I am planning to put a zc into my 88 civic. I have a question about the tranny. On hasport.com, it says any 88-91 civic/crx tranny is compatible but for the best acceleration use si tranny. I assumed that since the zc is si (i think??) they meant use the zc tranny. Then I saw debates about zc tranny vs si tranny. My question is what is the si tranny, what block does it come from, and where can I find it.

 

i have a dohc zc in mah crx. just las week i blew mah zc tranny. and recently just bought a crx si tranny. that **** picks up quik. i LOVE it....well im happy wit it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by whiteef-8 &raquo;</TD></TR><TR><TD CLASS="quote">i have a dohc zc in mah crx. just las week i blew mah zc tranny. and recently just bought a crx si tranny. that **** picks up quik. i LOVE it....well im happy wit it. </TD></TR></TABLE>What motor does that tranny come from?

 

the si tranny is the tranny in the civic/crx si. it comes from the d16a6 block and you can get one out of an si civic or crx

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx_si6 &raquo;</TD></TR><TR><TD CLASS="quote">the si tranny is the tranny in the civic/crx si. it comes from the d16a6 block and you can get one out of an si civic or crx</TD></TR></TABLE>So the zc tranny is the si tranny? thx.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JKingCivicSi &raquo;</TD></TR><TR><TD CLASS="quote">So the zc tranny is the si tranny? thx.</TD></TR></TABLE>

No. ZC tranny and engine come out of the JDM Civic SI. Here the USDM ZC was found in the 88-89 Integra, and is different from the one over there (i.e. less power). Make sure you get the jdm one.

The tranny they are wanting you to get is the tranny that came off the USDM SI, which is the d16a6 engine.

Main difference in the two is the ZC transmission has equal length axles. Most, if not all other honda transmissions usually have a shorter axle on the right.

If you go with the ZC tranny, you would probably get better gearing, yet you would have to find the axles in a junkyard, which is more money. Two of my friends have the ZC with SI tranny combo. Sounds cheap and economical to me .

 

build a ZC/si hybrid. It's the best for acceleration. Linkie
http://hybrid2.honda-perf.org/tech/zcsifdswap.html

 

Differences between the Si and the ZC transmissions:

The Si has a shorter final drive ratio (4.250:1). It's quicker to spin up, and quicker to accelerate because of this. The ZC uses a taller final drive (I think it's around a 3.8:1)

BUT - the ZC has closer-ratio gears on 2, 3, 4, and 5. So it's quick-accelerating, too.

The ZC uses an intermediate shaft and equal-length axles to help negate torque steer. So far as I've seen, you really NEED that ZC-specific intermediate shaft. The USDM Civic AWD Wagon ('88-'91) uses an intermediate shaft on a D16A6 block (think of it as an Si engine with an int shaft), but it's not quite the same. I learned that by buying an AWD transmission and int shaft for research purposes (I wanted its 4.410 final drive, too )

The best "compromise" I've found is to use an Si transmission, swap the ZC 1-4 gearsets into it, keep the Si fifth (the ZC 5th isn't one you'll like much on the highway - too high-revving for a long drive, and limits top speed to around 112mph), keep the Si differential and final drive, and use off-the-shelf Si axles. You get the close ratios of the ZC, but the better FD ratio of the Si.

And, just for trivia's sake, did you know that the ONLY difference in the DX and Si transmissions is the final drive ratio? First through fifth gears are the exact same - and the DX final ratio is the exact same as the ZC one!

To find a ZC transmission, call up your favorite engine importer and tell them what you're looking for. Be year-specific, and be sure to tell them how many splines are on the input shaft (20 or 21, meaning '89-'91 or '88-only transmissions). And see if you can get them to throw in the intermediate shaft for free. Even if you don't end up using it, you can always resell it for $50 or so...

Mike

 

can you use the zc tranny without the half shafts? i am having syncro troubles with my si trans and found a good deal on a zc for replacement.
my question is...can i use the new axles i have in the car now (from si trans) with a zc trans?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by peichie &raquo;</TD></TR><TR><TD CLASS="quote">can you use the zc tranny without the half shafts? i am having syncro troubles with my si trans and found a good deal on a zc for replacement.
my question is...can i use the new axles i have in the car now (from si trans) with a zc trans?</TD></TR></TABLE>
no, you must use ZC intermediate shaft and 90-93 Integra axles with the ZC transmission

 

i wouldnt even waste my time with an ZC tranny, and doing a hybrid zc/si tranny takes time and money ecspecially if you cant do it yourself..With all that money spent having a tranny done......could have put towards a b16 swap....If so worried about speed.

 

thanks guys, the reason i would have done the zc trans was the price. i dont even want to bother putting the half shafts in because i just put new axles in less than 3,000 miles ago.

 

I have a si tranny with my d16z6 and it picks up real bad. I also purchased a dx tranny, the dx tranny is the same as a si exept for the 5th gear.
Si - 5th gear - 60mph @3500rpm's
Dx - 5th gear - 60mph @3000rpm's
If you want, i'll let go the dx tranny with the shift linckage and the sock shifter, for a reasonable prize

 

I :heart: my ZC tranny

I owned some fool w/ the same engine as me ZC, but diff. tranny he had the Si. I raced him 5 times and smoked him by like a car and 1/2 each time and they switched drivers The funny thing was that he said he was gonna smoke me no doubt about it.

Also some1 said that you cant use SOHC axles w/ a ZC tranny, is this correct?

 

bullshit i am using my single cam axles on the dohc zc with the si tranny and the things works just fine although i heard the zc tranny has better gearing ratios on first second third and fourth gear and they end up swaping the si final drive into the zc

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmef1991 &raquo;</TD></TR><TR><TD CLASS="quote">bullshit i am using my single cam axles on the dohc zc with the si tranny and the things works just fine although i heard the zc tranny has better gearing ratios on first second third and fourth gear and they end up swaping the si final drive into the zc</TD></TR></TABLE>

Of course u can use SOHC axles on a Si tranny.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by z6_EF_obd1 &raquo;</TD></TR><TR><TD CLASS="quote">I have a si tranny with my d16z6 and it picks up real bad. I also purchased a dx tranny, the dx tranny is the same as a si exept for the 5th gear.
Si - 5th gear - 60mph @3500rpm's
Dx - 5th gear - 60mph @3000rpm's
If you want, i'll let go the dx tranny with the shift linckage and the sock shifter, for a reasonable prize </TD></TR></TABLE>

Bullshit.

The gear ratios are the same, first through fifth. The final drive is taller on the DX tranny. You probably don't have a true Si trans.

 

the zc tranny does not limit top speed to anywhere near 112 mph, i've had the speedo buried in my zc turbo with the zc transmission, top speed is more like 135mph depending on your rev limit.

 

the pg7 ecu will limit it to 112....
By an RPM calc, redlining an Si tranny gets you to almost 140.

 

Si tranny is better.

 

the pg7 ecu doesn't limit you to 112mph. The jdm Pm7 does. And neither of that has anything to do with the tranny just the ecu, so the zc tranny doesn't limit you to 112mph.

 

bullshit the pg7 does not limit you at 112 the pm7 does