...

Go Back   Lateral-g Forums > Technical Discussions > Transmission and Rear End
User Name
Password



Reply
 
Thread Tools Display Modes
  #1  
Old 01-19-2011, 10:35 AM
ScotI ScotI is offline
Senior Member
 
Join Date: Feb 2005
Location: Dallas TX
Posts: 623
Thanks: 68
Thanked 165 Times in 122 Posts
Default Determining Driveline Angles

I readily admit, my past projects have been drop & go w/o verifying the driveline angles. They were all mainly 1:1 final drive ratios so vibration wasn't an issue. I never had any issues to be honest & I've lowered almost every vehicle I've owned (GM trucks, ElCamino's, Malibus, Camaros, & 1 x-DPS Mustang). This time I'm trying to improve. I'm finishing up on a 'fresh' chassis for a 1964 pick-up/shop truck. I'm running a 700r4 w/factory style truck arms (2-link + Panhard bar) & understand the driveline angles become that much more critical for vibration free operation. So, I've been digging for info on driveline set-ups. What's correct, what's possible, 1pc, 2pc w/carrier, single u-joint, dbl CV joint, etc, etc.....

From what I understand, the angles @ each end of a 1pc d.shaft set-up should equal each other. I understand this as 3.0° @ the trans suggests I need 3.0° @ the rear end. Anyone want to confirm/correct this?

My reading also suggests these amounts/degrees @ each end of the shaft are to help cancel out the ocillation that occurs as the joint spins (speeding up & slowing down the shaft as it turns). By keeping the amounts similar, they help cancel each other out. Zero is not good either as the needle bearings won't lubricate/wear properly.... minimal (1-2°) difference is desired. Again, anyone that knows this stuff want to confirm/correct this?
If these statements are correct, it shouldn't matter whether the pinion is up or down, as long as the degree amount is similar.... Right??

Hoping this is correct, I played around w/the heights on my chassis until I could yield similar numbers (@ ride height). My starting point was: 4.8° @ the trans output shaft; 2.2° @ the drive shaft (climbing from the trans to the pinion; 2.0° @ the pinion). By slightly raising the trans tailshaft, I was able to achieve 4.2° @ the trans output shaft. I don't have room to raise it any higher for a lower degree.

I then swapped in some 2.5° shims & the new numbers were 4.2° @ the trans output, 1.6° @ driveshaft (again, uphill), & 4.5° down @ the pinion. The 4.5° @ the pinion is on the edge of acceptability from what I've read for a 'street vehicle'; the downside being increased wear on the u-joints. The plus side seems to be as the torque is transferred to the housing, I should remain within my 2° window. Is this correct?

If so, this is something I can live with. This also reduces the amount the truck arm drive shaft hoop must be raised by .500".

Allright experts..... chime in .
Reply With Quote
  #2  
Old 01-19-2011, 11:20 AM
The WidowMaker's Avatar
The WidowMaker The WidowMaker is offline
Senior Member
 
Join Date: Jan 2008
Location: Huntington Beach, Ca
Posts: 773
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Quote:
From what I understand, the angles @ each end of a 1pc d.shaft set-up should equal each other. I understand this as 3.0° @ the trans suggests I need 3.0° @ the rear end. Anyone want to confirm/correct this?
youre concerned about working angles (WA). the WA is a combination of both sides of the angle. so, if your ds was at 0* and your tranny at 2* you have a 2* WA. you want both of your WA's as close to 1* as possible, but not under (needle bearing issue you described). you also want both WA's no more than .5* different from each other. some will say 2-3* difference is ok, but like you said they help to cancel each other out.

if you really want it set up correct, dont fall into the camp that says "equal and opposite" when discussing the tranny and pinion. although that way will set it up correct 90%+ of the time it only takes a little time to measure your WA's and do it the best way possible.
__________________
"The WidowMaker"
70 Chevelle Pro Touring - Garage Built, Backyard Painted
Custom 4 Link & Watts, Rushforth Wheels, Ats Spindles, McLeod RXT Twin Clutch, T56 Magnum, C6Z Calipers & Ring Bros Hinges
Special Thanks To: Rushforth Wheels ; Kore3 ; SC&C
Build Thread : https://lateral-g.net/forums/show...ght=widowmaker
Reply With Quote
  #3  
Old 01-19-2011, 11:58 AM
ScotI ScotI is offline
Senior Member
 
