As I mentioned, my MAP reading is only 27 on the ground, at full throttle.  I thought I had this isolated to the intake being too restrictive, but Tracy suspects it's more a matter of the way the ports are positioned on the TWM throttle body.  He also mentioned that someone else (Al, maybe) had the same issue, with lower than expected MAP readings when using the ports on their TWM.  Is anyone using the TWM TB ports, and seeing near 30 MAP?  I sure wish I had documented this little tidbit of info from the previous version.

 

 

Rusty;

 

Just back from vacation.  I saw the same results with my TWM TB.  I have a bit of restriction up stream from the TB, but couldn’t believe it could be that much.  I had concluded (probably with some discussion with Tracy) that it was likely at least partially due to the post location.  Your data seems to confirm that.

 

There is likely some loss in the long TB barrel- I think it is about 4 ½” long.  My barrels are 44 mm dia.  What are yours?  You can see my plot of MAP vs RPM at http://members.cox.net/alg3/Dynamometer%20test%20report.htm

and scroll to near the bottom.  It went all the way down to 25” at 7000 rpm.  I’d be interested in what TWM has to say.

 

Al