JB4 and XHP issue 2022 X3M40i

[TSARTY]

Hi all,I have a question concerning launch control with my 2022 x3 m40i. Car is stock and running an E30 Jb4 map. Launch control worked fine before the XHP flash. When utilizing XHP map 2 and doing a launch, if I hold boost to about 3k rpm, once I let the brake off, the engine goes for a split second and looses power. I have to release the gas for a second, then reapply to drive. (Launch control message is showing up on dash). If I do launch control and let the brake off around 2500-2900 rpm it will launch. Is there a setting I need to adjust, either on the JB4 or XHP, so that I don't have to time the rpm's just right and I can have the car hold at 3k rpm like it did before the transmission tune? Thank you for your time. Tyler.

[Steve @ BMS/Fuel-It!]

To be honest, that's not an issue I am familiar with, I have XHP on our X4M (S58, not B58) and haven't found that to be an issue. I don't think there is a setting on the Jb4 side we can change to help with that but upload a log of the issue and lets see what it's doing.

[TSARTY]

Thanks for the response Steve, I attached a CSV. I was going to graph it, but wasn't sure what you wanted to see. On a side note, XHP told me to set the JB4 to Map 0, and try a launch. Im currently at half a tank of e30, so i will have to wait. Not sure how running Map 0 will help, as Im quite fond of Map 3.

[Steve @ BMS/Fuel-It!]

Yeah...you can try map 0 but the DME is the one pulling boost (bright red line) and closing the throttle (orange line). Since you are running an additive map, JB4 isn't pulling boost but the additive will also follow ECU_PSI which drops drastically.

You could try an absolute map but with the DME pulling boost, you're likely to be fighting the same issue regardless.

[TSARTY]

Any idea why it might be pulling boost? Car launched fine before the XHP tune, with just the JB4 tune on map 3.

[Steve @ BMS/Fuel-It!]

No, you'd have to consult with XHP and see if others are experiencing the same issues and if they found a fix without flashing the car and adjusting the tune.

[TSARTY]

I was finally able to change to map 0 and do a launch. Launch was normal and no issues. I also uninstalled XHP, and launched while in Map 3 and no issues. Once I got home, I uninstalled Jb4 physically, reflashed XHP, then reinstalled Jb4 and set to map3. Launch control had the same issue. XHP is telling me it's a JB4 issue and that the JB4 is "faking torque values, which leads that the transmission is working with wrong values and this can lead to strange behavior." Their website also states their tune is compatible with JB4. I tried searching online and lots of users are running both with no issues, but cannot find anyone experiencing the same issue as me. Just trying to find out what my options are as far as working out this issue. I appreciate your time and help, Tyler

[Prozack8684]

I was finally able to change to map 0 and do a launch. Launch was normal and no issues. I also uninstalled XHP, and launched while in Map 3 and no issues. Once I got home, I uninstalled Jb4 physically, reflashed XHP, then reinstalled Jb4 and set to map3. Launch control had the same issue. XHP is telling me it's a JB4 issue and that the JB4 is "faking torque values, which leads that the transmission is working with wrong values and this can lead to strange behavior." Their website also states their tune is compatible with JB4. I tried searching online and lots of users are running both with no issues, but cannot find anyone experiencing the same issue as me. Just trying to find out what my options are as far as working out this issue. I appreciate your time and help, Tyler

I have the same exact car with the same setup(jb4 & XHP) and have no issues launching. I am currently on map 5 running e30 and stage 3 on the XHP. Try turning the drag race mode on in your custom settings on XHP and see if that does anything for you. Once you check the drag race mode on, you have to refresh stage 3 but it adds your custom settings.

[cartman417]

It’ll be interesting to if this got fixed and what the problem was

[Zdigs]

I'm having the same issue. Is it because the dme is hitting torque limits? Did you figure out what is going on?