Alpha-N in 2020 - some questions for a newcomer

[Konig]

Hello group

I am preparing to take the leap to that wonderful carbon airbox life. I have been reading and digging and searching old threads, but the information is spread broadly and is often too in-depth for an amateur like me. I want to get some feedback and check my understanding of the different engine management options in conjunction with a carbon airbox and eliminated AFM.

Context: my car is a stock, recently-refreshed 2.3L US motor. My goal is increased throttle response and induction sound, more power is welcome but not really expected. Unfortunately a big constraint is that I'm in California and need to be able to pass an emissions inspection every 2 years. Therefore, revert-ability is a big factor.

What I think I understand:

• Maxx A-N
  • piggyback controller that uses throttle position (alpha) and engine RPM (n) to generate, from an internal table, a 'spoof' number for the AFM that it sends to the ECU
  • used on the race cars back in the day and used on street/track M3s throughout the years
  • crude compared to modern options but apparently robust if set up properly
  • can be tuned and adjusted on the fly with real-time feedback
  • can use closed-loop wide-band feedback and self-tune (to what extent...?)
  • some ECU connector pins need to be modified for installation
  • [unsure] only allows control of fuel?
  • [question] how does this interact with ECU chips? I have an iigomotiv 91 octane for a stock 2.3L. I guess if MAXX is spoofing an AFM value you still need an ECU chip configured for the setup, how would I achieve that? Does anyone make chips anymore...?
  • [question] Markus offers a "plug and play wideband setup" for the Maxx A-N, link here, I'm not sure I understand it. Are all of these pieces (and $500) required to use a wide-band sensor, or is it just offering some convenience or something? Markus tried to help me understand but there may be a language gap

• Miller A-N
  • uses throttle position and RPM measurements to replace the AFM, but not as a piggyback. WAR chip helps ECU take these new inputs 'raw' and run the car off of them (instead of getting spoofed AFM values), solving what Miller claims as some sort of lag in processing time with Maxx arrangement
  • newer product
  • cannot be tuned and adjusted on the fly with real-time feedback (WAR chip can carry 4 tunes on board), no datalogging
  • does/can not use closed-loop wide-band feedback
  • completely plug and play harness
  • [unsure] allows control of fuel and ignition?
  • [unsure] can be tuned using their software, or done remotely by Miller

• Miller MAF and WAR chip
  • replaces the AFM with a MAF to get rid of the 'garden gate' intake restriction, use WAR chip to process information from MAF and run the car
  • same tuning/feedback/harness details as Miller A-N above
  • [unsure] from what I read, MAF does not jive with a carbon airbox due to some pressure waves that can come back up the intake and confuse the MAF sensor. Results in poor part-throttle performance. Therefore not really an option for me since I am going carbon box.

• Full standalone ECU
  • VAC outlines their argument for their particular ECU over A-N
  • I have to imagine a modern ECU gives the best, fullest motor control with the latest modern tech, flexibility with tuners
  • Highest cost option, I imagine has the most setup time?
  • Seems like it would not be compatible with my needs to go back to stock for SMOG every couple years

This is the high-level understanding I have managed so far. I don't have any insight into the specifics of the different engine management options - which ones control what parameters, have good safety controls and engine protection features, outputs if I wanted an AFM sensor or something, how hard each one is to tune, where I can have them tuned/serviced in the future. From what I hear A-N is "set it and forget it" with a good initial tune, especially in the stable California climate, but I am thinking ahead to what I would do if I had an issue develop a few months after a successful initial install.

From my understanding so far, it feels like a hybrid Miller MAF/WAR with a carbon airbox would be the perfect combination of plug/play and what I want, but I guess the MAF just doesn't jive with the airbox. If I lived in a different state a standalone would probably be a front-runner option. The fact that the Miller A-N does not have wide-band feedback and cannot be tuned on the fly seem like big drawbacks. So I think I am back to the "vanilla" Maxx A-N option. The main tripping points for me on that are the issues of (1) engine chip to run the car, and (2) re-wiring required to the factory ECU harness that will complicate the SMOG hardware swap.

Many questions here obviously, if it's not already apparent I've never done any type of engine control / ECU stuff. I am going to have installation and setup done by a shop, but I like to understand what I'm doing to my car, even if I'm not turning the wrenches.

Other questions that come to mind:

• Has anyone made a MAF work with a carbon box, perhaps further 'upstream' in the intake where resonances and plenum bounce-back do not impact it?
• It seems like a skilled operator can map Alpha-N to be reliable, but I'm still a bit confused about how the motor "understands" load differences, whether it's under full throttle going uphill in high gear versus goin full throttle on a flat road in second gear. I believe the intake air temperatures sensor and baro sensor feed into the ECU and can help with changing weather conditions, but I do not understand the "load understanding" story.

