I own a boosted and built S2000 and I am having some concerns about the strength of my differential. I am now on my second stock differential.

It is known that the S2000 has a Mazda differential, and I am curious about the possibility of using an RX7 differential in the S2000.

I am pushing just over 400 rwhp before tuning (dyno tested) and I expect around 430 rwhp on pump gas when I am done.

First, how strong is the RX7 rear end? How much power will it support when launching? How much abuse can it take before replacment is needed? (I have a friend who claims 485 rwhp and that he is able to launch with out a problem?? Does this sound right?)

Does anyone have any thoughts about the potential of doing a rear end swap?

Thanks!

Chris

 

The stock rear end really isn't to strong and doesn't hold up to well to sustained abuse. We do break rear ends often around the 375-400 rwhp IMP. There is an option you can do. There is an upgraded diff. called a KAAZ diff. Search for it, you will find it. I believe this is the rear end you are looking for if indeed a Mazda diff. will fit.

 

Kaaz all the way, I have a 1.5 way lsd on my s13 (s15 conversion, jdm tail lights, gp sports kit.) and it kicks ***

If its strictly racing, go 2 way. If its for street racing, go 1.5. Response and control is amazing with the kaaz lsd. I drive the 240 occasionaly as the oil in the diff is supposed to be changed every 3000 miles.

Im pretty sure alot of highly modded domestic cars run Kaaz diff's as well.

-s

 

I actually have a Kaaz differential in my garage but I am not very convinced that it will hold up to 500+ rwhp. Is this the same differential that you guys love so much?? I wonder....

Is the Kaaz differential the most common upgrade for RX7 rear ends? How much power is it good for?

Thanks

Chris

 

Kaaz should hold your 500+rwhp as long as your axles will. There are other upgrades for FD owners when their diffs break or just want a stronger one. Like a TII diff. or even upgraded ones from Re Amemiya etc besides Kaaz..

 

Not sure on how much power it can hold but my s13 had the sr20 in it running 1.5 bars of boost and it held up fine. Just spoke to my friend who has a 94 cobra hes putting out 660 hp to the wheel and he has a kaaz lsd as well.

I payed 970 for my diff about a year ago, dont know if the pirces have changed much. I think they are about 700 though cuzz 970 included the half shafts I needed when installing it.

 

does anyone know the warranty on the kaaz unit. just cant see spending that kind of money anytime soon for something that isnt warrantied. i know for my honda world they have quaife, which is by far the best LSD imho. just too bad they didnt make one for the seven. maybe they make one for the S2000 and we can swap it in our cars since we can swap ours in yours. i know of one crx track guy(scca/nasa track events) that has broken the quaife and it was replaced without any questions asked. i kinda like that kind of warranty. they are lifetime. so what is kaaz people?
kris

 

Not meaning to get off topic but can you post some pics of your car cjb80? outside and some engine pics too if possible.
Thanks

 

I think KAAZ has a 1 year warranty. Quaife is the best lsd for a fwd Honda, not sure if they make it for the s2k yet or will, anyways I've seen plenty of those break but they were all over 600hp.

 

Info on my car can be found at http://www.chrisdrivesafastcar.com

Quaife doesn't make a diff for the S2000 at this point unfortunatly. I guess my next question at this point is, are all Kaaz differentials created equal?

For example, would it make sense to put in a RX7 rear end and then upgrade that to a Kaaz rear end? (I know it's starting to sound silly! I have no confidence in the S2000 rear end)

The housing of the differential it's self is made of an aluminium cast I believe which seems pretty weak. The mountins of the differential are weak....

Chris

 

That is one nice looking car. Probably my favorite new car on the market.

 

cusco also makes an upgraded unit

 

Sorry to bring this thread back from the dead.. does anyone have any thoughts on using a Supra rear end? How much power are they capable of holding?

Thanks!

Chris

 

Hell man, quit screwing around and use a Dana-44 with a spool and be done with it. Are you just concerend with the rearend taking a dive from street use, or are you slick-launching the car at the track? How much abuse is it going to be taking?

 

What the hell is a Dana-44 with a spool? Where can I get info on that?

I want to be able to launch it, but I don't abuse the car much.. the stock differential is holding up now but I am planning on switching to a larger turbo soon which would increase power to well in to the 500's..

Chris

 

Have you looked into a NSX rear-end? Maybe you'd have better compatability with another Honda diff.

 

The S2000 diff is a Mazda piece, which is why I am here

Chris

 

Ever heard of a Ford 9" or 12 bolt?

 

Ford 9" is what my engine builder went with on his drag CRX, however I would rather keep the stock S2000 suspension setup (not linked suspension.)

Oh well, I guess this post is out of the scope of this forum now..

Thanks for your help guys

Chris

 

I know jimlab is using a Cobra 8.8" diff in his V8 RX-7....should be good enough for his 700 bhp...

If the rear suspension of the S2000 is that close to the RX-7...I'm sure you could get the Cobra IRS to work...maybe worth some investigation

 

is the RX-7 Turbo II differential stronger than the 3rd gen diff? If so, can the tII diff plug right into an FD? I need something that can handle 500-600hp. The boost is gonna have to stay really low until I can afford to upgrade the rear end.

what would you guys replace first, the axles or the diff.?

Thanks, Rob