dohc zc swap Q

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efnick

New Member
so, this engine is a straight drop in. in terms of mounts, stock dx tranny, (exhaust manifold?) all the radiator lines etc... these are also direct bolt on from the dx? the only things that needs to be done so ive read, is the mpfi swap? what about running that dohc? what ecu will it run, and will that plug direct into the dx harness? if anyone has a link to a full swap with parts list etc... that would be much help. im trying to see what the most bang for buck is. ive read even a d16 supercharged is pretty slow, i was wondering whats the cheapest way to build a reliable 6-second 0-60 90 civic dx? thanks for any help, no flaming please.
 
the DOHC ZC is a direct bolt-in in the Civic DX using the stock DX mounts and transmission (the Si transmission would be a better choice) - you could use the stock DX exhaust, including the manifold, however, to get the maximum performance from it you should get a good aftermarket header and a free flowing 2 1/4" exhaust system - radiator hoses needed are 88-89 Integra upper and 88-91 CRX/Civic Si lower - you would need the fuel line from the filter to the fuel rail from 88-91 CRX/Civic Si - you would need to do the DPFI to MPFI wiring for the injectors (with injector resistor box) and add 2 wires for the Cylinder sensor which is on the end of the exhaust camshaft on the ZC - no wiring changes are needed at the distributor connectors - the best ECU is the JDM PM7 which is the stock ZC ECU - you could use a PG7 from 88-89 Integra which would run just about the same as the PM7 - you could also use a PM6 from 88-91 CRX/Civic Si, although the rev limiter on the PM6 is a little too low to get the most out of the ZC - i doubt that you could get a 6 sec 0-60 with a ZC in a stock DX
 
Yes the zc is a strout little motor and lot of capabilitys.

Slap a turbo or supercharger on it and it gets to be a quick little beast.
 
Dohc ZC stock is 130 hp. If you plan to do ALL MOTOR replace with 10.5.2 pistons and a chipped pm6 ecu and have head ported and polish. Or go with a homemade turbo. There is a turbo writeup in hondaswap. It is fairly easily to keep up with a b16 if you have the si transmission and dx chassis.;)
 
wow, thank you for all the great replies. i was looking at the zc because it looks like a fairly cheap, simple swap. im not thinking all-motor, or just yet. i just want the added horsepower of the dohc zc, and the potential that it carries as apposed to the stock d15xx? with the mpfi wiring swap, if i bought the rywire si/ dx harness, will the pm7 ecu plug right into that harness? and, are there any diagrams or photos of the 2 wires that need to be added, where to connect them on both ends? anyways, thanks again.

P.S. if i were to oreder the harness conversion from rywire, how good are their installation instructions for the harness, and how difficult is it to get out my whole dx harness? AND is it able to pass smog in california, if anyone knows?
 
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Rywire has very good products and instructions - be sure to tell them it is for a DX to DOHC ZC swap - it is not the same as DX to Si swap - the harness that you need the changes made on is the engine harness, which plugs into the chassis harness at the firewall on both sides of the car - the ECU plugs into the chassis harness - the PM6, PM7, PG7, etc. (any OBD0) ECUs will plug into the chassis harness - the added wires will need to be connected at the ECU connectors on the chassis harness - even if you get the engine harness from Rywire, you still need to connect the added wires at the ECU
 
know of any pics or diagrams of those two added wires? also, will i need to switch my axles out for some other axles? and smog in CA anyone?... thanks again for the great replies!
 
if you are using your transmission, you would have no reason to swap axles - i don't believe that you can get the DOHC ZC to legitimately pass smog in CA in the 90 Civic - there is no equivalent USDM DOHC D-series engine - i could tell you where the added wires go, but i don't have a picture
 
allright thank you. dang, bummer about the smog as this will be my daily driver in about two months, perhaps i should go with a sohc zc. they are just like putting in an si motor, but with a higher compression, more agressive cam, and higher compression from what i understand? and i have heard they are smog legal, just a little difficult to come by compared to the dohc version?
 
efnick said:
allright thank you. dang, bummer about the smog as this will be my daily driver in about two months, perhaps i should go with a sohc zc. they are just like putting in an si motor, but with a higher compression, more agressive cam, and higher compression from what i understand? and i have heard they are smog legal, just a little difficult to come by compared to the dohc version?
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SOHC ZC is an o.k. engine and yes, just like swapping in the Si engine - they aren't hard to come by - go here (bottom of page)

http://www.hmotorsonline.com/shop/sc2000search.cgi?what=category&keyword=JDM USDM Engines&hit=15
 
yea lol thanks for the reminder, but the dohc is not smog legal in CA, i believe.
 
i hear ya. just that ive read the refs in Cali are getting much more strict, and id hate to spend all that money time and effort on a dohc zc swap only to get a red flag from the ref lol...
 
the ref's are getting stricter than be nice and humble and say hi this is my car how are u doing thanks for passing my car. have a great day.
 
my understanding of the law regarding smog legal Honda engine swaps in California is:

1. The engine must be the same year or newer than the car that is receiving the engine.

2. The same equivalent engine (JDM or USDM) must have been available in another USDM Honda car, of the same year or newer.

3. once swapped, the year of the engine would determine the emissions level that the car had to meet, not the year of the car - for instance, a D16Y8 in a 91 Civic would have to meet all of the emissions requirements for the D16Y8

The DOHC ZC was not available in any USDM car at any time - the only DOHC D-series engine that came in a USDM car was the D16A1 in the 86-89 Integra - if you have a 88-89 CRX/Civic you could swap a D16A1 into it (if you wanted the hassle), but if you have a a 90-91 car, there were no equivalent DOHC D-series engines offered in USDM cars after 89, so you cannot swap a DOHC D-series engine into a 90 or later car - you could swap a B16 or B18 or SOHC D-series engine into a 90-91 car since they were equivalent engines offered in USDM cars after 1990 - i believe that one guy tried getting the JDM DOHC ZC legalized in a 88 or 89 car by claiming it to be essesntially the same as a D16A1 - as far as i know, he never got it accomplished
 
jlicrx said:
my understanding of the law regarding smog legal Honda engine swaps in California is:

1. The engine must be the same year or newer than the car that is receiving the engine.

2. The same equivalent engine (JDM or USDM) must have been available in another USDM Honda car, of the same year or newer.

3. once swapped, the year of the engine would determine the emissions level that the car had to meet, not the year of the car - for instance, a D16Y8 in a 91 Civic would have to meet all of the emissions requirements for the D16Y8

The DOHC ZC was not available in any USDM car at any time - the only DOHC D-series engine that came in a USDM car was the D16A1 in the 86-89 Integra - if you have a 88-89 CRX/Civic you could swap a D16A1 into it (if you wanted the hassle), but if you have a a 90-91 car, there were no equivalent DOHC D-series engines offered in USDM cars after 89, so you cannot swap a DOHC D-series engine into a 90 or later car - you could swap a B16 or B18 or SOHC D-series engine into a 90-91 car since they were equivalent engines offered in USDM cars after 1990 - i believe that one guy tried getting the JDM DOHC ZC legalized in a 88 or 89 car by claiming it to be essesntially the same as a D16A1 - as far as i know, he never got it accomplished
Click to expand...


Ah ha..loop hole..OBD1 DOHC ZC


Oh shit nevermind, those wernt availible here.
 
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