|
|
|
|
|
Hello All, I've started a bit of a project, I think i've got it pretty well figured out, but wondered if anyone had any advice, especially on the diffs... Here goes I bought a project 6r4 which consists of, a 6r4 body kit, a 1985 Metro V5C, a spaceframe chassis from some metro kit car and a metro bodyshell. The spaceframe chassis is mega heavy and a bit agricultural, so I'm planning to make my own chassis to suit. Current plan is: Jaguar 3.0V6 engine + 5sp Manual gearbox (Or 2.9 V6 Cossie engine and MT75 or BW T5). Milner off road 'Hedgehod' remote reverse transfer case, engine will be rear mounted in the same position as a real 6r4. And a Freelander viscous coupling to the front axle. I was thinking about using front / rear subframes from whatever (Depending on diff / hub choice) but will probably end up fabricating my own arms / links etc. Diffs.. There aren't manny compact front diffs out there, the rear diff's arent a problem, at this stage i'd rather keep the diffs as cheap open diffs with the intention to replace the internals with quaiffe bits later on (So Sierra diffs are ideal). But 4x4 front 'car' type diffs seem ultra rare.. Any suggestions? At the moment it looks like either BMW X5 or Sierra 4x4 diffs, but I need to make sure they're strong enough, The box will roughly split 50/50 front to back - a small loss witht he VC to the front (I think) What about using Subaru diffs, they can be flipped in the casing so I could get it driving the right way, but the pinion / CROWN wheel would be cut the wrong way for the drive... Would that matter if it was just driving the front?? I'd rather this didn't turn into a mega money project, as it'd mean it'd spend months sat around, and I can't wait to get stuck into the fab work! I need the engine, gearbox, transfer case and diffs before I can start the fab work.... All thoughts / opinions welcome  |
| |
|
|
|
|
|
|
|
|
|
|
I'm not sure how I managed to post this in here! Hopefully the mods will move it to technical where it was meant to be posted....
|
| |
|
|
|
|
|
|
|
|
Was this the one just sold on ebay?
|
| |
|
|
froggy
Posted a lot
Posts: 1,099
|
|
|
|
|
Give your choice or engines is 4wd really that necessary ?
|
| |
|
|
MonzaPhil
Posted a lot
Think like a man of action, act like a man of thought
Posts: 2,456
|
|
|
|
|
Don't use anything from a Freelander....... especially not with anything above the power of a 2.0 turbo diesel.
|
| |
This is now a clicky linky!  |
|
|
|
|
|
|
Don't use anything from a Freelander....... especially not with anything above the power of a 2.0 turbo diesel. I was just going to say the same. The Freelander viscous coupling is the weak point in it's drivetrain and the aspect everybody wishes Land Rover had used a proper system instead. Please don't use one unless BRAND NEW (expensive) otherwise you will regret it. Paul H |
| |
|
|
|
|
|
|
|
|
7 series diff flipped over seems to work fairly well in a lot of comp vehicles, as does the TVR unit.
|
| |
|
|
|
|
|
|
|
|
if you really want a rear mounted v6 as per 6r4,
a back to front audi s4 engine with gearbox rotated upside down would give you rear mounted engine and an output to a front diff. you could use the s4 rear diff upside down as the front diff too..
|
| |
|
|
froggy
Posted a lot
Posts: 1,099
|
|
|
|
|
Flipping diffs upside down puts all the stress on the coast face of the gears , it will work but how long is another matter in a road car .
I've been in a mid engined 6r4 rep with a supercharged Honda v tec that went really well with 280hp and 2wd
|
| |
Last Edit: Oct 8, 2012 8:22:50 GMT by froggy
|
|
|
|
|
|
|
|
Well it works on all the 6R4 reps doing comp safari putting 10 times the stress on you'll ever see in a road or track car.
|
| |
|
|
|
|
froggy
Posted a lot
Posts: 1,099
|
|
|
|
|
With your engine choice the sierra 6.5 front diff would do the job as long as you found a 3.62 rear diff to keep the ratios the same .i think the x5 ratios might be a bit low if your on 15 or 16" wheels .
|
| |
|
|
|
|
|
|
|
|
I'm with the sierra front diff at the moment, the only issue is, I need a viscous coupling because the reverse transfer box has no diff, my thoughts were that in the freelander it's under alot of stress as it drives the back axle, putting it to the front should alleviate this alot.
Lets n ot forget that regardless of power this will be nowhere near as heavy as a freelander... I was thinking a VC from a V6 freelander should be somewhere near strong enough.
