Carlitos

Most of the info that I've seen on MAF-T's have two settings to adjust. The base setting and the WOT setting. I just recently found a MAF that says you can change the settings across the rpm band:

"It will allow the user to adjust the A/F ratio across different parts of the RPM band. It is easy to make adjustments by simply turning some 16 position switches inside the unit that will make whatever part of the fuel curve you wish richer or leaner..."

How does the MAF know what the engine rpms are?

jpolser

iTrader: (3)

Dont quote me, but I would assume the same way that a shiftlite knows what rpm to come on. That being the tach wire on the pcm?

jeff

Carlitos

[quote]Originally posted by DanZ28:
<strong>Are you talking about the Split Second units?</strong><hr></blockquote>

Ummm...I don't think so. It just says "MAF Translator" on it. Try this link:

http://www.ls1motorsports.com/ls1ccomputer.asp

It's at the bottom of the page.

'Los

Camaroholic

iTrader: (1)

That looks like the Modern Musclecar unit.

Here's my ASSUMPTION on how it works. There is no tach wire connection.

The MAF curve (grams per second versus MAF frequency output) is exponential. At low grams per second, the slope of the curve is small. At higher grams per second, the slope increases upward. If you take this curve (it has a fixed number of data points in the PCM), and divide it by 16, you can individually segment each portion of this curve. I forget how many cells are in the curve, but for example, at 2 g/sec, it may be 1000 Hz. At 4, it may be 1250 Hz. At 6, it may be 1500 Hz... and so on. (It's not really linear like this, I'm just making this up <img src="gr_grin.gif" border="0"> ). Anyhow, the MAF translator may read a frequency of 1000 Hz, but your scaling may say to take it to 1100 Hz. The PCM may interpret this for fueling at 3 g/sec. Does that make sense? You're reading 2 g/sec at the MAF, the translator does its job of scaling the output frequency, and the PCM 'thinks' it's getting 3 instead of 2.

This 'curve' gets chopped up in to 16 segments, each of which can be controlled +/- a certain percentage, based on the input frequency and the user scaling.

Or I could just be full of hsit.

Eventually I'd like to build my own MAF translator. Just for grins, to see if I can do it. <img src="gr_grin.gif" border="0"> Then make it an open source project. <img src="gr_stretch.gif" border="0">

-Andrew

Carlitos

Camaroholic: sounds like your making this up! <img src="gr_tounge.gif" border="0"> <img src="gr_tounge.gif" border="0"> <img src="gr_grin.gif" border="0"> <img src="gr_grin.gif" border="0">

Hehehe...actually that makes sense. Hrrmmmm...I guess I'll just have to buy one and experiment. <img src="gr_eek2.gif" border="0">

<img src="graemlins/camaro.gif" border="0" alt="[Chevrolet]" /> <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" /> <--- road kill

'Los

ToplessTexan

Yes, that's the MM MAFT. It's not 16 switches, it's 8 positions on each of the two switches. There is no dependence on RPM beyond the assumed correlation between RPM and the input frequency supplied by the MAF. (Which changes as VE changes.) contributions from both BASE and WOT are always present but the WOT effects are attenuated below something like 8kHz input frequency. It's this 8kHz-ish value that defines what the MAFT thinks of as WOT. If Mike's here he can speak with a little more authority. <img src="gr_stretch.gif" border="0">

[ January 07, 2002: Message edited by: ToplessTexan ]</p>

Carlitos

Thanks, Topless!

'Los

DanZ28

iTrader: (5)

Are you talking about the Split Second units?