Rx8 with older 13b engine+weber 48ida
 

I own a 2005 Rx8. It is currently Automatic, and not running properly.
The engine needs to be rebuilt or replaced.
I have a spare rebuilt 13b engine that is from an rx7 gsl-se, a brand new weber 48ida from racing beat, new fuel pump, new intake manifold, new clutch and all that just sitting here..
I have been searching the internet for more information on similar engine swaps, but can't seem to find what i need. I am curios to see if anyone here has seen this done before? If there is any big reason this cannot be done please let me know!
I want to use this older style 13b engine because i got it for free and can imagine it would be a pretty nice compliment to the modern rx8. I have had many problems with this rx8 since i bought it 3 months ago, and would love to try and simplify things under the hood, if i can. If it requires a lot of effort to get done, i hope to justify that expense with a nicer car once it's finished. I have a medium-sized helicopter maintenance facility at my disposal so hope to get this done properly with the help of some friends.
I am almost finished building a engine run/test stand so i can make sure i mount the engine properly and prepare it for a clean install. I might need to get a custom tail shaft made and figure out something special with the 5speed manual conversion.
I really want to be 100% sure i am going ahead with this before i pull the rx8 engine, so that will probably get done in the next week or so.
I am busy with work and a few other project cars being put together, and all of their build threads will be coming soon. This may be a little slow to get going but we'll see!
Thanks for reading. Feel free to ask questions and yeah any help is appreciated.
From Jozey.

Call Mazda and give them your VIN.... you might be able to get a free replacement motor due to them extending the warranty on the engines.

Thanks for the good idea, but i already tried. Mazda said they require a full service history for the engine to be covered under the warranty. The car also needs to have under 100,000 miles. My rx8 has had 7 previous owners and 180,000 miles. :icon_tdow but i do look forward to improving this car.

no point on swapping a older engine in.that is taking 2 many steps backwards and noboby with a little bit of rotary knowlage will do this regarding of any situation even if the older engine is free........rebuild the motor or look into swapping a cosmo or rew engine in.

I dont see why you would have any problem putting it in there... the problem would be passing smog if you have it in your area? Other than that, I dont see why not. I have seen it done on 3rd gen rx7's! I have even seen NA 12a's stuffed in 3rd gen rx7's. Not that difficult to do I wouldnt think. I have a 6 speed from an rx8 in my rx3.

Absolutely not a good idea, You will regret it down the line. I've owned many Mazda's and always installed later set-ups.

You don't want to be that guy known for downgrading your Mazda.

thanks for all your good advice
the more i think about it, it seems like my only choice to go with the old carb 13b, unless i wait about 6 months until i can afford the turbo engine.. I can't afford to spend $2500+ fixing this renesis 13b when the housings might be ruined already and it's just another risk. I'd rather sell the blown renesis 13b and auto trans for around $2500 if i can. I'm not going to ruin the car, the old school carby engine setup will probably be temporary until i can afford to swap it with a proper upgrade one day. This would just be to get the car running and maybe learn some stuff along the way. I'll give you guys an update on the work soon

dude call Mazda and get a remanufacture engine it will cost you about 2gs and put it on your self, Guy I know bought one for his auto rx8 and it working perfect , I would do that then save for a real engine with time, cuz we all know one you start the wrong way its alot more expensive to redo it the right way. I rebuild my RX8 engine well my buddy did and im loving it , No problem what so ever but I spend the money doiing it right and im very happy, I could of easly bought a 13brew but Im sure I wouldnt be driving the car for almost another year lol

with the Rx8 the hard part is getting the electronics to work, the ECU runs a lot of stuff in the car.

a reman Rx8 engine is about $2k, its probably the best option

^ yep what he said