1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

AT Transmission Upgrades??

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Old 11-05-05, 12:29 PM
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AT Transmission Upgrades??

Other than the RB lightweight flywheel, is there anything else that can be done to improve the performance of an Automatic Tranny. I unfortunately have no clue in this are. thanks
Old 11-05-05, 01:02 PM
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ring & pinion will help close the gap between the gear ratio a manual would give you
Old 11-05-05, 01:07 PM
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for the rear end? i have an GSL limited slip rear end, wouldnt that do it. if there is better where would i get it and at what ratio?
Old 11-05-05, 01:35 PM
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you could swap it for a 5spd.... i'm really not that helpful but i have fun
Old 11-05-05, 03:57 PM
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Umm. . . . You can't use a flywheel with an automatic. They use a flex plate and a torque converter.
Old 11-06-05, 12:43 AM
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Aouto trans upgrades

It looks like tightening up the clearances and raising the linepressure might give more positive shifts.
Adding a turbo would allow building boost at the line.
Since you do not need to lift to shift you will get no spooldown as you would when shifting a manual.


Originally Posted by jonjonwells
Other than the RB lightweight flywheel, is there anything else that can be done to improve the performance of an Automatic Tranny. I unfortunately have no clue in this are. thanks
Old 11-06-05, 10:31 PM
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well ****, i cant afford a swap. is there an aftermarket torque converter that would be better for more aggressive driving. has anyone done upgrades to an AT
Old 11-06-05, 10:40 PM
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Decreasing clearances between the clutched "will not" give a more positive shift. Increasing clearance will, much the same impact as a shift kit in a v8 transmission. You could get a transmission convertor rebuild shop to customize your converter to increase the stall speed. Doing a trubo conversion while keeping the auto would work awesome.
Old 11-06-05, 11:08 PM
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swaps aren't that hard, and how much could a 5spd go for? I have like 3 extras...they aren't that hard to come by

you would rather pay for a new torque converter and a new flexplate?
Old 11-07-05, 12:05 AM
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trust me i wish i had a 5speed, but i dont have a place to do a swap right now, plus i have another rx with the manual that i want to fix up later so i dont want to take that one, i just want this one as good as i can get it
Old 11-07-05, 09:00 AM
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why not take whatever is good/useable from this one and put it in the 5 speed car? If thats an option. Im not sure if there is anyway to have a manual valve body installed or not in your AT either, but that would be an improvement.
Old 11-07-05, 09:13 AM
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my daily is a Grand National(only came in autos) I would hate having a manual valve body for it and I LOVE manuals. If you really wanted an auto but had enough money/space for a swap, I would got to a 4 speed auto OR! pay out the butt(like $1500 or so) for one of those overdirve units and have a 6 speed auto! Are you looking for streetability, drag, or road racing performance? If its an all out drag car, get like a 7000rpm converter(and maybe a lower geared -numerically higher- rear end) and have fun!
Old 11-07-05, 12:08 PM
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Alrighty folks (cracks knuckles) I have an '85 GSL with an auto tranny in her. I took her to a Transmission shop to get her tranny upgraded with a B&M stage 2 shift kit. You havn't ever heard a more pissed off car in your life after you have driven an RX-7 with an upgraded tranny. She is ready to eat anything and everything on the road. She will lay you back in the seat when the transmission shifts it is so crazy and it is loud. It scares some people when it gets going. Sort of like changing the timing gears on a mustang to make a whinny sound.

Just remember B&M stage 2 shift kit makes, faster revs, faster shifting, and more top end power. I was able to reach near 130MPH on the stock 12A with the upgrade and hit 87-88 MPH in the quarter mile.

All the manual guys just give me a look like WTF after I beat them with my silly little 105HP stock 12A mated to an Auto tranny... hahahaaa. I just give them a thumbs up for trying.

Only reason for me for getting an automatic was to see what it could do..lol yea yea I know what you guys are thinking, stop smoking the
and for doing that right? ...lol

But it does work!
Old 11-07-05, 03:18 PM
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just do a 5 speed swap it will only take a weekend, u need: a flywheel,clutch, tranny, driveshaft, clutch slave and master, new pedals, starter, and dont forget the shift ****

btw i would go with a lightend flywheel because u already have the light auto counterweight
Old 11-08-05, 01:59 AM
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'85GSL-SE, What shift kit did you use. I checked the B&M website and didnt see a listing anywhere for shift kits to match our cars. Do you have the actual part #. thanks
Old 11-08-05, 09:47 AM
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Stock torque converer stall speed is about 2400 rpm. I would think a 3000 rpm converter might be like a "wake up call" to the stock NA engine.
Did you also go with a higher stall speed torque converter? Can you tell us how they modified the trans? Are you running the 4.1 or the 3.9 or other rear end ratio?
If you were to boost it to 15 psi the transmission would "see" the engine as a 280 cu in (4.6 liters) instead of the stock 140 cu in. (2.3 liters). This would cause the converter to stall at a higher rpm as well. If you run boost, I wonder if the stall on the stock converter would increase enough without moding the converter?
Old 11-08-05, 10:02 AM
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Stock torque converer stall speed is about 2400 rpm. I would think a 3000 rpm converter might be like a "wake up call" to the stock NA engine.
Did you also go with a higher stall speed torque converter? Can you tell us how they modified the trans? Are you running the 4.1 or the 3.9 or other rear end ratio?
If you were to boost it to 15 psi the transmission would "see" the engine as a 280 cu in (4.6 liters) instead of the stock 140 cu in. (2.3 liters). This would cause the converter to stall at a higher rpm as well. If you run boost, I wonder if the stall on the stock converter would increase enough without moding the converter?
Old 11-08-05, 10:23 AM
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Originally Posted by jonjonwells
'85GSL-SE, What shift kit did you use. I checked the B&M website and didnt see a listing anywhere for shift kits to match our cars. Do you have the actual part #. thanks
I can get the part number for you on my way home from the transmission shop. I love the shift kit but it does require relearning your RX-7 again. The shifts are going to be harder and faster so be prepaired for a jerk, the jerk is OK! and makes you feel good!

I am parting out my '85 GSL after I pull the full interior out. So if you just want to buy the transmission only and have it prebuilt and ready to go just let me know I can do that as well. Myh '85 GSL was hit in the rear and I think it has a bent frame. It doesn't track right anymore. So the transmission is for sale if you want a pre done shift kittred auto tranny for an '85 RX-7. Let me know!




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