×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Four Link Suspension - Drag car

Four Link Suspension - Drag car

Four Link Suspension - Drag car

(OP)
Theoretically, how would I calculate the optimum instant center location for the four link suspension used in a drag race car?  Car specifics:
NHRA E/altered - competition eliminator
Door car - tube frame
Car weight - 2340 pounds
Rear weight - 1190 pounds (51 percent)
Wheel base - 105 inches
Height of C/G - 17 inches
Manual transmission - 3.25 low gear
Rear gear - 5.83
Motor HP- 800 (470 peak torque)
E.T. - 8.10; 1/4 mile speed - 167 mph
I need to improve, and I need help
Thanks,
Podo

RE: Four Link Suspension - Drag car

I'd run simulations with varing IC's and choose the IC that had the highest average rear wheel load over say the first 60ft or so, or however long you have traction problems. But their are probably other ways

RE: Four Link Suspension - Drag car

How do you intend to 167 mph with 5.8 gears.

What is your rolling dia of the tyre.

What RPM are you using.

Is the trans auto or manual.

What is your top gear ratio.

We run about 170mph at over 8000 rpm with 33"tyres and 4.3 diff, and a powerglide.

I can't help with the 4 link as we run ladder bars and set them up about parallel with the ground.

Regards
pat   pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: Four Link Suspension - Drag car

(OP)
To red300zx99x;
You described what I think I need - a good simulation package.  Do you know of any, and how do I obtain one?
Thanx,
podo

RE: Four Link Suspension - Drag car

Check the forum faqs

RE: Four Link Suspension - Drag car

A simple...yet very effective...setup is to keep each link pair parallel (i.e., upper link parallel to lower link), but angled up, from the rear, at an angle with a tangent equal to 17/105 = 0.162 (or 9.2 degrees). This will yield no squat or rise and, at the same time, will not give you any binding problems while cornering. (I'm assuming the links are in the normal "straight ahead" drag race configuration.)

If you wish to cancel out the driveshaft torque (and, of course, you do), add 5 degrees to the right side pair and subtract 5 degrees from the left side. This will get you very close and provide the best 60 foot times.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close