Mean Piston Speed
07-14-2011 | 05:21 PM
#21
Joined: Nov 2007
Posts: 5,100
Likes: 5
From: Maggie Valley, NC
Originally Posted by G' timestamp='1310608084' post='20777325
Really? I think we need to fact check that on the F20. I belive the fuel cut off is at 9200rpm.
Afaik, and I've been around here a while,
F20 - redline at 8.8k, fuel cut at 9.0k
F22 - redline at 8.0, fuel cut at 8.3k
If you take a close look at an AP1/F20 tachometer, you'll see it goes red just before the 9k mark, showing the actual redline at 8.8k:
or
The F22's IP is the same way, with redline shifted just to the right of the 8k mark.
Regardless, dynos show how the two engines behave. As others stated, Honda set the rpm to max based on piston speed, and since the AP2 engine's pistons move faster at relative rpm, it has the lower rpm limit.
I am sorry - I don't see anything saying fuel cut off in your pictures - produce real proof please.
07-14-2011 | 10:32 PM
#22
Community Organizer
Joined: Jan 2006
Posts: 7,961
Likes: 12
From: Oregon City, OR
Originally Posted by G' timestamp='1310608084' post='20777325
Really? I think we need to fact check that on the F20. I belive the fuel cut off is at 9200rpm.
Afaik, and I've been around here a while,
F20 - redline at 8.8k, fuel cut at 9.0k
F22 - redline at 8.0, fuel cut at 8.3k
If you take a close look at an AP1/F20 tachometer, you'll see it goes red just before the 9k mark, showing the actual redline at 8.8k:or
The F22's IP is the same way, with redline shifted just to the right of the 8k mark.
Regardless, dynos show how the two engines behave. As others stated, Honda set the rpm to max based on piston speed, and since the AP2 engine's pistons move faster at relative rpm, it has the lower rpm limit.
07-15-2011 | 06:04 AM
#24
Moderator
Joined: Jul 2004
Posts: 35,993
Likes: 215
From: Queen City, NC
Take a look at the dyno graphs for the two engines, they are all pretty consistent with where the engine maxes rpm. And remember, you can force the engine rpm higher through mechanical means.
07-15-2011 | 10:52 AM
#25
Registered User
Joined: Dec 2006
Posts: 1,174
Likes: 0
From: Palm Harbor, FL
Can you post a couple for each generation? I haven't been able to find these elusive dyno plots
07-15-2011 | 11:21 AM
#26
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Joined: Apr 2011
Posts: 30
Likes: 0
I could've sworn that the f20c has an 86mm stroke, not 84mm like the op said.
If stroke and bore = 86mm or 8.6 cm, then;
pi x (1/2 bore)^2 = ~58 cm^2
58 cm^2 x 8.6 cm = ~499 cc
499 cc x 4 cylinders = 1,996 cc
Honda says it's a 1,997 cc engine which can be accounted for in my rounding down twice. The stroke is definitely 86mm because I know the engine is a square configuration so the bore must be the same. I could've saved time and just looked it up lol this would make our mps about 26.5fps @ 9,200 rpm, for what it's worth.
If stroke and bore = 86mm or 8.6 cm, then;
pi x (1/2 bore)^2 = ~58 cm^2
58 cm^2 x 8.6 cm = ~499 cc
499 cc x 4 cylinders = 1,996 cc
Honda says it's a 1,997 cc engine which can be accounted for in my rounding down twice. The stroke is definitely 86mm because I know the engine is a square configuration so the bore must be the same. I could've saved time and just looked it up lol this would make our mps about 26.5fps @ 9,200 rpm, for what it's worth.
07-15-2011 | 12:01 PM
#27
Registered User
Joined: Dec 2006
Posts: 1,174
Likes: 0
From: Palm Harbor, FL
I could've sworn that the f20c has an 86mm stroke, not 84mm like the op said.
If stroke and bore = 86mm or 8.6 cm, then;
pi x (1/2 bore)^2 = ~58 cm^2
58 cm^2 x 8.6 cm = ~499 cc
499 cc x 4 cylinders = 1,996 cc
Honda says it's a 1,997 cc engine which can be accounted for in my rounding down twice. The stroke is definitely 86mm because I know the engine is a square configuration so the bore must be the same. I could've saved time and just looked it up lol this would make our mps about 26.5fps @ 9,200 rpm, for what it's worth.
If stroke and bore = 86mm or 8.6 cm, then;
pi x (1/2 bore)^2 = ~58 cm^2
58 cm^2 x 8.6 cm = ~499 cc
499 cc x 4 cylinders = 1,996 cc
Honda says it's a 1,997 cc engine which can be accounted for in my rounding down twice. The stroke is definitely 86mm because I know the engine is a square configuration so the bore must be the same. I could've saved time and just looked it up lol this would make our mps about 26.5fps @ 9,200 rpm, for what it's worth.
Using Honda's published bore and stroke numbers, the displacement for each are:
F20C 87.0 x 84.0 mm
F22C 87.0 x 90.7 mm
