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

Please help! (Fb Rx7 Gs 1984 automatic trans)

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Old May 7, 2022 | 10:41 AM
  #26  
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Originally Posted by Frogman
I'm the resident expert on automatics around here and that's very bad because I feel I know jack.
If your auto trans is not shifting, you will pretty much reach 7000 RPM and or grenade the trans, the first gear will not handle much more than 45 mph for more than a few mins without overheating and burning the clutches out.
Your vacuum diagram only helps smooth out shifts, if it fails you will suck ATF into the engine. Low ATF causes the trans to disengage from first at low RPM into neutral and then to brutally engage into first, even lower RPM will do this between first and second. I have never had issues with the electronic selenoids, so no idea what happens when they go bad. What it sounds like here is a lack of gas , your trans shouldn't limit your engine power or throttle response.
would manual swapping give me a significant boost in power?
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Old May 7, 2022 | 12:42 PM
  #27  
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Originally Posted by SenpaiRx7
would manual swapping give me a significant boost in power?
If the 12A engine mounted to your automatic is exactly the same 12A swapped with a manual transmission .. then the short answer is no .. there will be no boost in engine power.

Having said that, a manual 5-speed doesn't use a torque converter (which is a plus) .. there are more gears to help the engine power through the RPM range .. and the manual transmission will likely weigh a bit less (although insignificant).

Overall the manual swap will feel much more engaging to drive. You will improve off the line performance and acceleration with the same engine power.

Last edited by RX7_Renesis; May 7, 2022 at 07:27 PM.
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Old May 7, 2022 | 01:33 PM
  #28  
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A manual trans will not give you any more power. But it WILL 100% let you keep the car in it's happy-zone. 1980's auto's are for old lady's and keep the car down in the "MPG" range. Rotaries are not about mpg. They are about high rpm (because they ONLY make ANY power at high rpm's).

Modern cars have great auto trans, and get good power AND mpg from them. But in the '80's auto trans didn't give good power OR mpg. It was just for grandma who couldn't shift. Anybody driving an auto RX-7 who tells you it performs well, doesn't know how to drive a stick. Or is 80 yo.

Last edited by Maxwedge; May 7, 2022 at 01:35 PM.
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Old May 7, 2022 | 03:16 PM
  #29  
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Ac

My latest problem, My ac fuze keeps burning out after I turn the ac on, I’m guessing it’s ground but where.
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Old May 7, 2022 | 03:32 PM
  #30  
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Originally Posted by Maxwedge
A manual trans will not give you any more power. But it WILL 100% let you keep the car in it's happy-zone. 1980's auto's are for old lady's and keep the car down in the "MPG" range. Rotaries are not about mpg. They are about high rpm (because they ONLY make ANY power at high rpm's).

Modern cars have great auto trans, and get good power AND mpg from them. But in the '80's auto trans didn't give good power OR mpg. It was just for grandma who couldn't shift. Anybody driving an auto RX-7 who tells you it performs well, doesn't know how to drive a stick. Or is 80 yo.
I will gap every stick 7 80-83 above 40 mph on the highway, I have done it multiple times with a few friedns with a 80 and a 82 .. The Auto's have better high end gearing . Bellow that you gain a good 1.2 second advantage on 0-60 with a stick , and although going past 4.5 k is pointless , it sounds glorious.
MPG wise max is also right again under 40 mph, above 40 mph I'm getting around 25 mpg , under 40 mph 13~14 . If it is excessive stop and go it is 10-11. Then again I can always force the car to stay in first or second . If you do that you preety much eliminate all the advantages the stick has in a straight line , the only downside is that is incredibly hard on the clutch packs .
This auto trans is not a " Granny" trans , It was actually one of the best trans around and highly desired for drag racing , I have a stage 2 kit on mine and it hauls *** . The only thing I cant do is do a dead stop burnout doing forward, I can in reverse.
Fun wise , get a stick , but realisticaly , no matter how much people say otherwise , for a car driven in 80% city , Auto's are supperior . You will never ever convince me otherwise . Auto Swapping my mach 1 was the best thing i ever did and most muscle car guy's dont get **** about it because unless you are hauling *** every day , it gets tedious and annoying. If your 7 is your one a month weekend toy or a track car 100% swap it. If you drive frequently in any form of traffic , LOL have fun while im chilling with my AC and have instant power at any time above 40 at highway speeds without having to downshift and rev match.

