Revisiting bumpsteer kit settings - Ford Mustang Forums : Corral.net Mustang Forum
 
LinkBack Thread Tools Display Modes
post #1 of 8 Old 09-26-2017, 12:59 AM Thread Starter
Registered User
 
Trader Feedback: (16)
Join Date: Apr 2015
Location: AZ
Posts: 2,485
Revisiting bumpsteer kit settings

My next project is to install a MM bumpsteer kit. I've been reading up on the science of optimum outer tierod end setup. All of the racing sites refer to an upper and lower A-arm suspension and not a strut/ lower arm setup.

I'm trying to simplify the setup of the adjustable MM outer tierods. Why can't I just set the tierod parallel with the A-arm? Wouldn't the outer tierod and lower A-arm travel in the same arc?

I'm running H&R race springs with poly spring dampers on all 4 corners so the car is lowered a bit. I'm not racing but building for a daily driver with great cornering. Currently; the car hits bumps and the steering wheel turns with no input.

Thanks.


CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
Buyer Beware.
fasterthangas is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 09-26-2017, 09:38 AM
Registered User
 
Trader Feedback: (5)
Join Date: Dec 2013
Location: Camarillo, California
Posts: 265
If the car hits the bumps its not lowered a bit, its lowered quite a bit. If you are hitting the bumps then you will never be able to sort the problem out. That is always going to cause a problem. But that said everyone has a different way of setting up the steering. Over the years I have come up with a way that works for me. I have it set to stock specifications then take it to local track days and start to make adjustments based on what it is doing.

I have a 98 and the only way I was able to get everything to work the way I wanted was to add drop spindles. Once I did that I was able to get the steering angle where I wanted for the car to drive how I wanted.

Also do you want the car to drive real well or do you want track steering? Which for me is not enjoyable on the street.

Jake


After much research, consideration, and experimentation, I have decided that adulthood is not for me. Thank you for the opportunity.
Jakespeed is offline  
post #3 of 8 Old 09-26-2017, 10:00 AM
MFE
Super Moderator
 
MFE's Avatar
 
Trader Feedback: (9)
Join Date: Nov 1999
Location: Phoenix
Posts: 27,649
Getting the tie rod and A-arm parallel will get you very close. I have a laser bumpsteer kit you can use to set it precisely when the time comes. But most often, if the steering changes noticeably when you hit bumps, it's "tramlining", or getting steered by the ruts in the road, more than it is bumpsteer.
MFE is offline  
Sponsored Links
Advertisement
 
post #4 of 8 Old 09-26-2017, 12:29 PM
Registered User
 
Norm Peterson's Avatar
 
Trader Feedback: (0)
Join Date: Nov 2001
Location: state of confusion
Posts: 502
Quote:
Originally Posted by fasterthangas View Post
Currently; the car hits bumps and the steering wheel turns with no input.

Thanks.
Bumpsteer is most evident when you drive over smooth 'heaves' in a curve. Either the car steers slightly if you hold the steering wheel dead-steady (if you can keep yourself from trying to compensate) or you find yourself sawing away at the wheel in order to stay on the same curved path. It's caused by up/down suspension movement that doesn't need a sharp bump in order to happen.

When hitting bumps causes the steering wheel to move, that's more likely a scrub radius issue, where the rearward force from hitting the bump has greater leverage for steering that wheel.


Norm

Mine: '08 GT, 5MT, black/light graphite, un-Fstock (DD, occasional track day)
Wife's: '10 Legacy 2.5GT (DD, six-speed manual)
Spare:'01 20AE Maxima, 5MT (also my bad weather alternate)
Various Loose Parts: '79 Malibu
Norm Peterson is offline  
post #5 of 8 Old 09-26-2017, 01:04 PM Thread Starter
Registered User
 
Trader Feedback: (16)
Join Date: Apr 2015
Location: AZ
Posts: 2,485
Quote:
Originally Posted by Jakespeed View Post
If the car hits the bumps its not lowered a bit, its lowered quite a bit. If you are hitting the bumps then you will never be able to sort the problem out. That is always going to cause a problem. But that said everyone has a different way of setting up the steering. Over the years I have come up with a way that works for me. I have it set to stock specifications then take it to local track days and start to make adjustments based on what it is doing.

