You will need ecu programme adjusting, as the output 0-5v or what ever it is of the MAP sensor will now be for 0-4 bar and not 0-3 bar.
So the scaling is different.

 

 

Needs recalibrating.

I have a 4 bar on mine with the integral air temp sensor. I run a peak of around 3.5 bar.

 

Please excuse a silly question but when our turbos only run at say 2.2 bar why do we need 4 bar and where on the car do you see 3.5 bar?

Any why would Ian blow a 3 bar?

 

Pressure is absolute not gauge pressure.
The ecu needs to have the lowest pressure scaled against the voltage range.
E.g. 0.5v - 4.5v sensor range to the lowest pressure 30kpa or 0.30bar.
Remember your engine will run at vacuum. Vacuum is just low pressure. Lower than atmospheric.

Either over pressure on the sensor range (running more than 2bar gauge pressure) or shit sensors.

 

Got it, thanks

 

3 bar map sensor covers you for 1 bar vacuum pressure and 2 bar positive

 

Sensor could be failing due to the way they are mounted I.e too much heat or vibration

 

I would buy a 3bar from msd as it's the ones they now use.

James has said there are not enough map points in the table on a Weber ecu to make the engine run smooth with a 4 and 5 bar map.

 

This would be a rather more important question.

Although I suspect China might have the answer.

 

I run a 5 bar sensor on mine (still level 8 management), was then live mapped on the road

Cheers Paul

 

Heard them bhp sensors are rubbish too so I’d get a decent genuine one buddy

Cheers Paul

 

There should be little reason almsot any sensor could not be used, but yes the ecu will need re-tuned to suit the voltage/pressure scalings of that sensor.

Problem is most cheap sensors these days are Chinese.