AFM upside down? = richer AFR's

[rob2006]

Last week i had played with the map on my E7 to a point where i felt pretty happy with it.

Yesterday i decided to purchase a nice new big K&N from neverneverman to replace my HKS SPF. (just personal preferance)

Now last week I was in the 300 range load cells between 3.5k and 6.5k and my Map AFR's were into the 13.x range to get a 12 Actual AFR.

Tonight i fitted my K&N and also turned the MAF around as it was fitted upside down for some unknown reason. Took the car for a run and i noticed my AFR's at spool up were into the 13's.... it wasnt like that before.. I gave the car a bit more throttle and seen a 14.x whilst aproching 4k.

I've had to go over the fuel maps again and take everything right back by more than 2 full AFR points to get AFR's back into my targe range of 12.x

The logs i have now also show i'm no longer hitting the load cells in the 300 column, its now 280 max.

Whats caused this? The AFM being upside down or the increased surface area of the K&N getting more air in over the HKS, a combination of both?

[evonut270]

its more likely the K+N rather than the maf.it should not matter if its fitted upside down.

[sponners]

as above, position of the maf shouldnt affect it - but we know different induction setups can alter the airflow reading quite dramatically.

.....so your timing will also need adjusting now aswell