M30 Swap - Miller MAF Worth It?

[DesertBMW]

I've been telling people for years that these 'upgrade' chips are a scam. MAF conversion is a worthless mod. Both are waste of money.

BMW made the software to give you most power in worst conditions like hot weather and 87 octane fuel. Yes you can make like 5hp more with more aggressive timing but have to use higher octane fuel all the time and all of that and still avoid driving the car on a hot day. At the end of the day you still gained nothing and put your engine at risk.

MAF conversion is worse sense the system was never designed to work that way, people having all sorts of issues.

Megasquirt stand alone is another proof how well BMW and Bosch created their system. When Megasquirt announced PNP system for M20, everybody was euphoric. Belief was AFM will no longer be used and with MAP sensor there is no intake restriction the M20 will make more power and what not. Then Megasquirt did their own testing and were only able to achieve 1hp gain against M1.3 system.

[dishwab]

Have been running the Miller maf on my car for 3yrs now, biggest improvement was throttle response, & the pickup in midrange, I found the fuel economy improved which for anyone with an m30 fuel economy isn’t front of mind but the average usage improved by approx 2L/100KM

Thanks for the info. Any issues to speak of?

[nando]

I've been telling people for years that these 'upgrade' chips are a scam. MAF conversion is a worthless mod. Both are waste of money.

BMW made the software to give you most power in worst conditions like hot weather and 87 octane fuel. Yes you can make like 5hp more with more aggressive timing but have to use higher octane fuel all the time and all of that and still avoid driving the car on a hot day. At the end of the day you still gained nothing and put your engine at risk.

MAF conversion is worse sense the system was never designed to work that way, people having all sorts of issues.

Megasquirt stand alone is another proof how well BMW and Bosch created their system. When Megasquirt announced PNP system for M20, everybody was euphoric. Belief was AFM will no longer be used and with MAP sensor there is no intake restriction the M20 will make more power and what not. Then Megasquirt did their own testing and were only able to achieve 1hp gain against M1.3 system.

What are you talking about? More 100% BS from you, with zero evidence to back it up. I guess you only like tunes when you sell the ones you stole from MarkD, JimC, etc.

I don't even want to waste time arguing about your absurd and patently false MS "1 horsepower" claim, because there is no point. But to those who are new to BMWs and don't know HakkenTT, you would do well to ignore this person.

[ForcedFirebird]

https://www.diyautotune.com/support/tech/hardware/diypnp/documentation/application-docs/1987-1992-bmw-325/

A fair bit more than 1whp, but the example is anemic. Only ~130hp m20 I've seen was an eta endurance car. Stock b27 made 127whp before we started swapping parts around and re-visiting the dyno.

[e30davie]

I've been telling people for years that these 'upgrade' chips are a scam. MAF conversion is a worthless mod. Both are waste of money.

BMW made the software to give you most power in worst conditions like hot weather and 87 octane fuel. Yes you can make like 5hp more with more aggressive timing but have to use higher octane fuel all the time and all of that and still avoid driving the car on a hot day. At the end of the day you still gained nothing and put your engine at risk.

MAF conversion is worse sense the system was never designed to work that way, people having all sorts of issues.

Megasquirt stand alone is another proof how well BMW and Bosch created their system. When Megasquirt announced PNP system for M20, everybody was euphoric. Belief was AFM will no longer be used and with MAP sensor there is no intake restriction the M20 will make more power and what not. Then Megasquirt did their own testing and were only able to achieve 1hp gain against M1.3 system.

There is more to improving an engine than outright horsepower though. As long as the oem MAF is phyisically not too small that it restricts air flow, then making the MAF physically bigger wont make much difference to overall horsepower.

OEM bmw m20 doesn't have a variable TPS, so there is already crispness and throttle response left on the table that can be harnessed with a megasquirt or any sort of aftermarket ecu with a programmable throttle pump.

I'm not sure how these upgrading mafs claim to give more throttle response. Maybe they have some smarts in them to detect large changes in air flow and dump more fuel in. Be interested if anyone understands it.

[lukeADE335i]

The extra throttle response is just from removing the big spring loaded aluminium flap that sits in the airflow in the stock AFM. The flap in itself isn't particularly restrictive on an M30 (hence there's no big gains in peak power numbers with the MAF) it's just about the engine overcoming the inertia of the flap when transitioning from idle.

In my case, I needed a new AFM anyway, so getting the MAF at the time was actually cheaper.

