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7 in an 8

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Old Feb 12, 2017 | 10:10 PM
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Thumbs up 7 in an 8

Ok, For some squats and giggles, I am thinking after haveing looked into like a billion threads in the last 24 hours, I should drop an old 81-84 rx 7 engine into an 8 body and see what happens. I bet a rebuild would be as simple or better. Would have to run a choke line and drill a hole but no big deal there.

I like the old manual choke engines.

What say you?
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Old Feb 13, 2017 | 04:52 AM
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A 12a?
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Old Feb 13, 2017 | 05:39 AM
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I say you're crazy. Could it be done? Yes I'm sure it could. But while the 12A is an extremely reliable engine, it is also only rated at 101hp...which is less than half of what the 13B Renesis is rated at (238hp). Not only would the car be a slug without major porting, the cost of custom fitment in making the engine fit would far outweigh the cost of a stock replacement Renesis engine. I would debate that the better bet is a REW engine from a 93-95 RX-7 would be the best bet if you are wanting to get rid of the Renesis, but again, the cost of such a swap would far outweigh a stock replacement engine. If you are trying to achieve reliability from you 8, make sure you maintain the car, use the correct fuel, change the oil, replace the coolant every two years, check the spark plugs and coils yearly, replace the air filter every two years or less, etc.
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Old Feb 13, 2017 | 08:52 AM
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Yes, I believe the 12 A is what was in the 81-84, though I could be wrong. If I recall, and it was years ago, the 12A was the better of the 2.

Personally, I love the rotary engine. For me, you couldn't give me a 93-95 rx 7, well you might be able to pass off just the engine but take the body and all else and bury it. As for costs, if I with a friend modify my own it costs me little but time and I am not seeing it too hard to do, especially if I have a 7 body in front of me at that time, too.

As for crazy, well, I have been called worse. However, I am one to believe it is all in a matter of perspective. Thank you for yours. At the same time this is a decent conversation for me. Some of the old 7 (and I mean lovers of the 81-84) may chime in and like to discuss the idea too, maybe not.
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Old Feb 13, 2017 | 12:13 PM
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LOL...I'm doing the reverse

I'm going to put a built Renesis into an 84 RX-7
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Old Feb 13, 2017 | 12:21 PM
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I can see that! I could see putting one into an 81 too but I think the rear end would remain to light and you would get nothing but spin for the most part.
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Old Feb 13, 2017 | 12:23 PM
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Originally Posted by RX_4+4
I can see that! I could see putting one into an 81 too but I think the rear end would remain to light and you would get nothing but spin for the most part.
LOL...200ish wheel shouldn't be too bad. We have a local guy that has a built 1/2 bridge REW with a 9180 that makes over 600WHP in an FB.

That thing is scarey
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Old Feb 13, 2017 | 04:40 PM
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I know where I can lay my hands on at least one body and frame. Feel like leaving smallville for a while! lol
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Old Feb 14, 2017 | 02:18 AM
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The amount of farking around to do it and the result make no sense
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Old Feb 14, 2017 | 05:37 AM
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The 12A came in the 79-85 RX-7. The 13B was introduced in the RX-7 in 1984 in the GSL-SE model and made 135hp. This was the first time the RX-7 saw a 6 port engine in the U.S. as the 12A is a 4 port engine, the 12A 6 port engine was not available here in the states. If you port the engine to make significant power gains then the conversion may pan out well. If not, you will be trying to power a car weighing 3059 lbs with an engine designed to power a car weighing 2300 lbs. Probably will not be the most fuel efficient or quickest car on the road.

Now as far as reliability goes, the 12A is top notch. They last more than 150k miles without question. The 13B in the GSL-SE was the most reliable rotary engine ever built with some of our club members going over 300k miles on an original engine. Nearly unheard of in the rotary world. But the oil injection was very adequate for the engine and the larger oil capacity was a big help as well. Keep us posted with what you decide to do!
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Old Feb 14, 2017 | 08:05 AM
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Originally Posted by sinkas
The amount of farking around to do it and the result make no sense
Come on man, really, What else do I have to do with my time? and if the result I get is that I got the job finished and completed what I set out to do, did I not truly get the result I wanted? I may not get the result YOU want me to get but is that a bad thing?

I dont know, I am just thinking...
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Old Feb 14, 2017 | 08:12 AM
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Originally Posted by mazdaverx7
The 12A came in the 79-85 RX-7. The 13B was introduced in the RX-7 in 1984 in the GSL-SE model and made 135hp. This was the first time the RX-7 saw a 6 port engine in the U.S. as the 12A is a 4 port engine, the 12A 6 port engine was not available here in the states. If you port the engine to make significant power gains then the conversion may pan out well. If not, you will be trying to power a car weighing 3059 lbs with an engine designed to power a car weighing 2300 lbs. Probably will not be the most fuel efficient or quickest car on the road.

Now as far as reliability goes, the 12A is top notch. They last more than 150k miles without question. The 13B in the GSL-SE was the most reliable rotary engine ever built with some of our club members going over 300k miles on an original engine. Nearly unheard of in the rotary world. But the oil injection was very adequate for the engine and the larger oil capacity was a big help as well. Keep us posted with what you decide to do!
Wow! That is awesome.
It would be a long road for me to do it in the start but I really like the way you are thinking!!! I liked the interchangeability of the 81-84, and as you say the GSK-SE was the better of the two. Porting out a rotary?!. Oh man, That is a thought that escaped me, to be honest. My wife ran into a guy the other day, claims he collects the 7 and 8 and so I will try to look him up. Perhaps a body or engine or something and I can go hang at BHR for a while. Ha, that last part may be a dream.

Anyways, thanks for the kind words and well wishes.
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Old Feb 15, 2017 | 05:39 AM
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Have you considered buying an RX-7 from 81-85 and driving it for a bit before making a decision on what engine to use? Might be a great experience and you may just decide to keep the 7. I restored my 85 GS, which originally came with a 12A. I installed a 13B from a GSL-SE for reliability and power purposes and I couldn't be happier with the car. Its been a great car and I really enjoy driving it. More of a raw sports car compared to the RX-8.

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Old Feb 15, 2017 | 05:27 PM
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^ Lovely FB! I am looking for a GSL-SE as a future classic to keep.
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Old Feb 16, 2017 | 08:19 AM
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Originally Posted by mazdaverx7
Have you considered buying an RX-7 from 81-85 and driving it for a bit before making a decision on what engine to use?
I have owned 3 and all were from the 80s. I loved every one. I was always able to interchange anything and everything in the 81-84 range. I would love to find and restore one, but I would also like a different project. I have also thought about seeing if I could get one of the old engines to run on a compressed air or something. perhaps it could make its own air with the ability to also use its own air. If it ever happens, you heard it here first!
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