Dual Pivot K-Frame on '87 CSX

[Frank]

Are there any considerations I need to make or other gotcha's when putting a dual pivot k-frame onto the CSX? Do I need to worry about different ball joints or maybe different ____?

Thanks,
Frank

[BadAssPerformance]

Why? The 87 style isn't thaty bad.... and pretty nice with new bushings.

But if you go.... since its 87, it is easier to go with stamped dual pivot (89) style or if you go newer cast (91?+) you will need to get the knuckle splindles as well of the caster will be off. I forget if the actual; 89 and 91 style K-members are the same tho? Pretty sure Turbodave and CSracer figured this all out a couple years ago and was hoping it was in a KC article?

[Vigo]

Well, the castor will be off in the GOOD direction at least.

I put a cast-arm k-frame into an 87 csx. I would say the main thing to be aware of is it will move the wheels forward in the well slightly. Whether or not that will bother you is a preference thing. You'll also need to do a driveway alignment before driving it to a real alignment, or put it straight on the tow truck.

If you use the stamped arm 89-90 setup things will be a little easier/better overall. I dont think it will move the wheels forward or change your castor.

[Frank]

I was hoping for a smoother ride and a bit more firm feeling and response.

[BadAssPerformance]

For the smoother ride, put new rubber bushings in it, for better response, get better dampers/springs

[GLHNSLHT2]

Why? The 87 style isn't thaty bad.... and pretty nice with new bushings.

But if you go.... since its 87, it is easier to go with stamped dual pivot (89) style or if you go newer cast (91?+) you will need to get the knuckle splindles as well of the caster will be off. I forget if the actual; 89 and 91 style K-members are the same tho? Pretty sure Turbodave and CSracer figured this all out a couple years ago and was hoping it was in a KC article?

The stub strut kframe is horrible other than maybe for drag racing. It's flimsier than a 89+, and the stub struts add spring rate and flex to the chassis. Magnify that if you're running poly bushings in it.

Frank, go with the 89/90 setup. Then you can just use your stock stuff from the ball joint up. Make sure you get Energy Suspension bushings for the 89/90 setup though. Part # is 5.3135

[BadAssPerformance]

I wouldn't say "horrible", only about a million cars came with it

I like the PolyBushings bushings in the dual pivot arms I put on the Z, but if he wants a smoother ride, I would vote he goes rubber

[cordes]

I would use the stamped dual pivot control arms and the later cast arm knuckles. That gives you the best possible setup IMO. Run the later minivan caliper brackets and late 11" calipers and you've got some serious stopping power to go with it. Buy some brake pads and struts from Rbryant and you're about as good as it gets.

ETA: Who wants a smooth ride anyway? Get a Caravelle if you want an old man car!

[GLHNSLHT2]

it is horrible for ride and handling. Unless all you do is drag race. Unless your PB bushings fit way better than the ones I've seen or had in my 87 ShelbyZ with 89/89 kframe the ES bushings blow them away. Looking at this http://www.pnw-sdac.org/gallery/v/Me..._1743.jpg.html should convince anyone of that.

How many model T's were made? would you run their suspension on your Z just because about a million cars came with it?

The dual pivot with ES bushings will have a superior ride and handling. If the suspension is designed right you can have great ride and handling. I was so nervous making my spherical setup that the ride was going to be so harsh. Well after installing them the ride is extremely smooth. Why? because the suspension rotates even more freely now than it did stock, so it can move when it goes over bumps. Instead of getting a jolt with every bump the suspension just slides right over it. I can go WOT over a set of railroad tracks and it's like they aren't even there.

Ask people who are running DJ's tubular arms, I bet they say the same thing.

You want stiff bushings so the a-arms aren't doing the hula dance but you want them to be able to move in their intended arc of travel. If they can do that the ride will be awesome and so will the handling. Though you might want to increase the spring rate a bit now.

[Force Fed Mopar]

I put the '91-up k-frame, cast arms and matching swaybar, and spindles and brakes in the front of my '87 Shelby Z. Rode much better. FTR I had 89-90 controls and swaybar in for a while, and there was no difference in the wheel position between that and the '91-up parts. It rode stiffer but I had a 1.25" with the 89-90 arms and a stock '93 Shadow ES bar (1"?) with the '91-up arms. The 91-up swaybar bushing design lends to a smoother ride also I believe, looks to me like it pivots easier.

[BadAssPerformance]

I can go WOT over a set of railroad tracks and it's like they aren't even there.

