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Racingsnake
Racingsnake New Reader
10/9/20 2:10 p.m.

In reply to twentyover :

Cool, thanks. I'm hoping to start working on my Capri again and would like to upgrade the suspension. I'll be following this thread with interest.

twentyover
twentyover Dork
10/9/20 2:30 p.m.
therealpinto said:

Yes, the Sierra (XR4Ti) uses a spindle that clamps the strut tube.

....

In the US, parts are not as easy to come by so other parts may well be better suited. A Fox body or SN95 strut would be possible.

...

A downside of both the Capri/Escort and Sierra/XR4Ti front suspension is that the lower ball joint is integral into the arm so you can't really swap it to change the roll center.

...

I am myself very tempted do design a new set of TCAs with a removeable ball joint, probably something like the steering angle kits used on many drift cars. I want more steering angle and I would like to have a ball joint that could be swapped out.

Another possible strut donor is the Volvo 240, and 740.

...

When I modified my front suspension it took quite some time to get all things reasonably well in position and I am still not 100% satisfied. But I did shorten the strut tubes as much as I could, and also lowered then in the spindles as much as possible. So even though the car is quite low and I have a decent spring rate the ride is not too bad.

Gustaf

Heya Pinto-

Think my plan is to stick with the Capri legs right now, have a line on some shorty Konis that should work in shortened tubes. I plan on coilover sleeves and springs, and a top mount caster camber plate. It should be an easy starting spot to determine if this will take me in the direction I want.

When I break to track arms off the struts, I plan on getting geometry for the ball joint, and selecting a similar one from Howe or another rebuildable ball joint (may need to ream taper to a different size or taper angle) and fabricate longer track arm. In this case, I think maybe turn to a compression strut to isolate the location from roll control in the front anti roll bar. I would design the fabricated arm longer than the existing, to reduce lateral movement in compression/roll. Need to shorten the rack, so far this isn't particularly scary.

So I need to move the car from Michigan to my new home in Washington state. That should happen in early November

twentyover
twentyover Dork
10/9/20 2:47 p.m.
pres589 (djronnebaum) said:

A pair of pickup points grafted to the chassis and a custom control arm that uses two pickup points ....  I wonder if moving to a Fox Mustang spindle and strut would be not impossibly hard and get you some better options for brake rotors and calipers.  I also think that bearings would be easier to source with the Mustang spindle over the Capri. 

Fox Mustangs have a different strut/spindle angle relationship, I know of several abandoned attempts that forced the track width way too wide. True that the spindle /strut relationship is adjustable- I don't know how deep these previous projects delved into the option of modifying the relationship. One think I want is to keep the stock fender, no flare. This criteria is, in my mind, non-negotiable..

Brake kits Fox/SN95 would certinly have a better selection, but bearings are a non-issue- Capri uses a standard Set 2 and Set 21 wheel bearings

twentyover
twentyover Dork
11/20/20 11:15 a.m.

Moved th Capri out of the barn, washed the bird poop off, and loaded it for the trip to Washington

 

Unloaded it and pushed it into the barn at the new place, drove down to SoCal to spend time w/ friends and thaw out some. On the way down, stopped at Ground Control near Sacramento and picked up some double adjustable Koni's, coilover sleeves and camber plates.

I'll be back in Washington after Thanksgiving- I'll se about starting to make the conversion before Christmas.

 

As an aside, the track control arms used on the Capri are criminally short- about 9 3/4", so the lower ball joint moves in and out quite a bit as the suspension travels. I was toying with the idea of building a longer track arm to reduce the travel in compression, and was looking at Merkur Scorpio front suspensions. Called Rapido group, a purveyor of Merkur parts, and he scaled the Scorpio track arm at about 2 inches longer than the Capri. I have a set coming . I would need to address the bump steer issue, but I've had a Capri rack apart before. I think it can be shortened significantly without too much difficulty.

So can anyone critique may plan? Thanks in advance

pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
11/20/20 7:01 p.m.

Does the sway bar interfacing joint move outward from stock with this change?  This could affect things.

I wonder what would happen if you swapped the arms side to side so that the sway bar interfacing joint faced towards the rear of the car, and then ran a strut rod back to some solid location to control deflection of the control arm.  A different sway bar setup would need to be created obviously.  Should take some of the waywardness out of the front end; I don't remember how bad that was with my Capri of years ago but I think this could be a good improvement if done well.

 

therealpinto
therealpinto Reader
11/24/20 4:22 a.m.

The Scorpio arms should be fairly similar to (if not identical) to the Sierra arms I mentioned earlier. So the basic idea sounds pretty much OK to me but I'd consider widening the track as much as possible.

Instead of shortening a Capri rack, look into an Escort MkII rack perhaps? A Capri rack is 675 mm balljoint to balljoint, while a stock Escort should be 585-595 mm. Aftermarket ones are usually around 620 mm. Or look at a BMW E30 or E36 (600 mm) rack.

Running compression struts as is suggested above is surely an option. Generally it is advised to beef up the frame rails and their connection to the floor if you do that.

Gustaf

84FSP
84FSP UltraDork
11/24/20 7:41 a.m.
twentyover said:
therealpinto said:

Yes, the Sierra (XR4Ti) uses a spindle that clamps the strut tube.

