SWAP problem - JDM H23 VTEC engine

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Atrevido

Member
I own a Prelude 2.3 Si '92, and now in process of swap. For swap - JDM H23 VTEC engine from Accord SiR 1999. I got the ECU from the Accord, but I guess it's a wrong one. The full text printed on the ECU box reads:
2H
37820-PCF-N51
CY-EH2955A
NO, 11250 -1
Matsushita Co.

Questions:
1. Is it possible to use OBD1 P13 ECU with OBD2 engine H23 VTEC?
2. Is it possible to use OBD1 P14 ECU (my old one, non-VTEC) with OBD2 engine H23 VTEC? (I understand that VTEC will not work, but will the engine run at all?)
3. What is the code of my new ECU from Accord, is it CF?

Please help! SOS!
 
you can use a p13, but need to convert the motors electronics over to obd1 to match the ecu, i think distributor and possibly injectors are all that would need to be changed but not positive...

yes, your motor should run with the p14 minus vtec, but you would need to convert the motors elec's over to obd1...

check into a obd1 to obd2 converter, this might let you use the new ecu you got with the motor...

post pics of the motor please, i have never seen a h23vtec in real life, whats the block stamped as just h23? or h23a? or what?


this is a difficult topic cause not many people in the US, and i think no one on this board, have dealt with the h23 vtec...
why did you get this instead of just an h22? aren't they the same power ratings?
 
The engine valve cover is dark blue color. The letters are H23A.

I don't have OBD2 distributer for my new engine (it was broken during transportation). I have my old OBD1 distributer from my non-VTEC H23A1 engine. Does it mean that I'll not be able to run the engine if I use OBD2 ECU?

By the way, I want to use all my old harnesses OBD1. Since the japanese ones are too short (for right-side driving wheel). Is it OK?
 
as far as i know you can use the OBD1 harness on the motor...use the injectors/dizzy/ecu from the old motor..you might have to modify the dizzy.....and use an rpm activator or a vafc controller for the vtec...you might also need to run wires for the knock sensor......good luck post some pics....also call hasport....www.hasport.com they should help you with wiring products
 
Originally posted by formby@Jan 20 2005, 08:04 PM
as far as i know you can use the OBD1 harness on the motor...use the injectors/dizzy/ecu from the old motor..you might have to modify the dizzy.....and use an rpm activator or a vafc controller for the vtec...you might also need to run wires for the knock sensor......good luck post some pics....also call hasport....www.hasport.com they should help you with wiring products
[post=448660]Quoted post[/post]​


Thanks!
And what will I get in this case? A VTEC motor? Will it have all 200HP, or less?
 
Originally posted by Atrevido+Jan 20 2005, 01:35 PM-->
@Jan 20 2005, 08:04 PM
as far as i know you can use the OBD1 harness on the motor...use the injectors/dizzy/ecu from the old motor..you might have to modify the dizzy.....and use an rpm activator or a vafc controller for the vtec...you might also need to run wires for the knock sensor......good luck post some pics....also call hasport....www.hasport.com they should help you with wiring products
[post=448660]Quoted post[/post]​


Thanks!
And what will I get in this case? A VTEC motor? Will it have all 200HP, or less?
[post=448704]Quoted post[/post]​


what i meant was....use the harness from the motor already in the car on the h23 vtec engine....its already a vtec motor ...just use the vafc to activate the vtec
 
I was told that if I use P13 ECU with my new motor, it would not run perfectly as the fuel and timing maps will not be ideal because of the slight differences in the engines H22 and H23. Is that correct?
 
there is very little diffrence between the two motors so i think it will be ok...

only way to know for sure is to view the fuel maps for both

i think they both have 325cc flow injectors...
 
no one is telling me this...

i've been searching for info on this god damn motor all day and haven't gotten dick for information...

it has the exact same power ratings as an H22 so i think they just got the displacement up over 2250 so they could call it an H23, i think the h22 has displacement of about 2156....
 
not you man...the original poster....who is telling him it wont work...lol
 
I agree with you guys, I'd do a standard OBD2>1 conversion to the engine, use the stock harness. However, I think I'd run the VTEC wires and use a P13 until I could have it properly tuned. There have been a lot of people on here in the past using RPM switches and complaining, and a few that were happy, go figure.

