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Old 09-22-2010, 01:28 AM   #1
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Default Gear Ratio Questions.

Ok I am sure this has came up before but after some searching I still don't have a definitive answer. I have a 99 miata with a rather large turbo set up and an 03 block I have a stock rear end and 5 speed. The gears are so close it is ridiculous shifting when it spools threw. I believe my car has 4:30 gears and would like to drop to something much lower as I can not drive much on the highway and on the strip getting to 100 is impossible with my gear-set I need your expertise I have heard about OZ gears and old 1st gen Rx7's and even a rumor of old 626 gears. Would like to find an inexpensive set up to drop my ratio and make it a little more highway compatible. So I come to the experts for your most valued information. Thank you all for your time and info.
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Old 09-22-2010, 01:30 AM   #2
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626 gears work search them in conjuntion with joe perez we had a rather large thread on the subject about 1.5 yrs ago.
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Old 09-22-2010, 01:48 AM   #3
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I am a little confused as what I am going to need to buy for a 626 swap what should I search or ask for? Also would I be better off with a 6 speed or would this require me to change a bunch of parts but on the other had would this come with an lsd? I went on car-part.com but not sure what to search for. Thank you. My mechanic also mentioned a automatic transmission pumpkin would drop it a bit but how much and is this worth it also how do I search for this or ask for it at a parts shop. Oh btw I have a 99 Sport does this has posi or a torsen LSD. So many questions so little time.

Last edited by mach5; 09-22-2010 at 02:10 AM.
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Old 09-22-2010, 02:50 AM   #4
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I have a 99 as well...not turbo'd yet but in preparation I picked up a 3.9 torsen but gonna keep the 5 speed...should be a good combo

http://www.flyinmiata.com/tech/gearing.php
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Old 09-22-2010, 03:05 AM   #5
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So what is the 3.9 torsen is that the gear ratio as mine is 4.30? I know torsen is an lsd but is that also the gear ratio and lsd and what do I search for it under in looking for parts such as axels or rear diff. at car-parts.com there is not an option for differential. Sorry for my noobness.
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Old 09-22-2010, 04:14 AM   #6
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Yes, 3.9 would be the gear ratio of your differential and a torsen is a particular type of LSD as there are several types. A torsen being a "torque sensing" helical , as opposed to a clutch type or a viscous limited slip.

After your last post, I think you can stand to do some learning/ reading. I think this will help you make your decision on what you want to do.

http://solomiata.com/Drivetrain.html

and afterwards you can putz around here for other stuff.
http://www.miata.net/garage/garageengine.html
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Old 09-22-2010, 09:06 AM   #7
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I picked a 3.9 Ring and Pinion off an 84 RX7 and bolted it to my OS Giken (5 speed). It's a great combination for getting out of corners while not totally sacrificing top speed. My home track is Barber Motorsports park which is a very technical track with not much room for top speed, but can generally stay with the vettes, GT2s and M3s. Now at Road Atlanta - my *** is handed to me on a platter as I don't have the top speed they do. If you really want some length between shifts, get a 3.6 R&P - you'll sacrifice your acceleration but pickup top-end speed - if you have the hp to move it.

The final drive on the 6speed is lower than the the 5spd, so there will be MORE shifting in between with the 6 and will be less top end speed, but it's a beefier unit too. I hear using the 6 with a 3.6 is like having the shift points of a 5 w/a 4.1 but then you get a true over drive

Right/wrong?

Last edited by GeneSplicer; 09-24-2010 at 09:01 AM.
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Old 09-22-2010, 06:44 PM   #8
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I was reading this post under this website http://www.miata.net/faq/99central.html
I have a NC22-NAA which looks like I have a TorsenII? I am guessing. I have a 99 Sport Bose radio Nardi steering wheel and tan leather tan top.

How do I tell if my NB came with a LSD?

