Robin, you asked about an AFM alternative.

[Martin in Bellevue]

http://www.kineticmotorsport.com/catalog/images/PSC1.jpg
http://www.kineticmotorsport.com/catalog/psc1001-prog-wabsolute-sensor-p-62.html

I am now using the split second psc1-001 signal convertor, with built-in pressure sensor, replacing the pro m maf setup, that replaced the stock afm. The pro m signal box took a dump a while back.
It is running well, after some time measuring the afm output voltages. It was initially set to receive additional signal information from the furd maf, and ran well. I've since removed the maf, & am providing a conditioned signal based on manifold pressure & rpm's.

Things needed with the psc1-001:
·intake air temperature sensor, used from the pro m maf kit
·wiring harness, relayed & wired within starboard ebox.
·base signal map
·~3.2" metal pipe to replace afm
·wideband O2 setup to aide in calibration, I've not yet stepped up here, using the cheese narrowband gauge

[Jeff N.]

BTW, I think this is the coolest thing Martin's tinkering with here. He's basically dumped the entire AFM assembly and replaced it with a straight tube. T-ed the 3mm vacuum line off the manifold and it runs to the PSC1.

The software for the PSC1 allows you to map the "fuel" based on a 2-d map with RPM on one axis and inches HG on the other axis. Way cool.
Once Martin buys that Wide Band Sensor kit (that he'll loan me when he's done), we'll can really dial it in.

Pretty gosh darn cool if you ask me!

Jeff

[Maximabello]

Can't wait to check it out. What are the advantages over the MAF?

[Jeff N.]

Pro-M is gone.

Second, it's a heck of alot cheaper than a split second MAF solution as you don't need the MAF.

Trick will be to get a map that works with a stock engine. Martin's pretty close.

[genphreak]

http://www.kineticmotorsport.com/catalog/psc1001-prog-wabsolute-sensor-p-62.html

I am now using the split second psc1-001 signal convertor, with built-in pressure sensor... Class work Martin, its nice to see others are giving great thought to this kind of radical improvement. I've been toying doing a similar thing with a MegaSquirt, but given e34s run Motronic it's a 'throw out the baby with the bathwater' approach- but I am very keen to get this cooking too.

Am sure I can find a wideband sensor somewhere, but the time required to program it I don't have atm.. however the inclination is there for the near future:

Sounds like the PSC-001 is ideal for the job. If I get one and start work, would you mind providing your current program/values to help me out? Once the car is running I'll find a wideband sensor and dyno it once the figures are measuring nicely. Even if you have it all sweet by then too at least we'll have two sets of data to compare. My M30 is pretty tight with all new stock valvetrain- once I replace my ICV nothing will be old including the sensors and electronics.

:) Nick

[BigKriss]

may I, I'm liking the thought of it.

http://img299.imageshack.us/img299/6213/mapmartin3av.jpg

[emw525E34]

So you are converting from AFM, bypassing MAF to a MAP based sensor ?. Wow, way cool if the mapping can be done correctly. My 535i AFM is running off my Apexi SAFC2 and that piggyback can do many great things like doing MAP conversion mapping. I have not tried it since I got the 535 AFM working on my 525M20 motor. Correction factors of -15% to -26 applied across the RPM range. On a nice day, might try to tweak that with a similar MAP sensor from an older toyota straight-six that seems to have similar maps as the M20. Would be an interesting test.

I used to love "Crazy home tweaks" years ago but now computers and kids are taking most of my time.....

[Martin in Bellevue]

Sounds like the PSC-001 is ideal for the job. If I get one and start work, would you mind providing your current program/values to help me out?
I'd send ya the files that I have. The off-idle stuff might be trimmed, as I have 21lb injectors. It would still closely match the readings from a stock afm, which works ok on my car.
I think a good experiment would be trying it on an m30 with a hella-cam, like Jeff's mm, that doesn't pull the same vacuum. I'm guessing that the curve would take a mild shift along horizontal vacuum/absolute pressure axis to compensate for pulling less vacuum at idle.
The database files include more than fuel maps. There is information for engine settings, including cylinder count & type of pressure readings & output range. It seems to be a pretty interesting tool.

[Martin in Bellevue]

my Apexi SAFC2 and that piggyback can do many great things like doing MAP conversion mapping. I have not tried it since I got the 535 AFM working on my 525M20 motor. Correction factors of -15% to -26 applied across the RPM range. On a nice day, might try to tweak that with a similar MAP sensor from an older toyota straight-six that seems to have similar maps as the M20.
A throttle position sensor from an automatic gearboxed m30 could provide a good signal for mapping a fake afm signal. This would effectively replicate the Alpha-N setup that the s14 boys pay $$ for. Check the s14.net forum sometime, it is funny how they don't share the alpha N maps. A TPS would help with a more steady return to idle, that the vacuum sensing stuff has a little confusion with. The map stuff needs to drop to idle without thinking you're still on the accelerator pedal, sometimes keeping things a bit rich. Here is where the rpm sensing helps tremendously.

[Robin-535im]

Very cool Martin...

So let me get this straight. You have no more MAF or AFM, but the air flow voltage signal that used to come from one of these now comes from the new unit. Instead of measuring volume (AFM) or mass (MAF) of the air going by, you use just the pressure & RPM to calculate the air flow signal that the DME *thinks* is still from the AFM?

You say the temperature is an input too... just into the DME or does the SS unit alter its calculations based on the intake air temp?

I'll be interested to see how it all works out. $300 for a setup is pretty cheap! Wonder how it will do when the temperature / air density changes...

Great idea Martin. Work out all the bugs on your car and you can sell a kit to the rest of us for $500!!

- Robin

[Martin in Bellevue]

So let me get this straight. You have no more MAF or AFM, but the air flow voltage signal that used to come from one of these now comes from the new unit. Instead of measuring volume (AFM) or mass (MAF) of the air going by, you use just the pressure & RPM to calculate the air flow signal that the DME *thinks* is still from the AFM?

You say the temperature is an input too... just into the DME or does the SS unit alter its calculations based on the intake air temp?
- Robin
Yeah, my 535 runs with no stock afm, no maf.
The intake air temp sensor is independent of the map stuff, kinda like it is with the stock afm. The stock afm has an iat sensor, that can be replaced by the seperate iat sensor from tha maf setup. The psc1 is able to accept 4 additional inputs to further modify the map signal. This doesn't seem needed, when the idle values are brought down to about 1.15v, matching the afm. The SS unit does not alter calculations based on intake air temp, as I have it set up now. It can be made to do so.