ZC vs. Si Tranny

KahunaKahuna familEE
in Engine & Drivetrain
Which is better?
I'd like to come out of the hole better, but still have a good top speed.

I heard that the ZC is geared lower, but I don't know how the Si is geared.

I'm going to be doing a auto-to-manual to manual swap, and probably going to get a ZC as well. Let me know your input, Thanks!

Comments

  • HaydzHaydz Moderator
    ZC is my preffered gearbox but i think both would be just as good as each other... ZC box revvs higher in fifth gear though.
  • davensdavens familEE
    Excerpt from the Effin site:
    Effin D-series Hybrid Transmissions
    So you've got a CRX. The Si tranny is the best acceleration geared transmission you can get, right? Well...it's okay, certainly better than a DX or Hf. Then there's the ubiquitous ZC tranny. Have you ever considered using the best parts each model has to offer to make a hybrid tranny?

    Here's a brief breakdown of what you're dealing with:
    Si - The 1-5 gears are okay. This is made into a "performance" transmission by offering it with a sporty 4.25 final drive
    DX - The same 1-5 as the Si but with a more cruising oriented 3.88 final drive
    Hf - 1-5 is a step more spaced out then either of the previous transmissions but not extemely so. Where the Hf gets it's fuel sipping granny acceleration is it's final drive of 2.95.
    ZC - Tight acceleration oriented 1-5 but with a softer 3.88 final drive.

    The formula:
    So we take the ZC 1-4 and pair it with the Si 4.25 final drive. We also use the Si 5th gear so highway cruising is not compromised. The result is a more much more evenly spaced gear ratio that pulls significantly harder than an Si tranny. There are additional final drives and individual 1-5 gears available for one off custom applications. A good example of this is using a HF 5th gear for a car that sees lots of freeway cruising. Please contact us regarding your needs for the best suggestion.

    When building a transmission, we suggest doing a full rebuild...new synchros, bearings and seals so what you get is essentially a new transmission. The gearsets can be installed used with either a Si or ZC differential. Using the Si differential will allow you to use OEM available Si axles. Using a ZC case will require semi custom replacement axles and intermediate shaft.

    ZC box revvs higher in fifth gear though.
    This is a common misunderstanding...actually, when comparing stock to stock, they are within 500 rpms of each other in 5th gear.
  • KahunaKahuna familEE
    Who is we?
  • HaydzHaydz Moderator
    Kahuna wrote:
    Who is we?

    I think davens' quote is from an autoshop. So when they say 'we' they mean the people who work there i guess.
  • davensdavens familEE
    All that good information and he gets hung up on a pronoun?

    We is Effin Motoroworks.
    Comprised of myself, Kwicko, Reuben and Johnny.
    A little hobby business we had going for awhile...it could have took off, but none of us was willing to commit the kind of time/resources it takes to run a business, so it is effectively shutdown.

    Helpful friendly tip: Next time you want to know where something online comes from, just paste the title, or even a couple sentences into Google. It will find it. Its how learning institutions are starting to check for plagiarism (lazy students beware)
  • KahunaKahuna familEE
    So does this mean you could build me a hybrid tranny?
  • davensdavens familEE
    theoretically, yes.
    practically, no.

    http://www.gear-speed.com/ sells hybrids
  • duckie8310duckie8310 Senior Wagonist
    my dad always talked about getting a cheap DX tranny from the junkyard and rebuilding with the Si final drive. if you want the acceleration, go for the ZC, but you'll be shifting all the time. if you're in an area where traffic is inevitable, than that really isnt a good idea. you'll get annoyed really quick by having to shift gears much more often.
  • davensdavens familEE
    duckie8310 wrote:
    if you want the acceleration, go for the ZC, but you'll be shifting all the time. if you're in an area where traffic is inevitable, than that really isnt a good idea. you'll get annoyed really quick by having to shift gears much more often.


    Not true...a stock ZC performs VERY similar to a stock Si tranny.

    And even when you pair the aggressive Si final drive with the ZC 1-5 gears, its an awesome transmission around town...but it buzzes a little high on the freeway though.
  • duckie8310duckie8310 Senior Wagonist
    so which would be the tranny to get? i mean when comparing them side to side, which comes out on top? the ZC or Si?

    so for an autoX machine, the ZC 1-5 and Si final drive would be a good combo?
  • davensdavens familEE
    One last time...
    [analogy]
    Picture a 3 speed bicycle.
    One gear at the pedal crank and three gears at the rear wheel.
    The one gear is the final drive...the three gears are the 1-5 gear set.

    A Si bicycle has a very small(fast) pedal crank but very large(slow) gears on the rear wheel
    A ZC bicycle has a very large(slow) pedal crank but very small(fast) gears on the rear wheel.
    [/analogy]

    Which is better? Neither, really. If I had to pick: ZC...because if gives you equal length axles(but additional expense) and a beefier differential (better for high rpm clutch drops).

    While the 1-5 ZC gearset is a little more even spaced, its still paired to a dog final drive.
    The Si gets a great final drive, but its paired to the just-okay 1-5 that you also find in a DX.

    The best all around hybrid tranny is a ZC 1-4, Si 5th and Si final drive. If you use the ZC 5th, it's a little buzzy on the freeway (about 600 rpms higher than a Si).

    Check your class for autoxing...it might bump you out of your desired class.
  • akiraboyakiraboy HondaCivicWagon.com Founder
    yes, the holy grail: behold the mighty zc/Si hybrid

    zc 1-4 Si 5th
    Si 4.25 FD
    guy I know has this one in his ride, nice tight setup



    btw, is there any relation to Effin Vodka :roll:
  • HaydzHaydz Moderator
    akiraboy wrote:
    btw, is there any relation to Effin Vodka :roll:

    Theres a picture i want to post up but then i'd have to ban myself.
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