10:1 USDM H22
10.6:1 JDM H22
11:1 JDM Type-S H22

I know the Type-S has different pistons, but what is the difference between the USDM and JDM H22s?

As far as I know the individual parts are all the same, so is it the pistons, head, head gasket, or block deck height?

 

its the pistons....bigger dome...

on another note, the only other things different btw the two motors is the cams, internal coil, and the lack of a front coolant temp sensor on the jdm motor


Modified by mgags7 at 5:24 PM 11/24/2005

 

JDM and USDM cams are the same 99% sure
type-S JDM are different though, $300 different [pouts]

 

but theyre jdm y0, they have to be better....

i heard that somewhere a few times and have always thought it right due to the fact that .6 in compression probably doesnt account for 10hp at the crank.....but i have no evidence....

the type s cams are worth it...those things can put down some sick numbers....

 

yea im as sure as i can be for not having them in front of me that the JDM and USDM cams are the same.

and I bet the HP is from .6 compression as well as less JDM emissions.

and the ECU is different, so who even knows whats different in there.

so does anyone know what the difference is in a USDM and JDM H22 that makes the compression different?

 

i already said it dude....the pistons have a bigger dome

that i know 100% sure...i had my own fingers on them....

 

the piston?

 

are the valve clearance same or different?

 

valve to piston obviously different due to the larger dome

valve to valve will be the same though....

 

the cams have a slightly longer lift and duration, the transmissions are different shorter 3rd and 4th with 5th (overdrive being the same), the ecu has a little better fuel maps made for quick acceleration in and out of traffic for those crazy japan superways, the ecu has a 120mph governor which can and does scare the **** out of ya, less emissions running at higher octane fuels and as mentioned high compression. The jdm h22s stock for stock will pull and walk on usdm h22s no matter what generation prelude they are in. The JDM H22a is the way honda intended the engine to be....

 

higher domed pistons..

now i've heard two different people state that JDM and US H22 non type-S cams are the same, and different.

Any way to tell the difference, or numbers from the JDM / US / type-S?

---thanks for the piston info!

 

you may have answered your own question -- if the pistons have a higher dome then how could the cams be the same? the only way to know for sure would to be to remove them and take a micrometer and measure them.

 

the cams could be the same and the clearance could be less.

that was easy.

i wish i would have done this when i had both sets sitting in my garage for 3 months.

damn.

 

man I have seen this before -- a bunch of sites say they are different and as hard as it is to make horsepower gains with our cars it makes sense. Would you gain 10-15 extra horsepower just from a .6 compression bump? I would say no.... of course higher octane fuels come into play but in order to get those gains I would think it would require more than just compression. I know the H22a vs H22a1s vtec pulls harder so that would have to be more aggressive cams.....

 

it could be other things, two different engines of the exact same make and model are going to be a little different.

from my experience with my JDM h22 adding .6 compression makes a huge differnece.

I went from a 13.19 to a 12.88 by going from 10.6:1 to 11.2:1 and adding a lightweight crank pulley and removing the balance shaft belt.

so i'd say from personal experience with this exact engine and this exact compression bump that it is worth significant power.

 

so..if i want do the valve adjustment....what should i do? bz i had a jdm head.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by specialedition &raquo;</TD></TR><TR><TD CLASS="quote">man I have seen this before -- a bunch of sites say they are different and as hard as it is to make horsepower gains with our cars it makes sense. Would you gain 10-15 extra horsepower just from a .6 compression bump? I would say no.... of course higher octane fuels come into play but in order to get those gains I would think it would require more than just compression. I know the H22a vs H22a1s vtec pulls harder so that would have to be more aggressive cams.....</TD></TR></TABLE>

USDM 4th gen has more favorable gearing for acceleration, which seems to be the rare instance where JDM isn't necessarily better than its USDM counterpart (transmission, that is). If I had to guess, the JDM 4th gen H22A would be very close to a USDM 4th gen... the US gearing advantage might be able to offset the 10hp deficit.

Also, going from 10.0:1 to 10.6:1 isn't the same as going from 10.6:1 to 11.2:1 compression.