For 99-02 the quick method is to check the Model # against these lists (US). Your cars model # can be found on the Vehicle Information tag in the passenger door jam (lower left corner of tag).

Mazda stopped installing this tag mid-year 02. Most if not all 02 SEs do not have the tag.

1999 2000 2001-02
NC11 NC50 NC73
NC12 NC51 NC74
NC14 NC52 NC75
NC17 NC55 NC76
NC18 NC58 NC78
NC20 NC59 NC79
NC22 NC60 NC80
NC23 NC63 ND22
NC24 NC67
NC25 NC68
NC65 NC94
NC66 NC95
NC96
For 02+ cars without the ID tag, see the answer to the next question.

I'm looking at buying an NB and it doesn't have or I don't have access to the Model #. How can I know if it has a LSD?

For 1999 (Torsen II):
If the car came with cruise control, power antenna, windblocker and power door locks and/or tan leather interior/top, it has the LSD.
It it is a 10th Anniversary Edition (10AE), it has a LSD.
If it is a Sports Package, it has a LSD (see How to ID a 1999 Sports Package below)

For 2000 (Torsen II):
If the car is an SE or has tan leather/top and Bose Stereo (Miata LS), it has a LSD.
If the car has factory 15" wheels and the (99-00) STB in the engine compartment, but doesn't have power door locks and cruise control it has a LSD
For cloth interior cars with 14" wheels, if you can't get the Model #, then you will need to have the VIN # and phone Mazda Customer Service, asking them nicely to check what options were on the car as delivered.

For 01-02(Torsen II):
If it is an SE or has a tan leather interior/top and Bose Stereo (Miata LS), it has the LSD.
If it has a cloth interior with 5sp, factory 16" wheels and has the factory STB (see pic) but doesn't have power door locks, cruise control and remote keyless entry, then it has the Suspension Package option (see 01-02 HARD S) which included a LSD.

01-02 Miata (cloth interior, 15" wheels) could get a LSD as optional equipment. There is no way to visually tell if it has a LSD. But if it doesn't have power door locks, cruise control and remote keyless entry it can not have the LSD. Mazda required that the Convenience Package be ordered at the same time as the LSD. If the car has the Convenience package (possible LSD) and you can't get the Model #, then you will need to have the VIN # and phone Mazda Customer Service, asking them nicely, to check what options were on the car as delivered.

For 03 (Tochigi Fuji):
If the car is an LS or SE (leather, Bose Stereo, Silver interior trim) it has a LSD.
If it's a Shinsen Version (Titanium Gray Metallic paint, dark blue cloth top and blue cloth seats)it has a LSD.
A LSD was available for the black cloth interior models. They could have a LSD if the car was ordered with the Suspension Package option (see 01-02 HARD S) but a LSD could also be ordered separately.

Best bet is to get the VIN and call Mazda Customer service.

