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Pinion angles

Started by Canadian1968, August 02, 2020, 08:05:37 PM

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Canadian1968

Crawled under the car tonight and measured the angles of my tailshaft and diff .

THE tranny looks to be 2.7 down ( x pipe made this harder than it should have been !) And my diff is pointing up 1.7.

Although almost parallel they are opposite of what I want I want the trans up and the diff down. I'm wondering if my transmission mount is that worn that it is sagging a bit ? I will need some pinion angle shims to correct the diff housing

cdr

Quote from: Canadian1968 on August 02, 2020, 08:05:37 PM
Crawled under the car tonight and measured the angles of my tailshaft and diff .

THE tranny looks to be 2.7 down ( x pipe made this harder than it should have been !) And my diff is pointing up 1.7.

Although almost parallel they are opposite of what I want I want the trans up and the diff down. I'm wondering if my transmission mount is that worn that it is sagging a bit ? I will need some pinion angle shims to correct the diff housing

trans will be down about 3 that is the way they are built ,, what you have should be good, no way can you get the trans UP , it would hit the floor
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

Canadian1968

Alright.  I guess those specs give me 1* total down. u think I want to add 2* to give me a total of 3* see how the car likes it

cdr

Quote from: Canadian1968 on August 03, 2020, 07:37:06 AM
Alright.  I guess those specs give me 1* total down. u think I want to add 2* to give me a total of 3* see how the car likes it

are you having a problem now? if you are drag racing you would want the pinion down a little more, what you want is under a load to have them parallel 
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

Canadian1968

no vibrations at all. 
Yes I am looking for more bite at the track and just alround in general. Always felt the car seem very loose even for a street tire .

If I point the nose down to far will I not start to run into over all drive train problems ?

2 degree shim would put the diff more or less level but my overall pinion angle would be 3 degrew down from what I have been told .

if I were to put in a 4 degree it would put me at 5 .

cdr

Quote from: Canadian1968 on August 03, 2020, 10:26:54 AM
no vibrations at all. 
Yes I am looking for more bite at the track and just alround in general. Always felt the car seem very loose even for a street tire .

If I point the nose down to far will I not start to run into over all drive train problems ?

2 degree shim would put the diff more or less level but my overall pinion angle would be 3 degrew down from what I have been told .

if I were to put in a 4 degree it would put me at 5 .

leave it alone, in your case adding angle will not help your car get better traction, better tires will
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

XH29N0G

I'm with the others on this.  The general idea with harmonics is diff parallel with transmission under load.  I know moving the front down will have an effect, but do not know how much that would be.

I also agree that for traction, I would first look to tires. 
Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....

c00nhunterjoe

Leave it be. Why do you feel the pinion angle is causing traction problems? Im intrigued. Give me a rundown on the combination and what it is doing at the track.

Canadian1968

well one reason I thought it would be a problem is that the examples that I have read. Say that you want the nose off the diff down  ( how much depending onnyour setup ) . the reason being under accel. the diff wants to move up, and if your angle is down at rest the idea is to get to 0 or level to help the suspension push the tires into the ground .

So when i saw that my diff was already pointin up at rest I thought under accel it will be moving up even more and possibly pulling the tire away from the ground instead of into ?

The car jus breaks loose very easy Im jist trying to make sure evert thing is right before i start throwing more tire at it

XH29N0G

My guess is the breaking loose is the tires.  I suspect my set up is not that different from yours from what I have seen of your earlier posts and how my car seems to behave at the drag strip.  I had to go to a soft compound tire and use 255 M/T drag radial to keep it from breaking loose.  There are some disadvantages to those tires, but I like them. 

The alignment of pinion angles might not be right on full acceleration for me, but I do not know if we would feel it during the time we are there compared with the times we are driving normally.  I did move things around and found other things changed as I did.  I moved them around because I had driveline vibrations.


Who in their right mind would say

"The science should not stand in the way of this."? 

Science is just observation and hypothesis.  Policy stands in the way.........

Or maybe it protects us. 

I suppose it depends on the specific case.....

BSB67

The pinion angle and traction logic is very broken.  The pinion angle will not change the amount of axle wrap-up. It is the distance between the snubber and the floorboard at rest.


500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph