rx7 transmission - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Suspension, Brakes, Drivetrain discuss the wondrous effects of boost and your miata...

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 01-13-2010, 10:19 PM   #1
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Aug 2009
Location: WV
Posts: 151
Total Cats: 2
Default rx7 transmission

i tried searching though rx7 didnt turn up the result

i have a 93 1.6l miata, trans is ready to fall appart
i found a guy local with a 87 and a 90 n/a rx7 5 speeds
i looked them up, i like the higher 1-3 gears, and the lower 5th gear

what exactly do i need to do to put the rx7 trans in my miata aside from changing bell housings?
skullzaflare is offline   Reply With Quote
Old 01-13-2010, 10:50 PM   #2
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

You can make a transmission adapter plate

OR

you can hack off the front end of your miata bellhousing, hack off the front of the rx7 bellhousing, and weld the miata front onto the rx7 bellhousing. Someone here from Athens did the latter.

I guess you would also need a custom driveshaft and some way to mount the tranny to the PPF or chassis.
Faeflora is offline   Reply With Quote
Old 01-13-2010, 10:51 PM   #3
Elite Member
iTrader: (8)
 
Join Date: Aug 2007
Location: Bellingham, Wa
Posts: 2,732
Total Cats: 3
Default

IIRC, you'll keep the bellhousing and use an adapter plate instead.

You will weld tranny mounts in the transmission tunnel and i'm not sure what you'll do about the diff since you wont have the PPF anymore.

Its not easy, thats for sure. Its the one thing deterring me from doing an FE3 swap.
wayne_curr is offline   Reply With Quote
Old 01-13-2010, 10:53 PM   #4
Elite Member
iTrader: (12)
 
Join Date: Nov 2009
Location: Harpers Ferry WV
Posts: 1,521
Total Cats: 20
Default

I did a bunch of research on this when I did my last build and the best info i found came from here (Solomiata : Drivetrain : Interchange). According to my findings you need a bellhousing and a drive shaft. Then you will also need to find a way to adapt your PPF to the trans or make a cross member to bolt it to and support the trans.
Sean is offline   Reply With Quote
Old 01-13-2010, 10:59 PM   #5
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

Some reworking of the shifter fork among other things. Here, read this:
https://www.miataturbo.net/forum/t19010/
curly is offline   Reply With Quote
Old 01-13-2010, 11:14 PM   #6
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Aug 2009
Location: WV
Posts: 151
Total Cats: 2
Default

Quote:
Originally Posted by curly View Post
Some reworking of the shifter fork among other things. Here, read this:
https://www.miataturbo.net/forum/t19010/
after looking at this, i think ill save some money and just buy a 6 speed lol.
ill throw my 89 trans in for now

that looks like alot of work . i don tthink i could let my DD be down that long lol
skullzaflare is offline   Reply With Quote
Old 01-14-2010, 09:18 AM   #7
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,244
Total Cats: 291
Default

The NA RX7 transmission is the same gear box (center section) as the Miata 5 speed. Turbocharged Rx7s have the larger R transmission. For the NA Rx7 box you need to bring over the front section (bell housing) AND tail section from your Miata to the Rx7 center section (gear box). It might be worth it if he's giving them to you- just depends on what you can find a used Miata 5 speed for. Time vs. cash.
m2cupcar is offline   Reply With Quote
Old 01-14-2010, 10:05 AM   #8
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Aug 2009
Location: WV
Posts: 151
Total Cats: 2
Default

Quote:
Originally Posted by m2cupcar View Post
The NA RX7 transmission is the same gear box (center section) as the Miata 5 speed. Turbocharged Rx7s have the larger R transmission. For the NA Rx7 box you need to bring over the front section (bell housing) AND tail section from your Miata to the Rx7 center section (gear box). It might be worth it if he's giving them to you- just depends on what you can find a used Miata 5 speed for. Time vs. cash.
i have bad 93 5 speed in my car, i have a 89 5 speed sitting in my building
the 90 and 87 n/a rx7 5 speeds are $50 each
skullzaflare is offline   Reply With Quote
Old 01-14-2010, 11:59 AM   #9
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,244
Total Cats: 291
Default

I'd be inclined to find and buy a cheap Miata 5spd. I've seen them for $150 regularly. What's your time worth? I'm guessing it's 2 hours to swap the end sections IF all goes right. Pulling the sections apart is a bitch since they're sealed. I fab'd the puller/splitter below for the front section/bell.
m2cupcar is offline   Reply With Quote
Old 01-14-2010, 12:04 PM   #10
Junior Member
Thread Starter
iTrader: (2)
 
