I am looking for information and gears for a ZC transmission to put in my FP CRX Si tranny. I am switching from 15 inch wheels to 13s over the Winter and need to change the final drive and gearing over. I have used a gearing calculation program and have figured out that I need 2nd to 5th gears from the ZC transmission that was not officially sold in the US but have often been imported here with engines for swaps. I am also looking for a 2nd gear from a EF 4 speed transmission to try something as well.

I tried to do a search but the search system ignores two letter words like "ZC". I posted in the WTB list but there are so many posts that it gets lost into hidden pages in less than a day so it won't ever be seen or found with a search.

Has anyone here done gearing only swaps before? Do only the cogs themselves need to be changed over or the entire mix of rails and forks, etc. have to go over too? I have been inside a tranny once when I put in an LSD but it has been awhile. I have a good condition '89 Si transmission that just needs a few fresh bearings to be the recipient of the new gearing and a Mugen LSD that has been waiting on the shelf. Both the ZC and the Si gearboxes have the same 3.25 1st gear ratio so I am guessing that I can reuse the 1st gear that I have.

I checked with HART and they cannot order the gears alone as they were never imported by Honda to the US. If I really only need the gears, I might try to have a contact in Japan just order new ones. This might be cheaper than paying $300+ and freight for a whole used ZC tranny to get to me and then have almost a whole unneeded transmission. If anyone has or knows of a partial ZC tranny or just the gears that might be available, let me know.

Once this is done, I will have a the current '88 tranny with a nearly no use Houseman 4.71 final drive and a tighter than normal OPM LSD for sale. It is a perfect ITA/H4 set-up with under 10 hours of use since the gear and LSD were new in a freshened transmission.

 

contact user mista bone. he is the d-series tranny guru and built the tranny in the blue EP crx at the solo2 nats this year. he can probably help you sorce what you need and give you any tips and advice you might need.

nate

 

I spoke to mista bone breifly but didn't want to bother him too much at least at this point. I think I recall him saying that he didn't know of any gears available. He is just on the otherside of Cincy from my so he does figure in at least one of my backup plans.

Blake Meredith is also familiar with the inside of trannys but he is also at least shipping costs away. If I can do some of this myself, I'd like to as it is now I think the last area of racecar prep that I haven't really tackled myself (and my labor comes pretty cheap).


Modified by CRX Lee at 11:47 AM 11/25/2005

 

http://hybrid2.honda-perf.org/tech/zcsifdswap.html

EDIT - Found the link...hope it's helpful or will at least get you on the right track.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by solo-x &raquo;</TD></TR><TR><TD CLASS="quote">contact user mista bone.</TD></TR></TABLE>

Damn, you beat me to it. Tell him I said he has to help you in exchange for all of the beers and nights he's spent passed out on my couch.

 

I just rebuild my streetcar tranny with ZC 1-4, SI FD and SI 5th gear. I will email you over a .pdf that may answer all your questions, if not....feel free to PM me with any questions.

Wow, I get to help Lee for a change?!

 

It maybe possible to swap the gears from the 86-89 Integra tranny, being a d-series tranny.

http://g1teg.org/specs/

It has the same ratios as the JDM ZC for gears 2,3,4 and slightly taller 1st and 5th. Now, i'm really no tranny guru, but someone also told me that the Integra tranny is a slightly different animal internally, with the 5th gear location or something. So something to check for sure. Or maybe mistabone would know...

 

/\/\ Different animal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">I am looking for information and gears for a ZC transmission to put in my FP CRX Si tranny. I am switching from 15 inch wheels to 13s over the Winter and need to change the final drive and gearing over. I have used a gearing calculation program and have figured out that I need 2nd to 5th gears from the ZC transmission that was not officially sold in the US but have often been imported here with engines for swaps. I am also looking for a 2nd gear from a EF 4 speed transmission to try something as well.</TD></TR></TABLE>

The transmission you are looking for is off of the DOHC ZC engine. Talk to either Steve at HMonline.com or Import Auto Salvage in GA (I think), they will probably have a few in stock. Price is usually around $100-150 + shipping.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">
Has anyone here done gearing only swaps before? Do only the cogs themselves need to be changed over or the entire mix of rails and forks, etc. have to go over too? I have been inside a tranny once when I put in an LSD but it has been awhile. I have a good condition '89 Si transmission that just needs a few fresh bearings to be the recipient of the new gearing and a Mugen LSD that has been waiting on the shelf. Both the ZC and the Si gearboxes have the same 3.25 1st gear ratio so I am guessing that I can reuse the 1st gear that I have.</TD></TR></TABLE>

