestions.
Mods are JB4 G5 with custom E85 backend. BMS charge pipe and DCI. Stock FMIC and DPs. E60ish fuel with Walbro and HPFP is <1000 miles old. Walbro and new LPFP were put in about 4-5k miles ago.
The first photo is a log about a week or so ago. The 2nd picture is the dyno the past weekend. The next 6 photos are consecutive logs over about 1 hour after resetting adaptations tonight.
It doesn't look like you can upload the .csv files so I put there here in a dropbox folder
Thanks!E92 335is | DCT | JB4 G5 ISO | Custom Backend Flash | ETS 5" | BMS OCC | BMS DCI | BMS CP | BMS O-Tstat | catless DPs | Stage 2 LPFP | E60 | 436/479 (4th gear) DJ on stock DPs
03-28-2014, 09:15 PM #2
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03-28-2014, 11:28 PM #3
No experience trying to juggle flash load targets, WGDC.....and setting custom boost levels with the JB4...but have you told your JB4 to ignore the DME's boost targets?
Define "custom e85 backend"...as that is what I'd be looking at...
Not a lot of help, but this is pretty much appears to be a tuning issue and incompatibility with what you are then trying to do with the JB4.
03-29-2014, 01:13 AM #4
Hey Steve. I haven't tried the 4-2 ignore DME boost targets but I shall and will do a log and report back when I get some drier weather. My DME load targets are lower than JB4s at this point. That change helped cure the DCT slip vs the high load flash.
The E85 backend isn't drastically different than Terry's which it is based off. I base it off my stock rom vs a canned bin which shouldn't be an issue. I have worked with Terry on it and I don't think there is anything out of line with it.
Interesting enough the problem started after a DME update from the dealer and reinstall of JB4 with new charge pipe. I did use a different T-map sensor, one that was on my car before the original charge pipe blew up. I have a lot of logs on that T-map so I don't think its the issue. Crazy thing is if I didn't log so much I probably wouldn't know this was happening. Car feels stronger than ever.E92 335is | DCT | JB4 G5 ISO | Custom Backend Flash | ETS 5" | BMS OCC | BMS DCI | BMS CP | BMS O-Tstat | catless DPs | Stage 2 LPFP | E60 | 436/479 (4th gear) DJ on stock DPs