Join Date: Feb 2005
Location: Dallas TX
Posts: 623
Thanks: 68
Thanked 165 Times in 122 Posts
Default

Quote:
Originally Posted by The WidowMaker View Post
youre concerned about working angles (WA). the WA is a combination of both sides of the angle. so, if your ds was at 0* and your tranny at 2* you have a 2* WA. you want both of your WA's as close to 1* as possible, but not under (needle bearing issue you described). you also want both WA's no more than .5* different from each other. some will say 2-3* difference is ok, but like you said they help to cancel each other out.
if you really want it set up correct, dont fall into the camp that says "equal and opposite" when discussing the tranny and pinion. although that way will set it up correct 90%+ of the time it only takes a little time to measure your WA's and do it the best way possible.
It seems spacial concerns will hamper many targeting this 'ideal' range. What is the 'failure' if working angles cannot achieve that target range (as close to 1° as possible)? To ensure I understand this 100%, you add the sides together to yield the WA correct or how does it work (ex: trans output + d.shaft angle = 'front' WA; d.shaft + pinion angle = 'rear' WA)?

*EDIT* I did some additional reading of some GM tech-specs @ lunch & it stated: To calculate the working angle of each intersection subtract the smaller number from the larger to obtain the working angle.

So my set-up would yield 2.6° WA @ the trans & 2.9° WA @ the pinion. These are within the .5° range to be optimum. The spec sheet also indicates up to 4° is acceptable but not to exceed the range. It would seem I can leave things as is, or use a dbl CV style joint @ the trans & remove the pinion shim to put me closer to @ 2° down.

Last edited by ScotI; 01-19-2011 at 02:14 PM.
Reply With Quote
  #4  
Old 01-19-2011, 09:46 PM
The WidowMaker's Avatar
The WidowMaker The WidowMaker is offline
Senior Member
 
Join Date: Jan 2008
Location: Huntington Beach, Ca
Posts: 773
Thanks: 0
Thanked 0 Times in 0 Posts
Default

it depends on how you measure and if you have positive and negative numbers, but your method of subtraction is correct. i usually zero my digital on the ds and then there is no adding or subtracting needed. i just have to rezero every time an adjustment is made, but its a 2 second process.

what was 0*? i ask because if your trans was pointed down in the back, and your driveshaft was climbing up towards the pinion, then you have a 6.6* WA.

Tim
__________________
"The WidowMaker"
70 Chevelle Pro Touring - Garage Built, Backyard Painted
Custom 4 Link & Watts, Rushforth Wheels, Ats Spindles, McLeod RXT Twin Clutch, T56 Magnum, C6Z Calipers & Ring Bros Hinges
Special Thanks To: Rushforth Wheels ; Kore3 ; SC&C
Build Thread : https://lateral-g.net/forums/show...ght=widowmaker
Reply With Quote
  #5  
Old 01-19-2011, 11:45 PM
ScotI ScotI is offline
Senior Member
 
Join Date: Feb 2005
Location: Dallas TX
Posts: 623
Thanks: 68
Thanked 165 Times in 122 Posts
Default

Quote:
Originally Posted by The WidowMaker View Post
it depends on how you measure and if you have positive and negative numbers, but your method of subtraction is correct. i usually zero my digital on the ds and then there is no adding or subtracting needed. i just have to rezero every time an adjustment is made, but its a 2 second process.

what was 0*? i ask because if your trans was pointed down in the back, and your driveshaft was climbing up towards the pinion, then you have a 6.6* WA.Tim

The trans is pointed down, the d.shaft climbs up toward the pinion, & the pinion is now pointed down.
Reply With Quote
  #6  
Old 01-20-2011, 12:54 AM
Vegas69's Avatar
Vegas69 Vegas69 is offline
Senior Member
 
