I like the idea of the 4 link. You all know the advantages. Pictures online make me think that I could fab one. Sure sounds like fun. Has any one fab'd it? I sure would appreciate a picture of your art? Where did you get the coil-overs? Is there a make and model OEM coil-over that may be utilized? Sorry for all the questions but I just have questions and no stories to tell, yet.

Thanks in Advance,
Stephen

 

IMHO a simple parallel 4 bar is best suited to controlling hard accelleration (drag racing). A triangulated 3 or 4 bar if far more suitable for street use. The parallel 4 bar has become a fad, much like the Mustang II IFS, the original purpose has been forgotten, but is so common no one really cares, they just want it because it's the "thing to do" to impress others. That's why you see so many incorrectly designed parallel 4 bars. Parallel only refers to that the bars are parallel to the frame centerline. The top and bottom bars should not be parallel to each other nor the same length. The design of the panhard or watts link as well as it's pivot locations, is also critical to the geometry working in concert.

That said, whatever you want to build, all the components are available from Speedway Motors.

 

Ax racer is rite on!

A parellel 4 bar on the street is not really the answer for driveability. It is great for a hard launch and straight run down a straight road (dragstrip). A 3 bar is more forgiving, It will not bind like a 4 bar and is easier to set up. After several hours fighting weight transfer problems I discovered I had introduced a bind in the driveline of the drag car by mal adjusting the 4 bar. I also crew chief the same car at Bonniville for speed week. We run a 3 bar or a 4 bar depending on salt conditions. Loose salt wants a bit better handling and less launch traction. Out with the 4 in with the 3.

I plan on building a 3 bar setup for my truck.

 

3 bar also does away with the complexity of a panhard or watts link.

 

I just started putting one in on my 50 F1. I'm getting Monroe Sensa Trak adjustable coilovers.

 

Question for the people doing 4-link parallel or triangulated how are you measuring to determine the correct coilover shock?

 

You'll need to establish your mounting points, the ride height, the weight on the rear axle. The shorter the shock installed length the stiffer the spring you'll need to support the weight, the harder the ride. The usual method is to decide the spring rate you want to use based on ride and load capacity, the installed spring length that will allow that spring rate to still have sufficient room to compress without coil bind, then pick the shock length and working range for that installed length, then figure out how you will mount that length coilover. The coilovers should mount at a 15-30* angle tipped in at the top towards the center of the vehicle for street use. The upper mounting point tends to have a maximum height based on crossmember clearance, the bottom mounting point is more flexible, but is usually as low as possible without the bottom of the eye extending below ~ 1/2" above the wheel rim. Should you have a tire failure you don't want the shock to hit the pavement before the wheel rim.

 

The information that all of you provided has been very informative. Thanks a bunch.

 

I am sold on the triangulated setup but am i reading correctly that the 3 bar triangulated (top axle bars attach from axle near third member to a single point on a crossmember at a forward centerline point) setup is preferred over the 4 bar (top axle bars attach from axle near third member to separate points on inboard frame rails at a forward point) triangulated?

 

My '53 has a ladder bar suspension with Vega coil springs and adjustable air shocks. It wasn't overly expensive and rides/handles pretty good. I started with a kit like this: Competition Engineering C2006 - Competition Engineering Competition Ladder Bars - Overview - SummitRacing.com and fabbed the rest to be more like this: Summit Racing 15-0008 - Summit Racing® Rear Frame Rail and Suspension Pro Packs - Overview - SummitRacing.com.

Added: The Competition Engineering link also has instructions for set-up.

 

The 3 bar triangulated is less likely to bind, so it operates more smoothly and doesn't require a panhard bar. I'd need to review my racing suspension texts for determining the ideal length and pivot locations for the Y bar. The apex of the Y can be at a crossmember or reversed to be at the centersection with the 2 pivots at the crossmember, but IIRC the two separate bars should angle so they would theoretically intersect at the front driveshaft U joint. Best to use bushed eyes on the bar ends rather than heim ends for the street. Be sure to use a swaybar.

Ladder bars are designed as a race only suspension and has a lot of similar binding and strain issues as a parallel 4 bar with heim ends when used on the street. Inspect regularly for cracked welds, metal distortion, heim end wear/abuse, replace regularly. They put those safety loops around the heim ends for a reason.

 

i have the tci 4 link and really like it...the ss option also adds some bling too. no binding at all and very adjustable. i do not think you can go wrong with this set-up ..

 

I built a 3 link on mine, just cuz I used to run one on an oval track stock car. Take a look in my pic gallery. It was fairly simple to build.