ZC hybrid tranny with Si final drive, want to change 5th gear....

Reply Subscribe

Thread Tools

Search this Thread

Nov 25, 2003 | 06:09 PM

b17gsr

Thread Starter

Junior Member

Joined: Dec 2001

Posts: 244

Likes: 0

From: Ottawa, Ontario, Canada

ZC hybrid tranny with Si final drive, want to change 5th gear....

Ok, a buddy of mine has a 88 CRX Si. We installed a ZC motor and tranny. The guy that sold us the swap installed a Si final drive. Makes for fun acceleration, but 5th gear is useless on his long commutes on the highway.

I'm thinking of installing the 5th gear from either a Si or DX. Will the 5th gear from either fit on the ZC shafts?

TIA

Nov 25, 2003 | 06:34 PM

onePOINTsix

Member

Joined: Jun 2003

Posts: 2,262

Likes: 0

From: Somewhere in the lower part of, MI, U.S.A

Re: ZC hybrid tranny with Si final drive, want to change 5th gear.... (b17gsr)

yes! use the 5th from the Si tranny, the ZC one only drops about 600rpm between 4th and 5th

Nov 25, 2003 | 06:54 PM

davens

Honda-Tech Member

Joined: Jul 2003

Posts: 1,264

Likes: 0

From: Central Texas

In 5th at 80mph...
Si/DX will put you at 3900
The Hf 5th will put you around 3500

edit: 100 rpm correction

Modified by davens at 8:21 AM 11/26/2003

Nov 25, 2003 | 06:59 PM

b17gsr

Thread Starter

Junior Member

Joined: Dec 2001

Posts: 244

Likes: 0

From: Ottawa, Ontario, Canada

I like the RPM with the HF gearing.

Nov 25, 2003 | 11:14 PM

Mista Bone

D Tranny Guru

Joined: Oct 2001

Posts: 8,725

Likes: 8

From: Cincity, OH, USA

Re: (b17gsr)

go with the Si/DX .771 5th. The ZC needs the revs to make the power.

Nov 26, 2003 | 12:09 AM

CRX-RX

Honda-Tech Member

Joined: Jan 2002

Posts: 1,318

Likes: 0

From: Crystal Lake, IL, USA

Re: (Mista Bone)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mista Bone »</TD></TR><TR><TD CLASS="quote">go with the Si/DX .771 5th. The ZC needs the revs to make the power.</TD></TR></TABLE>
For sure

Very happy with my ZC fifth on three hour drives. But keep in mind it's mid range power. The DOHC ZC's get almost violent above 6,500 or so.

Nov 26, 2003 | 12:28 AM

^jefs0ng

Banned

Joined: Jul 2001

Posts: 10,768

Likes: 0

I just got my ls 5th gear for my b16 I'm so excited to see my revs ~1500 rpms lower than normal at 80!

Trending Topics

JDM honda del sol with B16A engine with Optional LSD? (LSD questions)

7

255
B16a 1989

5

235
BWR Throttle Body Gasket

8

238
Keyless Entry 2000 EX not working

4

183
Honda Element & CR-V Pictures

1.1k

989.3k

Nov 26, 2003 | 04:06 AM

virginia_dude

Honda-Tech Member

Joined: Jan 2002

Posts: 2,285

Likes: 0

From: Great Falls, VA, USA

Re: ZC hybrid tranny with Si final drive, want to change 5th gear.... (b17gsr)

DO the Si 5th, low enough to help but high enough to keep you near the power band.

Nov 26, 2003 | 04:21 AM

VelocityR

Junior Member

Joined: Sep 2002

Posts: 39

Likes: 0

From: Maybe, OH, USA

Re: (CRX-RX)

What RPM at 80 mph with ZC tranny. My ZC tranny is being installed in 2 weeks.

Nov 26, 2003 | 05:03 AM

#10

keithv

Honda-Tech Member

Joined: Mar 2000

Posts: 6,228

Likes: 0

From: MA

Re: (VelocityR)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VelocityR »</TD></TR><TR><TD CLASS="quote">What RPM at 80 mph with ZC tranny. My ZC tranny is being installed in 2 weeks.</TD></TR></TABLE>

A ZC tranny without the Si final drive is pretty low. I forget exactly how low and I don't have the numbers here.

Nov 26, 2003 | 05:05 AM

#11

virginia_dude

Honda-Tech Member

Joined: Jan 2002

Posts: 2,285

Likes: 0

From: Great Falls, VA, USA

Re: (keithv)

at 80 I am taching just over 4,000 RPM And thats not a hybrid tranny.

