Subframe connectors

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clv22p

clv22p

72 Dodge Demon 340
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My mopar performance subframe connectors will be here Monday. My plan is to bolt them on in my garage and have them welded in at a later date.

What is the proper way to lift the car in order to get under it to install them. The instructions from mopar performance say to lift it from the rear axle. The competition engineering instructions say to lift it by the front suspension. I've been other people say to support all four corners of the suspension. Then I've seen others say to support the front frame rails by the firewall to help get the sag out of the body.

So what is better and why? Thank you in advance.
 
If you are just bolting them in, at this point I don't think it's that crucial. Bolt in connectors are still going to have some movement, IMO.

When you have them welded is when you want to make sure the car is level, the doors open and close nicely, then weld.
 
take to a muffler shop that has a lift that the car drives onto and the car is lifted with the wheels on the lift ... that way its in its most natural stance...
 

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It depends on a few things: weight of the car/mat'l of the sfc, mount design/type, intended usage etc.
Some need preload, others dont and will turn the car into a pogo stick on rebound if you do load them.
 
You cant preload subframe connectors.....If you can please explain... we are not talking about Caltracs and the like... we are connecting point a to point b... thats all like a solid frame.... am i wrong?
 
tarvin890 said:
You cant preload subframe connectors.....If you can please explain... we are not talking about Caltracs and the like... we are connecting point a to point b... thats all like a solid frame.... am i wrong?
Click to expand...

Bowing the chassis, unnaturally. Maybe preload isn't the correct term lol. Turning your car into an inverted eaf spring may be closer, but semantics dude...
 
skizzo said:
Bowing the chassis, unnaturally. Maybe preload isn't the correct term lol. Turning your car into an inverted eaf spring may be closer, but semantics dude...
Click to expand...

not nit piking or semantics... just didnt think of it that way....just would think this... i can see what you mean... but wouldnt that warp (might not be the best term) the frame enough to cause door closing and fender lines not line up? Any chassis peeps here got a chassis mans view on this? you have my curiosity peaked on this now....
 
Things can be loaded just to that point. For a street app, I would just level it, check the doors and weld them in (not the doors, lol).

We installed a hitch on a buddies motor home to haul his race car. We attached the forward point, and put upward pressure on the tongue, essentially preloading it to compensate for the down force of the trailer weight.

I don't know if it made a difference but he thought so, lol.
 
Why not wait and just weld them in, why put holes in you frame if you really don't have to, my 2 cents.
 
tarvin890 said:
take to a muffler shop that has a lift that the car drives onto and the car is lifted with the wheels on the lift ... that way its in its most natural stance...
Click to expand...

What he said ^^^^^^^^^ Support from the suspension is the best way.
 
RustyRatRod said:
What he said ^^^^^^^^^ Support from the suspension is the best way.
Click to expand...

if your doors are fitting right and everything on the body is also, let it sit on the wheels. if you want the car straight, square, and level as possible, sit it on jackstands and level it. I welded mine w/ the jackstands shimmed and as level as I could get it. fortunately the doors didn't change any they stayed like the were.
 
I jacked my car up and lowered them down on 4 car ramps. I had the ramps facing away from each other so I had more room in the middle of the car. Andrew.
 
It seems that if your car is sagging in the middle and you suspend the car "in it natural stance" IE on the wheels, you are locking in the sag. This may be ok if all the doors line up etc etc.
But if not you may want to somehow also support the car in the middle of the car when attaching the frame rails.

Or your car could be bowing in the middle if you have a very heavy engine, in that case you may need to support the K-frame.

I guess it all depends on your car.
 
Mrpatel said:
I jacked my car up and lowered them down on 4 car ramps. I had the ramps facing away from each other so I had more room in the middle of the car. Andrew.
Click to expand...

that works too.... flat in its most natural stance............
 
UPDATE:
I recieved the subframe connectors yesterday and messed around with them in the garage. I did notice that my door doesn't fit quite as good as i thought. They are sagging some.

First I jacked the car up and put it on the stands like the instructions that came with the connectors, then did a test fit. The connectors hit the floor pan way before they will go into place and fit like they should. Door fit worse.

Next I jacked the car up in the front and put the stands on front frame close to the firewall. Rear is sitting on the ground. Connectors fit much better as did the doors. So I think this is the manner that I should install them in.

I also did try to put them in with all four wheels on the ground, it was hard to see much since my car sits pretty low, but it looked like it was very similar to jacking up the rear.
 
If you support with jackstands under the rear axle and on jackstands on either side of the K member, and keep the car level, the load paths for the sprung vehicle weight are unchanged from sitting on the ground. The only change is at the cross member where the T-bars connect into the chassis.
 
I jacked mine up a good 2 foot off the ground and supported it at all 4 corners on stands to load the suspension. Checked the doors / trunk lid / hood windows etc... All of that checked out so I began fitting them in place using the floor jack to gently push them up into place. I don't like the installations that cut through the floor pans so I just flattened out a section of the rear floor pans in order to get the 2"x3" tubing into place and in line with the front and rear sub frame sections. End result is a little hump in rear floor pan section, but that wont be very noticeable when the carpet is installed. The ones I made fit over the rear frame sections as far back as I could go and still weld them in without welding the spring shackle brackets and I plated a 3"x5" section of the front subframe where the connector butted up. Make sure you prep the areas really well before you weld them all back up, you won't be getting back in there anytime soon!!
 
Mine are weld ins that fit the profile of the floor.
The car was raised 24" and stands place as far
outboard as possible on the rear axle and under
the ball joints in the front.
The car was then jounced to settle the suspension
and let to set on the stands until I was able to weld them in.
My doors and trunk close and lock with the slightest pressure.
 
Curious to hear how the installation went and to hear from any others who have used the Mopar Performance connectors.
What are the extra plates for?
Did anyone have issues with fitment?... on Dusters or Demons in particular?
Was any tweaking required or did they slip right on?
 
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