Quote:
Originally Posted by puretone
Hmmm I wonder what the ECU will do tho, would it go 100% on the injectors at full 5v? I think I remember reading up about Denso MAF's and that anything above "0 psi" (so at normal atmosphere which is 1 bar to begin with) it won't read anything. So WOT = the most a standard MAF can read unless it's one of those Nissan Z32/33 MAF fenangles which were made for boost...doesn't the 3SGTE use a MAF as well?
I guess with the piggy-back you could always install a MAP sensor to read anything above "0 psi", at least it is what I would do for a turbo build....or if the voltage specs are available for the 3SGTE MAF...
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What the ECU does @ 5v depends on how the mfg tuned the ecu, some may go to a default map based on engine rpm & throttle position and run closed loop(or is that open loop? I always get them confused) since its at WOT. Others may go into limp mode. All will probably set a CEL light on newer vehicles.
Also, I 'think' most MAF sensors are oversized from the MFG otherwise they might run into issues due to variences in temp/air density/climates/ect.
Your forgetting one VERY important factor
. ALL maf systems on turbo & s/c are BEFORE they see boost. Boost is a non-issue with a MAF system.
The MAF will registers airflow, by measuring air passing through it INTO the compressor (either turbo or supercharger). The max cfm/flow reading based on it's size. If you have more flow/velocity than the max your MAF can handle, you go to a bigger MAF (larger size = slower velocity, lower voltage reading/output).
But doing so requires tuning to correct for the differences in readings for the fuel map. Most of the time you can 'cheat' the system with an SAFC or similar piggy back device, it won't do quite as good a job as a standalone, but it will work pretty well.
Andrew