Classic Mini 1275 cc cylinderhead airflow testing

Airflow testing of a mini head 1275cc version,  based on a MG metro 12G940 flatdeck casting done for 98% to the drawings in David Vizards Tuning the BL A-series engine.  A virtual copy of this head has produced 90 BHP and 125NM torque on a 1310cc with 1.5 rockers, Swiftune SW5 cam, HIF 44 with CalverST induction kit and small lcb+ rc40 exhaust.

It was however one of the first head I ever ported and there are certainly a few areas that can use a bit more detailed work and reshaping

Done with a manifold (minispares medium with a pipercross bellmouth , but no carburetor) attached to the head. Valve sizes are 35.7 mm intake (no backcuts yet) and exhausts 29mm  (not tested).

Same head now tested at 28 inch H20. This time with (black) and without (red) the minispares manifold. While the low lift flow can de improved quite a bit with better seatwork and a 30 degree backcut, the high lift flow seems to hit mud at 6mm lift worsening at 8mm but does not stall fully . I have to get back to this and see if I can improve that a bit by reshaping the area directly below the seat and in to the seat pocket as well as the chamber side.

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FLOW QUIK Compare Data Report
________________________________________________________________________________

No.        Date             Test Name               Manufacturer                 Model
—  ———-  ——————–  ————————-  ——————–
1   7/12/2012             12g940-30                        BMC                12G940
2   7/12/2012             12g940-31                        BMC                12G940
________________________________________________________________________________

CFM               DEPRESSION                  CFM DIF
Lift       No. 1      No. 2         No. 1      No. 2         No. 1      No. 2
——–    ——-    ——-       ——-    ——-       ——-    ——-
0.50       17.9       21.6         28.00      28.00           0.0        3.7
1.00       23.6       24.4         28.00      28.00           0.0        0.8
2.00       36.2       39.9         28.00      28.00           0.0        3.7
3.00       51.5       52.7         28.00      28.00           0.0        1.2
4.00       64.7       65.4         28.00      28.00           0.0        0.7
5.00       78.3       79.8         28.00      28.00           0.0        1.5
6.00       87.8       90.8         28.00      28.00           0.0        3.0
7.00       93.9       98.6         28.00      28.00           0.0        4.7
8.00       99.8      104.7         28.00      28.00           0.0        4.9
9.00      106.4      112.0        28.00      28.00           0.0        5.6
10.00      108.7      114.7       28.00      28.00           0.0        6.0
11.00      110.8      115.0        28.00      28.00           0.0        4.2
12.00      111.6      117.9        28.00      28.00           0.0        6.3
13.00      113.7      118.6        28.00      28.00           0.0        4.9
14.00                        119.5        28.00
——–    ——-    ——-       ——-    ——-       ——-    ——-
Average:       78.9       85.0         28.00      28.00           0.0        3.7

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