Exact Differences between USDM H22a1, H22a4 and JDM H22a

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Sep 4, 2006 | 09:51 PM

My292Ludes

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Joined: Aug 2006

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From: Dusk Till Dawn, HI, USA

Exact Differences between USDM H22a1, H22a4 and JDM H22a

What are all the differences between the three? HP and TQ numbers, redline, compression numbers, Any detail you can think of!

This is what I know for sure and please add to it as we go

H22a1-
OBD1 - besides 96
Closed Deck
50mm Mains
10:1

H22a4-
OBD2
Open Deck
55mm Mains
10:1

JDM H22a- are there differences between the OBD1 + OBD2
OBD1 or 2
50mm Mains?
Closed Deck?
10.6:1

Modified by My292Ludes at 1:42 AM 9/5/2006

Sep 4, 2006 | 09:53 PM

AnthonyG2003

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Re: Exact Differences between USDM H22a1, H22a4 and JDM H22a (My292Ludes)

Dude all you need to do is look in the FAQ's..ITS ALL THERE!

Sep 4, 2006 | 09:58 PM

My292Ludes

Thread Starter

Joined: Aug 2006

Posts: 149

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From: Dusk Till Dawn, HI, USA

Re: Exact Differences between USDM H22a1, H22a4 and JDM H22a (AnthonyG2003)

I have read the FAQs front to back all within the last couple weeks, some of it twice, and some of this info may be there but it is scattered and not organized at all. This thread will organize it into one place. If I am wrong please post a link!

Sep 4, 2006 | 10:46 PM

98vtec

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Joined: Oct 2002

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From: Cantonment, FL

Re: Exact Differences between USDM H22a1, H22a4 and JDM H22a (My292Ludes)

h22a1 and a4 are 10.0:1

H22a is 10.6:1

type S h22a is 11.0:1

a1 and A are closed deck
a4 and type S are open deck

Type S head has a factory port and polish as well as the iab plate ports being larger than the base. The Type S valve guides are also seated lower to give more clearance for the large cam.

https://honda-tech.com/zerothread?id=1232811