monkeygod11 4 Report post Posted October 16, 2022 E82 135i N54 6hp auto I'm getting overboost at the track (never on the road). My latest day at hampton downs with traction control fully off and the trans in sport mode (with XHP stage 3) I was getting overboost limp modes. I then changed to traction control fully off while leaving the transmission in drive and only using about 70-80% throttle and had no overboost limp modes. I've upgraded to a Tial BOV instead of diverter valves, a CSF intercooler to lower my IATs which were stupid before. Boost solenoids are new. I'm thinking it's either the tune (Eurosurgeon tune from a few years ago) or waste gate actuators. I've got logs from the day which I'll put below, if anyone can see anything that can point me in the right direction I would really appreciate it. Overboost - TC off, trans in sport mode (XHP stage 3) https://datazap.me/u/grayman11/hampton-28922-session-3-overboost-sport-mode-tc?log=0&data=3-23 No overboost - TC off, trans in D (XHP stage 2) 70-80% throttle https://datazap.me/u/grayman11/hampton-28922-session-45-no-issues-drive-tc?log=0&data=3-23 Quote Share this post Link to post Share on other sites
smiddy 76 Report post Posted October 17, 2022 No expert myself, but learning a bit doing logs for a custom tune on hybrid turbos. Could be heaps of things going on. Tune parameters, fuel settings, aftermarket inlets, vac leaks. Really need to log a non track pull, in 3rd gear, manual mode, traction control off, 2k to 6.5k. Would look at a custom tune, with upgraded inlets, even with stock turbos, if tracking a bit, there are gains. MHD V10 2+ has a lot of issues ironed out and more flexibility, maybe try that. 1 Quote Share this post Link to post Share on other sites
jon dee 500 Report post Posted October 17, 2022 Don't know if it is relevant or not, but where I have put the broken green line the achieved boost spiked more than 1psi higher than the target boost. Depending on what it takes to trigger an overboost reaction (% above target, duration etc) that might be enough ? It's almost like the wastegates or BOV are not reacting fast enough when the achieved boost reaches target. Wastegates are controlled by the DME so there will be some kind of PID control going on = tune function. Just guessing of course, but that is what I would expect. Cheers... 1 Quote Share this post Link to post Share on other sites
monkeygod11 4 Report post Posted October 17, 2022 Thanks appreciate you guys taking the time to look, going to try changing the overboost threshold on the tune along with putting the trans in manual so it doesn't pick weird gears on track. Quote Share this post Link to post Share on other sites
