Miata Gears in FC . Getting it done.

Reply Subscribe

Thread Tools

Search this Thread

Jan 23, 2016 | 08:18 AM

#26

lastphaseofthis

My job is to blow **** up

iTrader: (8)

Joined: Jan 2005

Posts: 2,903

Likes: 5

From: palmyra Indiana

cooing i believe.

no i dont have to leave it there, but if i didn't feel like shifting i could, or if i prefer i could drop back to third and ratchet away until im bored.

Jan 24, 2016 | 04:39 PM

#27

j9fd3s

Moderator

iTrader: (3)

Joined: Mar 2001

Posts: 31,837

Likes: 3,234

From: https://www2.mazda.com/en/100th/

Quote:

Originally Posted by Casual_John

Too bad, because the FC 5speed in an RX8, would be lighter and avoid some of that rapid rowing of the 6-speed tranny, making the RX8 a better highway cruiser.

the non north american Rx8's got a 5 speed as an option, its the T2/FD trans though, and not the NA style. so you loose no weight.

Quote:

Originally Posted by DeaconBlue

From what I have been told you can swap the 5th gear ratios between the S5 n/a, the GTU's and Miata tranys - I didn't ask about the odd ball '86 n/a 5th gear. This may not be the easiest of swaps, but it can be done.

Quote:

Originally Posted by fc323

Yeah, figured. Im presuming the box is tearable down to the gears, like other Japanese transmission. Im thinking that if the input shaft(miata) is the same diameter as the fc(because the miata one is only machined down instead of reducing diameter), then you could, in theory, swap the gears

the way the transmission is built, 4th gear, like said above just locks the input and output shafts together, which is 1:1. the 1-3 ratios are cast into the counter shaft, and thus must be swapped as a set. the 5th gear pairs are also separate, and can be swapped as a set.

there are basically three 1-3 sets, the SA-FC set, which is setup for economy. the miata, which is setup to be a more sporting closer ratio set and then the pickups, which had a granny 1st.

for 5th gears, there are lots of choices, the S4 FC has the tallest, and then something like the pickup, or the SA is the shortest, with plenty in between. so .625, to .725 to .75 to .825 to .862 or thereabouts

Jan 24, 2016 | 07:41 PM

#28

DeaconBlue

Living on the North Coast

iTrader: (31)

Joined: Mar 2009

Posts: 600

Likes: 7

From: Avon Lake

The non US RX8 with a 5-spd had the 4-port engine.

Yes there are a lot of 5th gears for the n/a trany to chose from, per MazdaTrix you have;

0.862 pickup
0.825 SA
0.814 Miata
0.807 GLS-SE
0.791 RX3/4
0.756 GTU's
0.711 '86 S4
0.697 '87 S4 thru S5

Feb 1, 2016 | 06:54 AM

#29

Molotovman

Thread Starter

Ban Peak

iTrader: (50)

Joined: Jul 2002

Posts: 4,250

Likes: 550

From: Northern Virginia

I just saw that this thread has been revived recently, if anyone wants my trans, it's for sale in my GTUs TII project part out.

Feb 1, 2016 | 10:35 AM

#30

MoNkEy_MaGiCx

Full Member

Joined: Oct 2004

Posts: 87

Likes: 0

From: Tustin, CA

If only you weren't on the east coast.

Apr 1, 2017 | 09:48 AM

#31

nitrofish88

It's 1620 somewhere...

iTrader: (1)

Joined: Feb 2012

Posts: 67

Likes: 0

From: Houston

I too will be taking dive into the gearbox swap! I just picked up a used 95 miata trans for $80 from a friend and its now sitting pretty in my garage. I know it was dogged before i got it, so I'll probably do a full rebuild just to be safe. I've got a 91' vert with a decent port job and now am looking to get every last drop of that power! So from what I've read so far, the swap is pretty straight forward, correct? I'm also curious about using the stock FC 5th gear with the miata box. Cruising at 80 doing 5k doesnt sound too appealing...