....

In the US, parts are not as easy to come by so other parts may well be better suited. A Fox body or SN95 strut would be possible.

...

A downside of both the Capri/Escort and Sierra/XR4Ti front suspension is that the lower ball joint is integral into the arm so you can't really swap it to change the roll center.

...

I am myself very tempted do design a new set of TCAs with a removeable ball joint, probably something like the steering angle kits used on many drift cars. I want more steering angle and I would like to have a ball joint that could be swapped out.

Another possible strut donor is the Volvo 240, and 740.

...

When I modified my front suspension it took quite some time to get all things reasonably well in position and I am still not 100% satisfied. But I did shorten the strut tubes as much as I could, and also lowered then in the spindles as much as possible. So even though the car is quite low and I have a decent spring rate the ride is not too bad.

Gustaf

Heya Pinto-

Think my plan is to stick with the Capri legs right now, have a line on some shorty Konis that should work in shortened tubes. I plan on coilover sleeves and springs, and a top mount caster camber plate. It should be an easy starting spot to determine if this will take me in the direction I want.

When I break to track arms off the struts, I plan on getting geometry for the ball joint, and selecting a similar one from Howe or another rebuildable ball joint (may need to ream taper to a different size or taper angle) and fabricate longer track arm. In this case, I think maybe turn to a compression strut to isolate the location from roll control in the front anti roll bar. I would design the fabricated arm longer than the existing, to reduce lateral movement in compression/roll. Need to shorten the rack, so far this isn't particularly scary.

So I need to move the car from Michigan to my new home in Washington state. That should happen in early November

You might consider mounting the camber plates sideways to gain more caster.  This radically improves the dynamic camber vs relying on static camber only.  I run -1.5 static which is more like -5 dynamic from memory (rusty). 

The positive is you maintain a better contact patch and street manners.  The negative is you significantly increase steering weight.  This was a game changer for my Rabbit.

twentyover
twentyover Dork
12/3/20 12:31 a.m.
pres589 (djronnebaum) said:

Does the sway bar interfacing joint move outward from stock with this change?  This could affect things.

I wonder what would happen if you swapped the arms side to side so that the sway bar interfacing joint faced towards the rear of the car, and then ran a strut rod back to some solid location to control deflection of the control arm.  A different sway bar setup would need to be created obviously.  Should take some of the waywardness out of the front end; I don't remember how bad that was with my Capri of years ago but I think this could be a good improvement if done well.

The intent would be to move the inboard pivot closer to car centerline, as the relationship between the ball joint  and sway bar mount should be very similiar between the Capri and the Scorpio

The Scorpio and Sierra (XR4ti in the US) both had sway bars mounted after of the front axle centerline. I have considered reversing the arms (so they are used as they were on the Scorpio) and running compression struts. Then dropping a link  from the sway bar the the compression strut where it pierces the track arm and projects forward. Will need some articulation to prevent binding. I think ultimately I will do this to separate location and sway control functions.

therealpinto said:

The Scorpio arms should be fairly similar to (if not identical) to the Sierra arms I mentioned earlier. So the basic idea sounds pretty much OK to me but I'd consider widening the track as much as possible.

Instead of shortening a Capri rack, look into an Escort MkII rack perhaps? A Capri rack is 675 mm balljoint to balljoint, while a stock Escort should be 585-595 mm. Aftermarket ones are usually around 620 mm. Or look at a BMW E30 or E36 (600 mm) rack.

Running compression struts as is suggested above is surely an option. Generally it is advised to beef up the frame rails and their connection to the floor if you do that.

Gustaf

One goal of this was no flares. I want to retain the slab sides of the MK II. I'll get the tires and wheels selected, then push the struts out as far as I can within the constraint listed above

I'm not sure I've ever seen a 'Scorty MK II in the US, don't think they imported them. I have seen a Mk I in vintage oad racing in SoCal, that's about it. Don't think I'll find one at a local breakers. I'll look into the E30/E36 suggestion.

Had not heard about the need to reinforce the frame stubs and floor when using compression struts. I'll investigate further. Thanks for the heads up.

84FSP said:

You might consider mounting the camber plates sideways to gain more caster.  This radically improves the dynamic camber vs relying on static camber only.  I run -1.5 static which is more like -5 dynamic from memory (rusty). 

The positive is you maintain a better contact patch and street manners.  The negative is you significantly increase steering weight.  This was a game changer for my Rabbit.

Interesting idea. The camber plates do have some caster adjustment built in, I though caster would be limited by the spring reinforcement welded to the inner fender in the wheel house. I'll check out clearance when I get in the struts cut down and ready to install.

I am worried about steering effort. The car has a non-assisted rack, and I plan on running a 205 or (hopefully) a 225/50-15. I was able to steer without too much difficulty when I was younger, but I'm not that anymore.

 

therealpinto
therealpinto Reader
12/3/20 3:05 a.m.

If you want lighter steering, a power rack from a BMW (or Volvo 240 if you end up needing something closer to the Capri in width), will be a nice upgrade.

A Capri with stock steering and suspension is reasonably tough to steer on 205's or 225's but it's also a matter of preferences. 

Gustaf

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