Adi

 

JDM H22A have bigger injectors, higher compression pistons (by 0.6 points) and the ecu is tuned a litle diff than the USDM ones... thats it, nothing more

thats could give you your extra 10hp you ask for...

**edit** for the USDM guys who want to build thier motors but they want a cheap bottom end build just replace your pistons with the Type-S ones and get a little thinner gasket, that will pump your compression at about 11.3:1 and with a well build head is gonna give verry good gains... don't bother go for the JDM pistons, the money diff is too little.

 

JDM has bigger injectors?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aRaBiAn RiCe &raquo;</TD></TR><TR><TD CLASS="quote">JDM has bigger injectors?</TD></TR></TABLE>
yeap... i'm not sure about the exact size but i thing USDM is 290cc and JDM 310-320cc

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Buffalo &raquo;</TD></TR><TR><TD CLASS="quote">JDM H22A have bigger injectors, higher compression pistons (by 0.6 points) and the ecu is tuned a litle diff than the USDM ones... thats it, nothing more

thats could give you your extra 10hp you ask for...

**edit** for the USDM guys who want to build thier motors but they want a cheap bottom end build just replace your pistons with the Type-S ones and get a little thinner gasket, that will pump your compression at about 11.3:1 and with a well build head is gonna give verry good gains... don't bother go for the JDM pistons, the money diff is too little.</TD></TR></TABLE>

thats bs the usdm and jdm 4g are 345cc p&h and the 5th gen are all 290cc saturated...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">thats bs the usdm and jdm 4g are 345cc p&h and the 5th gen are all 290cc saturated...</TD></TR></TABLE>

thats what i understood

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Buffalo &raquo;</TD></TR><TR><TD CLASS="quote">
yeap... i'm not sure about the exact size but i thing USDM is 290cc and JDM 310-320cc</TD></TR></TABLE>

That's not true in the first place because the injectors vary from generation to generation, not market to market for base H22A's.

Even if what you say was the case, I don't see how that would contribute to the 10hp gain... if anything the saturated injectors would be a little more "efficient."

Regardless, injectors don't have anything to do with the added compression or higher rated hp on JDM H22's.

Adi

 

The injectors size on the USDM 92-96 H22 is 325 and on the USDM 97-01 H22 is 275 and the reason you get a 20 HP gains out of the JDM Type-S is because 1. the cam profile is more aggressive giving a better lift and longer duration and 2. the compression is higher due to different pistons and 3. I am willing to bet the Type-S head flows just a lil bit better than the Jdm H22A but im not completely sure on that one i think its just the pistons and cam profile
As far as the difference between the JDM H22A and the USDM H22A1-4 nothing except compression probably due to One of the motors has a thicker head gasket thus giving a higher compression on the JDM from 10:1 on the USDM and 10.6:1 one the JDM thus giving a HP rating of 195hp in USDM; 200hp in JDM; and 220hp in JDM Type-S

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crzyfstsol &raquo;</TD></TR><TR><TD CLASS="quote">The injectors size on the USDM 92-96 H22 is 325 and on the USDM 97-01 H22 is 275</TD></TR></TABLE>

dude, get it right, injector sizes have already been said

345cc and 290cc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">and the reason you get a 20 HP gains out of the JDM Type-S is because 1. the cam profile is more aggressive giving a better lift and longer duration and 2. the compression is higher due to different pistons and 3. I am willing to bet the Type-S head flows just a lil bit better than the Jdm H22A but im not completely sure on that one i think its just the pistons and cam profile </TD></TR></TABLE>

The type S head has a factory port and polish.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
As far as the difference between the JDM H22A and the USDM H22A1-4 nothing except compression probably due to One of the motors has a thicker head gasket thus giving a higher compression on the JDM from 10:1 on the USDM and 10.6:1 one the JDM thus giving a HP rating of 195hp in USDM; 200hp in JDM; and 220hp in JDM Type-S </TD></TR></TABLE>

im doubting that they have different head gaskets but i could be wrong.