Respect to all members of the group!
I have a lot of questions. First I have to explain what kind of situation I am in. I have a 1990 Mazda RX7 Turbo, it hasn't moved in 20 years, the engine from that car is destroyed, there is no saving it, I have the opportunity to buy a Mazda RX8 engine complete with installation, is it a big procedure to do that, should I get into that story or I don't know what to do, what are all the things I have to do to put that engine in a Mazda RX7?
What would you do? I know that it is best to buy an original engine for 10/15k, but not all of us have that opportunity to enjoy our dreams, that engine, I think, everything under the hood of the RX8 cost me 700€...

 

I don't think an rx8 swap is either easy or worthwhile to swap into an FC. it's not to say that it cannot be done, but you would be better off trying to source an S5 turbo engine.

When you say there is "no saving it", what do you mean? Are there useable parts? if it's only a few components that need replacing, that can be done cheaper than trying to buy a whole complete engine.

 

Well, in 2004, the engine was stuck and my grandfather took it out, so I decided to revive the car, but the engine was thrown away or he doesn't know where it is. I know that it's best to find an original engine. I saw that the engine mounts are not the same, you have to weld something on, a little modification is needed, the gearbox is the same, I think they are the same, the only difference is in the cylinder, the basket and the lamellas fit, what's making me lose my will is that the ignition, the gas pedal, has to be installed, new wires and the fuel pump, I imagined it like the buttons on an airplane, to be there and to start with the button... I don't know, chaos 😅

 

It's a lot of work. The only similarity, really, is that they're both rotary engines. Beyond that, as you pointed out, there are so many things you have to custom make.

I'm not sure where MNE is, but do you have access to japanese imported engines? Those can sometimes be a better bet for something that's used, with relatively few KMs and will have everything you need.

 

Could I find a diagram or electrical diagram of the gas pedal so I can pull the cables and fuel pump? Where can I find where they come from, where they come from and where they end? I could do it all myself if I had that. The only thing I would need is an electrician to remove it so I can start the car later?

 

From the sound of your knowledge base swapping in an RX8 Renesis engine is not a good idea. Almost nothing is the same and requires large amounts of fabrication and an aftermarket ECU to even begin to consider this swap. As GitKyle said you should just find a series five T2 engine (Japanese Domestic Market, JDM, or other). You will be far better off, money ahead, and happier in the end. Looking at current prices here for a complete JDM S5 turbo 2 swap with ECU, wiring, transmission, etc. what I am seeing is between 6500 to 7500 dollars. While it is considerably more than they used to be it is likely still going to be cheaper than what you will ultimately have into the swap when done and it will produce less power than the RX8 engine. The amount of work to accomplish what you are considering can get completely overwhelming. First-hand experience talking. If you are truly determined to do this you will need to source a complete running RX8 and swap over everything engine, transmission, wiring harness, computer, (If you don't go aftermarket) exhaust, instruments, fuel pump and lines, etc. pretty much everything and you will still be getting check engine codes popping up constantly. Getting the stock ECU to run without the properly chipped key is another nightmare work around. If you were to get a donor car good enough to do this just drive the RX8. Just my advice to save you a lot of heartaches.