×
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

chapman strut/ mac ferson strut rear suspension
2

chapman strut/ mac ferson strut rear suspension

chapman strut/ mac ferson strut rear suspension

(OP)
I intend to use a strut-type suspension in the rear of a car. This is (initially) the engine/trans/suspension from the front of a full size GM car (3.8 + 4-speed automatic)
Will the software suggested for SLA suspensions help with this? How sensitive might this be to tilt of struts, either inward or forward/aft?
What about A-arm pivots- horizontal, or axis tilted forward/back?
Initially I intend to just lock the steering rack in a centered position, later replace with hard point mountings for the (formerly steering) links.
Comments? hazards? show-stoppers?
regards
Jay

Jay Maechtlen

RE: chapman strut/ mac ferson strut rear suspension

Tilt is very important, on a McPherson (please note)- the tilt in the YZ plane largely controls the roll centre position. In the XZ plane I think you may have a bit more freedom.

I'd be inclined to keep the A arm square to the strut in side view, and rotate the whole thing about the Y axis to get antidive or prodive.

I don't know about show stoppers, this has been done many times in the past. I'm a bit of a cynic about rear suspensions, so far as I'm concerned they mostly seem to just follow the front around.

 

  

Cheers

Greg Locock

RE: chapman strut/ mac ferson strut rear suspension

(OP)
"... they mostly seem to just follow the front around"
<chortle>
thanks for the info!
jay

Jay Maechtlen

RE: chapman strut/ mac ferson strut rear suspension

I think you'll at least want to use much more rigid control arm bushings when you swap that front end to the back, and you'll want to avoid toe-out in bump.  Some years back there was a group putting SHO Taurus powertrains in the back seat/trunk areas of Festivas (the "Shogun").  Early testing was reported as somewhat disappointing until somebody figured out that while understeer due to compliance up front was a good thing for keeping your average buyer/driver out of trouble with his FWD Taurus, it became vehicle compliance oversteer when the same parts were plugged in at the rear.

Norm

RE: chapman strut/ mac ferson strut rear suspension

Excellent point Norm.

It may be appropriate to soft mount the rack, or make one of the bushes soft, depending one where the rack is relative to the bushes. It is easiest to think about those suspensions which have a lateral arm parallel to the tie rod, and then a leading or trailing link, which can be ignored.

For instance, if the rack is in front of the axle then softening the bush on the lateral arm gives understeer at the front axle. So if you fitted the suspension the same way round in the rear, you'd want to soft mount the rack, to get compliance oversteer on that axle, or vehicle understeer.

And you ALWAYS want compliance understeer, I think.

Cheers

Greg Locock

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