Guys I just put a 3600 rpm stall in my truck .
Stock maf enable rpm is 4000rpm
Would I benifit from lowering the maf enable rpm ?
My VE is tuned but it's hard to hit the high Kpa / low rpm area .
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Guys I just put a 3600 rpm stall in my truck .
Stock maf enable rpm is 4000rpm
Would I benifit from lowering the maf enable rpm ?
My VE is tuned but it's hard to hit the high Kpa / low rpm area .
The stall speed and MAF high rpm disable are not really connected as far as I can see.
The MAF enable of 4000 rpm defines to the PCM when to use VE vs MAF in transient conditions and when to go purely with filtered MAF. The concept to the "blended operation " vs the >4000 rpm set MAF is to allow the VE to fill in the gaps when the MAF isnt really reporting accurate airflow information to accurately calculate the cylinder charge which is critical to further define the amount of fuel to meet the Air to Fuel Ratio (AFR). I know, that sentence is waaaaay toooo long :-) There are times when not all the air that the MAF is reporting, actually makes it to the cylinder. A good example is when you stomp the pedal....while the MAF is going to report a very large change in airflow, some of that air must fill the intake manifold while the rest makes it to the cylinder. During these transient times, the PCM decides to use the VE values as they are more representative of the actual cylinder charge at that specific load. It is assumed at the <4000 rpm area's, their will be a fair amount of acceleration and decelleration, causing these inaccuracy in the airflow. Beyond 4000 rpm, it is assumed you arre either cruising with little or no transient conditions or in a WOT pull.
As far as hitting the higher load/lower rpm area's you can either find a steep hill, ride the brake, use a higher gear or interpolate the delta changes from the lower MAP logging and correct the higher are's you cant hit using that average delta....will be close.
Ed M
Ive bounced it back and fourth from a 500 to 4000 enable and saw little difference on the butt dyno.
I was planning on leaving it around 4000 since my VE is dialed in very well. But would I benefit to lowering the Maf enable slightly ?
I see a lot of the car and trucks my buddies have run MAF only from other local "tooners" , besides the delay on the hit what other negatives does a MAF only tune have just out of curiosity ?
I am curious about this as well. Any luck finding out more info on this?
The stall speed and the MAF only enable rpm are not related.Quote:
Originally Posted by Jarrod.v
MAF only tuning is lazy, it will make the same power, but will lack in driveability due to poor transient airflow information, mind you that larger stall will be pretty forgiving. GM switched to MAF only at 4000 rpm (dynamic air turns off) as the ecu is borderline on processor, it starts to drop processor loops trying to calculate air flow from VE above that. Dynamic air is the combined VVE and MAF which is the best of both worlds due to MAF being less effective at low airflow and rapid throttle changes where the VVE helps prop up the Dynamic air calculation.Quote:
Originally Posted by Maxspeed96ct