AlphaN blending

[dnb]

Has anyone used alphaN blending?  Is it worth the effort of making the hybrid tables?

I am suspicious of using alphaN for the whole of my map.  I don't know why, but it just doesn't feel "right". 
But there is so little resolution at low RPM/low load that pressure based tables don't really work.
(MAP at idle is 60 to 65 kPa)  When the engine is loaded, the MAP works nicely as you'd expect.

I'm a bit worried that with the blended tables I could run off the top edge of the map - 104kPa is equivilent 40% TPS, isn't it? - so should I compromise the resolution at high RPM (in the SD region) to get some more range in the low RPM (AlphaN region)?  Or is it a case of 40% throttle will raise the revs so fast that it'll be speed density no matter what?  (I suspect this isn't the case for a large capacity v8 with enormous amounts of torque from idle, provided I'm engaged in the activity of moving imovable objects from rest ) 

Also, how do things like pressure based fuel cuts work with alphaN?  If I wanted to cut fuel at less than 20kPa, would that mean I cut fuel at 0% TPS, such that idle becomes rather troublesome? 

[rob@vems.co.uk]

I've had a play with the blending and decided that AlphaN was the prefered method with throttle bodied engines.

When I saw the way your engine moved around the load sites it looked so close to AlphaN behaviour as made no difference from what I could see.

Personally with big cams I'd be using AlphaN, in fact I think I'd use AlphaN on anything that wasn't turbocharged.

As for fuel cut, yes it will activate on TPS rather than MAP but its not really a problem because the RPM limits are changeable so it will start injecting fuel again when the RPM drops below the prescribed value.

I think you'll find that you'll get crisper response in an AlphaN setup.

[dnb]

My engine is still plenum based, although it does respond differently to most engines here due to the silly capacity.

I've tweaked the map to use alphaN up to 2000 RPM or so, so I'll see how that goes.  I should now get away with not having 5 MAP bins of 5 kPa around the idle area...