scribbles

Is the stock 88 MAF accurate in a blow through aplication? 6-8 psi. thanks in advance.

scribbles

i am actually running a wells thick screen variant, but same question.

tequilaboy

Under as little as 3-4 psi boost, the stock maf will peg somewhere between 4,000 and 4,500 rpm.

The accuracy depends upon the actual sensor as the output varies among sensors especially at higher than stock airflow.

It is only the first of a few limitations of the stock MAF/165 ecm system which will limit the ability to properly fuel a boosted application.

There are a few ways to get around the inherent limitations of the sytem, depending upon which way you want to go.

scribbles

I will be at WOT or close if I am above 4000 rpm, so it will be on tables by then and mostly ignoring the maf, from what I understand the maf is only really active at part throttle correct? In that case it won't really matter because boost will be so low it won't matter.

vipershark11

iTrader: (6)

I was running 8-9 psi before winter on my procharger blowing through my new remanufactured MAF from Bosch and everytime i hit 4k my wideband went super lean and i even added 100% pe fueling from there and up and it still pegged the lean side of the wideband. So 730 with code59 coming in a week it is.

tequilaboy

This describes the next limitation one will encounter when trying to compensate for boost with additional fueling in PE mode. It can be corrected with some special programming. I know Blowerworks offers a fix for this.

bl85c

iTrader: (2)

You can't tune like that with a turbo setup, airflow is nonlinear to rpm. You either need a larger maf that can read that much or a turbo maf ecm like a gn ecm.

scribbles

It is a supercharger if that maters, but what would you recomend? I am trying to decide if i put it before or after the SC, After would be much better for me if possible.

bl85c

iTrader: (2)

Ah, then you're in luck. Airflow should be pretty close to linear with a supercharger and you could get away with tuning it with the tables. Draw through with the iat sensor after the supercharger would be best, although the '165 ecm doesn't really use the iat for much. Being that the tpi maf is a heated wire maf you can run it in boost without it being terribly inaccurate, but I still think draw through is the best way to go. Do you have a wideband O2 sensor?

scribbles

not yet, I have a NB guage, and FMU, to start, then i will be upgradeing to a wb02 soon.
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And I am uning the film type maf, does that matter? I can find a bosh if ineed to. But like my wells.

bl85c

iTrader: (2)

You need to put it ahead of the supercharger then, frequency film maf's aren't accurate in boost.

scribbles

well that sucks... thanks for the info.