Is it possible to swap a 4.444 rear end with the newer 4.777 rear end by just swapping the actual rear end or do you have to swap the gears? In other words, can you just swap an 09 rear end to an 04-08 without any complications or, was there an actual change when the 09 came out?

 

That is a damn good question. I don;t know if you are going to get a great answer though unfortunately. Your best bet is to do your best at examining an R3 for yourself and see if the frame has been altered, maybe talk to some techs and see if they can get you an answer. Other than that I say just go for it man, just take lots of pics and make a sick writeup

 

Yes, this one calculates out to reality.

 

The news is in. You CANNOT just swap the rear end. There is a change in the rear end and how it mounts to the frame according to a tech at a dealership. If you want to do a rear end change to get a shorter rear end as found in the 09+ rx8, you will have to actually swap out the gears themselves and not just be able to swap the rear end. From what I hear, this is a costly modification that will, through leverage, give the 8 about a 7.5% increase in horsepower. According to Mazdatrix's page, it is just over $700 dollars to get the gears themselves. Unless you can do all the work yourself, it is going to range close to $1000 dollars or more. I hope this information helps those who were thinking of doing this.

 

the actual part that mounts to the subframe bolts onto the top of the diff housing. I'm pretty sure it will just swap over, but maybe I failed again

maybe Paul @ Mazmart would know

that particular part does appear to have changed

 

what? i believe paul commented back when the 2009 was just released that the rear diff is a direct swap and he is selling them. $600 iirc.

i'd trust paul over a "tech at a dealership."

 

You could probably modify it to make it fit if the only problem is the mounting :P

thewird

 

Finally making your post count higher THE WIRD

 

lol, starting to make it a practice to check the rx8 club forums after I check the rx7club hehe. But I still don't have much to talk about so don't participate much. Maybe that will change as I tune more turbo RX-8's

thewird

 

The differential "box" is a direct swap and is much better than the chance we had a couple of years ago to install just the shorter ring and pinion from FEED\Fujita. Even swapping just the stock 09 ring and pinion is way easier than making fujita's kit fit well.
So just buy a differential and swap it!

 

All I can say is that the tech told me the 'bracket' changed for the newer model. Getting around this is not my expertise at all but, I am sure that someone on here can do it or make a 'universal' bracket or something of the sort to make the swap easier. I am not familiar with this and just wanted to find out as I have not heard anyone on here address this.

I have heard of the feed gear swap and heard that it is somewhat difficult and time consuming. There are some out there that offer a 5.12 differential as well. I am looking to possibly swap my rear end in the future and was looking into it now to see what all was available. thanks for any help and let others know what is the best way to do this as far as money and time is concerned. I have seen the 5.12 swap that would be at least a $1500 job or more. Thank you for the info.

 

The 5.12 gears are sold through Mazdaspeed Motorsports, it's just the R&P. The R&P itself is almost $1500, it will cost several more hundred to have it installed. Don't forget another $1000 for a decent LSD too.

yes, the bracket that mounts to the studs on top of the diff housing changed, but again should be interchangeable -drop your diff, unbolt the subframe mounting bracket, bolt it onto the new diff, install new diff in early model RX-8. Look at the subframe picture above and connect the circled letter Z's together.

 

I believe you. I just dont understand why the 4.777 is about 700 and the 5.12 is over 2x that. Is it due to demand/production costs? also, what is wrong with the stock LSD? I have heard mixed stories about the stock one. Over time, I would like to beef up the car and put better and lighter parts on it over time after the warranty is done on it. I am just getting a collection of information so that I can make a good decision on what all I want to get and still keep in reasonable in price as well. Thanks again Team, for your knowledge.

 

because the 4.77 is standard equipment on 09+ rx8s and the 5.12 is sold ONLY through mazdaspeed motorsports to racing teams.

 

The stock lsd is a pretty good unit if you track it and use the proper oil. There are better 1.5 way differentials for sure but if you don't have to win a prize or need it to hold the extra power... Dunno for autoX though because it is something we don't do\like here.
The 5.125 costed the same when there was just the feed final gear out in 4.777 for around 700$

 

thats because mazdaspeed motorsports prices its own products and doesnt really care what the aftermarket does.