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

RX8 Engine into a 1st Gen RX7?

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Old 07-05-07 | 03:21 AM
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Question RX8 Engine into a 1st Gen RX7?

Has anyone heard of putting a new RX8 engine into a first gen RX7? Are there kits for this? Will the engine even fit?
Old 07-05-07 | 03:27 AM
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been done, but not with kits. The engine will fit - our bays are HUGE. if you want the whole engine, though, there's a lot of wiring involved.
Old 07-05-07 | 04:35 AM
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I've seen one somewhere on the forum or was it at NoPistons.com

Good luck post pics.

Anyway that tiny little powerpackage will fit just about anything, with proper fabrication skills.
http://www.five-speed.dk/Gallerisub/...07NCWankel.htm
Old 07-05-07 | 07:35 AM
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theres a bloke here in the ACT in australia who is in the middle of the conversion.

www.react.org.au.

im not sure if its in the main area of the site but search for adam davey
Old 07-05-07 | 12:03 PM
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Originally Posted by Ahimsa1973
Has anyone heard of putting a new RX8 engine into a first gen RX7? Are there kits for this? Will the engine even fit?
Anything can be done with enough time, money and effort.

If all you're looking for is the increased power, do a TII swap. It's easier, cheaper and much more documentation is available.

It won't be easy, and it won't be cheap, and it will take much time and effort.

Getting it mounted is the first obstacle. The engine and transmission mounts aren't in the same place, and the shifter isn't either. You'll need to fabricate some mounts and have a custom driveshaft made.

Once you've got it mounted, you'll need to figure out how to wire up whatever computer system you plan on using. If you're planning on using the Rx8 stock computer, then you have to plan on using the Rx8 console and fuel system as well, since it all ties together. Best base to start from is probably a GSL-SE, just because at least IT was fuel injected, so you might have a slightly easier time with the wiring, but it will still take quite a lot of work to figure out how to wire it in. Warm up your soldering iron, and break out the manuals, this one's gonna take a while.

Most FBs are carbureted, and as such the entire fuel system would have to be changed to accomodate the FI Renesis you're trying to drop in. Even the FI GSL-SE stock system wouldn't work if you are using the stock Rx8 computer because the Rx8 uses a returnless fuel system and a computer-controlled pump from what I remember.

So you've got the engine in there physically, you've wired up the computer, you've figured out how to get the shifter in the right place and the console mounted, you've got a fuel system setup, and a custom driveshaft to connect it to your differential. Now you have to get the rad and hoses setup, and clean up whatever odds and ends are left.


Keep in mind, this is just off the top of my head, from someone who has never done the swap. I also don't know rx8s inside and out like I know the FBs, so I'm sure I've missed a ton of stuff. But suffice it to say it's not a Honda. You can't just buy a "kit" and drop it in on a weekend with your mechanic buddy. You'll probably spend more on the installation than you will on the entire "long block" including ECU, transmission, fuel pump, harness, and all the other goodies.

Do a TII swap or buy a Honda. RENESIS, 20b and 3rd Gen 13b-REW swaps are not for the feint of heart.

Jon
Old 07-05-07 | 12:53 PM
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I don't have the pictures off hand, but there was that Japanese magazine article where a tuner shop in Japan had a renesis powered SA. IIRC they used most of the rx8 front subframe (including the rx8's steering etc) and they also used the gauge cluster and heater controls from the rx8. As jon said its not for the feight of heart and theres virtually no documentation on it. If someone has those scans of that article I'm talking about post them up, they show at least a little bit of the details....
Old 07-05-07 | 01:23 PM
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do able too much headache though ...
Attached Thumbnails RX8 Engine into a 1st Gen RX7?-2_g.sized.jpg  
Old 07-05-07 | 01:34 PM
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I found two on my hard disk. I had to reduce them in size by 50% so I could post them.



