R56 S 07 Boost Drop :(

[OrangeFlavor]

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

[Flyin EVO 2]

I'm almost certain it's the ecu turning down the boost either from the coolant or charge (boost) temp rising higher than what the ecu would like to see for full boost operation. You have several options to resolve this issue. First off would be to have the coolant fans runing constantly to keep the heat out of the engine bay as you slow down for turns and such, second option would be to add some heat wrap to the exhaust system as well as the turbine housing and exhaust manifold, third option would be to upgrade the intercooler as well as the raidiator. Running an unleaded race fuel will help keep temps in line as well because your exhaust gas temp will be lower.