GM A Body Drive Line Angles

FSA1673 · 08-16-2013, 03:23 PM

What are optimum angles for this type of suspsension system. It seems I cannot get the angle of the pinion and the crank to be parallel. The engine/trans is pointing down by 5 degrees, when viewing car from the side it slopes toward the rear. The pinion is currently sloping down toward the ground as well. I have adjustable top trailing arms with heim joints each end and can adjust the angle of the pinion, which also affects driveshaft angle. I can also shim trans mount some as well until header clearance becomes an issue. Should I be more concerned with trying to minimize operating angles of the u joints at each end rather than relationship of the pinion angle to the crank angle.

Any input is much appreciated.

Thanks, Scott

Run to Rund · 08-17-2013, 10:58 AM

The nose of the diff will rotate upward on takeoff, so it should point down a little at rest.

rallye bob · 08-18-2013, 08:08 PM

Quote:

Originally Posted by Run to Rund

The nose of the diff will rotate upward on takeoff, so it should point down a little at rest.

That statement may be confusing to some... And not exactly true....
This may explain the "pinion angle" concept better..... http://www.rosslertrans.com/pinion%20angle.htm

1320racer · 08-19-2013, 08:17 AM

Scott, I thought I answered all your questions/explained how to check/set in our PM's last week.

FSA1673 · 08-19-2013, 11:21 AM

Ed You did.

I just like to get other's opinions on the subject. Never hurts to have agreement. I have everything all set up and will try it in a week or two to see if the changes help.

Any opinions on anti roll bar settings? No preload or pre load passenger side and if so do I make the links longer or shorter?

Thanks, Scott

Stewart Way · 08-19-2013, 12:36 PM

One thing to remember as you look at the Rossler chart is that having zero zero is better than +two-two. Don't have the formula in front of me but I think a 3 degree ujoint misalignment eats 1% horsepower so if you are down 3 on the trans and up 3 on the rear to make them parallel then it is 1 or 2% loss. Don't remember if the formula is for 1 joint or a pair. Work to get 0-0 knowing sometimes you just cant.

1320racer · 08-19-2013, 04:57 PM

Quote:

Originally Posted by FSA1673

Ed You did.

I just like to get other's opinions on the subject. Never hurts to have agreement.

ok, just make sure that these others offering opinion have GM A body cars that leave on par with this one, launching off the footbrake and nearly 3900 lbs.

Jim Kaekel · 08-20-2013, 08:11 AM

[QUOTE=1320racer;395446]ok, just make sure that these others offering opinion have GM A body cars that leave on par with this one, launching off the footbrake and nearly 3900 lbs.

The all knowing, 1320 Racer, speaks again. Get over yourself. That car is not a Stocker, not a Super Stocker. Anyone (with enough money) can stuff a high HP BB Chevy in a Chevelle, Firebird, etc., and go fast.

Rusty Davenport · 08-20-2013, 09:04 AM

[quote=Jim Kaekel;395533]

Quote:

Originally Posted by 1320racer

ok, just make sure that these others offering opinion have GM A body cars that leave on par with this one, launching off the footbrake and nearly 3900 lbs.

The all knowing, 1320 Racer, speaks again. Get over yourself. That car is not a Stocker, not a Super Stocker. Anyone (with enough money) can stuff a high HP BB Chevy in a Chevelle, Firebird, etc., and go fast.

You took the words out of my mouth.....well said.

1320racer · 08-20-2013, 10:36 AM

it ain't about "go fast", it's about getting these cars to work and neither would you know anything about!

Meanwhile, show us your car no mind another GM A body that has gone 1.28 60 foot with a bolt on suspenion, using all and nothing but the factory mounting points, nothing welded and no anti roll bar, launching off the footbrake and weighing 3900 lbs.

The Proof is in the Performance!

08-16-2013, 03:23 PM	#1
FSA1673 Junior Member Join Date: Jan 2010 Posts: 83 Likes: 0 Liked 12 Times in 6 Posts	GM A Body Drive Line Angles What are optimum angles for this type of suspsension system. It seems I cannot get the angle of the pinion and the crank to be parallel. The engine/trans is pointing down by 5 degrees, when viewing car from the side it slopes toward the rear. The pinion is currently sloping down toward the ground as well. I have adjustable top trailing arms with heim joints each end and can adjust the angle of the pinion, which also affects driveshaft angle. I can also shim trans mount some as well until header clearance becomes an issue. Should I be more concerned with trying to minimize operating angles of the u joints at each end rather than relationship of the pinion angle to the crank angle. Any input is much appreciated. Thanks, Scott

08-17-2013, 10:58 AM	#2
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: GM A Body Drive Line Angles The nose of the diff will rotate upward on takeoff, so it should point down a little at rest.

08-19-2013, 08:17 AM	#4
1320racer VIP Member Join Date: Nov 2007 Location: New Jersey Posts: 2,628 Likes: 160 Liked 759 Times in 379 Posts	Re: GM A Body Drive Line Angles Scott, I thought I answered all your questions/explained how to check/set in our PM's last week.

08-19-2013, 11:21 AM	#5
FSA1673 Junior Member Join Date: Jan 2010 Posts: 83 Likes: 0 Liked 12 Times in 6 Posts	Re: GM A Body Drive Line Angles Ed You did. I just like to get other's opinions on the subject. Never hurts to have agreement. I have everything all set up and will try it in a week or two to see if the changes help. Any opinions on anti roll bar settings? No preload or pre load passenger side and if so do I make the links longer or shorter? Thanks, Scott

08-19-2013, 12:36 PM	#6
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	Re: GM A Body Drive Line Angles One thing to remember as you look at the Rossler chart is that having zero zero is better than +two-two. Don't have the formula in front of me but I think a 3 degree ujoint misalignment eats 1% horsepower so if you are down 3 on the trans and up 3 on the rear to make them parallel then it is 1 or 2% loss. Don't remember if the formula is for 1 joint or a pair. Work to get 0-0 knowing sometimes you just cant. __________________ Stewart Way 2424 SS

08-20-2013, 08:11 AM	#8
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,227 Likes: 133 Liked 530 Times in 108 Posts	Re: GM A Body Drive Line Angles [QUOTE=1320racer;395446]ok, just make sure that these others offering opinion have GM A body cars that leave on par with this one, launching off the footbrake and nearly 3900 lbs. The all knowing, 1320 Racer, speaks again. Get over yourself. That car is not a Stocker, not a Super Stocker. Anyone (with enough money) can stuff a high HP BB Chevy in a Chevelle, Firebird, etc., and go fast. __________________ Jim Kaekel 3836 STK

08-20-2013, 10:36 AM	#10
1320racer VIP Member Join Date: Nov 2007 Location: New Jersey Posts: 2,628 Likes: 160 Liked 759 Times in 379 Posts	Re: GM A Body Drive Line Angles it ain't about "go fast", it's about getting these cars to work and neither would you know anything about! Meanwhile, show us your car no mind another GM A body that has gone 1.28 60 foot with a bolt on suspenion, using all and nothing but the factory mounting points, nothing welded and no anti roll bar, launching off the footbrake and weighing 3900 lbs. The Proof is in the Performance! Last edited by 1320racer; 08-20-2013 at 10:48 AM.