F22a6 vs H23 intake manifold

[hatchninja]

debating on which to use. Of course the a6 manifold has an advantage because we already have it, but the h23 manifold has larger ports, and a bigger TB.

just looking for more information on the swap....btw this is going on our spare f22a1 head....after the swap we will have a complete a6 head/IM and Exhaust mani up for grabs....it will definitely be a while tho....probably late spring.

ps...i just saw an h23 mani go for 31 bux on ebay....had TB, fuel rail and everything

[MRX]

h23 plenum with tb for bore and overall volume then A6 runners because they are shorter and better suited for top end.

[HondaFan81]

A6 runners are shorter? Interesting...I have both of these units and now you're making me sorta curious on that statement.

Midnite, did you physically measure them both yourself?

I agree that the H23 plenum is better and the TB is larger than the A6 by 2mm. I just went with the H23 runners as well. I have a side by side pic.

The ports where the runners meet the cylinder head on both should be pretty much the same because they both share the same intake manifold gaskets.

[HondaFan81]

Intake Manifold comparison..

F22a6 on left.
H23a1 on right.

[MRX]

it was something i read a while ago. The article said something about the a6 runners being better designed because of the shorter runners. Which could have meant smaller diameter. If u can take off both plenums hondafan81, compare the geometry and design of the inside of the runners where the iab's are. I believe thats where the differences were

[HondaFan81]

I know both IAB plates are the same. Therefore, it would not make much sense that the ports in the plenum leading to the IAB plate would be much of a difference. However, the runners themselves may have slightly different design, but in the end they lead to the same intake manifold gasket, so they result in the same geometry by the end. The theory of A6 having shorter runners could still be true however. I'll go measure tonight, see for any visual differences. I'm not gonna spend forever on this, been working on our 91 SE and I'm just burnt.

[HondaFan81]

Side by Side...

F22a6 on left.
H23a1 on right.

[HondaFan81]

F22a6 runners...

Runner ports to cyl head are 2 inches wide @ widest point. This shares same IAB plate as the H23a1. Runner length approximately 12" long (measured from the outside of the bottom side of runners w/tape measure...IAB flange to cyl head flange).

[HondaFan81]

H23a1 runners...

Runner ports to cyl head are 2 inches wide @ widest point. This shares same IAB plate as the F22a6. Runner length approximately 12.5" long (measured from the outside of the bottom side of runners w/tape measure...IAB flange to cyl head flange).

[HondaFan81]

So it seems the H23a1 has approximately 0.5" longer runners than the F22a6, the plenums are different in design, the IAB plates are the same, the runner ports-to-cyl head are same, the TBs are different w/H23 having 2mm larger bore, they both share the same intake manifold gaskets....what else is there left to note?

[phatdoughnut]

and they both share the same intake mani gasket..

[HondaFan81]

I said that holmes, read above your post

[phatdoughnut]

my bad son, i just wanted to slip it in there, because their has been alot of misconception that the h23 runners dont work on the f22s. but they do!

[LX Rida]

so im guessing since the f22a6 IM has shorter runners? which makes it better?
and since the h23 plenum and the tb is bigger...i guess an f22a6 im with h23 plenum and tb would make the best setup?

[accordztech]

the h23 i found has a individual runners from the plenum down, as for the f22a6 only past the butterflies...they are all still on the same channel.