[nando]

It's not entirely the AFM. Motronic has only rudimentary methods for AE (acceleration enrichment) which on newer DMEs (including Megasquirt) are quite advanced. What happens on Motronic when you stab the throttle is the engine briefly goes lean, because it can't anticipate the quick rush of air like a MAF based (or advanced AE system) can.

[ForcedFirebird]

Stab the throttle on any cable-driven ECU and it goes lean :P There will always be lag time in an analog throttle. DBW cars don't do this because the computer "rolls" the throttle plate(s) for you, even though you stomped the accelerator - this gives the computer the power of "intuition" since it knows how much fuel is going to be needed vs calculating after the fact. If you remember early DBW systems, they felt "numb" or "throttle delayed".

It's actually the resolution of throttle input that's the big change when upgrading from Motronic. With the OEM switch, you get big jumps from table to table based on AFM door angle and IAT (the system is more speed/density, than mass air flow).

[e30davie]

My L-Jet M20 definitely has a nasty transition from idle to non-idle. But then again L-Jet is about as crude as you can get for EFI. Smooth enough when you get used to it but you always know it is there.

A liittle bit off topic but having no experience (yet) with tuning the acceleration enrichment in any ecu, I would have thought that with enough trial and error you could eliminate the engine going lean when you stab the throttle. Especially on an m20 where your intake track is fairly long. I understand mega uses the % in change of the throttle to enrich. say you go from 0% to 50% in 0.5 seconds, if you squirt in x% more fuel, does the engine still run lean momentarily and then potentially go rich with the wave of fuel before it stabilises out?

[Anthony B]

Thanks for the info. Any issues to speak of?

No issues I’ve seen in the time I’ve had it, the only initially issues was the 3” adapter was a bit rubbish so I modified to fit & it’s been perfect since.


I’ll be adapting the maf to be fitted to a m30 turbo build going into the fiancés car, with my only reasons to moving away from the millar setup being RHDengineeing’s m30 itb kit which he used my head as the mock-up & design part

[george graves]

As far as being open, have you ever looked at the files/software? It's a fair bit more open source than people think.

I get what your saying.....But.....It's open as far as your welcome to make changes to software. That's free. But if you improve upon the hardware and try to sell a PCB, they will put the hammer on you faster than someone selling fake mickey mouse ears at the entrance at disneyland. When you give the software away, but make all your money in the hardware, it stops being an "open project" when you threaten to sue people if they make deriterives. That's not open.

It's not entirely the AFM. Motronic has only rudimentary methods for AE (acceleration enrichment) which on newer DMEs (including Megasquirt) are quite advanced. What happens on Motronic when you stab the throttle is the engine briefly goes lean, because it can't anticipate the quick rush of air like a MAF based (or advanced AE system) can.

I'm sure it's some time based averaging as well that is causing a delay.

[nando]

I get what your saying.....But.....It's open as far as your welcome to make changes to software. That's free. But if you improve upon the hardware and try to sell a PCB, they will put the hammer on you faster than someone selling fake mickey mouse ears at the entrance at disneyland. When you give the software away, but make all your money in the hardware, it stops being an "open project" when you threaten to sue people if they make deriterives. That's not open.

If you don't like it then don't use it. I don't think you'll find any truly "open source" EFI hardware platforms that are actually useful. :p

On MS2 and MS3 you can use the GPIO headers to expand the hardware and you can mod the PCB to your hearts content - you just can't manufacture and sell PCBs or CPUs. I don't think there's anything stopping you from making your own PCB for personal use.

A liittle bit off topic but having no experience (yet) with tuning the acceleration enrichment in any ecu, I would have thought that with enough trial and error you could eliminate the engine going lean when you stab the throttle. Especially on an m20 where your intake track is fairly long. I understand mega uses the % in change of the throttle to enrich. say you go from 0% to 50% in 0.5 seconds, if you squirt in x% more fuel, does the engine still run lean momentarily and then potentially go rich with the wave of fuel before it stabilises out?

Megasquirt can use a TPS based AE or the wall wetting AE. I never liked the TPS based, it's pretty crude (although better than nothing I guess) and wall wetting is what all the OEMs use. It's tough to tune but it works pretty slick once you "get it". My M20 is slow as balls but the throttle response is nice and crisp. :)

[george graves]

If you don't like it then don't use it.

Ha! OK - well, I don't like a lot of things. So....

Fair enough. But it doesn't mean I can't call them out of their BS, bulling tactics, or outright lies of being "open". Yep, I still get to do that in my free time. ;)