Jim Galbally

keep reading about a lot of people on the BMW websites going crazy for "Alpha-N" chips which do away with the MAF and run purely from throttle angle. aparently this gives them loads more power as they dont have the (aparently) restrictive MAF in the way.

as far as i can tell this is done by editing the LOS map to contain the map you're interested in, so that with the MAF disconnected, the ECU enters LOS, and reads this now edited MAp and the car drives as intended.

in theory this sounds sensible(ish) but i'm sure it's a stupid thing to do?

also what are the cons of going from a proper MAF based system down to a purely alpha-n system. surely if there was no need for a MAF manufacturers wouldn't be using them? now i'm pretty sure i know the answers to all of these questions, but would be nice to get input from those that do this for a living (ie tony/stu/karl etc.) also would you personally ever sell such a chip, and if not, why not

thanks guys

Chip

iTrader: (3)

Cant comment on the particular chips as I havent run one, but the theory is sound.

The reason for the AFM is economy and emisisons.

For out and out power, they offer no advantage over throttle angle mapping or MAP mapping

Rick

Wouldn't

Chip

iTrader: (3)

Crikey Rick, can you hold back on the details, Jim is an inteligent guy and he wants to understand lots about it, but I dont think he can take in ALL that useful info you posted.....

pa_sjo

The MAF is also beneficial as an engine wears and it's VE reduces over time.. But not exactly relevant I suppose in this scenario as tuning a fucked engine isn't worth it.

It's not a great idea running an ECU in a failed mode as other things may come into play that these internet tuner goons may not know about (it's highly unlikely they completely understand the strategies in the ECU)..

Chip

iTrader: (3)

Agree totally on the failed mode stuff, it might take timing out when it switches to that map etc, although arguabley that could be put back in again.

Its a bodge fundamentally but it can and does work.

Rick

meant to say, wouldn't on anything that does a lot of road miles, unless it's running huge TB's and lairy cams.

Chip

iTrader: (3)

I agree, Id just look towards a less restrictive AFM, and a remap with that!

foreigneRS

i'd just leave it, it's probably powerful enough as it is without twatting about for a few extra bhp with the cost associated with it and any potential costs from engine damage. i think bmw m-division done a reasonable job on it overall, all things considered. fair enough on a track or race car of you've got money to burn, but not on a road car.

Jim Galbally

no, im DEFINATELY not considering doing this myself, im just questioning the people that may be buying these blindly

Chip

iTrader: (3)

Stick their car on the rollers with one of those chips in mate and I bet it makes either less power than standard, or barely any more, and I bet the AFR at points on the map is a MILE out.

DangerousBryan

there's a couple on e36 that have tried them jim. usually along with a carbon fibre inlet manifold,which doesn't have the space for the maf sensor.
bryan