Random Data Plots - M42 Engine Parameters Stock vs 2.1L Stroker

[varg]

Interesting to see how lean it runs throughout a WOT pull, I wonder how the AFR plot of a stock 318 looks. To get an M42 to 180hp NA, I think an AFM bottleneck would be the least of your worries. What does it need? Solid lifters, custom cams, porting, big valves, new intake manifold, new exhaust, higher compression... I'd probably go with ITBs if I was doing an NA build.

[bmwman91]

I did order up spare PCBs, so the MAF converter is something I can make more of once I do some logging and make sure everything is dialed in.

The MAF that I am using presently is probably good for up to 300hp. It was the stock VW MAF for most of the 1.8T and 2.0T engines in VW and Audi cars throughout the 2000's.

On an internally stock M42, I doubt that there is much to be gained in terms of power. Throttle response and idle stability seem to be a bit better though. If you are making over 180bhp though, I do think that the stock AFM starts to become a little bit of a bottleneck. The crossectional area of the M42 AFM inlet is the same as the M20 AFM, and the M20 benefits from the larger M30 AFM, so I think that there is a reasonable argument to be made that a high-flowing M42 can also gain from a sensor with larger crossectional area in the inlet.

[Balleristic31]

Is this something you ever think you will manufacture to sell? Could use if I ever decided to go FI.

+1 really interested to see if this makes any power NA as well.

[Gerta]

A couple of updates...

1) I installed my MAF conversion and it is up and running. This is the 7th iteration of the device (a project which I began in 2005 lol). This time around, it looks like I finally put all of my mad nerd skillz to work in the right way and it's a solid device.

2) I have added a 5th analog channel to the data logger, as well as RPM input. Within a couple of weeks I should have the VR sensor conditioner board and be able to get even more detailed logs for everyone's enjoyment.

Is this something you ever think you will manufacture to sell? Could use if I ever decided to go FI.

[DER E30]

Nice! Eager to see the results!

[bmwman91]

A couple of updates...

1) I installed my MAF conversion and it is up and running. This is the 7th iteration of the device (a project which I began in 2005 lol). This time around, it looks like I finally put all of my mad nerd skillz to work in the right way and it's a solid device.

2) I have added a 5th analog channel to the data logger, as well as RPM input. Within a couple of weeks I should have the VR sensor conditioner board and be able to get even more detailed logs for everyone's enjoyment.

[CorvallisBMW]

I love data, thanks for sharing :)

[ForcedFirebird]

Cool!

No matter what system you use, the AFR's will spike when stabbing the throttle.

Interesting to see the AFM is maxed out. Not surprising, though, when you increased the displacement by 20% or so.

I have found that the BMW's likes to run about 13.5:1 when in accelerator enrichment (WOT), most engines seem to like high 12's better. Stoich is more for idle, lean cruise will be in the 16's or so.

It would be interesting to add a tach input to log so you aren't judging by ms.

[ngampleh]

interesting ... !!!
any information more detail for MAF conversion?

thank you

[bmwman91]

Yeah, the aross-the-board 30-40% increase in air flow is a little surprising since displacement is only up 17%. Maybe 5-10% of it could be due to accuracy variance between the two different air flow sensors. But then again, the MM figure of 205bhp vs ~150bhp stock+chip is ~37% higher, which obviously means a lot more air getting in there. One of the big things with MM when I spoke with them was their emphasis on building a well-balanced engine that still retains a broad, useful powerband. Anyone can build a top-end screamer, but I think that their careful work on the head and cam profiles are a big part of why this thing sees gains across the entire RPM range, while still pulling hard all the way to 7700RPM. All I can say is that this engine wants to be driven hard...it takes a lot of restraint to not floor it every chance I get lol.

[DER E30]

Huh, that's very interesting. Probably some things to be learned about the volumetric efficiency of an M42 there as well. 17% increase in displacement over stock, but you're seeing a surprisingly consistent 30% improvement in airflow. I'd put a lot of that gains under any porting work that MM does, as well as camshafts, but the nearly constant improvement over the rev range speaks to how well developed their modifications are.

Yes that is interesting!

Too bad you're not closer, it would be interesting to compare mine to yours! Mine supposedly has a ported/flowed head with s14 profile cams.

[gearheadE30]

Huh, that's very interesting. Probably some things to be learned about the volumetric efficiency of an M42 there as well. 17% increase in displacement over stock, but you're seeing a surprisingly consistent 30% improvement in airflow. I'd put a lot of that gains under any porting work that MM does, as well as camshafts, but the nearly constant improvement over the rev range speaks to how well developed their modifications are.

[Dj Buttchug]

wow this is really cool.

[bmwman91]

Great info dude, love that you keep innovating and pushing forward with the M42 where most of us on here would simply dump the motor for a 24v.

Thanks. Life would be a hell of a lot easier if I stopped wanting to mess with the M42 and just dropped an LS1 or S52 into the car...but, I've owned M42 cars fro 15 years and might as ell keep going lol!

That's really neat! So are you gonna be selling the MAF conversions?

Funny question. So, the intent all along has been to sell MAF conversions. I even promised to make and sell a kit at least once. Then life got in the way (marriage, blown up M42, bought a house, etc). I would really like to sell a plug-n-play kit though. Once I have my "personal version" up & running, I will see. There is also an audio project that I put together (and posted about extensively on here) and still want to sell, but the head unit it was to go with is no longer available lol...makes it hard to sell the pre-amp boards!

[DER E30]

That's really neat! So are you gonna be selling the MAF conversions?