I am in the process of swapping an h23a1 head onto an f22a1 block. My question is about the secondary butterflies inside the h23 intake manifold. Can I remove them since I have no way to control them? The h23 motor didn't come with the vacum tank or IAB valve thinger. I will be running a t3 turbo tuned with uberdata so can I just adjust the air flow at low rpms to compensate for the extra open runners? Thanks.

Mike

 

Yeah, you can just take them out...maybe get a Blacktrax spacer or somthing.

Only downside will be like you said the loss of some low-end.

 

its a 1-2 hp loss without them but maybe 1-2 hpgain up top... i took mnie out and just jbwelded the holes shut--- no problems here

 

btw an h23a1 head onto an f22a# lock is an f22b as found in the 92-96 jdm prelude si.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbociv910 &raquo;</TD></TR><TR><TD CLASS="quote">its a 1-2 hp loss without them but maybe 1-2 hpgain up top... </TD></TR></TABLE>

I don't believe you...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">I don't believe you... </TD></TR></TABLE>
so what does that mean? you don't think it will matter or it will be more of a loss than 1-2 hp?

 

I do not think that it helps top end at all. There's been all sorts of testing on the OEM IAB H22 manifold (almost the same thing as an H23) with little if any gains. Hacking, welding, die grinding, keeping IAB, deleting IAB adding plenum volume etc., and it's barely worth the effort. For the record the only thing that seems to really help NA VTEC engines is the Euro-R IM which is not compatable with the H23 head.

On my nonTurboed engine IABs gave me 5ft lbs from 3200-4400rpm. I think that it is even less important on turboed engines since the dynamics of turbo selection can have huge effects on power curve unlike IABs. But hey, who cares about 0-10whp (or whatever) on a 300 hp turbo engine?

I say pay more attention to turbo selection and the tune than worrying about the IABs. Once you get that sorted out then start messing with the IAB.

Blue = IAB open for all RPMs (Vacuum hose pulled)
Red = IAB closed until 4800 RPM

same dyno, same day, same car, similar ambient air, IAT and coolant temps blah blah

Pirate

 

Thanks for the reply. That helps out a lot!

Also, on a non related note, can I use my f22a1 dizzy(OBD1) or do I need to find an h23 dizzy?

 

SOHC distributors will not work without custom fabbing.

Pirate

 

You will need an H distributor. I used the internal parts of my Accord distributor and the JDM H housing. I had to extend some of the wires but all in all it worked out well.