Moparts Tech Archive

Drag Racing Tips

Sub Frame Connectors

Theres probably a hundred different ways to add these connectors to your car. And as many ways to use them once they are in the car.

We use the sub frame connectors not only to stiffen the floor pan and chassis of the car but also to mount the ladder bars and land the roll cage or bar on also.

You can find a few ways we do ours on my race tech page at the link below, But no matter what or which way you decide to go. The bars will difinitaly help the cars performance and help keep the car from twisting up like a preztel and buckling the quarter panels, I even seen the door glass broken out of cars w/o the connectors from the body flexxing so much.

mulutchoker
Moparts Member

how do you know if you need them and how do they work and where do they go?

71ChargerSE440CI
Moparts Member

Our cars are of Uni-Body construction. There are front and rear frame rails of a sort (sub-frames or front/rear longitudinals), but the floor pan and sills (area under each door, edges of floor pan) act as a shear-plate or member of infinite forces/directions. Sub-Frame connectors act to tie the front and rear longitudinals together and strengthen the structure. In a way, you can think of them as a continuation of the existing frame rails to bridge the gap between them.

http://www.magnumforceracing.com/challenger1.htm

They are a very good idea for a quicker car, usually quicker than 12-seconds, to keep your rear quarter panels from twisting/buckling, especially with slicks.

Welding supports in the kick-up areas (four corners where the longitudinals connect to the floor pan) is a good idea as well, but best is to install a full Roll-Cage or at least a good roll-bar in addition to the sub-frame connectors.

Mopar Performance sells a kit as do many chassis builders (Chassisworks, Magnum Force Racing, ART, Competition Engineering, etc.

You can also just make them yourself from rectangular tubing.

Mike P
Moparts Member

http://www.bigblockdart.com/connectors/connectors.htm

kamstra
Moparts Member

They are designed to increase structural rigidity They tie the front and rear sub frames together. They are required with a high torque engine that will put strain on your chassis.

rrsbdh
Moparts Member

I bought a set for my 70 RR and 69 Bee. I bolted them in and then welded them in too. Cars are a lot tighter now.

74DartSport
Moparts Member

E-burg covered this in the latest Mopar Action. Here's who he used.

http://www.autorust.com/parts-form.html

Basically it's just rectangular tubing cut to fit

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