Attached Thumbnails RX8 Engine into a 1st Gen RX7?-3.jpg   RX8 Engine into a 1st Gen RX7?-4.jpg  
Old 07-05-07 | 03:27 PM
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Holy tinkering and ¥¥¥, Batman!

can you email me full sizes?
Old 07-05-07 | 04:09 PM
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I, too, would be interested in full size versions
Old 07-05-07 | 05:16 PM
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I don't care what anyone says. That's cooler than a TII swap anyday.
Old 07-05-07 | 05:24 PM
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^^ i agree, but you dont get as much "bang for your buck" with the swap. the renesis is a NB miata, now thats badass and what mazda should have done themselves.
Old 07-05-07 | 05:36 PM
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^^ i vote for this as an option they might offer that would be sweet.
Old 07-05-07 | 05:42 PM
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Did these work?
Attached Thumbnails RX8 Engine into a 1st Gen RX7?-3.jpg   RX8 Engine into a 1st Gen RX7?-4.jpg  
Old 07-05-07 | 05:51 PM
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I say Mazda should bring back the First gen with a rennisis and call it the fourth gen rx-7. Heck they could make it out of all aloys (instead of steel), and throw in IRS, and they will have more power and torque then an Exige, in a lighter car. Can you say zoom zoom? Not to mention how amasing the handling would be.
Old 07-05-07 | 06:11 PM
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Originally Posted by no_name
I say Mazda should bring back the First gen with a rennisis and call it the fourth gen rx-7. Heck they could make it out of all aloys (instead of steel), and throw in IRS, and they will have more power and torque then an Exige, in a lighter car. Can you say zoom zoom? Not to mention how amasing the handling would be.
Steel is an alloy
Old 07-05-07 | 06:14 PM
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^^+1
Old 07-05-07 | 06:41 PM
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Originally Posted by Jeff20B
Did these work?
Domo arigato.
Old 07-05-07 | 06:57 PM
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After performing this swap, you would get use to the 237 (claimed) hp and be wanting more. Then you would realize the Renesis is expensive to upgrade and can't take much boost......not to mention the 6speeds are ****.

It is definetly unique, but not my cup of tea.
Old 07-05-07 | 07:21 PM
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I dont know if it was mentioned yet, but aside from all the other hurdles of running the stock RX-8 ecu it uses input from the RX-8's ABS sensors to calculate the speed.

Not only is there no place on the transmission for a speedometer cable, but as soon as a single ABS sensor is disconnected the engine goes into "limp" mode.

I remember people having problems with the car on a dyno simply because the front wheels arent turning. I dunno if this issue has been remedied yet.
Old 07-05-07 | 07:26 PM
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Yeah it would be unique, and that would be the reason to do it. It would turn heads at all the rotary meets, though nobody else would really care because they wouldn't know what they're looking at or have any clue how much work it takes.

I just mentioned the TII swap because the vast majority of the time, people who ask this question aren't people with too much money and time on their hands looking for a unique project... they're regular fellas like you and I who are just wondering if there's a "quick" way to upgrade to something more powerful. The dead giveaway is asking if there are any "kits".

I'm all for the unique. That's why I'm trying to squeeze as much as humanly possible out of a solidly-built street port engine. People look at the list of mods I'm going to be doing to the engine I'm building and say "dude, you could do a TII swap for that much".... Yeah, but then I wouldn't be able to see what a 12a can *really* do without going bridge, PP, super or turbo

And with a full atkins/camden 7" kit including carb going for $3,000... once I build the engine, I'll be able to super it if I want. The engine will have all the oil and cooling mods needed to support a super.


Jon
Old 07-05-07 | 07:54 PM
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I am planning to do a stock 20B swap into my 79 rx7. Any suggestions?
Old 07-05-07 | 08:06 PM
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^ read lots
Old 07-05-07 | 08:08 PM
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Originally Posted by Fule Designs
I am planning to do a stock 20B swap into my 79 rx7. Any suggestions?
Have a local tailor make your pockets deeper.

But seriously, There are a few people that have done this swap. It's not easy or cheap. I think a saw an Aussy with an NA 20b in his FB. Have you searched?

Good luck.
Old 07-05-07 | 08:21 PM
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20b swaps from what I've seen cost about 20g

so 20b = 20g

Be prepared!



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