Alvin, if you had trouble with it, I probably won't be attempting it. . .

 

I second that!

 

If craig can get you something like a emulator to at least fast load new tunes it shoudn't be that bad.

I just wanted to make sure people knew it wasn't as simple as changin a few things. I completely had to rework quite a few things that never needed to be touched before.

 

If you are at this point why not just go DFI, you are doing the same thing with the stock pcm but i would think at a lower level, when aftermarket pcm can read boost + wbo2......and you can change live.......

 

Post got big over the weekend. If the MAF wouldnt max out then there wouldnt be a problem. I believe highlander was supposed to try a Pro M maf...but dont know if he did. Like many have said, there two problems with maxxing out the MAF:

1. Once the MAF is maxed, pushing psi on a hot day versus a very cold day will result in changing A/F's.

2. Changing boost levels (which occur above the MAF max point) will also result in changing A/F's.

The way around this, install WB O2 onboard and reate a bunch of different tunes:

hot temp (summer)
cold temp (fall/winter)
6psi tune
10psi tune
15psi tune

You get the idea. Thats a pain though, having to reload a tune frequently. WHAT IS THE SOLUTION when keeping the stock ECU...I plan on running a 2 bar MAP, which will help me with the timing, but the fueling is the issue. Is there a way to scale the MAf tables as well?

 

The root problem is the MAF maxing out. My Electrical Engineer buddy suggested that we (he) build a box that halves the frequency signal from the MAF. Then you could half the injector constant compensate. This would allow the computer to read double the airflow signal and raise the limit from ~500 rwhp to ~1000 rwhp, which would be plenty for 99.9% of us.

The only unknown is: does the MAF frequency signal continue to rise after the computer reaches it's limit of 471 gps? For instance, if the highest frequency the computer will take is 15000 hz, then does the MAF output continue rising beyond that point? I don't know.

Mike

 

I think it does,

theres no problem in adjusting what the PCM sees as far as a signal.. it has no idea what a real value is anyway.

Have you thought about using a mustang MAF and building a voltage to freq convertor

 

I am subscribing to try to soak up some of this info................keep talking guys.

 

How much higher do you think the stock MAF will go after the max computer reading?

Ooooooh. . . that sounds like a real calibration nightmare. I used to think that the car wasn't that sensitive to MAF calibration. However, this past weekend, I scaled MAF table 1 up by 10% hoping to get rid of a tip-in hesitation and the car wouldn't even run unless you gave it 1/2 throttle or more.

Mike

 

[QUOTE Thats a pain though, having to reload a tune frequently. WHAT IS THE SOLUTION when keeping the stock ECU...I plan on running a 2 bar MAP, which will help me with the timing, but the fueling is the issue. Is there a way to scale the MAf tables as well?[/QUOTE]

One thing that can help would be Alky for fuel ...for the summer and fall tunes you can just ture the alky up/down for fuel , a wb02 would be good for this as you can see what your afr is... as for the 10lbs and 15lbs just go with the 15lbs

 

Thats got to be the correct answer!

 

I have my Alky set up sort of like that. I have a low (11 psi) / high (19 psi) boost switch. The MAF maxes out in either case as soon as the turbo spools up. I tuned the PE table for 11 psi. My alky comes on at 12 psi and ramps up, giving the enrichment (and detonation suppression) I need at higher boost levels.

Mike