Nov 26, 2003 | 05:23 AM

#12

davens

Honda-Tech Member

Joined: Jul 2003

Posts: 1,264

Likes: 0

From: Central Texas

Re: (keithv)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by keithv »</TD></TR><TR><TD CLASS="quote">

A ZC tranny without the Si final drive is pretty low. I forget exactly how low and I don't have the numbers here.</TD></TR></TABLE>

4036 rpm

Nov 26, 2003 | 05:25 AM

#13

davens

Honda-Tech Member

Joined: Jul 2003

Posts: 1,264

Likes: 0

From: Central Texas

Re: (virginia_dude)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by virginia_dude »</TD></TR><TR><TD CLASS="quote">at 80 I am taching just over 4,000 RPM And thats not a hybrid tranny.</TD></TR></TABLE>

The math figure kicks out 3874 rpms
This will be off a little if you're wheels/tire diameter is different then stock. Also, stock tachs are notoriously inaccurate...a couple hundred rpms is common.

Nov 26, 2003 | 06:58 AM

#14

b17gsr

Thread Starter

Junior Member

Joined: Dec 2001

Posts: 244

Likes: 0

From: Ottawa, Ontario, Canada

Any special tools required to swap the 5th gear? Should we use the 5th gear from the Si tranny that was in the CRX, or buy a new one?

Nov 26, 2003 | 10:45 AM

#15

virginia_dude

Honda-Tech Member

Joined: Jan 2002

Posts: 2,285

Likes: 0

From: Great Falls, VA, USA

Re: (davens)

Yes, that is about right, No way would I stake my life on tack accuracy.

Nov 26, 2003 | 11:37 PM

#16

Mista Bone

D Tranny Guru

Joined: Oct 2001

Posts: 8,725

Likes: 8

From: Cincity, OH, USA

Re: (b17gsr)

what FD are you using and what is your goals?????

70 mph and 3200-3400 rpm are that target cruising goals.

CRX Si gearbox would be at about 3500 at 70 mph.

DEFINE YOUR GOALS!!!!!!!!!

Nov 27, 2003 | 07:05 AM

#17

b17gsr

Thread Starter

Junior Member

Joined: Dec 2001

Posts: 244

Likes: 0

From: Ottawa, Ontario, Canada

Re: (Mista Bone)

I can't believe Mista Bone missed "Si final drive" in the title.

The goal is lower revs, so the combined 2 hour daily drive on the highway isn't so buzzy and a bit easier on gas. Average speed around 120 km/h = ~75 mph.

Looks like the HF 5th gear might be the way to go.

Nov 27, 2003 | 01:42 PM

#18

LoneStarCRX

Honda-Tech Member

Joined: Aug 2002

Posts: 388

Likes: 0

From: Tejas

Re: (b17gsr)

I am looking at a ZC hybrid with Si FD and HF 5th for my highway cruising. Wacky, huh? Mike at Effin Motorworks has one and says it was a huge performance boost for him while having a very nice cruising RPM. He said it feels a little strange at first going from 4th to 5th.

My only concern is that some have said I will be "out of the powerband" with the HF 5th and will actually have less MPG. It will be 80 MPH at 3487. Surely the ZC is efficient at that point.

Nov 27, 2003 | 07:11 PM

#19

b17gsr

Thread Starter

Junior Member

Joined: Dec 2001

Posts: 244

Likes: 0

From: Ottawa, Ontario, Canada

So would I keep the ZC 5th gear synchro, or use the Si 5th gear synchro?

Anyone done this swap, any tricks? Time to read the service manual I guess.

Nov 28, 2003 | 01:50 AM

#20

Mista Bone

D Tranny Guru

Joined: Oct 2001

Posts: 8,725

Likes: 8

From: Cincity, OH, USA

Re: (b17gsr)

the synchros are the same, use which ever looks the best.

Inspect the 1-2 shifter fork also, major wear item.

BTW....Yeah I missed the FD issue, but you know how my boards I surf daily to provide correct info?????

TOO MANY!!!!!!!!!!

Nov 28, 2003 | 05:19 AM

#21

Giuseppe

Member

Joined: Sep 2001

Posts: 1,071

Likes: 0

Re: (Mista Bone)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mista Bone »</TD></TR><TR><TD CLASS="quote">the synchros are the same, use which ever looks the best.

Inspect the 1-2 shifter fork also, major wear item.

BTW....Yeah I missed the FD issue, but you know how my boards I surf daily to provide correct info?????

TOO MANY!!!!!!!!!!</TD></TR></TABLE>

Bone is the D series Tranny guru.!!!!
(period)