another jetting question

[dannygraves]

actually there is one other major disadvantage and why I had to shit can the one on my starion... they will only record so high, once you put more air though it than it can record, the ecm stops adding fuel. I blew up my starion becasue the stock MAF would only read up to the amount 14psi of boost was sucking through it, then it would simply stop reading any higher even though more air was going though it. this is what caused me to shatter a ring land when I had a boost spike... no bueno and something a map system would have caught (also the reason I went to forged pistons ). Even converting to a gen-1 eclipse MAF only raised the bar to 18psi. I put in my SDS system running map and could push to the 3 bar limit of the map sensor.

[britincali]

actually there is one other major disadvantage and why I had to shit can the one on my starion... they will only record so high, once you put more air though it than it can record, the ecm stops adding fuel. I blew up my starion becasue the stock MAF would only read up to the amount 14psi of boost .

Thats exactly why my truck blew up, the MAF on fords will accuratly read up to 13 or so PSI after that it just guesses the fuel needed. I now have a MAF extender (resistor) and a tune to compensate.

[M.F.D.B.]

actually there is one other major disadvantage and why I had to shit can the one on my starion... they will only record so high, once you put more air though it than it can record, the ecm stops adding fuel. I blew up my starion becasue the stock MAF would only read up to the amount 14psi of boost was sucking through it, then it would simply stop reading any higher even though more air was going though it. this is what caused me to shatter a ring land when I had a boost spike... no bueno and something a map system would have caught (also the reason I went to forged pistons ). Even converting to a gen-1 eclipse MAF only raised the bar to 18psi. I put in my SDS system running map and could push to the 3 bar limit of the map sensor.

Like I said before, there is no "one size fits all" but remember that MAP sensors also come in different flavors. Theres N/A ones which only read vacuum and then theres 1 bar, 2 bar, 3 bar, etc. Dont forget also that the ECM can only add so much fuel without a recalibration. I can tell you this, with as much as I was changing on my Vette a MAP system would have made my life WAAYYY harder. Not to mention, when I finally get that new motor going the Lingenfelter MAF will go a long way to protecting that engine till I get it properly tuned.

[dannygraves]

ya, thats what I meant about aplication. If I were building another high boost machine, I would invest in a standalone system running MAP (more tuning work, but thats to be expected in a high boost application). If I were building an all motor +nitrous v8, I'd stick to MAF. Plus the big v8s, camaros, vettes, mustangs all have pretty good MAF setups and lots of aftermarket oversized ones available, with my mitsubishi that simply was not an option making MAF a terrible idea.

[M.F.D.B.]

ya, thats what I meant about aplication. If I were building another high boost machine, I would invest in a standalone system running MAP (more tuning work, but thats to be expected in a high boost application). If I were building an all motor +nitrous v8, I'd stick to MAF. Plus the big v8s, camaros, vettes, mustangs all have pretty good MAF setups and lots of aftermarket oversized ones available, with my mitsubishi that simply was not an option making MAF a terrible idea.

I hear that...

[dannygraves]

what was this thread originally about?!

[M.F.D.B.]

what was this thread originally about?!

Hell if I know...

[Blusmbl]

Thats exactly why my truck blew up, the MAF on fords will accuratly read up to 13 or so PSI after that it just guesses the fuel needed. I now have a MAF extender (resistor) and a tune to compensate.

Kinda. All the newer-style Ford MAF's are 0-5v output. The transfer function is adjustable in the calibration, however at some point the airflow requirement is great enough that the signal is clipped. The only way to fix it with a production method is to increase the size of the MAF housing, so you have higher airflow capability before the MAF is reading 5v. Past that, you're stuck, it gives you the same fuel regardless of increased airflow because the sensor is past it's physical range of being able to measure. This point is different from vehicle to vehicle. A Shelby GT500 MAF housing is something like 110mm in diameter to be able to measure the 70+ lb/m of air that's being flowed at WOT redline.

Also- not all modern MAF systems have baro. It's inferred, as it's cheaper to cost reduce the sensor. A 3v Ford, for example, only has the air meter. No measured MAP, no barometer. Only MAF and IAT at both the air meter and intake. Some, like the 2v's, have MAP in the form of an electronic EGR valve that has a MAP sensor integrated into the housing.

A MAF doesn't measure pressure, only flow.

-Nick

[M.F.D.B.]

A MAF doesn't measure pressure, only flow.

-Nick

Sorry, what I meant was a MAF system (with a MAP and or Baro sensor) is not only MEASUREING air flow directly its ALSO measuring Pressure (Via Baro or MAP with Baro feature).

A MAF sensor by itself measures air flow based on how much current it takes to keep the wire heated to a set temp. This is why each MAF has to be calibrated to its Max CFM and this is the max amount of air it can "meter".

[Blusmbl]

Gotcha.