Looking for a really low gear ratio. Something along the lines of 4.44 or 4.88 or something like that.



Anyone know where to buy such a setup? I looked at the typical Mazdaspeed Racing beat sites but nothing. I know they exist just have to find out who sells them.

Jims... i remember mention of someone custom building R&Ps on the www.scuderiaciriani.com website, but i can't remember the company that was doing it. You might wanna nose around on there and see what you find.

I believe Rotary Performance were the ones that commented on that list that they could get 4.77 gears. They list 4.30s on their site.





I just bought a set of 4.77:1 gears in mint condition off the other forum. Came with a wrecked stock diff. https://www.nopistons.com/forums/pub...1047683329.gif

I'll check w/ Rocky and see.

Well after doing some research and talking to a friend I am gonna go with the 4.30's for now and see how they are. I have to remember that I run a 22" tall slick when I race which already reduces my final drive drastically.



I hope to order the gear set tomarrow.

What's the stock one in your car?

4.10's I had read that the 4.70 is a drastic change. The recomendation seems to be to try the 4.30's first.



Keep in mind stock wheel height is 24+" so when I run a 22" slick I have already altered the final drive.

I grabbed the 4.77s because I'll be using 26" tall tires at the strip and the periport just won't have the torque through the midrange of a turbo car..............

As I understand it. You can buy the 4.77's from Mazdaspeed. They are made for FB's and need to be modified, actually they need to have a lot of work done, to fit an FC rear. They are intended for 100HP cars and a 180HP IT car will be taxing it. A 460HP BP Autocross car like mine will probably destroy it like it was a bad joke.



Am I understanding this correctly??



If it is indeed a FB rear made to fit an FC I think I will go with the 4.30's and see how they feel, at least they will hold together.



TYSON - have you raced on you're 4.77's yet? What kind of RWHP do you run? How does it seem to hold up.

I think these are made for the FC/FD. I just got them last week, they're still bolted to the wrecked stock FD diff they came with.



Those 4.88s and 5.12s you see are for the smaller older diffs, I believe Mike posted he could get those from Hyundai for $250 or so.



I jumped on the deal when I happened to be browsing the for sale section and saw them posted. I'll be testing them out for the first time sometime in April. Not sure if I'll do a before and after though, I might put them in while I'm doing everything else. https://www.nopistons.com/forums/pub...IR#>/smile.png

I can get this, and have JR make it fit. I posted on RX7Club too as it seems to have more hardcore racers than here. The feeling I got from one member is that it will work. Its sort of a "must have" mod if youre gonna autocross.



I amgoing to order this gear set and give it a whirl. My street driving days are coming to an end.... or I am going to have to learn how to swap out gears and learn how to do it with ease.





http://www.mazdamotorsports.com/wcsc...12-27-110A.JPG

Jim, You will be essentially running a NA rear now. I have been modding my to handle the output of the PP and I have a few tricks up my sleeve that JR may not know about https://www.nopistons.com/forums/pub...IR#>/smile.png

Cruising at 3600 RPM might mean you avoid that annoying drone at 3000 RPM! https://www.nopistons.com/forums/pub...#>/biggrin.png



The 4.77 have a spacer between the diff and the ring gear, and a kind of collar that fits over the bearing race next to the gear on the pinion shaft.



I don't have a stock one in front of me to compare, but I'm thinking the only way it's stronger is right at that bearing race next to the pinion gear, as it would be about 4mm larger diameter, and the radial load at this location is higher due to a smaller diameter pinion gear on the 4.77 gear set. The ring gear is still 8" outside diameter with 43 teeth.



I would SUSPECT the 4.3 set uses this ring gear with a 10 tooth pinion, and the 3.9 set uses it with an 11 tooth pinion. This would likely explain the spacer behind the ring gear on the 4.77 set, as it's needed to engage the smaller 9 tooth pinion used for this ratio. But this is a bit of an educated guess until I take apart the stock one.https://www.nopistons.com/forums/pub...IR#>/smile.png

there are 3 different mazda diffs.



the 6" ring gear diff, its really only used in the 323gtx and 90-93 miata, T type



the 7" ring gear diffs, these are used in almost everything non turbo, r100, the trucks, all the NON turbo rx7's, this rear has all the cool gear sets, also the kia sportage uses these diffs and come with a $300* 4.77 gear set. the b2600 trucks have a 4.44, miata is 4.3 some years, fb's are 3.9 or 4.1, etc etc. this is the M type diff



the 8" ring gear diff, or P type, is found in the rwd turbo or v6 cars. turbo fc, fd, mpv, etc. the complication here is that the fc has the long pinion gear so nothing else fits without some pretty technical cutting and rewelding of the pinion. this is where the fc sucks the most as the only 3 ratios offered for it seem to be 3.9,4.1 and 4.3.





