Open vs Torsen
#1
Elite Member
Thread Starter
iTrader: (8)
Join Date: Oct 2007
Location: Dallas
Posts: 1,829
Total Cats: 0
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I had picked up a 96 rearend. It was the base model car with a/c, and mabe cruise, with steelies.
Anyway, I know the torsen locks both wheels when one slips.
Is the open one of those rearends where you go all the way down the track with one wheel spinning? Or do both lock up?
When my girl gets out of school, I'll probably hit the track. But for now $14 for all day fun at the strip, and $5.00 nacho's with the guys will work. And if the open is good for dragging, I'm good.
Thanks.
And yes I seached through the 1,000,000,000 pages.
Anyway, I know the torsen locks both wheels when one slips.
Is the open one of those rearends where you go all the way down the track with one wheel spinning? Or do both lock up?
When my girl gets out of school, I'll probably hit the track. But for now $14 for all day fun at the strip, and $5.00 nacho's with the guys will work. And if the open is good for dragging, I'm good.
Thanks.
And yes I seached through the 1,000,000,000 pages.
#3
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
the open diff wont be spinning 1 wheel the whole time. it will lock up sometimes and not other times. most of the time it wont lock up though (at least in my case)...torsen will lock up every time, and there is no comparison. the car does get ridiculously tail happy with the torsen though. If you're using it primarily for drag racing, I would keep the open simply because it is so much cheaper if you break it.
#4
Elite Member
Thread Starter
iTrader: (8)
Join Date: Oct 2007
Location: Dallas
Posts: 1,829
Total Cats: 0
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Thanks guys,
I hope mine is a torsen. I read some about the RX-7 guts swap in. But it was some what unclear. Will I still be able to use my half shafts?
Then I read where you bolt the front onto the rx7 rearend.
If I can put the guts into the 1.8l rearend and keep my half shafts, that sounds like the easiest approach.
I would apreciate some clearification, if someonw knows.
Thanks
I hope mine is a torsen. I read some about the RX-7 guts swap in. But it was some what unclear. Will I still be able to use my half shafts?
Then I read where you bolt the front onto the rx7 rearend.
If I can put the guts into the 1.8l rearend and keep my half shafts, that sounds like the easiest approach.
I would apreciate some clearification, if someonw knows.
Thanks
#5
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Open's don't break because you can't load them. You do a hard launch and it just wheel spins. You put a torsen and do a hard launch, and you get ~twice as much power sent through the diff/ring and pinion/etc. Open diffs suck for drag racing. So does IRS though.
Braineack has the RX7 diff swap outlined in this big faq IIRC. It's outlined on this site somewhere. All the info in the world.
Braineack has the RX7 diff swap outlined in this big faq IIRC. It's outlined on this site somewhere. All the info in the world.
#7
Elite Member
Thread Starter
iTrader: (8)
Join Date: Oct 2007
Location: Dallas
Posts: 1,829
Total Cats: 0
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Open's don't break because you can't load them. You do a hard launch and it just wheel spins. You put a torsen and do a hard launch, and you get ~twice as much power sent through the diff/ring and pinion/etc. Open diffs suck for drag racing. So does IRS though.
Braineack has the RX7 diff swap outlined in this big faq IIRC. It's outlined on this site somewhere. All the info in the world.
Braineack has the RX7 diff swap outlined in this big faq IIRC. It's outlined on this site somewhere. All the info in the world.
If he has anther post I'll check it out. And m.net again.
#9
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
You use everything except the circlips. Rx7 LSD, Rx7 circlips, Miata housing, Miata R&P, Miata stub/halfshafts. This is for an FC diff swap; the earlier FB diffs are different and harder to do.
#10
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
the open diff wont be spinning 1 wheel the whole time. it will lock up sometimes and not other times. most of the time it wont lock up though (at least in my case)...torsen will lock up every time, and there is no comparison. the car does get ridiculously tail happy with the torsen though. If you're using it primarily for drag racing, I would keep the open simply because it is so much cheaper if you break it.
Tony
#12
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
and if the open is a waste for drag racing, then the torsen will be an even more waste since its not much (if any) stronger than an open and costs more than double to replace.
for drag racing I have heard/read the rx7 clutch type diff holds up pretty well.
#13
Elite Member
Thread Starter
iTrader: (8)
Join Date: Oct 2007
Location: Dallas
Posts: 1,829
Total Cats: 0
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
The open then is basically the limited slip on a old chevy, one tire spins, sometimes you can get 2 to spin. And you go out to tape off the 2 tire spin marks when it happens. Lol
Thanks guys.
So would you do it? Or just leave it alone?
Sweet deal,
I would appreciate the info. So will the internals swap out, or are you swapping the entire rearend?
The rx8 has positive traction doesn't it?
Thanks again, Good Luck!
Thanks guys.
I would appreciate the info. So will the internals swap out, or are you swapping the entire rearend?
The rx8 has positive traction doesn't it?
Thanks again, Good Luck!
#14
2 Props,3 Dildos,& 1 Cat
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/smod.png)
iTrader: (8)
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
ok that part I was incorrect about. I guess what I was trying to say is that sometimes it will spin the one tire sometimes it wont. it doesnt ALWAYS spin one tire throughout a whole quarter mile pass.
and if the open is a waste for drag racing, then the torsen will be an even more waste since its not much (if any) stronger than an open and costs more than double to replace.
for drag racing I have heard/read the rx7 clutch type diff holds up pretty well.
and if the open is a waste for drag racing, then the torsen will be an even more waste since its not much (if any) stronger than an open and costs more than double to replace.
for drag racing I have heard/read the rx7 clutch type diff holds up pretty well.
torque spins tires, not diffs. but with an open diff, you get only one tire's worth of torque before you spin.
we all love the clutch type diffs. they are somewhat more forgiving and rebuildable than a torsen. cheaper too.
#15
Boost Czar
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/admin.png)
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,688
Total Cats: 4,113
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
An open diff is simply a basic non-locking differential. A differential allows one wheel to turn at a different rate as the other around a corner so the inside wheel doesn't skip, hop, and slide. the end.
this video is an oldie but goodie:
With that said, I do not recommend a torsen for drag racing. The hexicoil gears seem to be a weak point under load.
#16
Elite Member
iTrader: (22)
Join Date: Dec 2006
Location: Sunny Spanish speaking Non US Caribbean
Posts: 3,224
Total Cats: 3
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Give me a few days to get it and test it. I promise to pm you all the info. I can provide you which ebay vendor I bought it from. Let's see how it works first
![wink](https://www.miataturbo.net/images/smilies/wink.gif)
I'm only swapping the diff. Nothing else.
Thread
Thread Starter
Forum
Replies
Last Post