4x4s with independent front suspension & non-offset diff?

[rcx106]

I'm looking to build a custom trials/challenge vehicle and looking at drivetrains. I'm looking at solid axle on the rear and independent front suspension. But I want the front diff to be centred, whereas most 4x4s with independent front suspension have the diff slightly to the side, and not in the centre. This limits the length of the suspension arms and hence limits travel.

I could have the front axle case modified to make it symetrical and centred but then I'd still need need a matching rear axle with same ratio, or one of the propshafts will need to operate thru two angles which means I can't use a double cardon propshaft. I could live with this, but worth seeing if I can find a better solution.

Also, the diffs would need to have lockers available such as Kam lockers or ARB lockers, which limits my choices. And decent availability of gear ratio modifications either in the diffs or transferbox.

The transferbox/gearbox and axles don't need to be from the same car. So, basically, I'm looking for a matching rear solid axle, front independent axle which is not offset. And a transmission with transfer-box which also has centred output shafts.

I know there's specialist solutions for this but I can't afford them, so need to be from a production vehicle. If possible that is. Otherwise I'll just have to compromise somewhere.

[rcx106]

Thanks. Actually I'd only be taking the drivetrain from the donor cars. I could even take axles from one car and transmission from another. So travel would not be affected by the donor vehicle.

Suburu has independent rear. That's a compromise I could live with.

Would still need a transmission with centred output shafts and Suburu doesn't have a transfer box. Again I could live with that though not ideal. I was going to try to road register the car, dunno if that's easily possible these days, for some road fun as well, but that would need transfer box to switch between low and high ratio.

[rcx106]

I found the Freelander which has a centred drivetrain and independent suspension. But there are no lockers available for it :/

Ah yeah, a Suburu would have the front diff in the gearbox. So that won't work. Ok I see now why the front diff is offset to avoid the sump, didn't think of that. I've started going thru all the cars that ARB supply lockers for to see if any have the centred driveline and independent suspension or IFS.

[rcx106]

TooMany2cvs said:

Another transaxle, though - and one with a transverse engine, too, so not particularly centred.

K. It looks like I might be asking too much! I've found this company and their tech article which explains most things: http://www.proformance.com.au/#!ULTIMATE-IFS-WHEEL...

They are saying that most teams get the narrow diff by making or buying an aftermarket axle case and using a regular diff inside. But no word on how the prop shaft then needs to run diagnally or what in these home made solutions.

The same company produces an "underdrive" transfer box which lowers the output to clear the sump, so that solves things. They have all the solutions but prices are well out of my range.

So I either have to stick to solid axles or live with the shorter suspension control arms and limited travel.

[rcx106]

I only briefly considered a rear engine layout, partly because not many others are doing this, but also doesn't it mean that the diffs then need to run upside down and I don't like that kind of bodging.

Yes I can offset the engine. It's all about compromises hey! This may be the route to take; modified axles to centre the diff, and offset the engine.

[rcx106]

PugwasHDJ80 said:

The idffs con't have to run upside down
an LT230 can input power through the ouput side of the transfer case which automatically reverses the engine back to the "right" way for the diffs.
Couple of places also do reversing 1:1 gearboxes for exactly this problem

Sweet, I'm getting better tips here than on Pirate4x4!

[rcx106]

I know the Vitara very well, off by heart in fact. I know it's super light but it's a 100 bhp car with 27" tyres. It won't take the planned 300 bhp, 35" tyres, and planned abuse. I was thinking something like a Hilux or similar size/spec/strength. Half shafts should be easy to make. Rockwatt in Lincs modifies them for nice and cheap prices.

At the moment I'm thinking that to offset the engine is not a bad idea, or live with the shorter control arms or combo of both. I'm making the car quite wide for stability so that will also add suspension travel.

[rcx106]

Figuring out how strong the drivetrain needs to be is not going to be easy. I think that can only be figured out from experience and speaking to people who have experience. The Landcruiser is heavy and I'm trying to keep weight low. I was hoping something like a Hilux drivetrain would be strong enough, it's not too heavy, it's cheap, there's wide range of gear ratio mods available for it, and lockers are available.

From what I hear it's the axles that gives way a lot more often than transmission or tbox.