GM A Body Suspension ?.....

Wade_Owens · 08-10-2008, 01:52 PM

I have a 66 Chevelle 283/PG combo. When the car leaves, it hooks good initially, then unloads and spins a little. It seems to spin as the front tires come back down, unloading the rear tires. Will pinion angle cause this on these cars? I do have adjustable top bars where I can fine tune this. I have Calvert shocks and Santhuff front springs. If the track is really good, it never does this. All of my previous race cars have been leaf or ladder bar stuff. Just not sure what the coil cars like......

Any and all help and comments are appreciated!

Thanks,
Wade O

Alan Roehrich · 08-10-2008, 02:10 PM

Pinion angle is the included angle in the rear u-joint, AKA the difference in angle between the drive shaft and the pinion centerline. Nothing more, nothing less. The only reason to adjust pinion angle itself is to get it to be about 2 degrees down under power.

Are you sure you're not topping out the front suspension? If the front tops out too quickly, it will unload the rear tires, especially on a lower HP car that cannot lift the front tires and carry them. On a really good track it'll still hook because you don't need as much weight transfer to maintain traction.

Jeff Goss · 08-10-2008, 05:04 PM

If this isn't a Stocker, put an anti-roll bar in it. This will plant the tires evenly. A 283 isn't making any torque, so this should sort things out easily.

Jeff

08-10-2008, 07:32 PM

How about a good 12-way adjustable front shock to control how quickly the front end settles back down? If you could "slow" this down and control it perhaps you could keep from unloading the suspension too quickly. I know Hal (QA1) makes a very nice one that I've used but not sure about your particular application.

Good luck.

Mark Yacavone · 08-10-2008, 07:59 PM

Wade, Are you using Air Lift bags? How much preload?
How about no hop bars on the housing?
How much ballast?
What technique are you using to leave the line?
I think we need more info here.

Good luck at Indy.

greg fulk · 08-10-2008, 09:25 PM

Wade my car dose the same thing on a not so good track! I have air bags on both side 30lbs passengers side 10lbs on the drivers. The car wants to leave with the wheels up then unload spin then go again?

Wade_Owens · 08-11-2008, 09:50 AM

I do have an anti-roll bar on the rear. I have tried with and without an airbag at different settings. It has done this at "K" weight (which I'm a little heavy for), and at "M" weight, 3250lbs. I do have a weight box over the right rear tire, along with the battery and fuel cell.
The best percentage I can get is 52% on the nose, it only gets worse from there, unless I run the car well over min......

Wade O

Jack McCarthy · 08-11-2008, 10:20 AM

wade... delay the nitrous shot another 100 foot should take care of it

captain jack... cya at bowling green ?

p.s. wanna try that convertor at bg ... test on monday ???? let me know

Signman · 08-11-2008, 10:29 AM

Hook and spin generally indicates the tire is being thrown up into the wheel house. As the car moves down track the slick is trying to roll over itself. A stiffer compression setting in the rear shocks will help. Had this problem with my footbrake chevelle. Went to stiffer setting on the Konis and it does not do it any longer. Many A-Body cars that are successful run the rear shocks with loose extension and stiff compression. Just the basics. Oh yea, the Hoosier radials helped a bunch too.

Greg Barsamian · 08-11-2008, 12:52 PM

Wade, Check this out.http://www.bmrfabrication.com
It works on both Automatic & Stick applications.
Greg

XTREME ANTI-ROLL BAR

If your a drag racer, this is the anti-roll bar for you. No cutting or welding required and since we engineered this bar around the original contours, it clears OE and all OE-style rearends and aftermarket exhaust systems.

Massive 1-3/8" bar diameter
Easy bolt-on design with the option to be welded
Heavy duty 1/2" rod ends
Billet bushing saddles
The factory rear swaybar works well for handling but falls short when it comes to drag racing. There are two main reasons for this. One, the OE bar diameters are nowhere near the right diameter to control torque loading on a launch. And second, the OE-type bar only attaches at the control arms with no frame attachment points. This allows too much body separation and no way to control it. By attaching the endlinks to the frame, body separation is eliminated and that energy transferred to forward momentum. This, combined with the large diameter bar's ability to better control torque loading, creates more consistent and predictable launches and better 60 ft/times. Provided with all necessary Grade 8 mounting hardware. Available in Black Hammertone or red powdercoat.

XSB006 64-72 A-body Xtreme rear swaybar - 3" axle tubes $399.95
XSB006-3.25 64-72 A-body Xtreme rear swaybar - 3.25" axle tubes $399.95

08-10-2008, 01:52 PM	#1
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	GM A Body Suspension ?..... I have a 66 Chevelle 283/PG combo. When the car leaves, it hooks good initially, then unloads and spins a little. It seems to spin as the front tires come back down, unloading the rear tires. Will pinion angle cause this on these cars? I do have adjustable top bars where I can fine tune this. I have Calvert shocks and Santhuff front springs. If the track is really good, it never does this. All of my previous race cars have been leaf or ladder bar stuff. Just not sure what the coil cars like...... Any and all help and comments are appreciated! Thanks, Wade O

