M42 Alpha N options

[Motheye99]

A few questions, This is my first time researching a after market ECU/tuning
What are good options for ECU's for the m42 that would run a Alpha N tune. Im trying to set up some diy itb's, Alpha N would really simply the setup, as i wouldn't have to worry about a perfectly sealing air-box connected to a MAF
Mega squirt looks right but i haven't found a good guide on how to wire it up, or a PNP option. I know the M50 is similar so tht might be a good start.

VEMs is another option

Does miller WAR offer Alpha N capability?

Thanks

[Motheye99]

https://www.k-data.org/kdfi-pnp-bmw-m42.html

This Looks like a PNP Ms2 board that offers Alpha N has anyone used these guys? I haven't found a lot of info on them

[ccsdo5]

I have a megasquirt 2 v3.0 it works fine for my turbo car. My only regret is that I wish I built it myself. But I think someone on here had a turbo m42 and was using a kdata ecu. If I recall he had nothing but problems keeping it connected to tune the car but I can't speak first hand about it since I've never owned one.

[Digitalwave]

I wouldn't touch a Miller WAR chip even if it could run Alpha N (I don't believe it can).

Just about any standalone EMS is going to be able to run Alpha N for your setup easily. Megasquirt would be a cheap and easy way to do it. MS2 would probably be sufficient for what you're doing. You could also run Alpha N/speed density hybrid (ITB Mode).

[nando]

People think that Alpha-N is some magic HP gain - its really not. It literally means "throttle position VS RPM". Its an extremely crude approximation of engine load (throttle input) that determines spark/fuel along the RPM axis.

Its fine for a race car - you're at WOT most of the time anyway, which is essentially a 2D curve. But at part throttle and "daily" situations, it sucks ass. Throttle input rarely correlates directly with engine load - or things like MAF and MAP sensors would have never been invented.

Basically all computerized control algorithms are built around some sort of model - and Alpha-N is literally the crudest and most basic of all. If you have any choice that would work better, you'd best choose it.

I build a MAF delete tune for modern BMWs that deletes the MAF - but I dont call it Alpha-N, because its not throttle vs load. These DMEs have super fast wideband feedback loops and huge models of the engine (10,000 parameters and 4x as many variables). In some cases it works better than a MAF (airflow restriction, low speed, turbulence, etc), at worst it is equal. Miller couldn't come close to this, and even MS has better models (speed density/blended mode).

Basically, IMO leave "Alpha-N" to the dustbin of history, bespoke racecars and boy racer dreams. On a car you want to drive often, no fucking way...

[e30davie]

Nice post nando. Sums it up well. Alpha = angle of throttle body. N = rpm.

It's basically "last resort" type tuning. When nothing else works.

With a bit of research you will also realise that any decent aftermarket ecu will run any engine. Well any sort of commonly available engine anyway. Absolutely nothing special about an m42.

[DesertBMW]

Im trying to set up some diy itb's, Alpha N would really simply the setup, as i wouldn't have to worry about a perfectly sealing air-box connected to a MAF

That is true, Alpha-N is your only option if you want to run ITBs without air box. I don't think Megasquirt will work sense you can't use MAP sensor anyway.


But even if you figure everything out, it is still M42, you will spend money and won't make any power.

[e30davie]

Pretty sure you can put tps on the axis of the VE table vs rpm in megasquirt and get your beloved "alpha n". I'd have the check tunerstudio when I get home but I'm almost certain you can.

[Digitalwave]

There is an Alpha N mode for Megasquirt, as well as hybrid AN/SD.

[digger]

keep it simple. just get an aftermarket ECU and run Alpha-N. setup properly it runs quite well even without an O2 feedback. it really just needs the right load sites at low throttle positions, a good sensor and a proper tune. you don't need anything fancy

[Mykk540i/6]

If you're about DIY, check out Speeduino. I run one on a M60 V8 in speed density but it very easily can be set to run Alpha-N. I experimented with Alpha-N on mine and it worked well but ultimately felt speed density was better for my set up