OK, let's see if this works, not being quite sure if I can start a thread with only a couple of posts under my belt.

I have a plan. An "RS500", 2020's edition. The questions about a stroker engine I posted in another thread are just the tip of the iceberg. The preliminary planned spec is something like... :

RS500 look-a-like except for LHD, leather trim and AC.
AWD. Nissan Skyline R32 transmission w/ ETS-PRO, 7˝" rear and Oppliger-cased front diff, Quaife ATB LSD on both.
3dr front suspension w/ AWD driveshafts, 6° rear beam, coilovers, standard ride height.
Non-caged 909 or seam-welded and reinforced 3dr bodyshell.
Alu block tall deck stroker engine, EFR twin scroll turbo, Link or Motec ecm.
All auxiliary aftermarket bits and pieces, too numerous to list.

I'm completely aware of the fact that this will be a long-term project that'll obliterate my piggy-bank big time. However, 3dr is the only Cosworth I haven't ever owned; Sapphire 2WD, 4x4 and Escort I bought new in late 80's and early 90's and loved them to death. It's a kind of nostalgia blown out of proportion but I just want to do it.

Now, as it's already obvious, there's no point in b*stardizing a genuine RS500. They're spendy as-is, all of them RHD and there wouldn't be that much left of the original car when everything is said and done.

Another idea would be to start with a genuine 3dr Cosworth. Pretty much the same problem, except for €30-40k cheaper purchase price.

Next would be finding a genuine 4x4 Sapphire, to source all the parts not commonly found on pedestrian Sierras. Crashed ones are rare these days and I don't know if it's really worth it to buy a functioning 4x4 when all I really need from it is the steering rack, cylinder head, sump, front diff ring & pinion, front suspension, dash/cluster and AC components. Everything else will be uprated/custom anyway.

I still have a spare RS500 engine, a busted T5, 7" rear and assorted parts stashed somewhere; they're leftovers that have been gathering dust since 1992 when I bought the drivetrains off a crashed/scrapped RS500 and a Sapphire 4x4, but I'm not sure if they're of much use at this point. I already used most of the "good" parts for my 4x4 and Escort back in the day. And so much better are available these days that it's almost unreal.

All ideas are welcome at this point. I'm not really sure how to proceed, ie. what's the most cost-effective way to build an externally nostalgic but technically cutting edge "RS2020".

 

The skyline box is quite heavy and you have the issue of adapting to the Cossie engine. I did mine then ditched it and went for the oppliger long box close ratio.

marc Kinsey on here has converted the skyline box and now has gone for a sequential. Coleyst200 on here has also done his to skyline.

ets pro is really impressive

 

The Skyline 'box is an option because I have a couple of them laying around as a €/Ł/$0 (plus an adapter plate) option, also a Holinger dog box with an R33 transfer case but I want to keep everything as civilized as possible.

If I compromise with the engine and go with a 2.3l Ecoboost or 2.5/2.6l Esslinger Ecoboost stroker for that matter; the power and torque curves as well as response with an EFR, twin independent VCT and direct injection is nothing short of impressive, MT-82 4x4 transmission is more or less bolt-on. Along with a slight headache how to arrange front diff and driveshaft setup and have front and rear driveshafts made for it.

The more I think about this the more I'm leaning towards trying to find a nice, early Sierra Ghia 3dr and sourcing everything else separately. Too bad that there aren't many around anymore and finding Cossie suspension components might prove difficult unless I use aftermarket, billet/custom parts. As if the projected parts+labour budget didn't look ridiculous enough already, regardless of how much of the work I'm prepared to do myself.

Ouch.

 

A 3dr front suspension won’t work with a 4x4 drivetrain.

 

Wouldn’t touch anything ecoboost tbh pretty weak engines and everything is really thin which leads to cracks

 

What exactly gets in the way when combining 3dr upgrights, if they're simply machined for AWD driveshafts/hubs/bearings and larger diameter struts? I mean, there are aftermarket billet uprights that combine front driveshaft capability with 3dr-style (instead of later pinched bolt) track control arms, essentially resulting in 3dr suspension geometry. Keeping the roll center in check is a good idea, even at stock Cosworth ride height. The most likely combination is to run moderate camber and as much caster as an adjustable strut bearing cradle will allow so this may be a bit more of an issue.

As far as Ecoboost engines are concerned, I think the jury is still out. Now that the current Focus RS has been on the market for a while and Mustang people are making rather serious power, it doesn't look that bad, after all. They've come a long way from early Mazda MZR engines the block is based on, and while it's still an open deck design (blockguard, anyone?), 500-ish reliable BHP or even WHP isn't that uncommon these days. Cosworth's take on the MZR/Duratec subject, the YD, is atmospheric, which seems to have spawned from racing regulations instead of viability of building a decent turbo engine out of it.

A turbocharged 2.4l 9-10:1 compression YD might justify a "Cosworth" badge on the car, too...

 

The reason the 3dr knuckles give a better roll center than the 2wd Sapph knuckles is because the connection to the TCA ball joint is in a lower position. If you compare the 3dr knuckles to Sapph 4x4, there is not that much difference in the distance from the wheel bearing to the bottom ball joint. The reason that the roll center on the 4x4 is not that good as on the 3dr is because the 4x4 front crossmember also has the connection for the TCA at a lower point than the 2wd crossmember. It has to be like that on the 4x4 crossmember to make room for the driveshafts. So if you would combine the 3dr knuckles with the 4x4 crossmember you will not get the same roll center as with the 3dr knuckles and a 2wd crossmember.

But the roll center is not the only thing to keep in mind for the front suspension. The caster setting, scrub radius, Ackermann and bump steer are also factors to take into account. Just trying to improve the roll center without thinking about the rest will probably make the handling worse.

 

Thanks for noting that. Fortunately the Cosworth suspension is a fairly simple McPherson setup with no notable tricks. We recently made calculations to alter the subframe mounting points of my son's Celica GT4 for increasing caster angle, a royal PITA compared to Cossie. I haven't researched how much room there actually will be to play with mounts, at the very least with (custom?) offset bushes and full uniball arms, but the 3dr geometry seems like a good starting point and fortunately there are off the shelf solutions to tweak the track arm angle if there are any bump steer issues once everything else has been said and done.

I wouldn't imagine the suspension becoming a major problem, depending on how the front/rear roll centers will interact with each other in practise, of course. I'm no by means trying to re-invent the wheel unless it's absolutely necessary and knowing how many quick 4x4:s and Escorts are out there, it shouldn't be.