Hi guys, would it matter if I ran a 3-bar map sensor on my large turbo escort cosworth? its stg 1 but I want to change the map sensor as I think it is goosed

cheers sean

 

I just fitted a 3bar to my stage1 Esc Cos as I was convinced my standard 2.5bar was fooked and it sorted the problems I've had no worries since

 

Paul Ripley What were the symptoms to make you think your map sensor was goosed?

 

2.5 bar and 3 bar MAP sensors produce different voltages for the same pressure and you cannot interchange them without getting fuelling problems. Paul, I suggest you source a 2.5 bar to replace the 3 bar asap.

 

What he said. Basically the MAP sensor divides the boost range into voltage signals from 0 to 5v, so obviously you can see that that fitting the wrong MAP sensor to the wrongly matched EPROM would mean that the ECU would not be seeing true boost.

 

above = conditions for maximum smoke IMO


get the correct 2.5 bar one fitted ASAP,

 

i.e. 2 bar MAP sensor "sees" 1 bar above atmospheric (0-14.7 psi), this pressure is sent as a voltage signal to the ECU divided between 0-5v.
A 2.5 bar MAP sensor "sees" 1.5 bar above atmospheric (0-22 psi), this pressure is sent as as a voltage signal to the ECU divided between 0-5v.
A 3 bar MAP sensor "sees" 2 bar above atmospheric (0-29.4 psi), this pressure is sent as a voltage signal to the ECU divided between 0-5v.

Obviously running a MAP sensor not fit for purpose (such as in Paul's case), will mean that the car can run lean/rich. This is because when the the car sees it's max boost of 18psi, the EPROM won't see the correct voltage to go with this, and so will under / over-fuel.

 

but if you have a stage one chip with a three bar map sensor would that work?

 

it may run, but not correctly,


generally, stg 1 chuips will utilise the std injectors AND map sensor, its not just a case of bolting bits on and hoping it works you could have a stg 1 chip that is specifically designed for a 3 bar map sensor, but i doubt it very much

 

Hmm I'm getting a stage three done next month so I'll just take it easy till then, but since fitting the 3bar is been running mint, the over boosting and misfire has gone and its mega smooth now

 

maybe, but it may well be running very lean, as the 3 bar map sensor will be telling the ecu that at 1 bar actual boost, the ecu will only be seeing 0.8 bar and fuelling accordingly, you only need to run lean for a couple of seconds and pop goes the engine

really, u'd be better off putting the 2.5 bar map sensor back on and it overfuel a bit until u get it stg 3'd

 

okay thanks guys, who can supply me with a new 2.5bar map sensor? Cash Waiting!!!

 

STAND CLEAR its gonna blow

its not overboosting because at 14 or 15 psi the ecu thinks its only running about 6 or 7 psi, and only delivering enough fuel for the lower boost level DONT DO IT ITS BAD, BAD I TELL YOU