I have a 98 and the only way I was able to get everything to work the way I wanted was to add drop spindles. Once I did that I was able to get the steering angle where I wanted for the car to drive how I wanted.

Also do you want the car to drive real well or do you want track steering? Which for me is not enjoyable on the street.

Jake
I think you took me literally. When the tires roll over dips or bumps in the road surface; my steering wheel gets yanked in both directions in one quick movement. Yesterday it did it while driving in a straight line. I haven't noticed it in curves yet.
I'm looking for a great handling and predictable car for every day driving and the occasional curvy mountain road.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
Buyer Beware.
fasterthangas is offline  
post #6 of 8 Old 09-26-2017, 01:14 PM Thread Starter
Registered User
 
Trader Feedback: (16)
Join Date: Apr 2015
Location: AZ
Posts: 2,485
Quote:
Originally Posted by MFE View Post
Getting the tie rod and A-arm parallel will get you very close. I have a laser bumpsteer kit you can use to set it precisely when the time comes. But most often, if the steering changes noticeably when you hit bumps, it's "tramlining", or getting steered by the ruts in the road, more than it is bumpsteer.
I will have to drive over that same area of road again and see if it is a bump or groove. It felt like a bump, but not positive. The car does tramline but this was different. The steering wheel was yanked back and forth quickly when it happened. Thanks for the kind offer. I may take you up on that depending on how close you think that I need to dial it in for my use.
I had thought about putting the car on a drive on alignment rack. I then would attach a large ratchet strap from the rack to the car. This way I can ratchet the front end down a couple of inches thus cycling the suspension and watching toe changes in real time. I would then adjust the spacers as needed to get the least amount of toe change when cycling the suspension.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
Buyer Beware.
fasterthangas is offline  
post #7 of 8 Old 09-27-2017, 08:57 PM
Registered User
 
Jack Hidley's Avatar
 
Trader Feedback: (5)
Join Date: Apr 2000
Location: Danville, CA USA
Posts: 2,976
See the post linked below.

https://forums.corral.net/forums/8565296-post36.html

It has a drawing attached to it that shows the optimum geometry for minimum bumpsteer on a car with a strut. It is analyzed the same way as a car with an SLA, but the strut car has a virtual UCA, instead of a real one. To find the virtual UCA, you draw a line though the upper strut mount at right angles to the strut. This is what forms the upper line in the drawing.

Jack Hidley
Maximum Motorsports Tech Support
Jack Hidley is offline  
post #8 of 8 Old 09-28-2017, 01:18 PM Thread Starter
Registered User
 
Trader Feedback: (16)
Join Date: Apr 2015
Location: AZ
Posts: 2,485
Quote:
Originally Posted by Jack Hidley View Post
See the post linked below.

https://forums.corral.net/forums/8565296-post36.html

It has a drawing attached to it that shows the optimum geometry for minimum bumpsteer on a car with a strut. It is analyzed the same way as a car with an SLA, but the strut car has a virtual UCA, instead of a real one. To find the virtual UCA, you draw a line though the upper strut mount at right angles to the strut. This is what forms the upper line in the drawing.
Thank you Jack.

CHP/CPR (Coast High Performance) / (Custom Performance Racing Engines)347 lasted a whopping 500 miles due to poor machining, metal debris in main bearings, damaged cam bearing and a balance job that was off 64ozs!
Buyer Beware.
fasterthangas is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forums : Corral.net Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Bumpsteer kit question Wicked03GT General Mustang Tech 14 10-21-2013 12:51 PM
For Sale 11-14 NX Wet Plate kit 50-200 Jets Joey7489 Power Adders 4 10-08-2013 12:10 PM
For Sale Maximum Motorsports Bumpsteer Kit 79-93 Mustang "NEW" meangreen92lx Suspension 1 05-13-2013 01:53 PM
All Lowered cars need a bumpsteer kit ? frankstang General Mustang Tech 14 02-29-2012 04:19 PM
For Sale 94-04 mustang bumpsteer kit 6650GT Suspension 3 01-24-2011 07:03 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome