Car&Driver explains the FB

Old Feb 2, 2011 | 08:51 AM
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Car&Driver explains the FB

Good read for those interested in the main differences between the FB and EJ series engines.

Link
Old Feb 2, 2011 | 09:02 AM
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thanks for the share, interesting read
Old Feb 2, 2011 | 01:01 PM
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Good info. Thanks for sharing.
Old Feb 2, 2011 | 01:28 PM
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ugh, narrower valve angle and longer stroke, good thing they made this into its own motor and not all the EJs like that instead
Old Feb 2, 2011 | 02:20 PM
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Can't wait to see what they get out of a turbo'd version.
Old Feb 2, 2011 | 03:13 PM
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I don't really understand how they managed to increase the stroke without really changing the rod length.
Old Feb 2, 2011 | 03:32 PM
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Originally Posted by antonch
I don't really understand how they managed to increase the stroke without really changing the rod length.
in the crank stroke, rod length does not affect stroke
Old Feb 2, 2011 | 03:46 PM
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The intake manifold is plastic, like the outgoing EJ’s (save the cast-aluminum unit on the STI), but this new manifold incorporates four tumble-generation valves, one just upstream of each port. They look like half of a throttle valve and, through electronic control, manipulate the intake flow to maximize efficiency
O rly
Old Feb 2, 2011 | 03:50 PM
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Same as the older models. It's one unit per side that houses both tumble valves.
Old Feb 2, 2011 | 06:53 PM
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Older models had electronically controlled tumble-valves as well?
Old Feb 2, 2011 | 09:00 PM
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Originally Posted by Unit 91
Same as the older models. It's one unit per side that houses both tumble valves.
yea, thats why i dont understand why they had to bring that up as a point worth mentioning
Old Feb 2, 2011 | 09:42 PM
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148hp N/A FB20 does NOT sound very appealing at all.
Old Feb 2, 2011 | 09:43 PM
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For 7 yrs the Sti has put out 300 hp( nevermind the monstorous 5hp jump of late) so when will Subaru say "hey, look at that" in response to everyother company upping the anty? Looking at the preformance numbers for the '11 wrx and Sti and seeing the Driving sports video of the '07vs'11 sti quarter mile times in the low 14s? Really weak. When Subaru announces the arrival of the 375hp Sti, then improvements will be satisfactory. Isn't the Wrx and Sti supposed to be "giant killers"?Not anymore!
Old Feb 3, 2011 | 08:27 AM
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Originally Posted by antonch
I don't really understand how they managed to increase the stroke without really changing the rod length.
They used an asymmetric rod which does actually shorten the overall rod length. This allows them to run a longer stroke without changing the exterior dimensions significantly. Let's just hope those new rods don't have any issues.

-- Ed
Old Feb 3, 2011 | 08:30 AM
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Originally Posted by Krinkov
ugh, narrower valve angle and longer stroke, good thing they made this into its own motor and not all the EJs like that instead
A longer stroke and smaller bore is more efficient in theory. The EJ motors have a notoriously short stroke and many people blame that for their lack of efficiency as compared to the EVO motors. What I find funny is that they went to great lengths to fully redesign the engine but the gains are very minimal. Hopefully the potential will be revealed in the turbo applications.

-- Ed

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