question about MAP sensor

[archiboy24]

What would happen if I switched out my 2.5 BAR MAP sensor for a 3.0 BAR sensor, but kept the same boost and fuel chips?

[javispa]

I don't think it would work properly. The chips are designed to work using a MAP and I guess that there is no way that the ECU will know that you have changed the MAP. If you change the MAP, the ECU will work considering that the boost signals come from a 2,5 Bar MAP, which won't be true. Then if the ECU is mapped to give, let's say, 1,5 Bar boost, this means an imput signal of 4,8 V with the 2,5 Bar MAP, if you change the MAP, the ECU will make the engine work untill an imput signal of 4,8 V wich means, in a 3 Bar MAP, 2 Bar boost. The turbo will work with higher boost but the ECU will still consider that the boost level is lower than what it really is. I am quite sure that it won'k work fine and I suppose that some overboost protection (limp mode) will appear (correct me if I am wrong, but I guess that will happen as the signals from the MAF and the MAP won't match).
I don't know if I have explained myself right... but my answer is that I woudn't change it .
Cheers.

[driftin jo]

Or to simplify the above, it won't work , it has to be mapped to suit !

[Rocco]

jAvier

and then,why the original 315hp RS2 comes with 300KPA map sensor inside if never boost more than 1´3bar?? ,of course it was desinged and made the original ECU for work with 300kpa parameters and lower boost ( 250kpa map sensor would be enought true?? )

[javispa]

jAvier

and then,why the original 315hp RS2 comes with 300KPA map sensor inside if never boost more than 1´3bar?? ,of course it was desinged and made the original ECU for work with 300kpa parameters and lower boost ( 250kpa map sensor would be enought true?? )

Hi Rocco... about why does the RS2 use a bigger MAP... better ask Porsche . Seriously... I don't know it for sure right now, but I think that in overboost the RS2 boosts at 1,6 Bar. Anyway, I imagine that using a bigger MAP gives a margin to the boost level. Probably with a 2,5 Bar MAP the RS2 would be most of the time giving a signal very close to the limit. If for any reason the engine would not work properly and the boost would reach a higher level, with a 2,5 Bar MAP it would be difficult to detect.
I suppose that any of the forum gurus will know more about this.
Cheers.

[Rocco]

1´6bar 0 315hp?? ,i dont beliebe it....

[S2central.net]

What would happen if I switched out my 2.5 BAR MAP sensor for a 3.0 BAR sensor, but kept the same boost and fuel chips?

In short - it just wont run right as the scaling for boost control will be all out of whack. MAP change like that needs remap on the ECU.

[S2central.net]

1´6bar 0 315hp?? ,i dont beliebe it....

Not 1.6bar at peak power of course.

Porsche probably used a 3bar MAP during development to see how much scope/fun they could have - as we all know a highly tuned RS2 will embarrass many a porker - so they ended up detuning it so that whilst it was still fast - the 911 Turbo of the day still had the edge.

PAul