Hiya,

Wondering if anyone knows where to get the 4.77 ring and pinion gear in NorthAm. The only places I see them now is via FEED, RE-Am, etc... Seems the 4.33 is widely accessible here (I'm running that now) but the other set is rare.

TIA.

 

www.pettitracing.com has a 4.88 gear set

 

Damn, I could have sworn chris and ari over at www.rx7.com had it available, but it's not listed on their webpage. I recommend giving them a call, I'll bet they can get it for you

 

Rotary Performance used to have them on their site, but it's been a long time since I've seen them on it.

 

Thx...I heard RX7.com isn't selling the 4.77 anymore...I'll send Cameron an email to see if they still have them.

 

Hey Hedge...if you don't have any success getting it from the locals in the US, drop me a PM, and I'll get ya one from J-land

~Ramy

 

Perhaps Mazdaspeed Motorsports is confused, but I just spoke to them and they said the RX8 5spds in late models had the 4.77 and its interchangeable wit the FD. They said part number was RS08-27110.

Is this correct???

 

It sounds right. Excerpt from

http://www.autotrader.co.nz/View/Art...RX-8/2422.aspx

"...Mazda has lowered the final drive ratio to 4.77:1 which gives the RX-8 better bite off the line and out of second gear corners..."

Should be good news for SSM candidates budget...

- Sandro

 

This is correct, the part number is RS08-27-110 for the 4:77 out of a 2009. Price will be over $600 from a dealer, but as people start to total them we should start seeing them on ebay

Dan

 

Thanks autox gurus.

One more question... Dave at KDR said the 4.77 diff cannot take constant launch abuse (Drag / ProSolo) and that it is weaker than the 4.33. Dave said it is essentially a truck ring and pinion. If that is true, I am considering cryo treatment and shotpeening. Any thoughts on long term durability for ProSolo launchs? Dan?

BTW: Congrats on the SSM championship Dan!

 

Just saw a 4.77 set for sale in the 3rd gen classifieds might wanna check it out. heres the link
https://www.rx7club.com/3rd-generation-rx-7-1993-2002-parts-99/ca-down-pipe-flywheel-bmc-fuel-pump-misc-fd-parts-%245-%24750-864442/

 

I just checked on the Mazdaspeed website.

GEAR SET,FINAL
Part No: RS08-27-110
The regular price is $961.89
The sale price is $577.02

- Sandro

 

Dial 8 had a Garage Kagotani 4.77 available a couple months back.

 

Thanks for the heads up.

 

SSSsssshhhhh! You might put all the vendors out of business and people might actually start racing their FD's if they know about the support Mazdaspeed offers to active competitors.

 

Can't speak to the longer term survivability but Andy and I run one and Erik use to until he split the pumpkin on the diff and decided to give the 4.33 a try rather then source another 4.77 in short notice.

I actually think that the RX8 pinion might be stronger if they were made to spec for an RX8 differential. The after market ones that have been available up to this point required a spacer to be pressed onto the pinion because the shaft diameter is smaller than the bearing. This means the pinion shaft is thinner than it should be and could allow for flex under high torque. Not sure what power level you have to hit for it to be a problem as I don't think any of us (Andy, Erik and me) have hit it yet, but the potential is there.

I blew a rear-end in my Corvette because of something very similar, the people who built the diff before I bought it used a Dana 44 pinion with a spacer pressed on for the bearing to fit rather than a Dana 44 HD pinion.

Dan

 

Thanks Dan. I will try it straight out of the box. Hopefully it survives.

 

Please do tell if this works. Is everyone else going by what they have heard or are other using the RX-8 as a direct replacement on their own cars? I would love to report this back to the boys in J-land and save them from buying the expensive units there.

 

So, are we talking about switching out the entire differential here? Or are we speaking for just the ring and pinion?

 

Ring and Pinion, but if I am not mistaken an RX8 rear diff should work in an FD no problem.

 

I know the FD is a torsen type diff, what is the rx8's?

 

wow this thread is 4 years old lol

 

"Torque-sensing conical limited-slip differential" aka Torsen on manual transmission 2009/2010 model according to mazdausa.com

 

Yes it is, but props to the s1mpsons for searching and continuing a thread on topic with new information opposed to starting a new one and filling the forum with a bunch of threads that makes it impossible to search.

I'm fairly certain I will be doing some rear end work this winter and may end up pulling the trigger on one of these. I think it'd be pretty good for the road course as well.

 

My thoughts as well.

Which one are you referring to?

I have a 4.44 RX-8 diff ready to be installed in my FD.

I'm still having trouble deciding between that or going with a 4.77.

The 4.77 would be better for autox, but I also like to do track days, and the 4.77 might be a little too much for track days.

Anyone here used 4.77 on the track in an FD?