1991 fc3s rx7 turbo II 3.7l v6 twin-turbo swap
 

hey guys i´m sorry it´s not a v8
, so i have a 1991 turbo II with a POS engine and no mechanics who can repair it , i live in Portugal and it´s not exactly a rotary friendly place so unfortunately i have to swap the engine for something else and i´m planning a swap with a 3.7l v6 from other mazda models but actually a cyclone (FORD) engine , i want to stay with mazda engines , kinda, and this looks like a good choice. I have seen other swap´s in this forum including the 3.7l v6 , but i´m planning on doing it with the stock gearbox and rear end to keep it as close to original as possible and not have problems with shifter placement and i do like the way that gearbox feels when driving, the car only has 110,000 kilometers, that´s 68.000 miles and the gearbox looks perfect , as for the setup i already have a intercooler kit, i´m using twin garret´s gt 28´s and a haltech ecu , the wheels are momo racing 17" 245 in the back and 225 in front, if anybody has advice for me i would be thankful,

I am not an expert (or even close to knowledgable) but I believe the rotary gear box is unique. Due to the location of the eccentric shaft location relative to crankshaft. Maybe i am wrong but I would research this before you go all in.

I hope you post your build here. Always like to see unique stuff. People at Grassroots Motorsports Magazine forum are pretty knowledgable. Seems like someone there has tried anything you can think of. You can also check there for answers (and other ideas).

Hey Cristiano, have you checked out norotors.com? I know people have adapted FC gearboxes to other engines with little trouble. That motor seems like a decent candidate as long as it can handle the boost. Do you have the actual motor yet?

I tried to warn you I knew very little about the subject. Lol. Ha ha. Thanks for correcting me Freeskier.

the gearbox is not unique, with an adapter plate and the correct flywheel and clutch it will be fine as for the engine on stock internals my research has shown numbers from 400 whp to 450 whp in a reliable way

the gearbox can be found in the mazda b series pick-up and ford rangers and some other models that i don't remember now, and to fit the engine in the fc3s models they actually made a bigger trans tunnel instead of making a specific gearbox

i´ll need an adapter plate or a new bell housing, but in theory an adapter plate is easier.
i have checked norotors and there aren't builds with the stock box but here there´s someone doing a swap with the 3.7l with an automatic out of the mustang, mach80 and 30mpg are the guys doing the same or similar build , check out non v8 conversions https://www.rx7club.com/other-engine...v6-fc-1080545/

Last time I looked into it, while the gearboxes on the mazda pickups are very similar, they are not interchangeable except that they have the same bolt pattern and some parts are the same. Also, while the TII trans gear ratio's aren't ideal the pickup ratio's are absolutely horrible for a car. Well, you could always go for a 2.00 rear or something... The point being they're not good.

Regardless, yes, an adapter plate is MUCH easier assuming you have access to a good mill with a large enough bed to make it. Keep in mind that you'll also need to adapt the flywheel too; this required a good mill and lathe.

I recently had a person ask for my drawings related to my trans adapter pieces. I'll make a post about this tomorrow.

the ratio´s for the pickup´s are different, the rear end is a 4.10 in the turbo 2 but the gearbox ratios gives the car a really good top speed so i believe that it will be a good final result, since i don´t really care about tops speed but i´m more interested in a better acceleration overall

most of the work necessary for this build won´t be done by me since i don´t have the necessary tools and knowledge to do it ,so it will get expensive

https://www.rx7club.com/build-thread...1085623/page2/

Post #29 should have pertinent information. However, it's not a "how-to" and it isn't meant to be.

i'm surprised that there are so many swap kits on the net , and v8 would look amazing but i really want mazda engine , and the 3.7l v6 with 300 stock hp seems great , i have no need for more than 400, 450 whp so a v8 that gets super expensive to swap and almost as bad mpg as the rotary , but at this point ,before starting the build, i´m open to any possibilities and the swap kits available are a good option to consider, but to my surprise there aren't any swaps for mazda engines considering that they have good engines and that they are working with ford on those engines why not use one