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Budget Mazda G transmission set up.

Posted by NBS2005 
NBS2005
Jeff Rivera
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Location: Toronto, ON
Join Date: 01/31/2006
Age: Possibly Wise
Posts: 54

Rally Car:
1993 Mazda 323



Budget Mazda G transmission set up.
October 18, 2014 10:43PM
Looking to build a transmission for my '93 323 (NA stock B8, looking to tweak a bit this winter, but want to worry more about the gearbox) similar to what Clayton did for his EGT that's for sale here. I pinged him directly and he sent me some info on what he did but I'm looking to glean a little more info.

He's using the KIA transmission, which I assume is from the Sephia 95-97, correct? Is there a consensus on what had the best available (Maz, Ford, Kia) gear ratios? For final drive, he's got a 4.93. Is that the best choice? Is there a nearly as good choice that's more affordable and junkyard available (I think I read something about a 4.53 in another Mazda that would work)? And any other LSD options than M-factory?

Any and all tips and tricks appreciated. It's been a long time (almost 30 years) since I've had an engine out a car. Looking to make this a painless as possible.

And yes, RWD Volvo or Merkur would make this a lot easier ;-). But that's not the bed I chose to lie in. Thanks.
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Doivi Clarkinen
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1980 Opel Ascona B



Re: Budget Mazda G transmission set up.
October 19, 2014 02:05AM
I heard on the internet that a Toyota Celica Alltrac transmission just drops right in easy as can be, just ask Jay Woodward. winking smiley spinning smiley sticking its tongue out
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Pete
Pete Remner
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Location: Cleveland, Ohio
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Re: Budget Mazda G transmission set up.
October 19, 2014 06:01AM
I have not tried it yet, but if your inner CVs are 26 spline where they go into the axle, then clutch diffs from a '86-88 RX-7 will work in that trans. IIRC the problem (besides fighting Miata people for one of those diffs) is that you either need to machine down the small end for the speedo drive gear, or you lose the speedometer.

When Escorts were common up here (323s never were), people would break the OE diffs all the time when they'd get stuck in the snow. As soon as I learned about the cross compatibility, I had standing orders with vaerious local shops for a dead G-box diff so I can compare vs. an RX-7 one. That was when people stopped fixing Escorts so I never got a chance to measure.



Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.
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Rallymech
Robert Gobright
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91 VW GTI 8V


Re: Budget Mazda G transmission set up.
October 19, 2014 09:56AM
Ha ha ha..."drops right in". Not exactly.



Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.
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Pete
Pete Remner
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Location: Cleveland, Ohio
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Re: Budget Mazda G transmission set up.
October 19, 2014 10:17AM
I take it you have some experience with it? What are the issues?



Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.
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NBS2005
Jeff Rivera
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Location: Toronto, ON
Join Date: 01/31/2006
Age: Possibly Wise
Posts: 54

Rally Car:
1993 Mazda 323



Re: Budget Mazda G transmission set up.
October 19, 2014 01:00PM
What benefit do you get with the KIA case? I've got a spare g box that came with the car. I could just use that if it's not a big strength plus for the KIA box.

Thanks,

Jeff
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Clayto
Clayton McCrary
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Location: Olympia,WA
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XRatty purchased. Now build it!!


Re: Budget Mazda G transmission set up.
October 19, 2014 10:26PM
The kia axles are beefier and the cases are more plentiful mainly...but the case is relatively the same... axles have to be specific to the case, can't interchange.

Corksport has diffs but not cheap, unless they have used ones from the Miata guys
Quote
NBS2005
What benefit do you get with the KIA case? I've got a spare g box that came with the car. I could just use that if it's not a big strength plus for the KIA box.

Thanks,

Jeff
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jrally
Jon Rood
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Location: Phoenix, AZ
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'94 Escort GT (sold)



Re: Budget Mazda G transmission set up.
October 20, 2014 01:26PM
Having built a well sorted Escort for rallying in the SW on a budget, I have the experience that I feel can point you in the right direction. The Kia box is more or less the V6 Mazda box, but with the B8/BP bolt pattern bell housing. You have to use the larger axles from the Kia, and the larger intermediate shaft as well. The out of the junk yard final drive I found was the 4.39:1 final drive out of the 2nd gen. Probe GT V6 car. The LSD option I went with was the MazdaSpeed Protégé factory unit, which accepts the Kia axle splines. There are aftermarket options, but mixing and matching oem parts worked out well for me. The only non-factory thing needed were bolts for the ring gear, since Mazda rivets the ring gears to the diffs normally.

-Jon
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heymagic
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Re: Budget Mazda G transmission set up.
October 20, 2014 07:17PM
Rivets?? Interesting method of attachment. Did you have to thread the ring gear then?
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Rallymech
Robert Gobright
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Re: Budget Mazda G transmission set up.
October 20, 2014 08:46PM
Drill out the rivets and replace with nuts and bolts. VW did the same thing. Madness! When the rivets come loose it's called self machining syndrome.



Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.
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john vanlandingham
John Vanlandingham
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Re: Budget Mazda G transmission set up.
October 20, 2014 10:25PM
Quote
Rallymech
Drill out the rivets and replace with nuts and bolts. VW did the same thing. Madness! When the rivets come loose it's called self machining syndrome.

Everybody's doing it on FWD crap.. that and rivetting on balljoints. Big Evil Corps save a penny, you get to waste a ton of time. PROFIT!



John Vanlandingham
Sleezattle, WA, USA

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jrally
Jon Rood
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Location: Phoenix, AZ
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'94 Escort GT (sold)



Re: Budget Mazda G transmission set up.
October 21, 2014 10:00AM
ARP makes the bolts to replace the rivets you have to drill and press out. They are more or less shoulder bolts. The case had to be clearance a tiny bit to clear the bolts, but I'm sure if you forget that step, it would clearance itself.

-Jon
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