Huge wall of text, if you made it through I'd appreciate your thoughts and input. If I have my facts wrong, or have missed important distinctions, please weigh in.

[mlytle]

there is no vanilla AN...no solution is going to be plug and play. they all require some tuning knowledge, time and computer work to tune the car correctly. i run MAXX AN and i have spreadsheets devoted to analyzing the logfile data from the AN. not simple. does not self tune. you have to get the base map pretty close, then the system can make small adaptions as needed.

what about just getting a CF replica of the stock plenum? simple, keeps all stock systems in place, and makes a bit more noise than the heavy stock plenum if noise is all you are looking for.

[mwagner10702]

If increased throttle response and induction sound are your primary goals, I would think mlytle suggestion of a CF stock plenum would solve one of your needs Combine that with MIller MAF and optionally their WAR chip and this would meet both your goals. Note that their MAF comes with an ECU chip and doesn't require the WAR chip to run. The WAR chip allows you to program up to four different maps so you can fine tune the mapping.

The MIller MAF does require a small modification to the wiring harness at the ECU connector. Once the modification is made you can't go back to the OEM AFM unless you undo the wiring modification. I don't feel this is a show-stopper as you can wire a switch to switch between the MIller MAF and BMW's AFM. Gives you the best of both worlds when you have to pass California emissions testing. The MIller MAF also requires you to make a small modification to the top of your air box to enlarge the opening to match the size of the opening of the MAF housing. I'd recommend sourcing a used upper housing (or a complete EVO air box which draws air from the low pressure / low turbulent area behind the front bumper through a tuned intake horn into a larger air box) and modify that. Keep your OEM housing for when you need to return to stock to pass emissions.

Is it as sexy as a DTM-like CF airbox? No, but a lot simpler and less fiddly. As Marshal indicated a true AN solution will require a lot of time and money to get right.

[blyguy]

I only have experience with Maxx AN on a dedicated race car, and it is reasonable to get it up and running on a stock E30 M3 using a CF airbox. You only modify the fuel maps with Maxx AN, the ignition timing is determined by the DME and modified if you have an aftermarket chip (TMS, Dinan, iigo etc) The theoretical advantage to AN is you can change your fuel mapping with a change in engine configuration - the flip side to that is that any mechanical engine change you make requires you do update/retune your AN maps. If you have a stock engine and just want to add an airbox and remove the AFM, you could use a stock base map and be up and running. Best bet is to get a remap of your fuel on a dyno which can run 500$ or more at a shop.

It's not a bad system. It's old fashioned for sure, and not as sophisticated as even the factory Motronic. My understanding for MAXX AN is that closed loop is to make small, real time adjustments to keep Lambda at 1.0 and will not tune for you like advanced systems like Motec. Basically this is what the stock DME does too - via feedback loop w the o2 sensor. With MAXX you still have compensation for intake air temp and most likely if you follow a known stock base map, you will probably be rich versus lean and won't kill your engine.

You pose question I've asked myself to about CA smog and reversibility. Running AN and a CF airbox could be reversed in a weekend of work. It would involve several hours to re route breather hoses and brake reservoir, and wiring. Two options you might have considered-
1) With an M POWER sticker on the aribox, you MIGHT pass visual and are able to tune to be smog compliant. This would require finding a friendly smog shop and claiming its just a cosmetic change to look racy... cat, crankcase breather, carbon cannister would all stay attached. At some point, the idea of attaching a hollowed out AFM entered my mind ...
2) I've heard of some ways to get around smog with a cost that's cheaper than a per hour labor rate for you to reverse things to stock and then reinstalling. (I plead ignorance on those methods)

Good luck!

[stevesingo]

MAXX does not have the ability to change ignition maps and this is arguably more important than fuel maps. You need a custom chip (maybe they are supplied with the kit - I don't know).

For revertability, tunability and functionality, stand alone EMS is the way to go. This required a custom built engine loom, so you can save your stock loom for reverting back. Swapping the engine loom is easy with the airbox removed and reverting from CF airbox and stand alone EMS to stock should be a 2hr job with no evidence remaining for the fun police.

Downsides are cost. Probably $2-2500 for an ECU and loom plus tuning.

[Crank]

Surely there is a more modern option at this point than MAXX Alpha N....?

There are some interesting ECU’s out there, like VEMS, ecuMaster, etc. I don’t know enough about them, myself, or I would have one on my car, but I would think someone here knows about this stuff.

