Pinion Angle Changes After Adding Weight to the Front End

What have your experiences been with pinion angle differences between small block applications and big block applications in the same car...you do not have to dilvulge your actual angle if it is a secret just give a + or - number. I am going to throw out a number of -5^ to -7^ of pinion angle. For the baseline increase the launch HP on the big block say on average 200+ looking for the same Hook as the -200HP small block had previously only talking pinion angle not chassis adjustments/shock dampening/springs etc. So we are plus 160 lbs and 200+ HP what happens to the pinion angle?

pinion angle is about keeping the u joints happy......

richter69 wrote:pinion angle is about keeping the u joints happy......

^^^^ This.

"Pinion angle" (aka rear U-joint operating angle) is not and should never be used as a "chassis tuning tool", it can be dangerous. You only set a car's front & back U-joint/driveline operation angles to a given profile (street/highway profile vs strip only profile) to help keep the driveline "happy" under load to avoid vibration and/or the driveshaft "jump-rope effect".

Way back in the old days when tire tech wasn't as good as it is today, and again more recently with the advent of the small 10.5 tire craze, some people would adjust in an excessive amount of pinion angle/rear U-joint operating angle causing greater frictional losses & binding in the drivetrain to try to "help" spinning cars hook better by killing some of the HP/torque reaching the tires during the launch. Some people doing this mistakenly believed that the excessive pinion angles somehow magically changed the suspension's mechanical leverage in relation to the chassis & "hit" the tire harder to increase traction. They were thinking it somehow did the same mechanical change as actually changing/adjusting/moving a given suspension bar to a new hole. The pinion can't (excluding "pinion snubber" type traction setups of course) it's self actually interact with/against any part of the chassis & can't physically/mechanically change how a common drag suspension setup (like a  4-link or ladder bar setup) "hits" the tire.  

Instead of calling it a "chassis tuning tool" excessive pinion angle/U-joint binding is really more of an engine management tool since it in effect steals-away some power reaching the rear tires. Luckily these days there is no reason to use dangerous U-joint binding on a traction/tire limited drag car because of the advent of modern ignition boxes with programmable launch timing retard. Much safer to manage engine power during the launch by pulling some timing out vs doing it by increasing the frictional losses/binding on a spinning driveline assembly.

Thanks X2, The ladder bar and 4-link setups never seemed to have a problem that wasn't tunable, only the leaf spring cars with a trac bar, until the angle and the snubber height were correct they could be wild ponies. The straightest line with the least angle possible is the goal.

This is a very good explanatory video on driveshaft angle and phasing.

https://www.youtube.com/watch?v=T4P75ZQvpws

FalconEh wrote:......The ladder bar and 4-link setups never seemed to have a problem that wasn't tunable, only the leaf spring cars with a trac bar........

Leafspring cars are a whole different can of worms that I never want to mess with again. They can be way too violent with un-restrained big power, and they lack a bunch of adjustment. If allowed in a given class the launch timing retard boxes & traction control boxes would probably sell like hot-cakes to the leafspring guys with monster power.

DILLIGASDAVE wrote:

FalconEh wrote:......The ladder bar and 4-link setups never seemed to have a problem that wasn't tunable, only the leaf spring cars with a trac bar........

Leafspring cars are a whole different can of worms that I never want to mess with again. They can be way too violent with un-restrained big power, and they lack a bunch of adjustment. If allowed in a given class the launch timing retard boxes & traction control boxes would probably sell like hot-cakes to the leafspring guys with monster power.

Not that this small block hasn't been fun I am pretty sure this car won't be the receipient for the inagural BBF stroker, violent is a good term, expansion joints on bridges, and bumps in the road are enough to show the car behind you a frontal view of one of the doors followed by a NASCAR yellow flag side to side tire cleaning , although I does hook hard for small tire leaf spring car at the track.