Only the "cogs" or actual gears need to be swapped over. The 1st and 2nd gear is actually on the mainshaft itself, so you cannot seperate them. The easiest thing to do in your case would be to swap the entire ZC 1-5. The Si 1st and ZC 1st are the same and 2nd is *very* close.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">I checked with HART and they cannot order the gears alone as they were never imported by Honda to the US. If I really only need the gears, I might try to have a contact in Japan just order new ones. This might be cheaper than paying $300+ and freight for a whole used ZC tranny to get to me and then have almost a whole unneeded transmission. If anyone has or knows of a partial ZC tranny or just the gears that might be available, let me know.</TD></TR></TABLE>

It's going to be way more expensive to order the gears new from Japan. The used gearbox is the way to go here.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">Once this is done, I will have a the current '88 tranny with a nearly no use Houseman 4.71 final drive and a tighter than normal OPM LSD for sale. It is a perfect ITA/H4 set-up with under 10 hours of use since the gear and LSD were new in a freshened transmission. </TD></TR></TABLE>

PM me a price on that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jisu009 &raquo;</TD></TR><TR><TD CLASS="quote">

Only the "cogs" or actual gears need to be swapped over. The 1st and 2nd gear is actually on the mainshaft itself, so you cannot seperate them. The easiest thing to do in your case would be to swap the entire ZC 1-5. The Si 1st and ZC 1st are the same and 2nd is *very* close.

</TD></TR></TABLE>

2nd gear in the 4 speed is a 1.65.
With a 4.25 FD and 13" wheels that becomes an extremely usable start and traffic gear.
Assuming it will work. Blake thinks it will, but hasn't actually tried it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Catch 22 &raquo;</TD></TR><TR><TD CLASS="quote">
Assuming it will work. Blake thinks it will, but hasn't actually tried it.
</TD></TR></TABLE>

You can't seperate the 1-2 gear...they are both part of the mainshaft. You could use the 4sp mainshaft, but I am not sure if the 4sp will allow you to put a 5th gear on....it may. In the case that it does, there will be an "extra" bearing where the 5th gear would normally reside....

 

I think there is a spacer there, which is why Blake thinks it will work.
1st is the same in all of them I think.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Catch 22 &raquo;</TD></TR><TR><TD CLASS="quote">I think there is a spacer there, which is why Blake thinks it will work.
1st is the same in all of them I think.</TD></TR></TABLE>

yup, 3.25

 

So yeah, combining the 1st and 2nd from a 4sp with the 3-4-5 from a ZC gives you one helluva tight box.

Scott, who just wanted an excuse to say "one helluva tight box."

 

Looking at the numbers, it looks like it really could be interesting with that 2nd gear that would be more like 2.5nd gear compared to the Si and ZC ratios. That 10 mph at 7000 rpm could be a real advantage for starting races and exiting slower corners. My one big autocross event this year I hit the rev limiter at the top of 2nd twice as well so it might help there too although the real focus of the car is road racing.

I have been sent several leads on where to get a full ZC tranny and a good set of instructions for swapping the ZC gears into my Si box. I think I will try to find the 1st-2nd parts from the 4 speed and see what we can do. On paper it looks good, let's just hope the mechanical fit is just as good.

 

check PM!

 

you're lucky in that you're starting from a cable transmission foundation. I'm doing all of this with a hydro transmission for my d16y5 project in my 94 cx hatch.

just a few facts that i'm going to throw out there that took me a while to find out.

all cable mainshafts and countershafts are swappable
all hydro mainshafts and countershafts are swappable

you cannot put a cable mainshaft or countershaft in a hydro transmission
you cannot put a hydro mainshaft or countershaft in a cable transmission

USDM d16a1 gears are NOT swappable, they have larger shafts and only swap with the accord/prelude trannys. I believe these are the a20 12valve motors.

the 4speed STD and the HF transmissions use the same mainshaft. I have a 4speed mainshaft and countershaft and the only difference is that there is a spacer instead of a gear. Yes, one could actually create a 4speed zc transmission, if the rules won't allow converting to a 5speed. The spacer from the 4speed just "deletes" the empty space of the removed gears

there's sometimes a few JDM DOHC ZC transmissions on ebay, hmotorsonline.com carrys them.
the JDM DOHC ZC transmission used shorter gears, but a 3.88 DX final drive, this is why you will see "longer gears for a greater usage of torque" in the description on ebay.

