View Cart - Checkout

Fourlink (Drag Racing Chassis) Software

FOURLINK is designed specifically to help sort-out your chassis setup and four link (or ladder bar) rear suspension system, for any type of drag race car! FOURLINK allows the racer to use their PC to optimize their four link setup to provide the best launch, reaction time and 60 ft times possible - even before going to the race track with a brand new car! No more guessing about where to locate the four link bars or drawing out intersection points on your garage floor!

Fourlink software screenshot

FOURLINK is powerful software but was written with the novice PC user in mind. The FOURLINK User's Manual includes a simple, 5-step process to setup and optimize your four link suspension system. It even recommends the best four link settings for you! Technical support is always available to all registered users.

Included on this page are sample FOURLINK screens for a typical NHRA Pro Stock Car. FOURLINK includes all the variables required to determine the reaction of your racecar to changes in the four link bar and rear suspension settings.

The first step is to determine all the possible instant center locations that your four link bars will provide. This is done by inputing all the hole locations in the four link brackets on the chassis and rear end housing into the four link geometry worksheet. The FOURLINK program will quickly calculate and display up to 625 possible instant center locations.

To easily sort through this large mass of data and get down to a reasonable number of combinations, the FOURLINK software allows you to reduce the number of possibilities based on four specialized limits - shock separation, instant center window, percent anti-squat range and lower four link bar angle. Usually, a combination of these four specialized limits will get you down to a dozen or so possible four link bar combinations, or hole codes. You can even have the FOURLINK software "recommend" these limits for you, taking all the guess work out of the setup process

Fourlink software screenshot

Finally, the five-step process is used for your specific racecar setup, using your front and rear weights, wheelbase, rear spring and shock rates, tire diameter and estimated 60 ft times. Any of these variables may easily be changed, and the impact on the four link bar setup and racecar reaction quickly determined.

Fourlink software screenshot

Calculated FOURLINK output includes the forces in each of four link bars, the location of the instant center, the calculated percent anti-squat and rear tire "hit". The output also includes the powerful Dynamic Chassis Analysis which shows you what's happening in the critical first second of the launch. This detailed output includes the shock separation and separation velocity, forces in the springs and shocks, and graphically illustrates how the force pushing the rear tires into the pavement varies with time.

Fourlink software screenshot

If you're really serious about getting the most out of your four link rear suspension system, the FOURLINK software is the program for you! This software eliminates testing four link and ladder bar setups that won't work! Easily figure out what four link bar to change and what bar not to change! The FOURLINK software will help improve your knowledge and understanding of four link rear suspensions and also save you time and money!

Fourlink software screenshot


Fourlink - $79 Add to Cart

Software Runs on all versions of Microsoft Windows


Fourlink Math Book

Fourlink - The Book.
Get the formulas behind the Fourlink software.
More Info

Book- $97 Add to Cart

Package Deal:

Book & Software- $137 (Best Deal) Add to Cart

More package deals...

Home - About - Affiliate - Contact - Support - Package Deals
Share this page -