N54 possible boost leak?

[Wolfycruz]

I got a 2009 135 with 75k miles 6spd bms intakes, tial bov with charge pipe, cat less dps, jb4. Currently car makes hissing noise like air is escaping somewhere while accelerating , no engine codes, rpms going up way to high too quickly without the speedometer equally graduating. Car does in every gear, it will also cut itself off cruise control when needing to accelerate uphill,hoping someone can lead me somewhere

[TURBO8]

Sounds like a slipping clutch.

[Wolfycruz]

I put that in perspective as well but the clutch is good

[Tiffany@ActiveAutowerke]

Try looking at everything boost-related, Check vacuum lines/hoses, boost solenoids, wastegate for rattle.. Any broken connections that pressured air might seep out, even if its a small hairline crack. If you check/replace everything and the problem still persists. you may have to take a look at your turbos. My old N54 had that same issue, Underboosting 8 lbs and going immediately into limp mode if I remember correctly, I changed everything and it ended up fine. Good luck!

[SoFloE82]

How about a log to show target vs. actual boost and WGDC? Sounds to me like a clutch as well. Boost leaks wont cause the RPMs to climb too quickly. Slipping clutches or burning the tires off will.

[JPuehl]

Originally Posted by Wolfycruz

I got a 2009 135 with 75k miles 6spd bms intakes, tial bov with charge pipe, cat less dps, jb4. Currently car makes hissing noise like air is escaping somewhere while accelerating , no engine codes, rpms going up way to high too quickly without the speedometer equally graduating. Car does in every gear, it will also cut itself off cruise control when needing to accelerate uphill,hoping someone can lead me somewhere

If the engine is revving while in gear but the speed is not going up to match, assuming that's what you mean by "rpms going up way to high too quickly without the speedometer equally graduating." and you have a manual trans, your clutch is slipping. Even if your tires where just spinning, your speedo would increase.

Get a boost leak tester and check. I did that over the weekend and found that I had 3 leaks but never heard a hissing sound, or anything to lead me to believe I had a leak, I just tested for the heck of it. Just needed to tighten a few clamps. I checked my wifes car after mine and she also has 1 leak I need to fix where the FMIC outlet pipe connects to the FMIC.

Have someone drive your car that knows the speed should increase with the RPMs when in-gear. If your second opinion confirms your clutch is fine, do a boost leak test, fix any leaks them take the car to a shop to look at the rev issue.