MAFT Gen 2 - Anyone?

[Drweldin]

Originally Posted by twinturbvr4

Did you ever get this figured out? I'm having I think the same exact thing goin on.. When I just barely press the gas just to maintain speed it sounds like its drawing alot of air through the intakes and im getting some slight stuttering and its floating around 16 afr.. I've been trying to figure out in my head exactly HOW to adjust this since it can happen at any rpm, but obviously on the LOW load...

Also, whats a good way to richen slightly between shifts, seems that I get around 15+ AFR after I get back on the gas after I go into the next gear.... (feel free to slap me around if thats WAY too vague! )


EDIT: by the way.. thats from page 6

No, not really figured out....seems fine under load, so I dont worry about it too
much

[TurboBob]

Originally Posted by Drweldin

Couple of observations / questions:
1) I cannot seem to effectively lean the idle. I am going to reset base idle and look at IAC values later....
2) When leaning idle, how long can it take to change AFR? Is it usually instanteous? or should I be waiting a couple of minutes?
3) I can get lo-load page to give me stoich readings at each rpm level with the car warm, and stationary,me just applying and holding trhottle and adjusting....going up thru the rpm range....but, I have to add + 20% or so at 1200 and above-- is this "normal"? second,is this a proper way to tune lo-load?? So I effectively net -17% or so user tune (560 injectors)....but keep in mind, ported heads, free flowing exhaust bigger turbos, etc....so maybe its ok (?) It does sound and feel better with the extra fuel....I have not driven it yet. Im a little worried about the transition from -37 at 800 rpm to -17 at 1200 ....not sure if that will present any issues....
Any good links to tuning?

EDIT: #1 IAC Seems good, and seems to act normal. NEvermind on #3, experimanted and found this is not a good way to tune. While it works with no load, I was indeed rich at cruise afterwards, although a little more fuel in the lower range of the lo load page (rpms) does seem to smooth the car out a tad...

#2 when I make a change to idle, I rev the car a couple times and let it settle back in.....

I have been tuning all my part throttle stuff using the O2 trim. I tune the car a little rich so the trims all go to 81, then I tune for an O2 trim of 80 or so. This way I can see if the ECU is in open loop (stuck O2 trim) or not.... Works pretty well.

Bob

[twinturbvr4]

ugh.. time to dump my palm logger and get a scanmaster...

[twinturbvr4]

Originally Posted by twinturbvr4

Did you ever get this figured out? I'm having I think the same exact thing goin on.. When I just barely press the gas just to maintain speed it sounds like its drawing alot of air through the intakes and im getting some slight stuttering and its floating around 16 afr.. I've been trying to figure out in my head exactly HOW to adjust this since it can happen at any rpm, but obviously on the LOW load...

Also, whats a good way to richen slightly between shifts, seems that I get around 15+ AFR after I get back on the gas after I go into the next gear.... (feel free to slap me around if thats WAY too vague! )


EDIT: by the way.. thats from page 6

Any ideas Bob?

thanks.

[josevr4]

What are O2 trim values as in (81= rich) (?=stoich)(?=lean). I need to know since i dont have my AFR installed yet and im really eager to start tuning little by little.

[twinturbvr4]

any ideas?

[TurboBob]

Originally Posted by twinturbvr4

Did you ever get this figured out? I'm having I think the same exact thing goin on.. When I just barely press the gas just to maintain speed it sounds like its drawing alot of air through the intakes and im getting some slight stuttering and its floating around 16 afr.. I've been trying to figure out in my head exactly HOW to adjust this since it can happen at any rpm, but obviously on the LOW load...

Also, whats a good way to richen slightly between shifts, seems that I get around 15+ AFR after I get back on the gas after I go into the next gear.... (feel free to slap me around if thats WAY too vague! )


EDIT: by the way.. thats from page 6


Any ideas Bob?

thanks.

what injectors are you running? what MAF? What are your settings? What are your trims? What is your O2 trim doing when this is happening? Is your BOV open or closed ? (both ends connected)

B

[twinturbvr4]

Im running 450s with a 3.5" GM MAF.. open atmosphere BOV.. running -19 mainscale with 12.0 AFR tracking enabled at about 1.8 TPS and 2500rpm, everything else pretty much zero'd. I don't know what any of my trims are right now.


thanks.

[TurboBob]

Originally Posted by twinturbvr4

Im running 450s with a 3.5" GM MAF.. open atmosphere BOV.. running -19 mainscale with 12.0 AFR tracking enabled at about 1.8 TPS and 2500rpm, everything else pretty much zero'd. I don't know what any of my trims are right now.


thanks.

get some logs of driving when this happens, I want to see what the trims are doing. There are a couple of possibilities.

how is your PCV and crankcase vent setup?

Bob

[twinturbvr4]

Originally Posted by TurboBob

get some logs of driving when this happens, I want to see what the trims are doing. There are a couple of possibilities.

how is your PCV and crankcase vent setup?

Bob

I replaced the pcv a few months ago and am just running the stock setup on it with exception to the to crankcase venting to a breather (rather than back to the non-existent intake bubble) I'm in the process of getting a different datalogger, so I won't have any logs for a lil..