HELP NEEDED! FL C63 Sedan LOSS LOW END BOOST
Thread Starter
Junior Member
Joined: Jan 2024
Posts: 25
Likes: 1
W205 C63 Sedan
HELP NEEDED! FL C63 Sedan LOSS LOW END BOOST
Hey guys!
After a recent HOT track day, my car has been acting up since. The car lost its "no lag" title, and she laggy af. Full boost used to got on moment after WOT, even at 2000 RPM (do this quite often when I gather log). Now she would struggle to reach full boost until 3000 RPM.
Mods:
- Highflow downpipe (Checked, cat not metled)
- JB4 (Uninstalled trying to figure out whats wrong)
Here are some symtons:
- Noticed in tunnel that the car exhaust sound like a tractor after track day (Could be a JB4 issue, board got wet, sound seems normal now after uninstallation, not 100% confirm)
- Bad bad bad MPG
- Turbo lag, no more pushing you into the seat
- Wastegate rod rattle sound (new!)
What I've done so far:
- Oil and filter changed, air filter changed
- Sparkplug changed
- JB4 uninstalled
- Xentry scanned by dealership, no code, no nothing
- ECU reset using Xentry
Currently suspecting vaccum related issue, or wastegate rod need adjustment.
Help?
After a recent HOT track day, my car has been acting up since. The car lost its "no lag" title, and she laggy af. Full boost used to got on moment after WOT, even at 2000 RPM (do this quite often when I gather log). Now she would struggle to reach full boost until 3000 RPM.
Mods:
- Highflow downpipe (Checked, cat not metled)
- JB4 (Uninstalled trying to figure out whats wrong)
Here are some symtons:
- Noticed in tunnel that the car exhaust sound like a tractor after track day (Could be a JB4 issue, board got wet, sound seems normal now after uninstallation, not 100% confirm)
- Bad bad bad MPG
- Turbo lag, no more pushing you into the seat
- Wastegate rod rattle sound (new!)
What I've done so far:
- Oil and filter changed, air filter changed
- Sparkplug changed
- JB4 uninstalled
- Xentry scanned by dealership, no code, no nothing
- ECU reset using Xentry
Currently suspecting vaccum related issue, or wastegate rod need adjustment.
Help?
Last edited by Joey911; Apr 17, 2024 at 02:31 AM.
Hey guys!
After a recent HOT track day, my car has been acting up since. The car lost its "no lag" title, and she laggy af. Full boost used to got on moment after WOT, even at 2000 RPM (do this quite often when I gather log). Now she would struggle to reach full boost until 3000 RPM.
Mods:
- Highflow downpipe (Checked, cat not metled)
- JB4 (Uninstalled trying to figure out whats wrong)
Here are some symtons:
- Noticed in tunnel that the car exhaust sound like a tractor after track day (Could be a JB4 issue, board got wet, sound seems normal now after uninstallation, not 100% confirm)
- Bad bad bad MPG
- Turbo lag, no more pushing you into the seat
- Wastegate rod rattle sound (new!)
What I've done so far:
- Oil and filter changed, air filter changed
- Sparkplug changed
- JB4 uninstalled
- Xentry scanned by dealership, no code, no nothing
- ECU reset using Xentry
Currently suspecting vaccum related issue, or wastegate rod need adjustment.
Help?
After a recent HOT track day, my car has been acting up since. The car lost its "no lag" title, and she laggy af. Full boost used to got on moment after WOT, even at 2000 RPM (do this quite often when I gather log). Now she would struggle to reach full boost until 3000 RPM.
Mods:
- Highflow downpipe (Checked, cat not metled)
- JB4 (Uninstalled trying to figure out whats wrong)
Here are some symtons:
- Noticed in tunnel that the car exhaust sound like a tractor after track day (Could be a JB4 issue, board got wet, sound seems normal now after uninstallation, not 100% confirm)
- Bad bad bad MPG
- Turbo lag, no more pushing you into the seat
- Wastegate rod rattle sound (new!)
What I've done so far:
- Oil and filter changed, air filter changed
- Sparkplug changed
- JB4 uninstalled
- Xentry scanned by dealership, no code, no nothing
- ECU reset using Xentry
Currently suspecting vaccum related issue, or wastegate rod need adjustment.
Help?
you will find your answer there
good tools, good work
Thread Starter
Junior Member
Joined: Jan 2024
Posts: 25
Likes: 1
W205 C63 Sedan
Anyone? Went to dealership and tech couldn’t tell what’s the problem. I suspect it might have to something to do with vacuum system because of the slow spool, but it could reach max boost at higher rpm.
Thread Starter
Junior Member
Joined: Jan 2024
Posts: 25
Likes: 1
W205 C63 Sedan
Issue found, cause not known: Exhuast V band clamps leak if boost is tuned up with JB4.
- Not sure if stock boost level can cause leak on re-use v bands.
- Not sure if the original clamps are not supposed to be reused.
Symtoms when leaking:
- Loss of low end torque (super obvious when driving normally around town)
- Delayed boost on set, flooring @ 2000 RPM would have a 1 plus seconds delay
- Jerky shifting, especially 1 to 2 to 3, could jump back and forth
- AFR having hard time staying at stoich, it would bounce between 14.4 and 14.6, but when no leak, it would bounce between 14.6 and 14.7. Probs cause by false lean condition
- BAD MPG, like BAD
Hope it helps
- Not sure if stock boost level can cause leak on re-use v bands.
- Not sure if the original clamps are not supposed to be reused.
Symtoms when leaking:
- Loss of low end torque (super obvious when driving normally around town)
- Delayed boost on set, flooring @ 2000 RPM would have a 1 plus seconds delay
- Jerky shifting, especially 1 to 2 to 3, could jump back and forth
- AFR having hard time staying at stoich, it would bounce between 14.4 and 14.6, but when no leak, it would bounce between 14.6 and 14.7. Probs cause by false lean condition
- BAD MPG, like BAD
Hope it helps
