brat13bmpt

Hi guys, trying to find out what would be the best diff to put in my s3 Rx7. Car has a rx7 s5 13bt monsta street port (around 350hp), rx7 s5 turbo 5speed box, 3" tailshaft and rx7 s3 diff with welded centre. Diff is starting to clunk really badly around corners and would like to replace or possibly recondition my LSD. Not sure what to do, just thought i'd put it out there and see what my best option is. Anyone know of any bolt-in centres for rx7 s3 diff? If so, where can i find them? Thanks all!

thunkrd

iTrader: (1)

you could buy the kaaz 1.5 way (clutch type). some stores state that it's for a miata (MX-5). but that should be the one.

The other thing you can do is to get a completely different rear end.

Rotor_king

iTrader: (2)

Yeah alot of guys run ford rear ends once getting above the 300hp mark. Check these guys out http://www.grannysspeedshop.com/

brat13bmpt

Thanks for replying. I found a brand new kaaz diff on ebay for $1,200 Australian dollors, in my local area. Alittle rich for me at the moment, just after something to get me by for now. Can i put a Mx5 Lsd centre into my s3 diff? And if so what modle mx5 can i find it in? Or if anyone knows of any easy to come by diff centres for Rx7 s3 85, please tune in. Thanks again.

NoPis10

iTrader: (29)

I am currently using my stock GSL-SE rear with Racing Beat 4.44 gear set.
My Turbo FB is making 383HP to the wheels and so far so good. I just try to keep from lauching excessively hard and it has held up. If/when it fails I will probably switch to a Ford 8.8 rear.

L8R

WAS:12A

iTrader: (4)

I have a 85 S3 with 13BT as well.

I'm running a ford 9 inch LSD diff with 31 spline billet axles and a 4:3 ratio...not a cheap conversion, but well worth the peace of mind.

Works a treat! I shouldn't have any drama's in the future and can spin the rears knowing i'm not going to break it....which is nice.

Cam...

Dan_s_young

iTrader: (1)

I'm running the Grannysspeedshop setup, 8.8" torque arm setup, 4.3 gears, fully adjustable watts linkage setup, adjustable rear spring perches, wilwood 11" disc brake kit in the rear (Don't need C-clip eliminators). Think the whole setup ended up costing something like $3500 with brakes, not cheap but pretty bullet proof setup.

brat13bmpt

Nice setup dan, looks tuff as. I'd love to run this setup in my 7, but for $6k Au$$ie, I dont think i will do it this way. Wonder if anyone builds a similar kind of setup here in Australia??? Would this kind of setup be practical for everyday driving or more suitable for the drag strip? Thanks all for the replies, been very helpful :-)

WAS:12A

iTrader: (4)

Try looking on Ausrotary.com as i'm sure you will be able to find someone selling their already set up diff conversion.

Just keep checking the for sale sections and you should find someone parting out a S3 eventually.

Cam...

brat13bmpt

Hi cam, thanks for the info mate. Hey where did u get ur setup or did u build it? If u built it urself can u give details as to how u went about it. What kind of $$$. Thanks again mate.

dyoungre

Not positive, but if the Kaaz would work, then wouldn't a Miata Torsen work as well with the '85 S3 axle shafts? I know we can find them (at times) here in the states for about $400 US.

thunkrd

iTrader: (1)

should work.

Jimbo II

try a toyota hilux diff. They're lighter than ford 9' and can handle a whole lotta power. You just gotta get em shortend and change the mounts on them, and maybe raise your floor pan a bit around the head to avoid banging noises. Plus they shouldn't be too dear

brat13bmpt

Been doing abit of research and found that mx5 (94+) Lsd centre in a straight bolt-in iteam for s3 rx7 only. It takes the 26 spline axles and you dont have to cut or extend axles to fit. Only thing is i dont trust the strength of it, judging by the power out put of the Mx5. Please correct me if im wrong, this just stuff that i've read of the net. :-)

brat13bmpt

Hi Jimbo, i've always heard alot of talk about hilux diffs in 7s, and have only ever seen them in s1-s2 Rx7s. Can this conversion be done on a s3 Rx7 or only for s1-s2, will it effect the s3 stud pattern. Im not sure of the hilux year model or type, if its the 4wd or 2wd and what gear ratio's. Also what spline are they?

thunkrd

iTrader: (1)

hey all i've got a question. what is the weakest link in the rx7 rear end?

Jimbo II

Can be done to any first gen sev. Just get some hub adaptors made up for your wheels, or run series 4-5 rear brakes mounted to a hilux diff. It'll have to be shortened for any of the sev models. You can get 4.1?, and 4.5, 4.8 ratio LSD diff heads for them. Unsure what spline size they are though

brat13bmpt

Hi Jimbo, im abit unsure of what to look for when it comes to hilux diffs. Would u know what year model hilux diff are best to use s3. I found a complete front diff out of a 1994 hilux 4x4, priced at $250, could i use this or would the rear diff be better?