*we dont have kia anymore, so the price is gonna be higher

So the FD doesn't use the longer pinion?

nope, the fc uses the wierd one. we looked at putting a short pinion diff in the fc, you'd have to come up with a front mount for it but it fits

so which ones are compatible with fd's and fc's? just the type p?

the fd is a p type, like the rx8 which has 4.44



the fc's are compatible with only themselves, unless you can cut and lengthen the pinion gear. the na fc uses the m type diff, and the turbo fc uses the p type diff

Don't forget the odd 7.5" diff, which looks like a 7" until you try to swap the gearsets.

[quote name='Jims5543' date='Mar 13 2005, 07:59 AM']I can get this, and have JR make it fit. I posted on RX7Club too as it seems to have more hardcore racers than here. The feeling I got from one member is that it will work. Its sort of a "must have" mod if youre gonna autocross.



I amgoing to order this gear set and give it a whirl. My street driving days are coming to an end.... or I am going to have to learn how to swap out gears and learn how to do it with ease.

http://www.mazdamotorsports.com/wcsc...12-27-110A.JPG


[/quote]



From what I understand the NA rear has a smaller diameter ring gear, 7" I believe. The turbo ones are 8" rings so it won't just bolt onto your car. You would have to run a NA differential with that ring/pinion setup your posted.

[quote name='j9fd3s' date='Mar 13 2005, 09:52 AM']the fd is a p type, like the rx8 which has 4.44



the fc's are compatible with only themselves, unless you can cut and lengthen the pinion gear. the na fc uses the m type diff, and the turbo fc uses the p type diff


[/quote]





Hmm...I was looking into running a 4.10 or 4.30 ratio in my RX8 when it get's turbo'd(sometime in the future, like when it's paid off). I'd like a lower RPM while cruising and the better mpg it gets, but then again the project can go whole different direction and be a track/autocross/drift car.....hmm....4.77's?

There is a 4.77 gear made for the TII diff, by some company in japan, and from what I hear theyre next to impossible to get in the states.



Ever thought about swapping to a ford 8.8" IRS rear end out of a mustang cobra?

They are cheaper and easier to find from a 90's Thunderbird. If I remember right, the supercharged models with traction control even had 3.73 gearing. On one hand, they are iron as opposed to aluminum. But on the other hand, they are IRON instead of ALUMINUM. I'd take the iron case any day.



You want to be careful, though. Only V8 and supercharged models had the 8.8 rear. The base V6 models had the 7.5. (Different from the Mazda 7.5)

[quote name='heretic' date='Mar 14 2005, 08:06 PM']They are cheaper and easier to find from a 90's Thunderbird. If I remember right, the supercharged models with traction control even had 3.73 gearing. On one hand, they are iron as opposed to aluminum. But on the other hand, they are IRON instead of ALUMINUM. I'd take the iron case any day.



You want to be careful, though. Only V8 and supercharged models had the 8.8 rear. The base V6 models had the 7.5. (Different from the Mazda 7.5)


[/quote]





Hmmmm..... very very interesting. Well the engine was swapped in may as well keep with the frankenstien theme.





I have been considering a custom CF driveshaft this would make for a perfect excuse to do it.

so i guess out of all the available ring and pinions.... the 4.44 would tbe the cheapst and readily available since its for an exsisting car that breaks drivetrain parts a lot

And you will break it a lot martin...

so rx8 would be the cheapest and most available to get?

[quote name='FikseRxSeven' date='Mar 31 2005, 05:52 PM']so rx8 would be the cheapest and most available to get?


[/quote]



yeah, it'll be here on tuesday

[quote name='j9fd3s' date='Apr 3 2005, 06:39 PM']yeah, it'll be here on tuesday


[/quote]





How much $$$?

nearly $700, i guess they dont want to sell those.....

[quote name='j9fd3s' date='Mar 13 2005, 11:11 AM']

the 7" ring gear diffs, these are used in almost everything non turbo, r100, the trucks, all the NON turbo rx7's, this rear has all the cool gear sets, also the kia sportage uses these diffs and come with a $300* 4.77 gear set. the b2600 trucks have a 4.44, miata is 4.3 some years, fb's are 3.9 or 4.1, etc etc. this is the M type diff




[/quote]

Does the kia sportage or the b2600 ring and pinion fit into the N/A FC diff without modification?

[quote name='RONIN FC' date='Apr 12 2005, 06:03 PM']Does the kia sportage or the b2600 ring and pinion fit into the N/A FC diff without modification?


[/quote]



no fc has an extra super duper long pinion, and is unique to itself

Damn, those 4.77s sounded good! Would relieve some stress off the N/A gearbox too.

Woot, old thread revival!









What ring and pinion would a 1998 B2500 use?

there are 2 different ones for those trucks. a 7.5" ford and the 8.8. they dont list what comes with what



i list 3.08, 3.27, 3.55, 3.73, and 4.1 for the 8.8 diffs, still in the $450 range though

Too bad you can buy them from Randy's Ring & Pinion for probably $99-150 or so.

hey dont burst my bubble! i was all excited we could even buy something potentially cool! most of the cool stuff they dont want to sell you

I buddy of mine has a 5.10 on his fc. That thing can redline 5th with out thinking about it. He raced with it and it held up fine. He would have sold it to me but I took the 4.33 instead for gas economy and daily driving comforts.