Need Diff Advice

Right I've got a bit of an interesting one, I'm building a compition 4wd and need to modify the rear axle to strengthen it

The rules limit me to internal modifications only (can't change the outside of the housing) this limits me to 6.5" or 7" diff head this is where I need some sugestions I'm a bit out of the jap racer scene and I'm after sugestions on what to look at

What I'm looking at doing is machining a new 4 spider diff head into the housing I've got and resplining hilux axles to fit inside

Cheers Reece
De Ranged Engineering

a competition 4wd 200sx? interesting. (im assuming 200sx since you talk like your from the u.k.)

sounds like you have a plan already. but isnt the rear diff on those an R200? thats a 200mm (7.87") differential. its already good enough for quite a bit of power, and there are several off the shelf options for higher performance. depending on what kind of diff you want, nismo, kaaz, quaife, and several more companies make reliable LSDs. im not sure yet why you think you need to strengthen anything, but call the driveshaft shop and you can order custom axles and driveshaft, plus do some transmission work or whatever and you should be fine, i would think, for some big power.

:lol: a pom, na mate from New Zealand

the trails truck its going into is a lada :rolleyes:, I've dropped a CA18de into it along with the auto trans... I've gone with this as they are cheap as chips, so costs bugger all when I kill it from over boost, the NOS or seize it after a roll over its a cheap swop and away again
I'm fitting a SC12 supercharger off a toyota levin, and possibly NOS if I can build up some stonger axles
The class I'm racing dosn't allow LSD's I've got to run open diffs hense the 4 spider oh and to make it more interesting I'm only allowed to modify the inside bits of the axles not allowed to change the housings, otherwise I'd just cut the current 6" lada diff out and fit a 8" Hilux one
As for the work :smokin: I'll be doing it all myself ... I run a small 4WD custom shop

At the moment what I'm looking at is finding a small 4 spider carrier and fitting it into the Lada diff head housing.... the other option is if the heads are similar modify the new one to look like the lada one .... either way works with the rules

Cheers Reece
De Ranged Engineering

sorry bout the assumptions, i guess i am just an ignorant 'murrican. anyways, the 94+ mazda miata has a 7" ring gear, you might try that, it also came in 2nd generation rx-7s. also im sure you know the early s13 models with the ca18 had a 7" rear end (the r180). the ae86 levin/corolla had a 6.7" rear end. that gives you some options, but it seems like rules prohibit anything that might already be proven strong, so i guess i would just take whatever 7" rear diff that would fit and has strong axles stock, and try to reinforce it as much as possible. im sure cryotreating will go a long way, if they allow it.

Yes the class rules do ham string things a bit :sunglasse but I just see it as a challange.... part of the reason I chose to do up a Lada :lol:

The rules do allow me to do what ever I want internally, hense my request for info... the S13 might be the best option for availiblity, rx anything is pretty hard to find over here (have been forced into paying almost a weeks wages for a headlight suround on my RX3:shakehead ) have never heard of the Miata, probably a model we don't get
the S13 had a slippery option (from memory) if it is, then theres a good chance it will be 4 spider.. remove the clutch packs and replace them with spacers and I have a 4 spider open :iceslolan
Oh and if I can sort this yes I will cryo it... more than likely I'll cryo a set of brand new gears.... just to give the diff the best chance of surviving :lol:

thanks for the tips, your advice is the best so far

I'll keep ya posted, might even throw up some pics

Cheers Reece
De Ranged Engineering

nice oh and a miata, called a eunos roadster or mx-5 in most other countries, is this http://images.automotive.com/reviews/images/96miata.jpg http://www.autobytel.com/images/carPics/TestDrv/Lyons/400/04_Mazdaspd_Miata_ft1.jpg

Doesnt that guy driving the miata look g--, to keep it PC, not manly.

I know, I know, miatas look "not manly" and get a bad rap for looking like a hairdressers car but a car from the mx5 cup would pretty much roll on just about everyones 240.

i would already have a miata if i could fit in the damn thing. i can barely fit in the newest one. and yeah the dude in the blue miata looks gay. i mean cmon he has highlights and his glasses lenses are the size of quarters. i cant imagine him going home and putting on anything but a sweater vest over a denim button down shirt. and a fanny pack.

I really dont have any I dea what might be available to you that you guys havent covered, I would have to agree with using the best one that will fit and freezing, maybe shot peening it.

Thanks for the sugestions, I had a look at several of them and I just kept coming back to the fact that no matter what I did I wasn't gona be able to make it reliable enough to warrent all the machining... that and I had a set of axles out of a Hilux sitting there :lol: so I've jumped up a class, I'm just about to hack out the IFS, the back is done just stripped the mounts from the lada axle and made em fit the bigger hilux one, now all I need to do is build a brace around the back of the crown to tie the carrier bearings :shakehead I know these are sposed to be good for 400hp, but when your lifting and spining up a wheel or launching, the 250hp + 33" mud tires at 6lb will lunch them :lol:

if your interested heres the build thread
http://www.offroadexpress.co.nz/viewtopic.php?f=18&t=9575

thanks for the help

Cheers Reece