Fb lsd?

Madmen · 07-25-2016, 01:09 AM

Can anyone please point me where I may find and LSD from my FB? Not for racing but spirited street use. Any advice would be greatly appreciated.
Thanks.

Madmen · 07-25-2016, 01:39 AM

Hang on...you can swap it for a miata diff with a torsen???

t_g_farrell · 07-25-2016, 07:27 AM

GSLs had LSD in em OEM, so if you can find one of those from a junkyard, your good to go.
May want to rebuild the LSD before plunking it in there.

Madmen · 07-26-2016, 08:45 AM

Hi t_g_farrell.

No scrap yards in Manila sad to say. Also Mazda never sold any rx7s over here.
I read somewhere that a miata torsen will fit into the diff of an early FB. Anyone here done that?

Whizbang · 07-28-2016, 09:43 AM

Only the 7" miata diff since the rx7 differential is 7". Dont get the smaller one. Also i think it will only accept the 84/85 axle siince those years have larger spline and bigger bearings.

Madmen · 07-29-2016, 01:44 AM

I thought I replied with my thanks to Whizbang already but I don't see it.

Trying again.

Thanks Whizbang!!!

Sh00bs · 10-09-2016, 12:02 AM

did you try google?

ok so
gsl's have 3.90 lsd, but after 1983.5, they became large axle through end of production year ('85)
gslse (84/85) have a 4.11 lsd, big axle of course
Yes Miata pumpkins can be swapped in

so can, mazda 80's truck front diff's which are 4.44

So can kia sportage (90's) front diffs, which are 4.77

you can also source custom lsd's, like I just picked up an '81 GSL rear with 4.88 gears in it

Just bear in mind your axle to what pumpkin you're putting in it, OR if you swap the whole rear to acquire disc's, that's fine but you also have to swap out the proportional valve up by the master cyl AND WHAT MOST PEOPLE FORGET ABOUT is you'll need different E brake cables for the disc rear

So if you find a LSD/Disc rear at the junk yard, make sure you get
1) complete rear with calipers
2) take the proportional valve from the engine bay
3) get those e brake cables

probably more than you were looking for but hopefully the next person searching will find this thread and the above info and it'll solve duplicate posts down the road

07-25-2016, 01:09 AM	#1
Madmen Rotary Fan in Training Join Date: Jun 2016 iTrader: (0) Posts: 56 Rep Power: 9	Fb lsd? Can anyone please point me where I may find and LSD from my FB? Not for racing but spirited street use. Any advice would be greatly appreciated. Thanks.

07-25-2016, 07:27 AM	#3
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 757 Rep Power: 0	GSLs had LSD in em OEM, so if you can find one of those from a junkyard, your good to go. May want to rebuild the LSD before plunking it in there. __________________ 1980 GS stockport, Fat Nikki, RB Dual Facetfuel pumps, Holley regulator, RB Street port exhaust, 2GDFIS, MR2 MK I electric fans, 2G strut bar, relayed fans, lights and fuel pump, LEDs Project Fat Nikki Budget 12A rebuild Video setup < $30.00

07-28-2016, 09:43 AM	#5
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	Only the 7" miata diff since the rx7 differential is 7". Dont get the smaller one. Also i think it will only accept the 84/85 axle siince those years have larger spline and bigger bearings. __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook

10-09-2016, 12:02 AM	#7
Sh00bs I5's Doritos & dualsports Join Date: Dec 2014 Location: Pasadena, MD iTrader: (0) Posts: 24 Rep Power: 0	did you try google? ok so gsl's have 3.90 lsd, but after 1983.5, they became large axle through end of production year ('85) gslse (84/85) have a 4.11 lsd, big axle of course Yes Miata pumpkins can be swapped in so can, mazda 80's truck front diff's which are 4.44 So can kia sportage (90's) front diffs, which are 4.77 you can also source custom lsd's, like I just picked up an '81 GSL rear with 4.88 gears in it Just bear in mind your axle to what pumpkin you're putting in it, OR if you swap the whole rear to acquire disc's, that's fine but you also have to swap out the proportional valve up by the master cyl AND WHAT MOST PEOPLE FORGET ABOUT is you'll need different E brake cables for the disc rear So if you find a LSD/Disc rear at the junk yard, make sure you get 1) complete rear with calipers 2) take the proportional valve from the engine bay 3) get those e brake cables probably more than you were looking for but hopefully the next person searching will find this thread and the above info and it'll solve duplicate posts down the road __________________ '85 GS frankenstein 13b bridge Gf's '79 LE sa w/85 12a GF's 04 rx8 dyno'd 189whp, meh not bad

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07-25-2016, 01:39 AM	#2
Madmen Rotary Fan in Training Join Date: Jun 2016 iTrader: (0) Posts: 56 Rep Power: 9	Hang on...you can swap it for a miata diff with a torsen???

07-26-2016, 08:45 AM	#4
Madmen Rotary Fan in Training Join Date: Jun 2016 iTrader: (0) Posts: 56 Rep Power: 9	Hi t_g_farrell. No scrap yards in Manila sad to say. Also Mazda never sold any rx7s over here. I read somewhere that a miata torsen will fit into the diff of an early FB. Anyone here done that?

07-29-2016, 01:44 AM	#6
Madmen Rotary Fan in Training Join Date: Jun 2016 iTrader: (0) Posts: 56 Rep Power: 9	I thought I replied with my thanks to Whizbang already but I don't see it. Trying again. Thanks Whizbang!!!