Stock Maf Limits

Mitco39

While I agree with you on basis I would argue that real world adjustments to the fact would cause very little if at all 0 changes to the overall output of the engine since we are not dealing with direct injection engines. That argument would be valid if we were talking about emission generation and controlling the hydrocarbons. But usually when one is concerned about that it is during a constant state operation such as idling or cruising down the interstate.

On a direct injected engine that does not rely on the fuel evaporating (and thus cooling the charge before it hits the engine) I would say that yes it becomes a greater concern, in fact all the diesels I tune have a IAT right before the air hits the plenum for that exact reason. The IATs have a large effect on the burn rates in direct injected engines because you do not have the cooling evaporation effect before the air enters the combustion chamber.

Again its just my opinion on the matter. Plus if you look at the Uprev timing tables there is only so much fine adjustment available to the end tuner. Its a limitation to the memory in the ECU.

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1slow370

I'm sorry but IAT's play a HUGE role in detonation threshold so what you are basically doing is pumping a whole hell of a lot of air that can be 50-150 degrees above ambient/what the MAF is telling the ecu it is and expecting it's effect on ignition timing to be negligible? That is why the stillen kits clack away like a tap dancing festival once they are heat soaked and the ecu starts pulling gobs of timing as the knock sensor pick it up.

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Mitco39

I didnt think of the supercharger situation with the "suck through" maf. I was thinking only of the Turbo setup with the Mafs in their stock locations. But your right if the Maf is upstream of the FI setup (turbo or supercharger). The fix to that problem is just to move the MAFs to right before the throttle bodies. Then you can deal with it in much the same way we do with the turbo kits.

So yes your right didn't think of that condition during my reply but its an easy fix that would make that kit much easier to tune.

I was thinking more along the lines of a 5-10F increase as the metered air enters the heat soaked plenum.

__________________
2007 Chevy Duramax - EFILive Tuned By Me
2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me
The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her
My Build --> http://www.the370z.com/members-370z-...39s-build.html