Join Date: Aug 2009
Location: WV
Posts: 151
Total Cats: 2
Default

Quote:
Originally Posted by m2cupcar View Post
I'd be inclined to find and buy a cheap Miata 5spd. I've seen them for $150 regularly. What's your time worth? I'm guessing it's 2 hours to swap the end sections IF all goes right. Pulling the sections apart is a bitch since they're sealed. I fab'd the puller/splitter below for the front section/bell.
your right on on the price
last night i found a 94 5 speed on craigs for 175, i emailed him, im picking it up for $150 next week

id rather the 94 over this 89 lol
skullzaflare is offline   Reply With Quote
Old 01-14-2010, 12:24 PM   #11
Elite Member
 
Join Date: Feb 2008
Location: Victoria, BC
Posts: 2,322
Total Cats: 12
Default

Quote:
Originally Posted by m2cupcar View Post
The NA RX7 transmission is the same gear box (center section) as the Miata 5 speed. Turbocharged Rx7s have the larger R transmission. For the NA Rx7 box you need to bring over the front section (bell housing) AND tail section from your Miata to the Rx7 center section (gear box). It might be worth it if he's giving them to you- just depends on what you can find a used Miata 5 speed for. Time vs. cash.
I actually have 3 spare 5 speed transmissions in my garage, and wouldn't mind tearing one apart to try this. What exactly are the benefits to going to a NA RX7 transmission?
dustinb is offline   Reply With Quote
Old 01-14-2010, 12:32 PM   #12
meatbag
iTrader: (50)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 7,357
Total Cats: 26
Default

I also have a spare 5spd in my garage...and would be up for trying this.

So we just have to source the NA RX7 center section?

Anyone wanna sell one?
gospeed81 is offline   Reply With Quote
Old 01-14-2010, 05:03 PM   #13
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

Are the N/A Rx7 center section gears stronger than the Miata gears? If not I don't see the point. Love to know if those gears are stronger though.
cueball1 is offline   Reply With Quote
Old 01-14-2010, 05:49 PM   #14
Junior Member
iTrader: (1)
 
Join Date: Apr 2008
Location: Bristol
Posts: 442
Total Cats: 0
Default

Quote:
If not I don't see the point
Different ratios, much nicer 5th

86-91 NA RX-7 3.475 2.002 1.366 1.00 .691, 86=.711
Miata 3.136 1.888 1.330 1.00 .814
Duckie_uk is offline   Reply With Quote
Old 01-14-2010, 06:13 PM   #15
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

The taller 5th I get. Most people complain that 1st is too short already with the stock tranny. Can't imagine wanting 1st to be even less useful than it is already. Maybe with a rear end change it makes sense like with the 6 speeds.

Still. My number one question would be - is it stronger! Would love to have a stonger gearbox alternative other than 6 speed (stronger gears but weak forks) or Rx7 turbo 2 with the adapter plate/ PPF hassles.
cueball1 is offline   Reply With Quote
Old 01-14-2010, 06:31 PM   #16
Elite Member
iTrader: (1)
 
Join Date: May 2009
Location: Jacksonville, FL
Posts: 4,682
Total Cats: 216
Default

yah, longer 5th is good, buut shorter 1st-3rd probably not too good
Full_Tilt_Boogie is offline   Reply With Quote
Old 01-14-2010, 10:04 PM   #17
Junior Member
iTrader: (2)
 
Join Date: Dec 2004
Posts: 201
Total Cats: 1
Default

Speaking of which, does anybody make an adapter plate for the turboII transmission?
db84drteg is offline   Reply With Quote
Old 01-14-2010, 10:08 PM   #18
Elite Member
iTrader: (12)
 
Join Date: May 2007
Location: Austin, TX
Posts: 1,923
Total Cats: 0
Default

Quote:
Originally Posted by db84drteg View Post
Speaking of which, does anybody make an adapter plate for the turboII transmission?
Might check on this thread, not sure if he's still working on it though.
JayL is offline   Reply With Quote
Old 01-15-2010, 10:56 AM   #19
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,244
Total Cats: 291
Default

No- it's not stronger. Most are equal to the early Miata trans, and even older RX7 trans may be weaker depending on the running changes. IMO just about everybody would be better off buying a Miata trans of any year given the used prices and the newer the better. BUT if you have a free rx7 trans laying around, can live with the gearing and have no money- it's a good option. Dare I say you can do the same with the B2XXX gear box? Truck gearing ftl.

Jay/db84dreg - that's an interesting thread on the TII trans adapter for the block/bell and ppf. Though it would at least need a hybrid drive shaft and a miata clutch with an rx7 TII splined hub. In the end would it cost more than a 6 speed?
m2cupcar is offline   Reply With Quote
Old 01-15-2010, 03:09 PM   #20
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

Quote:
Originally Posted by m2cupcar View Post
In the end would it cost more than a 6 speed?
TII would cost the same or more with all the conversion parts and fab needed but should be stronger than the 6 speed. Six speeds have weak forks and mediocre syncros.
cueball1 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 08:58 AM
Transmission Heat Shield Thread patsmx5 General Miata Chat 46 06-06-2016 11:27 AM
WTB Bellhousing Bolts patsmx5 WTB 1 10-01-2015 10:43 AM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 04:11 PM.