Just seems like Alpha N has been around since E30 M3’s were pro race cars, and we are still looking to it decades later - I would think something better is available these days.

[jimmy p.]

Surely there is a more modern option at this point than MAXX Alpha N....?

There are some interesting ECU’s out there, like VEMS, ecuMaster, etc. I don’t know enough about them, myself, or I would have one on my car, but I would think someone here knows about this stuff.

Just seems like Alpha N has been around since E30 M3’s were pro race cars, and we are still looking to it decades later - I would think something better is available these days.

Well MAXX is a system thats relatively painless to implement and there is a large knowledge base for S14 users, so its become very popular.
The world is limitless of alternatives of stand alone ECUs from simple and cheap to the highest end of pro gear, but as noted above ALL of them regardless of complexity or options requires commitment in time and dollars, an engine harness to be fabricated, a slew of new senders and input devices, maybe new injectors and / or drivers, and most importantly experienced tuning.
Most importantly experienced and knowledgable tuning (I felt I should say that one twice).

Even after all these years / decades even simple Alpha N strategies work pretty well on the S14.
I have full sequential Alpha N with MAP assist on both of my race cars, both of my street cars have ancient 25 year old Cyntex "chip AN" on them. In both instances they do what they are supposed to do.
There is a very wide wide range of ways to get the AFM off the car, it really all depends on the commitment of the owner.

[Crank]

Is anyone here knowledgeable on the aftermarket ECU options?

[stevesingo]

There are many aftermarket EMS options. If not DIY, then find out what your local engine tuning specialists use. There is nothing more important than having access to somone who knows what they are doing with the system you have.

[jimmy p.]

Is anyone here knowledgeable on the aftermarket ECU options?

I heartily recommend Neel Vasaveda at Apex Speed Technology.
https://www.facebook.com/apexspeedtech/
He can guide you on ECU choices and also provide engine harnesses and provide tuning. One stop shopping.

[Crank]

I heartily recommend Neel Vasaveda at Apex Speed Technology.
https://www.facebook.com/apexspeedtech/
He can guide you on ECU choices and also provide engine harnesses and provide tuning. One stop shopping.

Thank you!

[JimK]

i am using a Haltech Elite and a MAF. Minimum model for a S14 is an Elite 1000. After using other ECUs (on other engines), this and the MAF is by far the easiest to tune. The ignition advance map is on you though, as it is with other systems. Am also using a knock sensor tuned for the engine (needed to tune the knock sensor settings on a dyno, doable on the road, but not advisable).

[Reelizmpro]

If you are asking for opinions, I would say not to do it. That ship has sailed many moons ago. The point is to maximize engine potential, particularly, those that are heavily modified. I don't say this to trash the method or any particular system. Each option above has it's pros and cons. It's just that I don't think you want to open this can of worms for just induction sound. There's more to it than bolting on a box and switching computers. You will have to learn how to diagnose, tune and keep it in tune, get a wideband, wire in a true TP Sensor, fabricate an air filter, rotate the dipstick, remote locate the brake fluid reservior with 2002 res, move the power steering reservior and finally deal with smog. Alpha N without closed loop means you are flying blind and can damage your engine. Even with closed loop, I've had Bosch wideband sensors fail and had to limp home. I now keep an extra sensor and socket in the car. The risk is high, cost is high and the gains will be minimal on your stock engine which is getting more expensive to replace by the day. There are many good things about it like many have touched on but I feel compelled to discuss the downsides.

[JCGus]

Interesting feedback - I think insight like this is always ultra-useful and not often shared. Real world usability really is the main thing.

Carbon airboxes sound pretty cool though...

[JimK]

If you are asking for opinions, I would say not to do it. That ship has sailed many moons ago. The point is to maximize engine potential, particularly, those that are heavily modified. I don't say this to trash the method or any particular system. Each option above has it's pros and cons. It's just that I don't think you want to open this can of worms for just induction sound. There's more to it than bolting on a box and switching computers. You will have to learn how to diagnose, tune and keep it in tune, get a wideband, wire in a true TP Sensor, fabricate an air filter, rotate the dipstick, remote locate the brake fluid reservior with 2002 res, move the power steering reservior and finally deal with smog. Alpha N without closed loop means you are flying blind and can damage your engine. Even with closed loop, I've had Bosch wideband sensors fail and had to limp home. I now keep an extra sensor and socket in the car. The risk is high, cost is high and the gains will be minimal on your stock engine which is getting more expensive to replace by the day. There are many good things about it like many have touched on but I feel compelled to discuss the downsides.

+1, it's not plug n play.