For 04-05: (Tochigi Fuji):
If the car is an LS (leather interior, Bose Stereo, Silver interior trim) it has a LSD.
A LSD was available for the black cloth interior models only if it was ordered with the Suspension Package option. Unlike the previous years it could not be ordered separately. Unless you can see the car up close and know exactly what to look for, it's very had to tell if an 04-05 was order with the Suspension Package. Again, best bet is to get the VIN and call Mazda Customer service.
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Old 09-22-2010, 11:00 PM   #9
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Quote:
Originally Posted by mach5 View Post
How do I tell if my NB came with a LSD?
Go find a turn where you can safely corner near the limit at second gear, 4-5000 rpm speed, and floor it. If the inside rear lights up and the outside rear doesn't do much, you lose. If both rears light up, you win. Of course, you better be ready to drive a little sideways and hope there aren't any cops around...
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Old 09-23-2010, 02:35 AM   #10
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Quote:
Originally Posted by SolarYellow510 View Post
Go find a turn where you can safely corner near the limit at second gear, 4-5000 rpm speed, and floor it. If the inside rear lights up and the outside rear doesn't do much, you lose. If both rears light up, you win. Of course, you better be ready to drive a little sideways and hope there aren't any cops around...
So Drivers side or passenger side? right or left turn?
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Old 09-23-2010, 04:09 PM   #11
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there is a code in the door jam that you look up to see what options it came with from factory
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Old 09-23-2010, 11:26 PM   #12
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I am sure that you want a 3.636 with a 6 speed. I was going to do this rear with a 5 speed but i know i will just break it. It should give you a top speed of like 159 ish.
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Old 09-24-2010, 12:10 AM   #13
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+1 a 3.636 with a 6-speed is great especially if you have 250+ RWHP or so.
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Old 09-26-2010, 03:39 PM   #14
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I came in to ask the same question, my 92 is frankly pretty uncomfortable trying to make time on the free-way. did a run out to the nurburgring last weekend and the 7 hours on the motorway at 4200 rpm have convinced me its time to upgrade the diff and change the gearing. So working on the understanding that I do not have a massive junkyard full of mazda's right next door, where to I get the 3.636 gears from? Or are they going to cost so much new that its worth waiting for a used set? what models were they used in? just that old 626?

Has anyone here actually changed a set? I was always under the impression that setting up the shims on a rear end was one of those things that just takes practice, and so best left to a trained hand. Any truth to that, or is it just one of those ways to keep tranny shops in business?

And on a related note, what exactly is needed to swap in a 6 speed? just the box? What is up with all the discussion I hear about 6 speed shifters?

And as ever yes I have searched but all I ever find are little snippets here and there, never a real breakdown of the process. If there is a build thread that details any of this please point me in the right direction.

Sorry for the thread jack Mach2, but they would have all screamed bloody murder if I started a fresh one
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Old 09-26-2010, 07:23 PM   #15
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Quote:
Originally Posted by ZX-Tex View Post
+1 a 3.636 with a 6-speed is great especially if you have 250+ RWHP or so.
It makes life worth living. Gears are nice and tight on the track (tighter than a 4.30 5-speed), and I can cruise at 75mph/3400rpm all the way home from the track. Its great. I may put my spare 6-speed and spare 3.63 in my daily driver...lol.

I had to buy my R&P from Mazdaspeed. Setting a R&P takes practice and feel to get it perfect. I had a seasoned vet do mine, a good friend too. The 6-speed is a Mr. Potato Head affair, bolt and go.
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Old 09-27-2010, 01:41 PM   #16
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I cant wait to have mine in. It is about like a 5 speed with a 4.10 plus an extra gear from the research i have done. All i have to do is finish up my 6 speed. You can get the r&p from mazda comp or a 79-82(?) 626. I saw one for sale a while ago too. Watch the classifieds. I got a steal, and paid 450 for a 4.10 torsen and the r&p.
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Old 09-27-2010, 04:08 PM   #17
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If anyone want a 3.9 to go with their 5 speed I will have my torsen w/ 3.9 gears for sale in a few days. I am putting in a 3.6 (bought from ebay) with a rx7 clutch diff.

BTW so are the part numbers actually different for the 03+ torsens? If so, that explains why I could launch mine horribly over and over and over and over again for three years with no problems at all. 03+ torsen was chiseled out of titanium by the hand of god.
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Old 09-30-2010, 07:24 PM   #18
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I hate to be a pain in the ***, but anyone got a link to where I can get a set of these 3.63 gears? I have searched mazdaspeed but only get places selling t-shirts.....
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Old 09-30-2010, 08:04 PM   #19
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corksport.com 400 shipped with new speed sensor for dash to read right also.
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Old 09-30-2010, 08:36 PM   #20
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They are only there occasionally on ebay. I actually paid only 20 less than new because I had to buy a speed sensor seperately. Blah

Do a search here:

user: joe perez
search for: 626 (in body of post, not title)

and you should find his thread for which 626 gears work.
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