Newbie with MAF questions

[Johnyhotrod]

I tried to tune a friends 99 Ls1 that is in a street rod with a 6 psi Vortech, 42# Ford injectors, and return style fuel system.

Everything went pretty well with the VE table tune, but later the MAf tune exposed some serious problems.

Due to the proximity of the MAF to the inlet of the blower, the MAF signal is very erratic at low engine speeds, causing bucking and surging. Drives fine mafles, but cant of course go into boost....logging shows very erratic maf signal down low, and more negligible with increased airflow.

Is there anyway to "blend out" maf operation at low engine speeds/loads?

Is my only option to complete re-tune with 2002 file, and then go COS?

It works so well at heavy load and WOT, I really did not want to re-tune with a 2 bar SD.

Thanks for the help.

[mr.prick]

I don't know if 6psi is enough to max out the MAF but 1 BAR MAP will be,
You might want to try a COS anyways. IMO
Most will say go with a COS for FI.
You may also need to do RAFIG again after re-enabling the MAF.

[joecar]

Can you move the MAF...?

Do yo have a pic of engine bay showing MAF location.

[Johnyhotrod]

No, I dont have a picture, but its a all custom rod Model A Ford, the supercharger is down very low, and the inlet and maf are kind of under the engine, off to the side...kind of beside the oil pan, under the headers (shorties), maf is less than a foot directly behind the supercharger inlet.

MAF is not maxed, but are you saying the stock MAP may go that high? Our ambient is only ~89 kpa, so 6 psi is only about 128 or so kpa But the top row of the VE table is 105?

He bought a 2 bar MAP anticipating the custom OS 2 bar SD.

What is RAFIG?

Thanks for any advice.

[Baldric]

2 bar map goes to 285kpa (i think) im running boost @ 9psi and im running 2 bar map and 2 bar COS tune

when you upgrade to the cos that suits your controller type there is a boost VE table and that will go past 105kpa which will enable you to tune to boost better