Either way will work.
 
Originally posted by formby@Jan 20 2005, 11:57 PM
not you man...the original poster....who is telling him it wont work...lol
[post=448765]Quoted post[/post]​


They didnt tell me it would not work, they told me that it would not work perfectly. The reason, - different fuel and timing maps.
 
Originally posted by reckedracing@Jan 20 2005, 11:28 PM
no one is telling me this...

i've been searching for info on this god damn motor all day and haven't gotten dick for information...

it has the exact same power ratings as an H22 so i think they just got the displacement up over 2250 so they could call it an H23, i think the h22 has displacement of about 2156....
[post=448751]Quoted post[/post]​


Here are some charecteristics of H23 and H22 engines for comparison:

Model---------------------------------Accord 2.3 VTEC SiR-----------Prelude 2.3 Si----------Prelude 2.2 VTEC
Doors---------------------------------5D-------------------------------2D-----------------------2D
Year----------------------------------1999-2000----------------------1992-1996---------------1993-1996
Body---------------------------------GH-CH9-------------------------BB2----------------------BB1
Engine code-------------------------H23A (for Japan)---------------H23A2 (for Europe)----H22A2 (for Europe)
Displacement (cm3)-----------------2258-----------------------------2259-------------------2157
Bore x Stroque (mm)---------------87 x 95--------------------------87 x 95----------------87 x 90.7
Compression ratio-------------------10.6:1---------------------------9.8:1-------------------10.0:1
Valve gear ---------------------------VTEC DOHC 16v----------------DOHC 16v------------VTEC DOHC 16v
Maximum power---------------------200PS/147.10kW/6800rpm----160PS/118kW at 5.800rpm---185PS/136kW at 6.800rpm
Maximum torque---------------------22.5kg-m@5300----------------21.3kg-m@4500rpm----21.2kg-m@5300rpm
----------------------------------------220.65Nm(at5300/min)--------209Nm(at4.500/min)----212Nm(at5.300/min)
Power density-------------------------7.15/7.2-------------------------?-------------------------?
Redline (rpm)-------------------------7200-----------------------------6300-------------------7500
Fuel (90/120/city/mix) l/100km-----8.7-------------------------------6.8/8.6/11.0/8.8------6.9/8.6/10.9/8.8
0-100km/h (0-62m/h)----------------?---------------------------------7.7 sec-----------------7.1 sec
Max. speed-----------------------------?----------------------------------217 km/h-------------228 km/h
 
Before I get a P13 ECU I want to temporarily use my P14 ECU. Without any VTEC connected.
In this case, theoretically will I have 160HP or less/more? As far as I understand, since the compression ratio is higher at the new engine, - it should be more productive (or there's nothing to do with the comp. ratio). Is that correct?
 
it has to do with the comp ratio, but the h23vtec head design is made for the low rpm rockers and then the 3rd vtec lobe...

i would assume you should be approx around 160

my friend had an h23 in his accord, swapped to h22, but ran it on the h23 ecu until he got the p13 and i THINK it didn;t pull quite as hard... but it was a close match, but the h23 had 160K miles and the H22 had less than 20K so...

who knows..
 
Originally posted by reckedracing@Jan 21 2005, 08:03 PM
my friend had an h23 in his accord, swapped to h22, but ran it on the h23 ecu until he got the p13 and i THINK it didn;t pull quite as hard... but it was a close match, but the h23 had 160K miles and the H22 had less than 20K so...
[post=449151]Quoted post[/post]​


So, your friend ran VTEC engine H22 with non-VTEC ECU (P14 I assume)? How did the engine work? Did he make any additional changes when running with non-VTEC ECU, like distributor, injectors etc.?
 
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