Air ride suspension geometry - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Suspension - Brakes - Steering
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 03-20-2009, 12:04 PM
tubbedz's Avatar
Registered User
 
Last photo:
Join Date: Jun 2007
Location: United States
Posts: 120
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Air ride suspension geometry

Hey guys, I'm helping a friend with a "stock", "granny" owned, 1967 Chevelle with a 6-cylinder. The first mod he wants is an "air bagged" suspension. He wants the slammed looked, but wants to hit the drag strip when he replaces the 6-cylinder.

Looking at the rear, coil sprung, suspension we came up with a couple of questions. 1)If we install "air bags" and raise or lower the suspension wouldn't that drastically change the pinion angle?? not good for drag racing 2)Would the driveshaft have to be shortened or lengthened as when the car is lowered the driveshaft would be pushed closer to the trans, then raised, it would be pulled out of the trans???3)Obviously the car would have to be at ride height to have the optimal pinion angle, so that means broken joints/vibrations if drag raced with it lowered or raised???

Thanks for any constructive help, as I would think it would be easier to just lower the car, set the driveshaft/pinion/transmission angle once and go drag racing. Then forget about the "elevator" ride suspension.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 03-20-2009, 01:53 PM
Registered User
 
Last photo:
Join Date: Nov 2005
Location: Windsor
Age: 34
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If you set the length of the upper and lower rear arms properly, there should be almost zero pinion change. My truck is set up with 14" of adjustability, and after a bit of trial and error it runs smoothly with half a degree difference. As far as the driveshaft, it wouldn't pull out of the trans or jam into it with that little travel. Your friend could also look into some of the bolt on kits already made for his car.

http://www.airassisted.com/Bolt-in-A...duct_info.html

This is a great shop to deal with as well. Its Canadian, but they do also have an American warehouse.

You should also look into the rules at the dragstrip as far as suspension requirements, around here, they aren't too fond of air equipped vehicles racing.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 03-20-2009, 03:19 PM
tubbedz's Avatar
Registered User
 
Last photo:
Join Date: Jun 2007
Location: United States
Posts: 120
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Scotto
If you set the length of the upper and lower rear arms properly, there should be almost zero pinion change. My truck is set up with 14" of adjustability, and after a bit of trial and error it runs smoothly with half a degree difference. As far as the driveshaft, it wouldn't pull out of the trans or jam into it with that little travel. Your friend could also look into some of the bolt on kits already made for his car.

http://www.airassisted.com/Bolt-in-A...duct_info.html

This is a great shop to deal with as well. Its Canadian, but they do also have an American warehouse.

You should also look into the rules at the dragstrip as far as suspension requirements, around here, they aren't too fond of air equipped vehicles racing.
Thanks Scotto!!
The reasoning to all these questions was that another friend has an S10 Blazer with 4" lowering blocks in the rear and a 200r4 trans that had to get his driveshaft shortened due to it "kissing" the trans. Also, on our race car with a 4-link suspension, any change in ride height affects our pinion angle and our driveshaft angle. Which affects our instant center and throws the "launch" off.

I hope we're not over thinkin' this.....the pre-made kits should already be engineered correctly
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-12-2009, 10:19 PM
Registered User
 
Last photo:
Join Date: Apr 2009
Location: Amarillo
Posts: 75
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Bags and the strip generally don't work too well together. If he wants a low stance and good grip on the strip...look at coilover suspension. It'll allow the low ride height along with the adjustability that air bags give. But coil springs can be wound to be progressive -- i.e., the first inch of spring compression takes 100 pounds of weight, the second takes 200 additional pounds of weight. These progressive spring rates generally give the best of both worlds...a comfortable ride along with limiting how much the suspension will squat on the line.

The suspension was designed from the factory to limit the pinion angle change to a minimum under normal suspension cycling. When you move away from 'normal' design specs, you just may adversely effect the pinion angle. If it were mine, I'd pull the coil springs then see how much pinion change there is during the entire range of axle movement. If you're talking about more than a couple degrees, then I'd look at some adjustable control arms. If you're serious about the strip, then you're probably going to want to upgrade to some tubular control arms anyway, since the stock stamped pieces aren't known to take the abuse of high horse motors of today.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-13-2009, 02:21 AM
tubbedz's Avatar
Registered User
 
Last photo:
Join Date: Jun 2007
Location: United States
Posts: 120
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thank You hinklejd!! We did remove the coil springs and moved the suspension up and down. With air bags the suspension would probably be raised/lowered several inches more than a stock suspension. So we went past the OEM height and well below the OEM spec. Guess what, the pinion angle changed drastically.

Scotto in your gallery, you have a pic of a truck titled, "rear_frame_clip" and it is slammed on the ground. In that pic the differential is drastrically pointed towards the ground. That is severe negative pinion angle and that would definitely not work at the track. How did you get 1/2 a dgree of pinion angle change when the differential is severly pointed into the ground?? See attached pic
Attached Thumbnails
Click image for larger version

Name:	severe angle.JPG
Views:	166
Size:	12.1 KB
ID:	37589  
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-13-2009, 02:41 AM
powerrodsmike's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Make a fiberglass fan shroud
Last journal entry: Next.. ..Bagging the king B (barge)
Last photo:
Join Date: Jan 2005
Location: gilroy, california
Age: 53
Posts: 4,108
Wiki Edits: 161

Thanks: 0
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by tubbedz

Scotto in your gallery, you have a pic of a truck titled, "rear_frame_clip" and it is slammed on the ground. In that pic the differential is drastrically pointed towards the ground. That is severe negative pinion angle and that would definitely not work at the track. How did you get 1/2 a dgree of pinion angle change when the differential is severly pointed into the ground?? See attached pic

hahahah...I don't think ScottO drives that truck in that condition..
If you look closely at that picture you will see no driveshaft, no brackets or suspension bars...(look at the shadow under the truck, and the ratchet strap in the vicinity of the rear axle...I;ll bet there is a 2x4 in there somewhere too.), and it looks like a first mockup with wheels..The pic of the front shows no motor or trans either..

later, mikey
__________________
my signature lines...not really directed at anyone in particular..

BE different....ACT normal.

No one is completely useless..They can always be used as a bad example
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-13-2009, 09:01 AM
Registered User
 
Last photo:
Join Date: Nov 2005
Location: Windsor
Age: 34
Posts: 126
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
exactly Mike, that was just to roll the frame out of the garage for working. Now its set up and the rear is at 2 deg down, and I just have to pick up a 2 piece driveshaft. I have since put a wishbone on the top to limit front to back and side movement.
Reply With Quote Quick reply to this message

Recent Suspension - Brakes - Steering posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Push-in style air fitting leaks on air suspension shad9876 Suspension - Brakes - Steering 10 02-18-2009 06:24 PM
suspension geometry rachet ralph Suspension - Brakes - Steering 16 12-25-2008 02:06 PM
air ride suspension PaulNJ53Ford Suspension - Brakes - Steering 6 01-13-2006 02:45 PM
Air Ride questions Dknife9 Suspension - Brakes - Steering 6 12-22-2005 06:59 AM
Orange peel in the clear Montypierce Body - Exterior 13 03-06-2005 08:49 PM


All times are GMT -6. The time now is 03:39 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.