F23 intake manifold vs H22 (lowers)

[Chrisnick]

Let's just say this thing has serious potential for a street manifold when ported. Yes, the runners are smaller in diameter than the H22's, but for an ideal torque peak in the 4800-5500 range, the F23 just needs a little bit to be just about perfect. A little over 2" square for area. The potentially huge plenum easily rivals that of the H22, this is definitely the choke point as cast which makes the engine draw vacuum and flatline around 5000RPM. The F23 is wider, deeper, but shorter front to back than the H22.








H22 butterflys on F23 lower



Post-porting pictures and before/after dyno coming soon.

[GhostAccord]

I know that the F23 IM is a well known and documented upgrade for the 94-97 F22B1 And F22B2 engines. Not sure if it's worth the trouble to port match and adapt it to the F22A head. How does it line up with the head? I never went the F23 route!


Although there are a few guys out there making H2F and K2F intake adapter plates for the SOHC F series engines.

[Chrisnick]

Ah, this is going on my straight F23 CD7. Just thought I'd post it for those who are VTEC swapped. To be honest, I doubt the factory intake is much of an upgrade at all. The runners all look to be the same length, the TB inlet is the same size; the plenum IS larger, but not really a whole lot. EGR is much simpler!

K2F might be beneficial on the larger ports of the F22A's, but on the later/VTEC heads, I don't see the point as the port is so much smaller.

[Chrisnick]

Gotta clean up the runner entry a little bit, but this should make some power! Runners used to extend all the way to the flange and have a plenum "pocket" in the area in front of them, this makes them about 3-4" shorter and the entry will be opened up a bit more for smoother entry.

[Jarrett]

Awesome! Do you plan on having it dyno-tested and tuned?

[Chrisnick]

Yessir, April 17th is the retune date.

[GhostAccord]

Nice looking work!

Looking forward to your results!

What is the difference in runner length now? Seems as though 1 & 4 are a touch longer. Wonder if it would make much of a difference if you were to leave a few inches on the inside for runners 2 & 3 to equal out the lengths.

I noticed that some bike manufacturers make up for uneven runner filling by making the trumpets different lengths.

[Chrisnick]

If you look at the underside pictures, Honda cast the manifold with different runner lengths to take that into account.

[Chrisnick]

Cleaned up and ready to go.

[Chrisnick]

Intake on, egr deleted, and swapped to a no coolant JDM B20 IACV. Idles better. And pulls HARD as F to fuel cut at 6500. I think I'll be revving it to 7000 the way it keeps pulling. Zero loss of torque. Can't wait for Sunday.

[dwhacks]

What is this No Coolant IACV you talk about? I googled it and found one that looks like it has a removable coolant plate, do you just install a block off plate?

Im currious to know why or not you would want coolant running through the IACV.

[GhostAccord]

It uses coolant for the same reasons that they have coolant flowing through the intake manifold, PCV air intake and the throttle body. 1. To keep everything the same temperature 2. to keep the valves and throttle plates from icing up in colder climates. 3. to help keep any moisture from condensing on the inside of the engine.

[Chrisnick]

Ported and stock side by side. Forgot to post this.

[Chrisnick]

Well, results are in. Ported intake was worth some torque down low, about 10whp near Red line. Played with VTEC engagement and found it worked best around the factory engagement at 2400RPM. Gained an assload or torque under 4000RPM. Final run numbers were a little bit lower due to higher IAT's than the initial run, but you can see the old numbers, ported intake+old tune(crome), and new numbers(neptune). Not a big difference in overall peak numbers, but under the curve is sooo much better than before. 14's should be easy with all the new stuff done. At this point, it looks like the camshaft is holding it back.

[GhostAccord]

Need a camshaft that equals out the 2 off VTEC lobes and extends there duration. Then you can raise up the VTEC lobe lift and bump that crossover up a bit more.