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Sierra Based Independent Rear
NelsonFB - 8/9/13 at 09:37 PM

Hello all,

Firstly thanks for reading, hoping someone can offer some knowledge, and a push in the right direction.

I've been researching the best and easiest way to get independant rear suspension on my Capri, and have decided after much debate and different consideration, the easiest and most affective way to do it is how you guys are doing it, using sierra parts and afew off the shelf fabricated locost parts. Building a simple rear end, keeping the orginal sierra dimentions (no shortening half shafts and so on)

Question I have is though... Whats the best book to buy that has good drawings and dimentions in to work from?

I'm hoping I can simply fabricate the diff carrier, with mounts for diff and wishbones. Then buy the rest of the parts needed and bolt it all together.

I've seen some wishbones on rallydesign I beleive are for this setup, and they look more than up to the task. Then I've found the fabricated rear hubs, not altogether too sure on what coilovers I want to be buying, but then the rest should just be welding and sierra bits... diff, cv's, halfshafts...

Thanks for reading and would really appciate any advise anyone can offer

[Edited on 8/9/13 by NelsonFB]


NigeEss - 8/9/13 at 09:43 PM

Hello and welcome/

You could take the whole Sierra subframe and graft it in, chopping and welding the body as required. I doubt
if you'll find a book with correct dimensions for Locost type wishbones for a Capri, but I guess if you buy the Haynes
Roadster book it will give you an idea how it's done.


NelsonFB - 8/9/13 at 10:01 PM

Using the standard Sierra rear end has been a consideration, but was told its geometry isnt great, as its not adjustable enough.

I figured if I had some simple dimentions for a diff carrier, so I know where my wishbone mounts need to be. It should be fairly simple, then I asume the off the shelf wishbones you can buy for the locost, use the same length half shafts, but I have alot more scope for camber

[Edited on 8/9/13 by NelsonFB]


Smoking Frog - 8/9/13 at 10:39 PM

If you're planning to run a 302 engine I don't think the sierra diff would be up to the job (not 100% sure). How about a jag rear axle, comes with it's own sub frame. Welcome to the forum BTW.


snapper - 9/9/13 at 07:55 AM

Sierra Cosworth did will take the power
Haynes roadster frame will work


NelsonFB - 9/9/13 at 04:01 PM

After doing a little more research I think I have indeed hit a snag...

Found a thread on another forum (slightly anoying I cant find it again) where someone is considering an independant rear on a mk2 escort, and the isue of the top arm (with a twin wishbone setup) hitting the bottom of the rear arch / chasis leg

I can see this being a deffinate problem

I had considerd the Jaguar IRS rear, was abit unsure about it because of the weight factor, and its slightly over engineering things

I've seen alot of V8 powerd things where a Sierra rear diff has been used. This said, what do the saph lads do when their running a 450-600hp YB Beast? I know its not V8 torque, but I only plan on having around 300hp, I dont think I really need anymore than that with a car that weighs under a ton. I know a 302 isnt the lightest of lumps going, but I'm hoping with the eddition of ali heads, lightweight starter and alternator, with the engine and box as low down and far back as possible, the car will still perform well in the twisties. The 3.0 in the Capri weighs more and they handle well ounce everything else has been messed with, with the engine in the standard location

I've been looking into the Sierra XR8 alot trying to use that as a starting/learning point for ratios and the such like, also have been looking at the mk1 capri perana (with a 302 v8) for refference in gearing ratios

however I have just come across this beast

http://www.djm-motorsport.co.uk/mkii_escort_mcrae.html (very nice)

either way I'm off topic now, I'll be in trouble with the mods for talking about non locost related things

[Edited on 9/9/13 by NelsonFB]


jacko - 9/9/13 at 04:43 PM

If you go down the sierra diff idea have a think about using a 7.5 diff as the 7in diff is getting harder to find and the 7.5 is stronger.
When i did grass track i had a Jag rear end but replaced the big heavy bottom arms with home made arms out of 25mm box much lighter
Jacko


NelsonFB - 9/9/13 at 05:30 PM

too right, the 7.5 is the bolt in type shafts as well rather than push in. I beleive (not 100%) that the LSD ones are only 7.5" as well, I dont think any of the 7" were LSD type (could be wrong though)

