hey i just picked up a 91 si and the guy put a new motor in. he said the new motor came shipped from japan. i kno its a d-series but its stamped with a "ZC" and nothing else. is this a d16a6 or something else?

 

the sohc zc is the Japanese d16, it has a different cam and ecu good for about 118 hp. 10 more than the d16a6
Other engines also have a zc version, that one is the 88-91 sohc zc on vtec

 

Pics would help, but I'd say from your description that it's a JDM SOHC non-vtec ZC, basically the same as a D16A6.

 

looks like this and its stamped with "ZC" . so i guess i can say its a jdm zc motor. not a d16a6, but very similar. =D

 

yep pretty much. there not bad engines really. the a6 is fairly "zippy" for a non-vtec sohc, and the jdm zc has a little bit more oomph to it in comparison, so really its not a terrible engine to tool around with. till you can find something quicker that is.. and with 2 cams

 

Good ol' SOHC ZC, the Japanese economy engine that's still better than our top-of-the-line selection. As far as I know, it's identical to the D16A6 but with a different cam. I have one in my hatch and I'm interested in finding more info on it.

Different ECU really? I wonder what ECU is in my Si...

 

oh did you mean it has potential to be 118 hp? or it does have 118hp?

 

It does have 118 hp.
Google "D series Honda"
It has a different camshaft and ecu.
It's a great motor, I have it in mine.

 

The cams are almost identical

 

30020 - 88-92 SOHC ZC longblock
120Hp 100Trq 9.1 compression (JDM)
$ 450.00 Plus shipping and handling.


Quoted from Hmotors.

 

Okay, but your admitting that they are different. Where's your proof? Where would the extra 1o hp come from then, everything else is the same.

http://www.hondacarforum.com/honda-2...cam-specs.html

http://en.wikipedia.org/wiki/Honda_D_engine

Hmotors is wrong already, 88-91 zc is a different motor then the 92-95 zc, this one has vtec.

 

Physically the A6 and sohc ZC are the exact same engine with the only difference being the cam. I've had both, and have switched the cam from one to the other with minor performance differences.

 

I've believed this for years, but then this thread came along...

 

^^ Exactly true.

A6 intake 227.5, ZC intake 233

A6 exhaust 194.5, ZC exhaust 196

Funny thing. I had an D16A6 stock in a 1990 crx Si last year, and decided to swap it in favor of a sohc mpfi cam from another engine i had sitting around. First off, there is definitely a difference in the way the cams perform. I liked the original A6 cam better though. It had more low end power and seemed more torquey.
The zc cam made more power on the top end, it was kind of peaky.....i didn't care for it.
I changed nothing else in the car.

 

So 10hp comes from that minor difference?

Also, I don't understand why the lift starts, ends, and peak are exactly the same, but the "actual lift" is different. Could just be my ignorance of cams. I'd like to get a full explanation though.

 

i thought that was odd too, but like you i also lack the understanding of how that is possible lol.

 

No, not entirely....

its also the use of the higher octane fuel they use there, as well as the fact the ecu would have a slightly different program.
Remember, i mentioned that the extra hp, it only at the very top end of the rpm range....a little blip to bump up the number imo.

 

Higher octane has nothing to do with it, the compression isn't nearly high enough. Furthermore, I always run my ZC on 87; when I put 89 in, I had a noticeable loss in power, especially at high revs.

The ECU mapping makes sense though. What's the SOHC ZC ECU? I haven't pulled back my carpet to check, but I have an inkling that I'm using the stock 1991 D16A6 ECU (PM6?).

 

zc ecu is stamped pm7 according to hondata

# PG7 : 86-89 Integra (86-87 vac advance, 88-89 electronic advance)
# PM5 : 88-91 Civic/CRX DX
# PM6 : 88-91 Civic/CRX SOHC Si
# PM7 : 89-91 DOHC ZC (JDM 'EF' ECU)
# PM8 : 88-91 CRX HF
# PR2 : 89-91 ZC (Euro)
# PR3 : 89-91 JDM B16A EF8/9
http://www.hondata.com/techecuid.html

 

Less power? Hmmm, i had the great performance with the better fuel running the engine. Back in the day when i had a zc, it also ran an nos system, i could punch off high 13 second 1/4 mile times in my crx.

 

The 'actual lift' could also be listed as 'duration at 0.050 lift' or similar. Basically the ZC lobe is shaped like a U and the a6 lobe is shaped like a V.

 

did you mean the 88-91 zc came with vtec? or the 92-95? im pretty sure you;re talking about the 92-95 right? lol

 

yea yea, the 92-95 zc has vtec I think. It's the jdm version of our d16z6 or something, the motor in the 92-95 civic I assume.

 

oh ok cool. alright i've been reading through a lot of forums about the sohc no-vtec zc, and i have one question. how much hp does is give to the clutch? i've seen people say 108. i've seen 118. one guy even said it gives 130! (i dont believe 130 ;]) so can someone please tell me the facts? haha thanks a lot!

 

Well, most say hp not whp or b hp, so I guess that's at the clutch.
The d16a6 has 108 hp.
The sohc zc non vtec has 118
The dohc zc, which is the d16a1 offered in edm crx's is the one with 130 hp. This has no vtec.