11-08-2021, 03:04 PM
(This post was last modified: 11-08-2021, 03:46 PM by Mike Costigan.)
Looking at the technical specifications published in sales brochures over the years, the official power output of the Seven is given as follows:
1922-23 10bhp at 2,400 rpm (696cc engine)
1923-32 10.5bhp at 2,400 rpm (747.5cc engine, up-draught carb)
1933-35 10.5bhp at 2,400 rpm (side-draught carb and revised exhaust manifold)
1935-36 13.5bhp at 3,000 rpm (presumably higher-comp 1A684 cylinder head)
1936-38 17bhp at 3,800 rpm (3-bearing engine with high-comp cylinder head)
Which raises a few interesting questions (well, it does to me!).
Did the 7.5% increase in engine capacity in 1923 really only provided a 5% increase in power?
Doesn't the 1933 side-draught carb and associated manifold not provide a bit more power?
If the earlier engines are rev'd to 3,000rpm as quoted for 1935-36, how much more power is achieved?
Similarly, if revs are increased to the 3,800rpm used for the 3-bearing engine, how much more power do the earlier engines produce?
Thoughts, anyone?
1922-23 10bhp at 2,400 rpm (696cc engine)
1923-32 10.5bhp at 2,400 rpm (747.5cc engine, up-draught carb)
1933-35 10.5bhp at 2,400 rpm (side-draught carb and revised exhaust manifold)
1935-36 13.5bhp at 3,000 rpm (presumably higher-comp 1A684 cylinder head)
1936-38 17bhp at 3,800 rpm (3-bearing engine with high-comp cylinder head)
Which raises a few interesting questions (well, it does to me!).
Did the 7.5% increase in engine capacity in 1923 really only provided a 5% increase in power?
Doesn't the 1933 side-draught carb and associated manifold not provide a bit more power?
If the earlier engines are rev'd to 3,000rpm as quoted for 1935-36, how much more power is achieved?
Similarly, if revs are increased to the 3,800rpm used for the 3-bearing engine, how much more power do the earlier engines produce?
Thoughts, anyone?