Not too sure what I'm going todo in this department yet though due to ratios


jacko - 9/9/13 at 06:09 PM

quote:
Originally posted by NelsonFB
too right, the 7.5 is the bolt in type shafts as well rather than push in. I beleive (not 100%) that the LSD ones are only 7.5" as well, I dont think any of the 7" were LSD type (could be wrong though)

Not too sure what I'm going todo in this department yet though due to ratios


There is LSD 's in both 7 and 7.5 diffs if you look in my photo archives there is a list or too showing different diffs
Jacko

Have a read of this too
http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=85080

http://www.super7thheaven.co.uk/Sierra_Rear_Differential
[Edited on 9/9/13 by jacko]

[Edited on 9/9/13 by jacko]


snapper - 9/9/13 at 08:49 PM

DeDion the Sierra rear and use Escort type twin trailing arms a panard rod or watts linkage and turret the coil overs


Camber Dave - 9/9/13 at 09:05 PM

The MG modifiers Hoyle have a complete rear end on a subframe that will take the power and car weight.

See http://www.hoyle-engineering.co.uk/html/body-html/body_suspension.html#rearsuspension

You may need to modify the subframe a bit but that's a lot easier than starting from scratch.


mcerd1 - 10/9/13 at 07:23 AM

quote:
Originally posted by jacko
quote:
Originally posted by NelsonFB
I beleive (not 100%) that the LSD ones are only 7.5" as well, I dont think any of the 7" were LSD type (could be wrong though)
Not too sure what I'm going todo in this department yet though due to ratios

There is LSD 's in both 7 and 7.5 diffs if you look in my photo archives there is a list or too showing different diffs

^^ what he said

if anything there were more 7" LSD's built, but they are so popular that they can be hard to find these days...
(nearly all the 4x4 sierra's had a 7" LSD - only the 2wd cossie's and a very small number of other models had 7.5" LSD's)

the rwd cossie's (and a small number of V6's) will have a 7.5" LSD with a 3.64 ratio
thats the highest geared standard LSD you'll get (I'm assuming your V8 will want a higher ratio than most) - if you want higher than that you'll need to mix and match





I think the main reason for using sierra diff's in the past was there availability - this just isn't the case anymore

the Jag axle could be a good option - its plenty strong enough and can be tweaked (its used by some of the cobra replica kits with big V8's)

the other option to look at would be BMW - a lot of kits are starting to use them, there are some good ratio's for V8's and they are only a little heavier than the sierra




the other one I looked at a while back was the XR6 turbo axle (the 2002 - 2008 ford falcon's) - modern 'control blade' style rwd setup a bit like the focus
don't know anyone thats used this setup, but it looks interesting....



[Edited on 10/9/2013 by mcerd1]


jacko - 10/9/13 at 03:52 PM

Don't forget the Nissan skyline diff very strong

rear axle
rear axle


[Edited on 10/9/13 by jacko]


franky - 10/9/13 at 03:57 PM

E36 328i Sport Diff Differential Non LSD 2.93 Ratio


S2kPower - 10/9/13 at 04:01 PM

I've got a sierra lsd that i need to get rid of with shafts, PM me if you're interested, I want shot so happy to negotiate if it's what you're after


NelsonFB - 11/9/13 at 06:53 PM

got to say guys, thanks very much for all the replys, its given me some really good leads, really appreciate it!

I think the route I'm going to look into is the Escort WRC hub/upright, with a 7.5 diff

then once I've got the uprights in (after welding the turrets/tops in)

I'll then be able to work out my cradle and bottom arm points from here

The escort WRC hubs look to make the job very straightforward.

Using this for the inspiration...





[Edited on 11/9/13 by NelsonFB]


Simon - 11/9/13 at 07:48 PM

I was going to use Jag IRS in my locost but the weight is phenomenal.

As per the Skyline post, another variant on the same theme is the RX8 Mazda rear end - http://www.ebay.co.uk/itm/261264013882. Was going to use all the running gear from an RX8 in an MGB, but keep changing my mind about projects while I wait for the garage extension to happen

ATB

Simon


NelsonFB - 11/9/13 at 10:26 PM

Does anyone happen to know if...

Rear drive shafts have the same splines as 4x4 front outer cvs?

So the splines inside the front 4x4 outer cv, would be the same as any rear shafts?

[Edited on 12/9/13 by NelsonFB]