i have heard mix opinions about these trannys which is better ?

 

depends on what your goin for if your looking at staing all motor I would suggest a zc tranny shorter gears to keep you in your power band the only down fall to this is that the final drive on a zc is pretty low like a L3 tranny so your running at high rpms in 5th gear, but add a si final drive and you would have a nice tranny for all motor

si tranny on the other hand the gears are somwhat shorter, so in a boosting condition this would be more ideal alowing the turbo to work longer and have a larger gain the only down side to this is that a si has more torque stear

Those are the main differances I have learned so far

 

i've heard that the spacing between the gears on the zc tranny is much better, and more consistent than the si. but like was said above, because of the FD the si has overall shorter gears...

personally i'd choose the si just because its less hassle... i don't need an intermediate shaft and i don't need different axles.

if i had all the parts, i might choose the zc tranny.. less torque steer because of the intermediate shaft.

 

Like he said above what are you trying to do with your car?? what are your goals/needs?

 

Stock to stock, the Si and ZC trannys perform nearly the same.
The Si has a good gear ratio and great final drive
The ZC has a great gear ratio and good final drive
...making them about equal.
However, if you take what's great about both of them and put them together, it makes one fast tranny. The ZC 1-4 gears, the Si 5th gear and the Si final drive can even be put in the Si case, eliminating the need for a ZC intermediate shaft so you get to use of your original Si axles.

 

Dom't know much about the ZC tranny but I have a SI with my ZC and love it. Great gears ratio from 1st to 4th...I do wish that 5th was a little higher.....just my $.02 worth.

 

IMO the ZC tranny is a little short if you ever hit the hiway, also from what Ive read and been told, on boost the ZC tranny is just too short to be of any real use. Basicly you start racing to race the shift light.

If your an all motor ZC and dont do alot of hiway driving, stay ZC tranny. If your going turbo or drive a hiway for more than an hour or so on a regualr basis, go SI. The one problem with that is the no intermediate shaft on the Si tranny.

Finnaly I found someone who had put the Si gears into the ZC tranny case. My problem was solved, the gears I want for the turbo setup, and I still get the intermediate shaft! Now someone get me the stock ZC LSD!

 

To all the retards that keep saying the ZC tranny is not a "hiway" transmission...

ZC:80 mph, 5th gear = 4036rpm
Si: 80mph, 5th gear = 3874

For a difference of a whole 162 rpms.
How is one any better or worse than the other? I think what a lot of people are trying to parrot here is that if you leave the stock ZC 5th with the Si final drive it'll rev higher. Like 4412 rpms.
Too high? That depends on the driver's taste. Enough to make me pull mine out after a year and swap in a Si 5th gear. You can even use an Hf 5th to drop it down to 3487 rpms.


Modified by davens at 6:24 AM 8/24/2003

 

Thanx alot daven for clearing things up. my overall set-up is simple a jdm sohc ZC w/greddy turbo kit and MPR intercooler, RC injectors, and hondata or Zdyne boost ECU. I didnt know which one was better Si or ZC tranny, Si;s are very rare around here and usually expensive, peeps charge alot. I seen a site where the ZC tranny is 150+ shippin, so is the Si tranny better for a turbo'd car?

 

$150 then they charge $100+ to ship...

Get some good info L3 tranny info here:
http://tjshondas.20m.com/l3.htm#new

And while it is hotly debated, there are more than a couple forced induction guys that prefer the DX tranny...it allows them to stay in boost longer and the milder 1st and 2nd doesn't lose traction as easily