Intake manifold height and benefits

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dayno
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Intake manifold height and benefits

Post by dayno »

Hey all,

My car is a 91 legacy.

I have 2 intake manifolds, both came from legacy's, 1 from a 91 ej22m and a 96 ej22. The 96 manifold has longer tubes to the heads. I estimate it to be about 20-30mm higher from the top of the block.

The 91 manifold would be better if you had a top mount, but are there any benifits to having the taller manifold? air velocity?

I'm not looking to turbo the motor any time soon.


Cheers
Dayne
91 Liberty EJ22 auto BLOWN HG. :( FIXED
91 liberty rebuilt EJ22 5mt swap, Starter button :D
sobe_death
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Re: Intake manifold height and benefits

Post by sobe_death »

The longer runners help to shift the torque curve to a lower RPM range. I'm planning on using the manifold from the '06 impreza 2.5i (any 2.5 NA single cam if I'm not mistaken) due to its larger plenum volume and longer runners.
Legacy777
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Re: Intake manifold height and benefits

Post by Legacy777 »

Dayne,

I would confirm whether you can use the 96 manifold on the 91 heads. Check the intake manifold bolt pattern and spacing to see if it will even bolt up.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

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dayno
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Re: Intake manifold height and benefits

Post by dayno »

Thanks for the prompt replies.

legacy I will check if they bolt up when get the motor out of my car. I have both engines complete both running the 96 appears to be in better condition considering the 91 has been overheated.

if using the 96 heads I know I will have to change the exhaust manifold but other than that they appear to be similar from the outside. Will I run into issues with the 91 computer running the 96 heads manifold and throttle body with 91 tps?

Sobe are there any losses in top end torque or just moving torque lower in the rev range?
91 Liberty EJ22 auto BLOWN HG. :( FIXED
91 liberty rebuilt EJ22 5mt swap, Starter button :D
sobe_death
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Location: Atlanta, GA

Re: Intake manifold height and benefits

Post by sobe_death »

The torque curve shifts lower while pretty much maintaining its shape. The result is that it won't have the same amount of torque up high, but if you have other mods that are geared towards the higher rev range (cams, etc...) you shouldn't notice it too much.

I think that for your purposes, either manifold will work just fine!
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