swapping map sensors on power fc????

[dac69er]

from reading a few posts it looked as though you just fit the new sensor, select it on the commander or setup the offset and scale and then your map will be fine.

i just recently got a new map sensor from an st205 which should read a bit higher than stock, selected sw20 sensor as its the same and the car runs fine, boost reading matches my boost controller so looks good.

only problem is my fuelling seems to have richened up a bit. by approx 0.5 afr across the whole scale. i have the datalogit software so i can just knock the whole fuelling map back until i was back to where i was. just wondered if this was normal or if i missed anything?

 

[sx_turbo]

what you have done is correct,

it has probably got ricjher because the scale is different to what it was with the stock sensor,

 

[dac69er]

it makes sense. i was just sure i read somewhere that you just swap them over, change the setting and everything stays the same. must have been seeing things

i have a tad more knock also as it has obviously had the same effect on the timing map. will have to get re-mapping i guess

 

[sx_turbo]

it doesnt read the same, it reads very similar but not the same,

you wont get 2 different map sensors with different scales to read exactly the same, you can only get them to read similar.

the 1 bar map sensor will have a wider scale than the 1.5bar map sensor,

basicly if you scale a 1 bar map sensor in 20 points, then scale a 1.5bar map sensor in 20 points the reading of the sensors will be different because you need to squeeze the extra 0.5 bar in there somewhere.

i hope that makes sense it does in my head lol

 

[dac69er]

i do process engineering mate so know exactly what you mean. as said. i was sure i read somewhere (possibly on here) that the software re-scales everything in such a way that your map stays the same. but as i have now seen first hand, this is just not true

 

[sx_turbo]

sorry duncan, meant more as to whether i wrote it down right more than u understanding

 

[dac69er]

no problem. probably wont get round to doing much more on the car this year as the winter is now drawing in

 

[weeJohn]

Lads I think you have got it wrong with the sensor pressure reading and the scale. If a sensor reads 2 bar, then it gives out a varying voltage for each point over the 2 bar it reads. The scale setting in the software (be it a fixed or a scaled option) tells the software how to interperate that voltage output into a pressure reading. The P01 to P20 settings (pressure) are fixed as indicated on settings page 3 so the map reads from that and revs and decides what to do with the fuelling and ignition.

If the cars not fuelling the same after fitting a new sensor then either the old one was not reading as per the set scale or the new one is not. The map is fuelling the correct ammount for the ammount of air it is being told is in there by the map sensor, but as there is an error in the translation, the ammount it is fuelling is giving a different AFR from before.

There is a way of correcting a map without having to go all over it, but I would give it a thorough check anyway. If you look at the software guide, section 1-4, there is a guide to recalculate the base, I think that will work for you Dunc.

 

[dac69er]

both sensors read correctly when compared to my greddy boost controller.

re calc base map just sets the inj correction table to 1 and adjusts the base map to compensate. i cant see that helping? or am i missing something?

if you have 20 points on the map to adjust the fuelling/timing across a set map sensor range then it makes sense to assume that there will be a difference when you increase the maximum range.

for example, if you divide 2bar by 20 you get different increment points compared to dividing 3bar by 20.

all i wasnt sure about is whether the software recalculates the fuelling automatically based on the new range? but as i have seen it hasnt.