My head hurts after trying to read all of this.
This.
Is their any way somebody can summarize this entire thread and put it into SUPER STUPID layman terms?
I'm installing my 1 piece driveshaft today and instructions say to make pinion angle is at zero. I have an angle finder tool (that aluminum square with a skinny ruler thingy tacked to the middle that has degrees marked).
I have adjustable lowers with CHE lowering brackets. I have NO idea what the angle is now, lol. I just know the car spins like it has 700hp but its probably got closer to 310, so maybe angle is out of adjustment?
You got it! That's what always confused me I thought it was literally supposed to be pointed down but it's not, just supposed to be x degrees down from the trans angle.
This.
Is their any way somebody can summarize this entire thread and put it into SUPER STUPID layman terms?
I'm installing my 1 piece driveshaft today and instructions say to make pinion angle is at zero. I have an angle finder tool (that aluminum square with a skinny ruler thingy tacked to the middle that has degrees marked).
I have adjustable lowers with CHE lowering brackets. I have NO idea what the angle is now, lol. I just know the car spins like it has 700hp but its probably got closer to 310, so maybe angle is out of adjustment?
Yes.
Preliminary foreword for Noobs: Pinion angle matters when you lower your car and / or add an aftermarket driveshaft. Improper pinion angle can make noise and wear out your driveshaft joints.
I want to help clarify pinion angle, as nobody seems to understand it, and even fewer can explain it. I don't even know if I can explain it without pictures, but I will try. (I will add pics / drawings if necessary)
A proper target according to BMR and Steeda is to have the rear pinion flange at minus 1 to minus 2 degrees...with 1.5 being a nice compromise for a street car and -2 being good for drag racing. Coast Driveline Manufacturing, on the other hand, says to set them perfectly parallel. More on that in a few paragraphs.
Here is the skinny. On our cars, according to Coast, the engine / tranny are angled such that the tranny output flange is tilted downward roughly 2.7 degrees.
Imagine if you will for a moment that we LIFT the rear of the car so that the engine crankshaft (and transmission output flange) are perfectly parallel to earth, IE zero degrees of tilt. ...THEN we adjust our upper third link so that the pinion flange also had zero degrees of tilt, it would be parallel to earth...thus our pinion angle would be zero, correct?
Some more examples of ZERO pinion angle (which is what Coast recommends...again, I'll discuss that in a moment):
If the tranny output flange was set to minus one degree, we would have to set the rear pinion flange to plus one degree...they would be perfectly parallel then...thus ZERO pinion angle.
If the tranny output flange was set to (-2) then we would have to put the rear pinion flange at (+2)...they would be parallel...again, zero pinion angle.
If the tranny output flange was at (-3) the rear pinion flange would have to be set at (+3) in order to have zero pinion angle (The Coast recommendation).
Let's discuss the Coast zero degree pinion angle recommendation and what Steeda and BMR say (Rear pinion (-1 to -2 with -1.5 being a great compromise): What happens is when we launch the car, the car "squats" in the rear...the rear pinion flange tilts up, and if you were to put a magnetic angle finder on the front tranny output flange, since the engine and front of the car are raising upward, the tranny output flange would tilt downward (in relation to earth).
If we were to run solid bushings for hard-core drag racing, we could get away with the coast drive-line recommendation of setting zero degrees pinion angle, since squat would be minimized.
However, most of us run polyurethane bushings (BMR calls them "Poly" and Steeda calls then "Urethane"...but it is all the same thing)...and those bushings flex just a little bit. Not as much as stock, but more than solid bushings.
Because of the polyurethane bushings, Steeda and BMR say we should set the rear pinion angle at (-1) to (-2) in relation to the front tranny output flange) so that when you do launch the car from a stand-still, and the suspension squats, the AMOUNT of squat is in that 1 to 2 degree range, and therefore when the driveline is under the MOST stress, the pinion angle is zero and all is parallel.
So, let's run a hypothetical scenario. WE measure a given Mustang, and the front tranny output flange is sitting at (-3) (pointed downward toward ground) you would have to point the rear pinion UP to (+3) if you wanted ZERO pinion angle (remember, zero is parallel), point the rear pinion flange up to (+2) if you wanted (-1) degree of pinion angle, and point it to (+1) if you wanted (-2) degrees of pinion angle.
If you want precisely (-1.5 degrees) of pinion angle which is a good compromise between street and drag, you would have to set the rear to (+1.5 degrees)...again that is if your front tranny output flange is at (-3) degrees.
Whew...that is my best attempt at a textual description.
For stock bushings it doesn't hange that much. It doesn't look like it could be more than 1 degree.
I can't imagine poly bushings in the whole area.
Not really sure why.
What happens when you guys click the pic?
Here is a direct link:
http://s455.photobucket.com/user/bmrfabrication/media/Kelly_Quick_Pinion.mp4.html