Dude, you missed all the Apten and porting blower threads recently There's almost as many of them as there are SRT-10 threads.

Here's the latest:
https://www.f150online.com/forums/sh...hreadid=141588

Due a search on Apten for more.

 

Easter,

I think that the lightning engine will respond a little different than the Cobra because of the 2 valves vs. 4 valves. The DOHC engines make peak TQ and HP higher in the RPM than the SOHC engines.

 

just to clear a few things up

The cobra gains power because of the increase in mostly adiabatic efficiency, so it doesn't gain boost. And because of the gains being mostly abedic, the gains are higher as the RPM increases (low power gains are not high). There is no real boost increase with the cobra supercharger.

The lightning pickup about 1/2 of it's power gains from adiabatic efficiency, but the other 1/2 from volumetric efficiency. This means that the supercharger actually moves more air at the same RPM, creating more boost. That is why the lighting superchargers not only pick up more boost but actually make most of the power gain thru the whole powerband instead of just thru the higher end like the cobra ones do.

Hope that helps.
Brian Herron

 

That makes sense because the port job is opening up the intake of the lightning case where the rear entry cobra already has a better opening.

 

I picked up 30 rwhp across the whole field a quick search and you can find my dyno charts i posted awhile back

 

exactly!

The outlet work increases adiabatic efficienty, the inlet work increases volumetric efficiency. Since the lightning inlet is so restrictive, there is quite a bit if room for improvment there. While there is some improvment done to the cobra inlet, there is not as much room to grow as there is on the top-fed lightning.

Brian

 

If you got my chart handy brian post it up it will save me time looking for it

 

By 'abedic' I assume you mean adiabatic efficiency, which is basically the measure of how much a compressor heats the air. I can see why the ported blower would show more gain at higher rpm. With a roots blower, you have lobes trying to move the air around the outside of the case, while at the same time lobes are rising in the center, slinging air upwards into the upper plenum. Eventually the rising lobes slinging the air upwards creates so much turbulence that it robs air from the descending lobes trying to pack the charge around the case and into the engine. Thats why gains from bigger and bigger pullies start to fall off very quickly (10# vs. 4#, for example), combined with compression heat, frictional heat from the internal gears, and shear heat from the air whipping off the rotors. It seems Apten has found a way to scavenge more air to the descending lobes, thus raising the effective rpm potential of the blower before the central rising lobes create too much turbulence.

 

the air/fuel stays the same?! did I hear that right? how can this be? if more air is being forced into the motor, how can the ratio stay the same?

if this is true, this is really awesome!

-Mike

 

the cobras usually have the same air/fuel ratio, the lightnings sometimes do and sometimes they slightly change. It all depends on how close you are to the limitations on your MAF meter and how much boost it's making. Not a bad idea at all to have it dyno checked if you are running a lot of boost or a tune on the edge.

Brian

 

I'm a lawyer, not an engineer!

layman terms, so people can understand --> it makes power!

I don't like when people write stuff that the average person (read non-engineer) has difficulty understanding (that's a joke of course)

 

Or the Below Average People like me I got one big headache ever since the PCV and Apten Post's went overboard

 

AMEN TO THAT BRO!

 

ditto that!