Outer Limits 4x4 Board

Just putting this out there for comment/criticisim.

IF you were going to build an IFS 4WD race truck......
What center/CV's/hubs would you use and why.

My thoughts atm are 9" with probably a currie housing, 30 series CV's and custom spindles with Unit hubs like the Spidertrax ones.
Another option would be use bits of IFS hilux and cruiser and build up my own center in a custom housing, and maybe cryo'd T100 CV's

what sort of races are you talking about for a start
and how big of a vehicle are you talking about
and as for diffs a late model pajero rear diff would be a good diff to start with (they are IRS) and strong enough

Offroad racing, ie Cross country ralleys and maybe winch challenges.

300+hp and 35"-37" tyres

corperate 14 bolt with vz commo cvs

Can the Pajero rear (iRs) and corperate 14 bolt be flipped for the front ( iFs)?

why not a supra diff ithe put them in surfs and shit i think i seen a write up on the
surf forum

Problem with all the above diffs, is the gear set would be running on the coast side of the gears.

I think it really comes down to how much you want to spend vs. how often you want to spend on repairs, spares, sitting under your junk in the pits while everybody else continues racing.

I'll be going Hi-9 or mega Hi-9, in either a spider or diamond housing - but that's a "to hell with the cost" attitude because i'm sick of faffing about with jap shit.

I don't know much about CV's, but is it possibly better at looking at putting some heims/arm on some reid knuckles and then using CTM uni's instead?

In one of the US mags they did a build up recently of a f150 running 40's on IFS.. a kind of to hell with the expense deal ..

They used a dana 60 centre section porsche 930 series ( i think) CV's and spidertrax knuckles, custom chromo arms. I imagine the $$ would have been a few $$ spent

here is a link to the build

http://www.4wheeloffroad.com/ultimatead ... index.html

200 series cruiser front diff, they are 9.5" in size and run 34 spline driveshafts.

Bolt on a current tundra Total Chaos or Camburg or similar long travel suspension kit and you'll have a great performing setup.

Aftermarket diff gears are available aswell upto 4.88:1

I would get the guys over in WA at Proformance to build me one of ther custom set ups.....they built a special housing using huge bearings so the diff end cvs could be inboard mounted in the housing, allowing the shafts to be longer and therefore more travel for less angle.....

Black Bull wants to build a race truck.....can the front diff be center mounted in a race truck?

Black Bull, what is the donor vehicle that will be used for this?

You may have problems running the front tailshaft to a 100% centrally located front IFS diff, depending on the transfercase setup of course and the front output location.

Anything is possible if you throw enough $$$ at it, and also its easier if your building a custom buggy to build things around it, but if the vehicle is a truck Im sure there would be some limitations to what you could and couldnt do, aswell as what will and wont work.

Black Bull, can you dish out any more info on your project?

the "truck" for all intents and purposes will be a tube framed buggy, It'll have just enough of the original chassis to satisfy most comp rules and I'll graft a hilux shell onto it.
Engine will most likely be mid mounted (set back 8-10 inches) and will be around 400 cubes

As was mentioned by Mmaax, I'm leaning towards something similar to a camburg front end, but I'll build my own so I can offset the diff centre enough to clear the sump.


I was planning on buying some 3140 or 300m and turning up stub shafts myself and getting a friend to broach the splines, then heat and cryo treat them.

My main issues are the center and CV's, 37" stickies are heavy.
While a fabbed housing with a strange or Hi9 center would be great, I don't like the idea of having to wait for parts from overseas if I happen to break something.
Hell, with me there's a good chance of that!

Black Bull wrote:the "truck" for all intents and purposes will be a tube framed buggy, It'll have just enough of the original chassis to satisfy most comp rules and I'll graft a hilux shell onto it.
Engine will most likely be mid mounted (set back 8-10 inches) and will be around 400 cubes

As was mentioned by Mmaax, I'm leaning towards something similar to a camburg front end, but I'll build my own so I can offset the diff centre enough to clear the sump.


I was planning on buying some 3140 or 300m and turning up stub shafts myself and getting a friend to broach the splines, then heat and cryo treat them.

My main issues are the center and CV's, 37" stickies are heavy.
While a fabbed housing with a strange or Hi9 center would be great, I don't like the idea of having to wait for parts from overseas if I happen to break something.
Hell, with me there's a good chance of that!

Re the Hi9 .. the only bits that would break .. ie crown wheel or pinion .. why wouldnt you buy a set as a spare ... No need for an entire third member.

I would have thought with a Hi9 in an IFS app the axles or CV's would be your weakest link not the centre itself.

If you run the larger bearing center, you can fit up to a 40 spline axle in them.
CV's are going to be an issue, but a lot of desert guys run cryoed 4130 or 300m 30 series CV (they're huge) with reasonable reliability.
Not cheap though at $1000 JUST for the CV, then you still need 4 stubs and a pair of axles.