You're train tracks must be better kept than the ones around here! I would not want to see what damage you would cause to yoru car by hitting them around here at WOT!

I agree that eliminating binding of the stub-strut will aid in performance, and they obviously did that for a reason, however, with good OEM rubber bushings the stub stru is not as bad as you say it is... although yes with PU the stub strut is the harshest combo for our cars.

Even though the dual pivot is betetr, I can not believe that a PU or steel joint will perform as well as a rubber bushing with the goal of "smooth ride", but maybe thats up to the perception of the driver as I am OK with solid motor mounts and some think they vibrate too much for their liking...

FWIW, the PB's in my car fit perfectly

[Frank]

Now I just need to find a k-frame and dual pivot 89 control arms...

[2.216VTurbo]

It's a small thing Frank but while everyone debates which is better and why, I'll answer the question you asked The steering rack on the 87 takes 13mm bolts, the double pivot takes 15mm so you will have to open up the holes in the rack 'strap' and the other solid side too. Check to see that the rack is tight on the donor, if the blind/welded nuts are stripped on the donor its a PIA to window the double pivot frame to fix them. Make sure you grab that hardware from the donor car as well. BTW I thought it made a huge difference when I did it 15 years ago on my SL# 748

[BadAssPerformance]

Good points on the hardware!

[Frank]

It's a small thing Frank but while everyone debates which is better and why, I'll answer the question you asked The steering rack on the 87 takes 13mm bolts, the double pivot takes 15mm so you will have to open up the holes in the rack 'strap' and the other solid side too. Check to see that the rack is tight on the donor, if the blind/welded nuts are stripped on the donor its a PIA to window the double pivot frame to fix them. Make sure you grab that hardware from the donor car as well. BTW I thought it made a huge difference when I did it 15 years ago on my SL# 748

Thanks. I actually have a new fast rack sitting here and that is why I was contemplating doing this while I am at it.

[turbovanman²]

Now I just need to find a k-frame and dual pivot 89 control arms...

I have them,

Agreed with Jay except PB bushings are fine.

[RoadWarrior222]

You're train tracks must be better kept than the ones around here! I would not want to see what damage you would cause to yoru car by hitting them around here at WOT!

I dunno there's a bit of a secret to going over some of them here, go over at 25mph you shake your teeth out, go over at 35mph plus and you barely feel them.

[GLHNSLHT2]

You're train tracks must be better kept than the ones around here! I would not want to see what damage you would cause to yoru car by hitting them around here at WOT!

We have some pretty bad ones. It's not so much the un-levelness of them that I'm referring too though. Hit them at WOT and stock bushings and the tires will want to spin because they loose touch with the ground even if just for a 2nd. Hit the same tracks at WOT with sphericals and the tires are able to maintain such a better contact patch they don't want to spin, you just fly across them. Hard to explain, you really either have to just get it or ride in the car.

Even though the dual pivot is better, I can not believe that a PU or steel joint will perform as well as a rubber bushing with the goal of "smooth ride", but maybe thats up to the perception of the driver as I am OK with solid motor mounts and some think they vibrate too much for their liking...

Took my stock 89/90 rubber bushing a-arms out, and put the sphericals in. Ride quality was sooooo much better.

FWIW, the PB's in my car fit perfectly

So you had to freeze them to get them to go in right? And the poly is at least 90A, and you clamp up on the poly before the sleeve right? If not then they didn't fit perfectly. Oh and they're about $30 more expensive than the ES versions

except PB bushings are fine.

Sure if you don't corner hard, if you don't have your alignment dialed in different from stock then you'll never notice. And as above I'd rather save the money on the better bushings.

[rbryant]

The later style cast steel arms will help the ride compared to the stamped arms.

The cast steel doesn't flex so all of the shock of a bump will transfer directly into the bushing instead of the rest of the suspension.

The rigidity of the arm was the reason for the change from stamped dual pivot to cast dual pivot. It was aimed at making a more comfortable ride in the heavier cars. A friend of mine knew the designer and had a conversation with him about it.

-Rich

[turbovanman²]

The later style cast steel arms will help the ride compared to the stamped arms.

The cast steel doesn't flex so all of the shock of a bump will transfer directly into the bushing instead of the rest of the suspension.

The rigidity of the arm was the reason for the change from stamped dual pivot to cast dual pivot. It was aimed at making a more comfortable ride in the heavier cars. A friend of mine knew the designer and had a conversation with him about it.

-Rich

That's great info, you've never said that before.