Why h23 IM?

[According_to_ME]

Forgive me but why is it always the h23 upper plenum being swapped onto everyones F22? Could the h22 IM/TB be used?

[zigg_1311]

the h23 upper plenum with the f22a6 lower plenum offers the best gains low end but i will be doing a full h23 im swap, i want it to breathe a bit better up top, and i am removing the butterflies too.

[CB7Man]

Removing butterflys will diminish low end considerably

I believe the H22 uses either larger or smaller airways, they dont line up
Ofcourse with $$$$$ anything is possible

[deevergote]

The H23 throttle body and plenum are identical to the H22 parts. The runners are not the same, and the H22 part won't bolt up to the F22 head. The H23 runners will.


And yes, removing the butterflies will decrease low end, but it will free up the upper range a bit (since it removes the restriction)

[According_to_ME]

What are the advantages in the h23 runners?

[arcadiacb7]

H22 runners DO NOT fit

H23 plenum and throttle body are the same as the h22.

h23 runners are longer which are better for bottom end
f22a6 runners are shorter which are better for top end.

If you do a h23 IM swap you can use both the runners and plenum but you must use h22/23 TB.
If you put the h22/23 Plenum on a6 runners then you must use h22/23 tb.

f22 tb is not compatible with the h series plenum. There is a diy in the diy section. I have h23 IM on my auto f22. My bottom end is horrible anyway but it pulls very hard to the rev limiter. Doing the whole swap is really the way to go. But the easy way is to use the a6 runners with the H series plenum. With no butterfly plate bottom end is lost but it really isn't that noticable. The best thing i have found to do is to remove the butterflys by taking out the 8 screws, then on the end furthest away from the vaccume acctuator, remove the small phillips screw and pull the rod out. Then find bolts that almost fit (I can get a size tomorrow) and get a corresponding tap and tap the two wholes on the side. After tapping them put some teflon tape on the bolts and tighten them down. Do not overtighten or you will be drilling and retapping the holes.

[CB7Man]

Are you afraid of some 1/10" piece of metal blocking your 2" airway?
Just take your TB flange out too lol

[deevergote]

It's amazing what a small obstruction can do.

[arcadiacb7]

agreed deev. Look at mandrel bending over crush bending. And why a nice smooth header tube over a rough manifold. Little shit makes a difference and it all adds up.

My old setup didn't have the plate in at all and the intake sounded like i was in vtec (you know that real throaty sound) It pulled real hard up to 7k too.

I put the butterfly's back in with my a6 after i blew up my h22 non vtec and the sound is no where the same, and the top end just don't pull as hard as the first sohc i had in that car. Me personally i would leave that plate out period. But i don't really care for the look of my intake manifold being emersed by the valve cover and firewall. I like it right up where i can see it.

**Also if you run A6 runners you have to run the butterfly plate, The IAC won't fit without it. The two tubes on the bottom hit the egr ports**

[bcjammerx]

I thought the h22 plenum and tb were the better option for the f22a6 runners...is there any benefit over h23 vs h22 on the plenum and tb?

[deevergote]

They are 100% identical.

[Losiracer2]

doing this swap helps out in the bottom end, probably accelerating from 0-30mph and considerably in passing power from 65-85. I did this swap yesterday and my car seems to have a lot more torque throughout the entire rpm range. Helps w/ drivability around town too b/c of the added torque.

[Granite CB7]

Just like stated, the H23 and H22 plenums are the same, both are stamped P13, runners are different, H23 (F22a port pattern)= P14 stamp, H22= P13.

[owequitit]

It is really a matter of convenience.

If you have A6 runners, you don't NEED H23 runners.

If you have an F22A1 or F22A4, I would probably just swap the whole thing.

[90ACCORDLXGUY]

Will a F22 TB fit on a H23 IM? i will get a H23 TB soon but i can get the rest of it for $30