StupidFast

I am maxing out my MAF sensor at 456g/sec and would like to move it to 512. I am sure that there are posts about this but, for some reason I am having no luck with finding them.
How do you do it? Is there anything I should know before I do it? Drivability issues? Thank You.

AzzHauler

iTrader: (3)

If you look at the maf table and go to the graph page, you should see it rise up then flatline at the end. If this is the case, then you go back to the table page and find the cells on the right that are all the same value. Just add some to them and keep checking the graph to smooth it out, with 512 in the last cell.

jimmyblue

iTrader: (11)

I'm guessing that the MAF is pegging frequency
below the maximum engine RPM, and this upper
limit is interpreted by the PCM as 456 g/sec?
Or is the flow/frequency table flatlined at 456?
With big boost you might be past the MAF's hard
limits.

If this is going on then you can scale to
whatever, and you'll still have a MAF output
that does not actually indicate airflow. A
frequency counter or a 'scope that will give you
afrequency readout should be hung on the MAF
output and logged against RPM. If it's clipping
right there, you need a MAF that's capable of
reporting (faithfully) a higher airflow, and then
scale for that. The output needs to be linear all
the way up past your max RPM, at the source, as
well as whatever you do inside the computer.

NoGo

iTrader: (2)

I do sorta like Azzhauler suggested and grab the first value at the 456 flatline. Add 20 to this value (476), add 40 to the next value (496), set the next value to 512, and flatline the rest at 512. That should do the trick.

Make sure that you check your MAF fail frequency as well and ensure that it is well above 12000 (16-17 kHz should do fine)

Don't shift the entire MAF table whatever you do. Being you are open loop it will COMPLETELY goof up your running.

Increaseing the MAF is only going to give you a pinch more distance in your RPM (maybe 200 rpm). Once you get that sorted out you can move on to the VE table at 105 and begin adding fuel at the MAF max rpm on up.

Good Luck

MIGHTYMOUSE

iTrader: (59)

only 99+ computers can do this and get a g/sec value up to 12khz, whereas 98 cars stop at 11,250.

nogo, why ve instead of pe? i saw you mention that you go to the ve table when you reach the max freq. on your maf table.. i run out of maf at 3600rpm and then go to the pe/rpm table to compensate, what are the pros and cons of ve adjusting vs pe adjusting? thanks

NoGo

iTrader: (2)

The great thing about the VE table is that it has a 105 MAP setting. Atmospheric pressure is 101.3 MAP, so 105 MAP is almost solely seen under boosted conditions. Kind of like our own boost map. This aspect of the VE table is very helpful for Turbo cars which don't have a repeatable/predictable boost curve.

Also, StupidFast, like many all trucks out there, suffers from PE delay. Even with this delay set to zero, there is still a few (3 or 4) second delay before the PE table kicks in. This is very dangerous for boosted trucks. If he is racing somebody on the freeway, gets out of it at 4000 RPMs, then suddenly gets back in it, his truck will run under boost without Power Enrichment. Potentially, he could blow his engine.

There is no delay or consideration for the VE table. It goes directly into the base calculation for fuel.

Good Luck

MIGHTYMOUSE

iTrader: (59)

that really sucks for trucks, glad i dont have that.. but since i have a 98 i also dont have ve tables above atmospheric. so im out of luck there.

NoGo

iTrader: (2)

98's have their VE table to 105 as well..... at least all of the 98 files I just looked at ??

felton316

Yeah, my 98 goes up to 105. Are you looking at the right table?

MIGHTYMOUSE

iTrader: (59)

hmm ill have a second look, i must be looking at something else.. nogo, could you be a pal and send me an edit file example of how you tailored the 105 row or columm.. ive been scared to look into ve stuff so far, but if it can work more consistantly with weather than the pe table does, i'll switch over..just gotta break the ice with it.. i can send you my edit file if you are interested as well. thanks

NoGo

iTrader: (2)

I will send you a good VE file when I get back to the shop late next week. I am currently in Texas (tuning a turbo big enough for me to sit between the impellers )

The VE deal is still not a clean tune when you max out the MAF. On turbo cars I like to use it kind of like a hobs switch wired to an extra pump.

If you have your car all ironed out on the PE table then it probably isn't worth your time to switch to the VE table IMO.

MIGHTYMOUSE

iTrader: (59)

ok, nevermind then, not doing anything is easier

Ragtop 99

iTrader: (7)

good info. TTT