I would really rather not use a freelander diff, but can't think of anything else that uses an external VC???
And.. Yes it does have to be 4wd, just because I want to see if I can get it to work (Havent seen a good one yet) The back diff needs to sit under the engine so flipped Audi gearboxes are a no go, the only way to do it is with a transfer box and 2 diff setup, without the reverse transfer box I could flip the diffs, subaru diffs can be flipped in the case, but then there's a whole new problem of 4x4 car boxes are rear biased, which would make it front biased... Unless there's a way round this? And the rear diff would be driving the wrong way, being a rear i reckon this will put it under too much stress, so I'd need to get a set of custom reverse cut gears made for it... It's always an option...
|
| |
|
|
froggy
Posted a lot
Posts: 1,099
|
|
|
|
|
I tested a similar setup recently , engine in back to front then a centre box if cogs that reversed the drive to a coupling that connected to the front and rear props , the issue would be obviously a locked centre diff and having to spin the front diff backwards although an open front diff would help . I will say though that the car I mot,d ram a Maserati bi turbo engine and the transmission noise was horrendous on the road .
|
| |
|
|
|
|
|
|
|
|
The Freelander VC's seize solid. Nothing to to with the amount of power transmitted - just poor design. In a Freelander such causes damage to the gearbox (IRD unit). Later Freelanders had a different system. Any secondhand VC is either going to be already duff or could fail at any time hence if you insist on using one ensure brand new. Use secondhand at your peril and be prepared to accept major mechanical damage to other components if it fails in use.
Paul H
|
| |
|
|
|
|
|
|
|
|
If I decided to use the freelander VC i'd buy a new one, my brother has a knackered one i can have while i'm building so I can buy it at a later date. I've been looking at this transfer box, it seems to have been fairly widely used with no complaints about diff windup....
I had assumed that it had no centre diff.. I could be wrong! They do a helical version of it which will be quieter than the straight cut version.
Looking at the pics it's alot fatter than I thought it was, so maybe it does have a diff or VC internally... It's the Milner off road racing hedgehog that I'm thinking of, anyone know?
I'll give them a call and ask about it when I'm near a phone and they're open....
And the front diff would be driving the right way with the transfer box wouldn't it? I'm basing this on my knowledge of off road 4x4's (Landies and such). There are reverse cut kits for the front diffs because they naturally drive them the wrong way, if you use a front diff as a back diff it's driving the right way, ergo the front diff must be driven in the opposite direction from the back, which means both shafts spinning the same way when looking from the front or back...
If it's spinning the wrong way for a front diff then it's easy, just use two rear scooby diffs and spin one in the case..
|
| |
|
|
|
|
|
|
|
And the front diff would be driving the right way with the transfer box wouldn't it? I'm basing this on my knowledge of off road 4x4's (Landies and such). There are reverse cut kits for the front diffs because they naturally drive them the wrong way, if you use a front diff as a back diff it's driving the right way, ergo the front diff must be driven in the opposite direction from the back, which means both shafts spinning the same way when looking from the front or back... I'm not sure what you mean. Take Land Rover (Series, Range Rover, Discovery & Defender) for example. The diffs are the same unit front and back. In fact found a 24 spline unit today when tidying up and can't remember if it came out of the front or rear of a new Defender 300 TDi but doesn't matter as they are both the same. If you are going to use a 3.0 V6 Jag engine why not go the "whole hog" and use 4x4 3.0 V6 X-Type running gear albeit somehow sorting the diffs so they run the opposite way otherwise you'd have 1 forward and 5 reverse  paul H |
| |
|
|
|
|
|
|
|
|
Ok.. The X is transverse for a start, so you're right i'd have 5 forward gears and 1 reverse, the engine would be in the wrong place and the back diff would be the front...
Witht he S type engine, I would use the standard 5 speed RWD box, driving a 1:1 reverse remote transfer case, the transfer case reverses the drive rotation, which means the gearbox and transfer case basically spits out the correct drive direction for standard Diffs... This means I can use a front diff as a front diff and a rear diff as a rear diff with no issues...
As for the landies, the reason you can use a front diff as a back is because the drive to the front diff is backwards out of the factory, I think the idea is that the front diff is lightly loaded unless you're trying to back out of a hole, in which case the diff is cut right for the job... That's the only reason I can think of anyways...
Cars not so much, they aren't designed to back out of holes so the front diffs are reverse cut
It's because both shafts spin in the same direction, so when looking from the transfer diff the back axle is actually driven in a different direction to the front.
