gains from removing afm or upgrading to MAF?

[mspiegle]

does anyone know how much to expect in gains by removing the AFM (alpha/n) or converting to a MAF on a mostly stock M20 motor?

I have a crazy idea on how to convert my car to an alpha/n style management... but i'm very curious as to the gains.

thanks!

[diegom6]

first of!! you won't gain any shitt taking out the AFM and runing it alone like you are saying...

Second: exist some kits to upgrade to MAF conversio, they are overpriced, but Custo3 a memeber here, was offering the same system cheaper I think....anyway I'm uppgrading with a e36 325i MAF soon...since I got my SMT6 to tune it and other parameters of the engine...


Gains with MAF? don't know exactly, probably at least 10 hp at the flywheel....just my 0.2...

and no!! you can't just plug the MAF instead of the AFM, they have differents signal volts...

[mspiegle]

actually, if my solution works out, it will cost me about $25 to get alpha/n style intake system on my car which theoretically is better than a MAF since there is NO airflow restriction.

I will basically be replacing my AFM with a circuit that puts out a constant 2.5V signal and use the SMT6 to make that signal seem like an AFM signal. I have already ordered a TPS and will hopefully get to experiment with this in the next few weeks.

[diegom6]

Oh shitt, now I remeber you, well Gunni told me we can make the MAF work just pluging it or wiring in the AFM cable, once it's done, ( I did it before) you are able sopoused to tune it just with the SMT6, i tried it, with oput the SMT6 of corse, with a potentiometer...but you need a stable or variant volts for idle and other volts for wot... we will see...anyway, the MAF uses 12 volts source if you are interest in put it...

hope tomorrow can install the smt6, once it's runing good I will make the swapp...

[m42technic]

actually, if my solution works out, it will cost me about $25 to get alpha/n style intake system on my car which theoretically is better than a MAF since there is NO airflow restriction.

I will basically be replacing my AFM with a circuit that puts out a constant 2.5V signal and use the SMT6 to make that signal seem like an AFM signal. I have already ordered a TPS and will hopefully get to experiment with this in the next few weeks.

Sp youre saying that youre gonna just run a constant 2.5v to the DME that wouldnt change with load and RPM?

[mspiegle]

i run a straight 2.5 to the SMT, the smt will vary that 2.5v signal going to the ECU based on my current throttle position and RPM. I would have to install a TPS, fake a bunch of signals, and spend alot of time tuning, but it sounds like fun to me and could yield very good power gains.

[EVOIIIM3]

i run a straight 2.5 to the SMT, the smt will vary that 2.5v signal going to the ECU based on my current throttle position and RPM. I would have to install a TPS, fake a bunch of signals, and spend alot of time tuning, but it sounds like fun to me and could yield very good power gains.

I think you need to find out how A/N works and how the AFM works with motronic.

A/N uses throttle position to deliver fuel and spark.It's knows that at X throttle you are pulling in Y air volume. It compensates for load with RPM. Even if you are at part throttle, at 2000rpms you will pull more air at the same throttle at 6500rpms, so you need more fuel.

The AFM uses air volume to meter fuel, it is not linear over the rpm range and once it is all the way open it looses it's resolution. It also uses RPM to deliver the proper fuel.

What you want to due is going to be next to impossible with the tools you have. You can't substitute the AFM for a TPS. They do not work the same way. Throttle position is not going to be the same as AFM position threw the RPM range. When you hit the gas, the computer will be messed up by delivering fuel, but the TPS signal will stay constant thew the RPM band where the AFM will go up with RPM. Basically you will run SUPER rich, then SUPER lean, get horrible throttle response and eventually blow the engine.

[mspiegle]

thanks for the input, that's stuff i definately will be looking into. I still gotta try it though...