Hi all,

I have this boost issue on my Mini Cooper S R56, year 2007 (JDM). went to circuit to test the car's performance, however after 5 laps I noticed the boost pressure dropping as the water temperature went up during the track driving. I am not sure if you guys have encounter this problem, but here is what I have experience:

The track condition - ambient was about 40°C. (tropical weather)
- track length is 5.543KM.

Lap 1 & 2: Car performed consistently
Lap 3: Water Temp 105°C +-, Boost Pressure 1.3 Bar reduced to 1 bar
Lap 4: Water Temp rised, Boost Pressure 1 bar reduced to 0.5 bar
Lap 5: Boost Pressure reduced gradually
Pit in: Cooling Down
Then, I went out to test again, boost pressure and water temperature back to normal figure, however, the same problem arise after few laps.


I have done these changes to my car upon the issue arise. Compression & leakdown tested, electric Fan in good condition, intercooler installed, changed to Forge BOV from stock, temperature sensor changed.

Does anyone face this problem? Thanks