rx7learner

Is there a simple list of pumpkins that would be a direct bolt on swap for a 85 GSL with higher gear ratios than the 85 GSL?

None of the threads I find just give a straight answer... most are multi page without just straight answers (unless I missed some).

I'm still not sure about the kia front diff.. rear dif ... what years.... whether its even possible... whether there are valid pictures... or whether the whole thing is a conspiracy...

Any help appreciated.

81gsl12a

iTrader: (1)

lol there is lots of info... there is 1 post that list all the diff gears and 3rd members that can be used i will try and find it... and yes the kia FRONT diff can be used its a open diff

trochoid

iTrader: (6)

Are you looking for shorter or taller gears? It's a bassackwards terminology. Short gears have a higher ratio, 4.44, 4.88. and 5.12 are the common ones available for our diffs. Racing Beat and Mazdatrix, maybe even Mariah sell them for over 400 a set. Not sure where you would go is you want taller gears.

The stock diffs come in basically 2 ratios, 3.909 and 4.10. The shorter gear only came on the Manual SE.

12akid

https://www.rx7club.com/1st-generation-specific-1979-1985-18/rearend-swap-375159/

rx7learner

Trochoid yes I am looking for Shorter gears in the 4.44 to 4.88 range however I wasn't thinking about installing the gears myself (heard that was a rather difficult task) rather just pulling a pumpkin at a junk yard to just bolt on directly to my 7.

12akid... How did I miss that post! thanks!

In the link you provided Goopy mentioned in his post that the following are direct bolt ons to the GSL-SE rear end (which have the "larger axles" as I have read)... but I think I read that there is no difference between 85 GSL rear ends versus the GSL-SE (both have the larger axles)... I even read in one post that the larger axles were used on all 7's 83-85 (not sure whether that statement is acurate).

Can someone simply confirm which rear ends have the larger axles?

The simplified "Direct Bolt on Pumpkin swap" assuming you have large axles
1994 Miata and newer LSD with the 4.30
B2600 4x4 truck front diff 4.44
1994-2001 Kia 4x4 front diff 4.88


Can someone confirm, add onto, or remove from the list?

aussiesmg

iTrader: (1)

This link may help

http://www.mazdamotorsports.com/wcsc...Drivetrain.pdf

http://www.mazdatrix.com/g5.htm

rx7learner

Thanks aussiesmg.

From the 1st PDF document looks like the ring and pinion are interchangeable for the 79 throu 85 Rx7s.

However the question is... what about the 3rd member (or more commonly called pumpkin). The mazdatrix link you provided says that the 3rd member is interchangeable between 84 & 85 and does not specify SE or GSL so I would think that they should be the same other than gear ratio...

83-84 12A = 3.933
85 12A =3.909 (damn thats me... would be the lowest)
84-85 13B GSLSE 4.076

So is the short and sweet of it...

84 & 85 Direct Bolt on Pumpkin Swap
1994 Miata and newer LSD with the 4.30
B2600 4x4 truck front diff 4.44
1994-2001 Kia 4x4 front diff 4.88

vipernicus42

iTrader: (4)

IIRC '84-85 pumpkins are direct swap-ins. Earlier cars had a different sized flange for the driveshaft, so they don't interchange, but all '84-85 ones should, GSL-SE or not.

The only real difference I know of about the -SE rear ends is that they get vented discs, so also different calipers, and they have the different gearing. I think other than that it's all the same.

Jon

rx7learner

Thanks vipernicus42.

Given that... We can agree that 84 & 85 3rd members are the same regardless of GSL or GSL SE.

Can there be some consensus that the following holds true.

84 & 85 Direct Bolt on Pumpkin Swap
1994 Miata and newer LSD with the 4.30
B2600 4x4 truck front diff 4.44
1994-2001 Kia 4x4 front diff 4.88

Or does anyone know for sure? I want to go to the pick and pull but I dont want to waste money. I'm sure there are others out there that want to do the same. We just need someone to chime in that KNOWS that the list is worng / write / or missing some entries. Please let me know. Thanks.