the JDM DOHC ZC transmission that came with an LSD will not let you use a 4.25 si final drive. there is a rare 4.437 final drive that came in integra zxi's that will fit in the transmission. But even if you were to find one, i found a guy that was going to sell it to me for 500 bucks. Even if i were to get this final drive, this is only a 4.4% difference in gearing. If you're that concerned, just run a slightly smaller wheel diameter.

all first gears are the same at 3.25

you have three options for 2nd gear
1.65 4speed STD, crx HF
1.894 civic dx, si
1.944 jdm dohc zc

if you were to have a 22inch wheel and redline at 7000 along with a 4.25 final drive
your gears would end at the following speeds
1.65 = 65mph shifting into 1.346, rpms would fall to... ~ 5700rpm
1.894 = 57mph shifting into 1.346, rpms would fall to... ~ 5000rpm
1.944 = 55mph shifting into 1.346 rpms would fall to... ~ 4800rpm

the taller your second gear, the further it's going to carry you into third gear. if you were to make a rolling start from say, 40mph, the 1.65 would be optimal.

no matter what, you're going to want to use the zc 3rd and 4th gears of 1.346 and 1.033

with the same wheel, redline, final drive
1.346 = 80mph
1.033 = 104mph

your choice of 5th consists of
0.878 = 123mph (80mph @ ~ 4550rpm) JDM DOHC ZC 5th gear
0.771 = 140mph (80mph @ ~ 4000rpm) Civic DX/SI 5th gear
0.694 = 155mph (80mph @ ~ 3600rpm) CRX HF 5th
0.702 = 154mph (80mph @ ~ 3650rpm) 92-00 civic 5th

as you can see, the 0.702 and 0.694 are hardly any difference at all, 0.008 of a difference.

because of the math, final drives affect lower gear ratios the most.
a 3.25 final drive in first gear ends at 43mph
a 4.71 final drive in first gear ends at 30mph

this is both ends of the spectrum and only provides a 13mph difference


no matter what you're going to want to be using the zc 3rd and 4th gear along with at least the 4.25 final drive. with a zc 4th and a 4.25, 7000rpm redline, 22" wheel diameter, you're going to end at 104mph. If you plan on racing well above 104mph, then by all means use the zc 5th. If you're like most of us, you want those rpms to be lower for highway cruising, then use a different 5th. 0.702's are easy to come by. (I have an extra one)

if you race from a stop, use the zc 2nd 1.944 gear. If you race from a roll, use a 4speed/hf 1.65 gear.

i hope all this helps, feel free to ask me more questions, i love helping out


Modified by Bense at 1:49 PM 11/27/2005

 

I have been using the ZC 1-5 gears for almost a year now. The car is a daily driver and SM autocross car. The gears just swap over onto the counter shaft of your choice, and you use the mainshaft that came with the gears you are using (assuming I am correct in that the countershaft is the shaft with the pinion teeth on it).

This setup has been fantastic for autocross, and a real blast for street driving. It gets a bit anoying on the highway though, because 70 mph is 4,000 rpm. I know this is not a factor for you Lee.

Should you end up parting out that tranny, I am really interested in the Houseman 4.71 FD.

Thanks

Jacques



Modified by Jaker at 10:58 AM 11/27/2005

 

That's some great info in this thread that answers questions that i've been looking for a while. Also thanks for clarifying the difference with the D16A1 tranny. Now one more question on the D16A1:

Is the FD and diff incompatible with the other L3 trannies as well? The reason i'm asking is that I have a custom mounted D16A1 race motor and tranny in my SM EF now and in case i'd want to go to a more common D-series drivetrain in the future, it'd be nice to know if the Houseman FD and the Mugen LSD in there now would swap over to other L3 trannies?

Thanx.

 

Excellent thread. This needs to be archived.

--Andy

 

another thing i forgot to mention.

the JDM DOHC ZC transmission has a differential which uses larger axles. the JDM DOHC ZC transmission runs with a half shaft and equal length axles. Since these axles aren't available over here you have to get the mainshaft, get b18a axle inner joints (i think) and mate them up with some other axles. I am not very knowledgable on what it takes to run this with the halfshaft. But i mean think about it. You're going to be doing all that work just to run different axles with a midshaft, when you can just use any cable open differential and not have to worry about all that crap.

I have read that USDM 1st gen integra axles will not work. If you install them they will pop out within 30feet of the install area. (garage, driveway, etc.)