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Discussion Starter · #3 ·
You are..
You are having fun that does not involve her!..
That must be it!

Lowering the maf voltage at a constant airflow results in a decreased load calculation. So it advances the timing and leans the fuel. Both good sounding as the 1zz ecu runs too rich at wfo. The possible bad thing it also does is change the vvti target.

By Increasing the MAF Housing.. we are reducing the Velocity of the Intake Gasses.. and the ECU does it's Load Calculations on Velocity by way of the MAF Sig.. then ECU thinks the Engine is not working as hard, and will give it more Ignition Advance. ( We are fooling the ECU ).. but the Draw back to this is the ECU will also reduce the Injector Pulses... So less Fuel..
Now this is where it get 'Complicated'.. The ECU will sense the Lean Mixture in Closed Loop, and Fix that by Adding Fuel.. ( + on the Fuel Trims ).. BUT when the Fuel Trims get past about 10, the 'Rate' of fuel Enrichment will not carry over into the Open Loop Wide Open Throttle Territory.. and the Fuel Mixture will get Lean at WOT..
So to fix that, either ADD injector Size so the Fuel Trim is Less than 10.. Or Add Fuel Pressure.. Same thing..
If the Fuel Trim stays ABOUT + or - 5, then the WOT will be ABOUT right.. There is a Compromise.. the ECU will naturally add too much fuel at WOT, so you really want the Fuel Trim to be -5 to 0..
It's all a Balance.. And with the Cute Trick of adding the Spacer Below the MAF.. I can Taylor the MAF sig to give me any ignition advance I want.. then by adjusting the Fuel pressure, I can fix the WOT fuel Mixture..
I'll edit this and add my thoughts and comments when i get home.
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