Join Date: Dec 2006
Posts: 8,663
Thanks: 86
Thanked 210 Times in 119 Posts
Default

With a driveshaft sloping UP towards the rear, you add the working angles. A driveshaft that slopes up is no bueno...
__________________
Todd
Reply With Quote
  #7  
Old 01-20-2011, 09:54 AM
ScotI ScotI is offline
Senior Member
 
Join Date: Feb 2005
Location: Dallas TX
Posts: 623
Thanks: 68
Thanked 165 Times in 122 Posts
Default

Quote:
Originally Posted by Vegas69 View Post
With a driveshaft sloping UP towards the rear, you add the working angles. A driveshaft that slopes up is no bueno...
How is it different vs. a d.shaft sloping down?
Reply With Quote
  #8  
Old 01-20-2011, 10:02 AM
Vegas69's Avatar
Vegas69 Vegas69 is offline
Senior Member
 
Join Date: Dec 2006
Posts: 8,663
Thanks: 86
Thanked 210 Times in 119 Posts
Default

Your driveshaft and driveline/pinion are on different planes with a driveshaft sloping up. Compare it to bending your arm at your elbow.

With a driveshaft sloping down, it's on the same plane as the pinion and driveline.

For instance:

Driveline angle/Pinion Angle of 4.2 degrees
Driveshaft slopes up 1.6 degrees
Your current front working angle is 5.8 degrees
Exaggerated example /\

Ideal:
Driveline/pinion at 3 degrees
Driveshaft slopes down 1 degrees
Your working angle is 2 degrees
//

With a working angle of 5.8, you are in jacked up 4x4 territory. I doubt the car will be happy at high speed. All my research calls for less than 3 degrees of working angle for high speed. 1-2 degrees is really ideal. You will need to chop your tunnel or compromise on working angles by running non conventional angles.
__________________
Todd

Last edited by Vegas69; 01-20-2011 at 10:06 AM.
Reply With Quote
  #9  
Old 01-20-2011, 07:23 PM
The WidowMaker's Avatar
The WidowMaker The WidowMaker is offline
Senior Member
 
Join Date: Jan 2008
Location: Huntington Beach, Ca
Posts: 773
Thanks: 0
Thanked 0 Times in 0 Posts
Default

the problem with "is it sloping down or up" is what is that in relation to? if you zero the level on the tranny, your ds will almost always point up. if you zero it on the driveshaft then it brings things back into perspective a little. and its easier to tell what the trans and pinion are doing.

i would put a level on the driveshaft and zero it. i would then put it on the tranny and see what you have. i would next put it on the pinion and adjust it till it is the opposite of the trans. this will give you something like "\_____/" instead of the traditional "\_____\" and it will drop the back of the driveshaft down and improve your front WA. like todd said, you might need to raise the back of the tranny a bunch to make it all work.

let us know what you come up with......
__________________
"The WidowMaker"
70 Chevelle Pro Touring - Garage Built, Backyard Painted
Custom 4 Link & Watts, Rushforth Wheels, Ats Spindles, McLeod RXT Twin Clutch, T56 Magnum, C6Z Calipers & Ring Bros Hinges
Special Thanks To: Rushforth Wheels ; Kore3 ; SC&C
Build Thread : https://lateral-g.net/forums/show...ght=widowmaker
Reply With Quote
  #10  
Old 01-20-2011, 07:44 PM
Vegas69's Avatar
Vegas69 Vegas69 is offline
Senior Member
 
Join Date: Dec 2006
Posts: 8,663
Thanks: 86
Thanked 210 Times in 119 Posts
Default

It really does matter. If your front ujoint is higher than your rear ujoint, you must add the angles. The car could be on it's roof, the same math applies. I remember setting my car up 3 years ago and speaking with knowledgable people inthe industry. They said to subtract the angles. The were wrong then and still are today.
__________________
Todd
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump


All times are GMT -5. The time now is 03:43 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright Lateral-g.net