Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Neon Body Roll

Status
Not open for further replies.
EMc

EMc

Automotive
Nov 25, 2001
19
Now, where was I?

Thanks to NicB, and Evelrod for engine advice. I wanted to post in this forum since it's a suspension question.

I got an '02 Neon, and immediately began thinking about the usual wheels-springs-exhaust-intake dance routine.

A friend of mine, upon hearing the words "aftermarket springs", immediately says: "Eibach". So, I went to Eibach's website, and got a part number.

Okay... Great. But I read a compact car magazine that said the Neon has a shorter than normal suspension travel, and lowering it at all just makes it slap against the bump stops. The method that was used by the magazine's garage staff was to mount ultra-hard springs (600 lb front and 700 lb rear! The car only puts 675-some pounds at each wheel!) on it. I'm sure it corners like crazy, but I'm sure you also feel it through the seat every time you go over crosswalk lines!

Is there a middle ground between the bump stops and the truck suspension? I would be happy just reducing body roll, if that's possible. Does anybody know?

Thanks,
EMc
 
Replies continue below

Recommended for you

Sort by date Sort by votes
Reducing the body roll is easy and you don't need to touch the coil springs. Up the diameter of your sta bars, throw away the standard rubber bits that link the sta bar to the suspension arms, use ball joints (preferably) or neoprene parts instead, and consider getting different shocks. I found that the body roll as you enter a corner is strongly affected by the shocks, and that subjectively this is a more important effect than the actual roll during steady state cornering.

Note that this will REDUCE your ultimate cornering ability on real road surfaces.

One catch when messing about with suspensions is that people ignore the velocity ratio, that is the ratio of motion at the contact patch, to that at the spring, or shock, or its inverse (I've seen both used). If your VR is say 1.3 then every time you talk about a 650 rate spring then you are 'really' talking about a 500 spring, as far as the contact patch is concerned. Cheers

Greg Locock
 
Upvote 0 Downvote
I agree with Greg. The best solution is to decrease your roll flexability by upgrading the sta bars. Changing a bar diameter is a lot easier than changing springs. Be sure to try and keep the roll couple distribution about the same to start with.
Use the shocks to help fine tune your transient response. This will be difficult without take-aparts. And those (if available) are $$$. Best bet would be to find a manufacture that has off-the-shelf hi-perf shocks.
Another fine tuning tool is to adjust the camber a little bit. Some vehicles have adjustable thrust plates at the top of the shock/spring tower, sometimes rivited into select pre drilled holes. I'm not familiar with the Neon, so I don't know if it does.
Kevin
 
Upvote 0 Downvote
I know Greg was just kidding with his 650 and 1.3 example and really meant to write 384 lb, I know it... Blackbirdblue
"A Honda Blackbird - in Blue - is my company car."
 
Upvote 0 Downvote
Adjusting Camber without knowing what you are doing is a really really bad thing. If you don't have the right equipment (can't measure the angle to 0.1 degrees, I wouldn't touch it. If the Cross Camber or CrossCaster is greater than 0.5, you're gonna feel a pull, you might not be able to pull out of turns as fast and your tires might get chewed up.

If you want to get rid of the body roll, try connecting the two strut towers with a sway bar. You should be able to find one on Ebay or just fabricate one yourself. Or, if you have more $$$ to spend, replace the lower swaybar, change your bushings.

 
Upvote 0 Downvote
Changing camber a little bit has very little effect on tire wear. Toe is the greatest contributer to tire wear. It should be noted that some vehicles have different side to side camber and caster (shock inclination) angles to compensate for torque steer. The statement that changing these could have an adverse effect on torque steer, or pull in straight line driving, is a good point.
Kevin
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

ksw100
  • Locked
  • Question
Designing Roll Moment behavior with increasing body roll.
Replies
7
Views
1K
cibachrome
cibachrome
ksw100
  • Locked
  • Question
Benefits of body roll for street performance cars? 3
Replies
19
Views
2K
cibachrome
cibachrome
ksw100
  • Question
Tire deflection impacts on determining roll center?
Replies
3
Views
2K
GregLocock
GregLocock
ksw100
  • Locked
  • Question
Roll Center analysis with steering angle? 1
Replies
6
Views
1K
cibachrome
cibachrome
afo10
  • Locked
  • Question
Roll Center Documents of Cars
Replies
2
Views
338
cibachrome
cibachrome

Part and Inventory Search

Sponsor

Back
Top Bottom