Speed density vs ALPHA N

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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LT401Vette
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Post by LT401Vette »

I think the definition of hot cam needs to be a little clearer. It is common knowledge that Alph-N is primarily for setups, cams in particular where the MAP signal doesn't have much resolution. However, I think we often loose site of the different perspctives for what a cam of this definition is. Looking at a typical small block, A "Hot" cam on a street car can mean 215° of .050" duration, but that is WAY off from needing Alpha-N. A radical street cam may fall into the 240°+ @ .050" lash range, but this is still seriously doubt full that you should even consider Alpha-N.
Pretty much any cam that is so hot it requires Alpha-N is very doubtfully used on a street car. On a v8, it is usually cams with 270°+ duration at .050" lash that should start considering Alpha-N. Usually Alpha-N is used more by drag cars with 280 or even 310° of .050" lash duration. As you can imagine with 300° .050" lash duration there is little resolution to work with.
Naturally there are many other factors that can move that number up or down primarily lsa and displacement, but it seems common to jump to trying Alpha-N because you have a "Hot" cam, but it is "Hot" in a whole other perspective.
Phil Tobin
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diegom6
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Post by diegom6 »

yes, when I said HOT I meant for a very lumpy cam, especially for N.A. cars wich are builded for drag or circuit racing.

I forgot to ask, what If I use a MAF instead of APLHA N for a hot N.A. engine ( Hot cam) ? Would be more usefull?
BMW 325is Turbo (m20b30) MS I 2.2 029q2 MSNS
Jeep Cherokee 4.6L Stroker Supercharged
65looter
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Post by 65looter »

I have a compcam 280H-R10
http://www.compcams.com/Technical/Searc ... r=35-430-8
and speed density is not working for me.

Using Alpha-N.
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