Using 3 bar map sensor on 2.5 bar map car

http://forums.tdiclub.com/showthread.php?t=374131&highlight=2.5bar+map+sensor+3bar

http://forums.tdiclub.com/showthread.php?t=311032&highlight=2.5bar+map+sensor+3bar

Looking at changing the 2.5 bar map sensor to the 3 bar on my ASB engine in my A6.

I'm doing some mods now like 3" down pipe and decat, air intake etc.

Will it be ok to run before mapping??

No needs to be tuned in when you change it.
It's pain to align the headlights on this when changing the Map sensor - I've done it a few times now.

It will overboost

Good to see people bumping my old threads. I should have realized at time MAP calibration would be required

Yes, it should be installed and re-tuned if you are going to change from a 2.5 bar to a 3 bar MAP sensor. But, if by adding 20% more boost there will be no harm done, why not? I upgraded my turbo and nozzles and the nozzles were quite smoky w/o being re-tuned. Adding 3.6 PSI of boost in my case was a really good idea; I have better power and almost no smoke right now. I still have 2.4 PSI of room left in my turbo, and when my tuner gets his flash tool back, hopefully I will be next to use it.

Ive read that some cars seem to be more sensitive about it than others. sometimes you can get away with it, assuming the turbo can handle the extra boost. sometimes the ECU doesnt like what it sees and you just get limp mode because the low end voltage is now lower than expected.

if school and work would stop burning all my "performance enhancement" time, i would have tried this out already. i have the stuff to do it and just havent gotten to soldering the adapter on the ECU. Mines a B4 so MAP is internal to ECU...

at the end of the day, a tune is the right way to do it, but there's nothing wrong with experimenting as long as you understand the potential issues that can arise.