Strange Re-mapping issue!

[Lum]

Bit of an odd problem this, i\'m hoping someone on here can shed some light on it?
This is the spec of my car
Street port
1680cc secondarys
Adjustable FPR
Bosch 044 pump
Blitz FMIC
Full de-cat
Apexi Power FC
Along with all this i was running a Garrett GT35R turbo (1.06A/R), had it all mapped & it made a healthy 400FWBHP at 1 Bar.
Then i threw 4 tips at rotorstock due to detonation caused by a split in the vacume line to the FPR.
I\'ve since rebuilt the engine using the same plates with exact same porting but have changed the turbo for a garrett T04Z (1.00A/R)
Now last week i had the car remapped by the same person who has done all my tuning!
This is where it gets odd, the old map (for the GT35) was far too rich, so despite now having a bigger turbo we\'ve had to take nearly 10% fuel out of the map to get the AFR\'s down to an acceptable level. Apparently the map now has less fuel at the top end than the apexi base mod map??
So the AFR\'s are safe & the car drives fine & pulls hard but why have we had to take so much fuel out?? surely a T04Z would require more fuel adding to the map??
I hope someone can help cos we\'re stumped!!:confused:
Thanks

[memski]

Maybe because you\'ve got 1600cc secondaries now the stock map can be leaned out to compensate? I know it\'s a rich base map but that\'s a lot of fuel to take out. How are you finding the to4z in comparison to the gt35 btw?

[Carl]

First thing to consider is that the very problem that caused your first engine failure could be the cause of this,if when the car was mapped originally it had the split hose to the FPR then the map would be richer to compensate for the slightly lower fuel pressure.
How did you measure the AF\'s?
Wideband lamda sensors can easily read a long way out from what they are supposed to.
Also the weather conditions,and if the air in the atmosphere itself was at low or high pressure and even humidity can affect mapping.
Regards
Carl

[Lum]

Don\'t think it\'s that mate cos i was runnin 1680\'s when it was mapped for the GT35 and we\'ve had to take about 10% of fuel out of that map to get the AFR\'s down to a decent level??
T04Z comes on full boost about 500-800 rpm later than the GT35 but has a bigger kick and never runs out of puff! I run out of revs well before i run out of boost! only running it at 1 bar at the minute though!

[Lum]

First thing to consider is that the very problem that caused your first engine failure could be the cause of this,if when the car was mapped originally it had the split hose to the FPR then the map would be richer to compensate for the slightly lower fuel pressure.
How did you measure the AF\'s?
Wideband lamda sensors can easily read a long way out from what they are supposed to.
Also the weather conditions,and if the air in the atmosphere itself was at low or high pressure and even humidity can affect mapping.
Regards
Carl

Thanks for the tips carl
I was thinkin about the possibility of the FPR not rising the rate correctly during the original mapping! But my new map has less fuel at the top end than the base mod map? Does that sound rite?
AF\'s where measured the same way as last time, with a wide band lambda in the backbox. The wideband has only just been refurbished & callibrated. This is the first time it\'s been used since so don\'t think that is the issue.
Is it possible that a problem with the laptop used could be to blame??
Possibly file corruption??
Because it did have some problems that we thought were all sorted.
The car runs fine and feels like it\'s making good power with safe AF\'s, but the numbers just don\'t seem to add up??