One more comment on intake manifolds & race results.   Do not ignore the benefits of a really clean air inlet with ram air recovery BEFORE the manifold.   At 1125 ft  msl, 220 IAS, I saw manifold pressures around 31.8" Hg.  Ignore this factor and you throw away about 6% "free" horsepower.

 

Al,  I forgot to comment on your last note about your MAP tap in manifold.  I think it is highly possible you were seeing errors induced by air stream eddies or some other unpredictable factors caused by that location.   It is a challenge to get MAP measurements when you have no real plenum, only runners with high velocity air.

Tracy

 

I use the stock ports in the TWM throttle body.  I assumed they would know where to place the port to get a good measurement.

Where do you measure MAP on your system?  I can’t believe that you could see that kind of pressure at the engine end of a long intake tube.  But I remember once before when I was wrongJ.

Al

I measure it at the dynamic/plenum chamber, just under the throttle body.

Tracy