08-10-2008, 02:10 PM	#2
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,915 Likes: 996 Liked 1,044 Times in 274 Posts	Re: GM A Body Suspension ?..... Pinion angle is the included angle in the rear u-joint, AKA the difference in angle between the drive shaft and the pinion centerline. Nothing more, nothing less. The only reason to adjust pinion angle itself is to get it to be about 2 degrees down under power. Are you sure you're not topping out the front suspension? If the front tops out too quickly, it will unload the rear tires, especially on a lower HP car that cannot lift the front tires and carry them. On a really good track it'll still hook because you don't need as much weight transfer to maintain traction. __________________ Alan Roehrich 212A G/S

08-10-2008, 05:04 PM	#3
Jeff Goss Member Join Date: Nov 2001 Location: Burlington, WA Posts: 361 Likes: 1 Liked 0 Times in 0 Posts	Re: GM A Body Suspension ?..... If this isn't a Stocker, put an anti-roll bar in it. This will plant the tires evenly. A 283 isn't making any torque, so this should sort things out easily. Jeff

08-10-2008, 07:32 PM	#4
Gear Jammer '94 Guest Posts: n/a	Re: GM A Body Suspension ?..... How about a good 12-way adjustable front shock to control how quickly the front end settles back down? If you could "slow" this down and control it perhaps you could keep from unloading the suspension too quickly. I know Hal (QA1) makes a very nice one that I've used but not sure about your particular application. Good luck.

08-10-2008, 07:59 PM	#5
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,418 Likes: 2,582 Liked 4,453 Times in 1,694 Posts	Re: GM A Body Suspension ?..... Wade, Are you using Air Lift bags? How much preload? How about no hop bars on the housing? How much ballast? What technique are you using to leave the line? I think we need more info here. Good luck at Indy. __________________ We are lucky we don't get as much Government as we pay for..... Will Rogers Last edited by Mark Yacavone; 08-11-2008 at 12:54 AM.

08-10-2008, 09:25 PM	#6
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	Re: GM A Body Suspension ?..... Wade my car dose the same thing on a not so good track! I have air bags on both side 30lbs passengers side 10lbs on the drivers. The car wants to leave with the wheels up then unload spin then go again? __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

08-11-2008, 09:50 AM	#7
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	Re: GM A Body Suspension ?..... I do have an anti-roll bar on the rear. I have tried with and without an airbag at different settings. It has done this at "K" weight (which I'm a little heavy for), and at "M" weight, 3250lbs. I do have a weight box over the right rear tire, along with the battery and fuel cell. The best percentage I can get is 52% on the nose, it only gets worse from there, unless I run the car well over min...... Wade O

08-11-2008, 10:20 AM	#8
Jack McCarthy VIP Member Join Date: Feb 2002 Location: lyndon ky. ... louisville area Posts: 1,284 Likes: 22 Liked 352 Times in 92 Posts	Re: GM A Body Suspension ?..... wade... delay the nitrous shot another 100 foot should take care of it captain jack... cya at bowling green ? p.s. wanna try that convertor at bg ... test on monday ???? let me know __________________ Jack McCarthy 3609 STK "the Captain"

08-11-2008, 10:29 AM	#9
Signman Member Join Date: Oct 2003 Location: Lower Slower Delaware Posts: 493 Likes: 14 Liked 199 Times in 74 Posts	Re: GM A Body Suspension ?..... Hook and spin generally indicates the tire is being thrown up into the wheel house. As the car moves down track the slick is trying to roll over itself. A stiffer compression setting in the rear shocks will help. Had this problem with my footbrake chevelle. Went to stiffer setting on the Konis and it does not do it any longer. Many A-Body cars that are successful run the rear shocks with loose extension and stiff compression. Just the basics. Oh yea, the Hoosier radials helped a bunch too. __________________ Frank Ferrucci ?/SA 1271

08-11-2008, 12:52 PM	#10
Greg Barsamian VIP Member Join Date: Jan 2002 Location: Central Massachusetts Posts: 1,383 Likes: 609 Liked 390 Times in 84 Posts	Re: GM A Body Suspension ?..... Wade, Check this out.http://www.bmrfabrication.com It works on both Automatic & Stick applications. Greg XTREME ANTI-ROLL BAR If your a drag racer, this is the anti-roll bar for you. No cutting or welding required and since we engineered this bar around the original contours, it clears OE and all OE-style rearends and aftermarket exhaust systems. Massive 1-3/8" bar diameter Easy bolt-on design with the option to be welded Heavy duty 1/2" rod ends Billet bushing saddles The factory rear swaybar works well for handling but falls short when it comes to drag racing. There are two main reasons for this. One, the OE bar diameters are nowhere near the right diameter to control torque loading on a launch. And second, the OE-type bar only attaches at the control arms with no frame attachment points. This allows too much body separation and no way to control it. By attaching the endlinks to the frame, body separation is eliminated and that energy transferred to forward momentum. This, combined with the large diameter bar's ability to better control torque loading, creates more consistent and predictable launches and better 60 ft/times. Provided with all necessary Grade 8 mounting hardware. Available in Black Hammertone or red powdercoat. XSB006 64-72 A-body Xtreme rear swaybar - 3" axle tubes $399.95 XSB006-3.25 64-72 A-body Xtreme rear swaybar - 3.25" axle tubes $399.95