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12a turbo s4 auto trans

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Old 11-05-14, 11:41 PM
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12a turbo s4 auto trans

Alright I know you guys are wondering why. Am trying to put together a Toyota starlet with a 12a streetport nikki blow thru for my wife so she could drive on the weekends to car shows and once in a while to strip. but nothing serious just a fun car. she really doesn't like driving manual, so here is where my idea come into mind. I was thinking of using a 4n71b jatco out of a s4 rx7. I was wondering if using the rear 12a auto counter weight with s4 torque converter and flexplate with the s4 trans work on the 12a. any thoughts or opinion I will appreciated. ps I would post some pics of the starlet tomorrow.
Old 11-06-14, 09:04 PM
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Pics of the Toyota
Attached Thumbnails 12a turbo s4 auto trans-forumrunner_20141106_210130.jpg   12a turbo s4 auto trans-forumrunner_20141106_210145.jpg   12a turbo s4 auto trans-forumrunner_20141106_210209.jpg  
Old 11-06-14, 09:22 PM
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Your idea should work but I have zero experience with FC autos. Only limited experience with the 84-85 and some minor experience with the Jatco from a 76 Cosmo, which I promptly removed for a 5 speed swap.

Now tell me something. What mods did you do to the Nikki to prep it for boost?
Old 11-06-14, 11:13 PM
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I have done everything like you have on your carb expect the air bleed mods. My vac/boost reference line is hook up on the turbo housing with a one way check valve so that way it never sees vacuum just pressure.
Old 11-09-14, 05:32 PM
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I don't think the turbo housing ever sees vacuum. But then the Mallory isn't rated to go below 3psi anyway. Mine is hooked to the carb hat and it can go down to 2psi or hover around 2.5 depending on temps and its mood.

I ahd to add a calibrated boost leak inline between the mallory and the carb hat which helped reduce unwanted flooding. I have yet to correct my backwards fuel line sizes though.

So you have an MSD 2225 fuel pump then?
Old 11-09-14, 07:17 PM
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Yes msd fuel pump. I still get a weak vacuum signal on the turbo housing. And for fuel lines am running 3/8 feed and return
Old 11-09-14, 09:00 PM
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Ok. I hope you don't get a minor flooding problem. It probably won't happen, but if it does, try making the send line 5/16".
Old 11-10-14, 01:38 PM
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I had the car running and it was a running a little lean. But never drove it enought to run into problems. The rear end was making noise so am swapping a Chevy 10 bolt. And decided I want it to go auto. on the auto trans I did some research on ausrotary I think the 4n71b would work. Behind the 12a. Apparently the 3 speed jatco is stronger than the 4 speed.
Old 11-19-14, 11:41 AM
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Originally Posted by chiquito1228
Alright I know you guys are wondering why. Am trying to put together a Toyota starlet with a 12a streetport nikki blow thru for my wife so she could drive on the weekends to car shows and once in a while to strip. but nothing serious just a fun car. she really doesn't like driving manual, so here is where my idea come into mind. I was thinking of using a 4n71b jatco out of a s4 rx7. I was wondering if using the rear 12a auto counter weight with s4 torque converter and flexplate with the s4 trans work on the 12a. any thoughts or opinion I will appreciated. ps I would post some pics of the starlet tomorrow.
that will work fine, make sure you use the flexplate and starter for the s4 trans...I like your setup, and your carb hat looks fabulous!!!
Old 11-19-14, 03:29 PM
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Originally Posted by chiquito1228
I had the car running and it was a running a little lean. But never drove it enought to run into problems. The rear end was making noise so am swapping a Chevy 10 bolt. And decided I want it to go auto. on the auto trans I did some research on ausrotary I think the 4n71b would work. Behind the 12a. Apparently the 3 speed jatco is stronger than the 4 speed.
that is what i've heard too, but the FC trans was in a 150hp/2800lb car, so it should be ok with a little more power in a lot lighter car...
Old 11-19-14, 04:47 PM
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Yesterday I received the Moser axles for the rear end. All I got left is swap the brackets or make some new one
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