Also the auto's from experiance have better condition engines and the trans itself is bullet proof.+ no dealing with the slave cylinder that has a tendancy to go bad every 30k miles from what I have read. Plus they came with slightly larger secondary jets from factory if i remember the FSM right .

Last edited by Frogman; May 7, 2022 at 03:37 PM.
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Old May 7, 2022 | 03:54 PM
  #31  
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Originally Posted by Frogman
I will gap every stick 7 80-83 above 40 mph on the highway, I have done it multiple times with a few friedns with a 80 and a 82 .. The Auto's have better high end gearing . Bellow that you gain a good 1.2 second advantage on 0-60 with a stick , and although going past 4.5 k is pointless , it sounds glorious.
MPG wise max is also right again under 40 mph, above 40 mph I'm getting around 25 mpg , under 40 mph 13~14 . If it is excessive stop and go it is 10-11. Then again I can always force the car to stay in first or second . If you do that you preety much eliminate all the advantages the stick has in a straight line , the only downside is that is incredibly hard on the clutch packs .
This auto trans is not a " Granny" trans , It was actually one of the best trans around and highly desired for drag racing , I have a stage 2 kit on mine and it hauls *** . The only thing I cant do is do a dead stop burnout doing forward, I can in reverse.
Fun wise , get a stick , but realisticaly , no matter how much people say otherwise , for a car driven in 80% city , Auto's are supperior . You will never ever convince me otherwise . Auto Swapping my mach 1 was the best thing i ever did and most muscle car guy's dont get **** about it because unless you are hauling *** every day , it gets tedious and annoying. If your 7 is your one a month weekend toy or a track car 100% swap it. If you drive frequently in any form of traffic , LOL have fun while im chilling with my AC and have instant power at any time above 40 at highway speeds without having to downshift and rev match.

Also the auto's from experiance have better condition engines and the trans itself is bullet proof.+ no dealing with the slave cylinder that has a tendancy to go bad every 30k miles from what I have read. Plus they came with slightly larger secondary jets from factory if i remember the FSM right .
Oh wow this is fresh information for me
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Old May 7, 2022 | 10:45 PM
  #32  
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I respectively disagree with Frogman.

I've owned manual transmission cars since 1975 .. and it wasn't until I purchased a 2012 Acura TSX that the 6-speed automatic delivered marginally better fuel economy (2 mpg highway) compared to the 6-speed manual. I purchased the 6-speed manual anyways for the fun factor.

When comparing gear ratios between a stock automatic vs. a stock manual 79-85 RX7 .. there shouldn't be any reason why you would gap your friends unless they were in the wrong gear or suffering from performance issues.

In the 47 years that I've owned manual transmission cars, I've never replaced a slave cylinder .. including my 1980 RX7 (which I still have).

Rotary engines loved to be redlined (check out the term Italian Tuneup). I've read that auto RX7's suffer from a higher rate of carbon deposits which can result in loosing compression (stuck apex seals, side seals, and/or corner seals).

My daily commute to work included a combination of highway and stop-and-go traffic during rush hour. I honestly can't say that my drive was ever tedious or annoying. This is a personal choice and is not intended to suggest that a manual transmission is the right choice for everyone.

Both of my daughters learned to drive using a stick (1998 Acura CL). Both of my daughters felt that learning to drive a manual made them a better driver (more attentive) .. and both chose to purchase a manual Mazda3 as their first new vehicle.

It pains me to think that my next new vehicle may be an automatic .. or even worse a 1-speed EV. If I had to buy an automatic today, I would look for a vehicle that offered a DCT.

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Old May 8, 2022 | 11:16 AM
  #33  
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Originally Posted by RX7_Renesis
I've read that auto RX7's suffer from a higher rate of carbon deposits which can result in loosing compression (stuck apex seals, side seals, and/or corner seals)
Never heard this but it makes sense to me. I have a 79 manual and 80 auto transmission Rx-7s. Both run like a top but the auto engine is much less stressed. It shifts so low in the power band it never really has a chance to rev out unless you're obliterating the speed limits on the highway.

Can't speak for Frogmans setup, he must overriding the stock shift modulator. I prefer to keep my cars stock.
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Old Oct 1, 2022 | 06:44 PM
  #34  
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Agree Frogman. My 83 rx7 auto shifts at 6000 rpm when it is floored and has really good kick down again shifting at 6000 rpms on the upshift to second or thrid. . While not a fast car it is really sporty and has plenty of passing power
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