Black Bull wrote:Problem with all the above diffs, is the gear set would be running on the coast side of the gears.

common place for guys in the usa to use 14b up front in low pinion configuration with no issues
on 49 inch tyres and big block engines .

flexytj wrote:

Black Bull wrote:Problem with all the above diffs, is the gear set would be running on the coast side of the gears.

common place for guys in the usa to use 14b up front in low pinion configuration with no issues
on 49 inch tyres and big block engines .

May be the case for Rock crawling and short course stuff, Some stages I'll be running are 200+ km at high speed.
I dunno how they'd survive that.

If you are considering entering any CAMS offroad events you may want a smaller motor, last I knew they limited motor size to 6L which is around 366 cubes

Not building primarily to cams specs, but to CCDA buggy class.
I'll do barwork etc so I can run cams if I want at a later date. I'll probably just pinch the LS out of the cruiser in that case

Does anyone run Cornay joints at all ??
they were supposed to revolutinise this area but never heard anything more about them ...

Interesting, Seems the jury is out as to the cost of them V's reliability/longevity though, and from what I can find they have a less then spectacular rate of reply. I'll send them an email tomorrow

I have been following this for a while, and just thought maybe you could clarify things and put it all into perspective.

Your type of racing - criteria is

Black Bull wrote:Offroad racing, ie Cross country ralleys and maybe winch challenges.

300+hp and 35"-37" tyres

OK- so:
Offroad racing - can be done very successfully in 2wd,
Crosscountry - as above + hi range 4wd
Winch challenges - hi/lo with std gear reduction, 200-450hp.

So in terms of front diff strength, guys are winning winch challenges with stock GU diffs and std locking hubs. Therefore any diff that can handle 4500-5000ft/lb of drive torque would be sufficient. IE a well built lux 8" diff can transmit 8000+ft/lb , so an IRS pajero would be ample / overkill for your application.

I feel you need to think more realistically about what you need not what you want to hear!

Cheers, I was hoping for your input.

1MadEngineer wrote:an IRS pajero would be ample / overkill for your application.

I've spoken to one guy who is a specialist Mitsubishi guy building Rally cars for Fink and other events, (he puts these diffs in all sorts of things)
In thier given application they're fine (ie Rear application) , but there are still guys who bust CV's with 33" tyres on the back of Pajeros.

What are your thoughts about running a center backwards for prolonged periods of time?

Also, with Winch trucks,
GQ/GU stuff might be fine for short course events, but after 4 years of Cliffhanger I've seen Hubs, CV's, inner axles, rear axles even the swivel balls break in half (twice actually).
Only toyota diffs I know of at cliffhanger was in Paul Gambels's 6cyl 80 series and it no longer competes after being rolled
And Also the venezuelan's Factory backed 78 series which had still had some money spent on it and it was well down on power next to a lot of trucks

In a rock crawling situation, I'd agree with you %100, but I think in these types of endurance events the constant shock loading brings them undone.
The only truck I've seen with zero drive train issues is Madica which runs built D60's with a blown 6l and auto

I'm not aiming to build the most powerfull truck out there, but I want to build the most reliable, bang for buck one I can, And I like being different from everyone else, hence trying to build an IFS car

you will find the mitsu inner cv's are equal to a 934. change the inner shafts to slip, then run toyota 80 series longs on the outer to allow for boots + custom knuckles. this will be far stronger than most and will be cheap for spares, plus the advantage of running FWH's for 2wd events.

And running the center backwards for long periods ? your thoughts ?

just a few comments from my experience running a supra 8 inch in the front of my surf.

100% centred diff was not an issue running a but clearance to gearbox may be an issue in an auto, I run a manual with twin hilux transfers.
The stress on the front is a hell of a lot less than a rear so worrying about people breaking massive cv's on a rear diff is irrelevent to an ifs setup. I used to break 8"toyota diffs in the rear constantly but in the front couldn't break it even when trying, massive revs wheels in the air coming down etc.
Cv changes on an ifs is a 10 minute job without breaking a sweat or getting greasy so they are a cheap easy weak link on a winch style truck, off road racing I doubt you'd break fronts as the load is generally in the rear.

My car is a hilux surf with a 308 holden v8, twin transfers and 37 inch boggers, the 8 inch supra diff worked extremely well and I couldn't break it.

Hope that helps.
Leeham

Black Bull wrote:And running the center backwards for long periods ? your thoughts ?

the mitsu 9" irs will be fine! hey most big us rigs were designed with a std rotation d60 in early years. 40/60series run same direction.... and so on. What you will find is the key to success in otp spec offroad race cars is diff coolers w/ pumps.