You can turn the diff upside down, or scooby diffs can be flipped in the case, but there would always be one that would be driven incorrectly due to the gear cut.. I was thinking, if it was the front maybe it wouldn't matter so much... If it was the rear it would...
|
| |
|
|
MonzaPhil
Posted a lot
Think like a man of action, act like a man of thought
Posts: 2,456
|
|
|
|
|
P38 Range Rovers have the drive train the wrong way round (amongst many other things)... they might work and you don't need to look far to find a broken one and they seldom die from mechanical failure or work for long enough to wear anything out......
|
| |
This is now a clicky linky! |
|
|
|
|
|
|
So, what you're saying is that you want to accurately replicate the 6R4's drivetrain layout, including a V6 mounted backwards, then a transfer case to separate front and rear diffs? I have a few ideas: With any separate diff designed for independent suspension, you could flip the entire housing over. This lets the gears work as designed, but means you have to pay attention to lubrication issues like blocking the old breathers, working out the new proper oil level and then putting a new breather in the top. The other way to flip diffs is to unbolt the CROWN wheel and flip it over to the other side of the pinion. Whether this can be done or not varies depending on the type of differential. As far as I know, helical-cut diff gears can be flipped, but hypoid gears cannot. For example, the diff inside a Subaru transaxle cannot be flipped because it is a hypoid gear. There is an Australian company called Subarugears, who make a reverse-cut ring and pinion, allowing the diff to be flipped for $1500. www.subarugears.com/Are you going to pass one of the rear driveshafts through the sump like a real 6R4? Also, do you want the propshaft to the front diff to run in the centre of the car? If the answer to both is yes, then the Nissan R32-34 Skyline GT-R drivetrain might work for you. Manual gearbox with transfer case, rear propshaft (front for you) comes out the centre and the front (rear) propshaft heads back towards the engine with an offset.   You could use the complete drivetrain of gearbox/transfer and both diffs. All you need to do is flip both diffs and it should all work. I don't actually know whether you can successfully flip GT-R diffs, that's something you would have to check with experts. I don't see why not though, from photos it looks like there is room in the case to do it. You could even use the GT-R engine if it will fit in the back of a Metro. If not, I believe that you can swap on a Nissan VQ V6, as seen in the 350Z, Murano and so forth. If the front diff won't work for you then you could use a second Skyline rear diff. As you say, Subaru WRX rear diffs should work for you in both front and rear locations. I'm not sure whether the Subaru rear diff can be flipped. The key question I would have is, how much room do you have from the back of the Metro to the point where your firewall will go? The original transmission/transfer case setup was quite short, as shown:  I would guess that if you put a separate transfer case on the front of a conventional 5-speed from another car, it's going to be occupying the space where the driver's seat should go.  Note that in the drawing above, it shows the propshaft to the front diff running offset on the right-hand side of the engine/box. For some odd reason almost all transfer cases exit on the right-hand side, rather than the left, so when you turn them around in your application, the drive will be on the left. This layout would require an offset transfer case, in the style of a Land-Rover transfer case. |
| |
|
|
|
|
|
Oct 10, 2012 21:09:48 GMT
|
|
Those pictures are awesome! Really helpful, thanks!
The remote transfer box Idea came about because the unit I have in mind is fairly compact and could be oriented to suit..
I can't use a standard 4x4 gearbox driving from the back without some form of modification to the centre diff, as they bias power to the back, which would be the front... No good for what I want...
And I don't think the front diff would be strong enough as a back diff, although I'm not sure...
The reverse transfer box would solve diff problems as it'd drive the shafts the right way so back diff could be a back diff etc...
I havent decided exactly where the diffs will be located yet and how I'm going to work around the sump, although I'll fab one if I have to and the pickup pipe's etc... I figure once I get set on what drive gear i'm using I'll get it and set it out next to my metro shell, do some measuring and work from there.
In my head I pictured it with the rear diff under the sump (Maybe a modded sump to be flat at the front of the engine, i.e the back of the car.. but offsetting it could solve that problem..
I'm intrigued about range rovers driving backwards.... The range rover gear isn't suitable because of size / weight... but if they drive backwards a modified transfer box hould be a winner... 4x4's tend to be 50:50 front to rear I think...
Keep the suggestions coming, it's all interesting!
I'm in the process of restoring a 1985 Honda CR500 while I get my head around what drive gear to use... so no mad rush to decide just yet.. It'll probably take me a few paydays to get the bits I want anyway.
|
| |
|
|
|
|
