LS/4l80e swap angle
12-27-2014, 12:28 PM
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Car: 1987 Z28
Engine: 2005 5.3L, LS6 Cam
Transmission: T56
Axle/Gears: DTS 9" 3.50 TrueTrac
LS/4l80e swap angle
well i finally got the 4l80e bolted up to the 5.3L (which is using spohn mounts and poly bushings)
Now my car is on weight jacks and is lowered around 2 inches and I set the trans and motor at 3 degrees down in the rear like most and the trans seems to hang WAY to low. I have a BMR track pak torque arm mount with the hump for the exhaust which as is is around 2.5" off the ground and scraps. The trans pan seemed to he level with that. Now is I set the motor/trans at 0 degrees it seems to tuck up nice and close to the trans tunnel (after hammering)
What is everyone else setting their drivetrain at? Will it have harmonic issues at zero?
Jay
Now my car is on weight jacks and is lowered around 2 inches and I set the trans and motor at 3 degrees down in the rear like most and the trans seems to hang WAY to low. I have a BMR track pak torque arm mount with the hump for the exhaust which as is is around 2.5" off the ground and scraps. The trans pan seemed to he level with that. Now is I set the motor/trans at 0 degrees it seems to tuck up nice and close to the trans tunnel (after hammering)
What is everyone else setting their drivetrain at? Will it have harmonic issues at zero?
Jay
12-31-2014, 11:22 AM
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Car: '86 Camaro, '94 Camaro, 3 others
Engine: LG4 ->L29, L32->LR4, L36, LG4, L31
Transmission: 700R-4, T5WC, 4L80E, SM465, 4L60E
Axle/Gears: 3.42, 3.23, WTB/WTT 2.93
Re: LS/4l80e swap angle
There needs to be some driveshaft angle for keeping the u-joints unseized, but the pinion offset takes care of that. With the torque arm, the rear axle doesn't need the pinion down 3-4 degrees. Angling the engine and trans makes no sense, put them how they fit the best. Ideally, the trans output shaft should be pointing at the axle pinion shaft at static ride height, and vice versa.
To better help illustrate this, If this was a 4x4 truck with a lift, and a multi-link rear suspension, not leaf sprung, with equal-length upper and lower longitudinal links, you'd want the trans angle and pinion angle both at zero, all the angle would be in the driveshaft. But in this example the angle is vertical, so the pinion can be centered.
In our cars, the pinion angle is already horizontal, with any and all of the bolt-in axles, so you don't need any vertical.
But because U-joints are not constant velocity, not only do the need to be in phase when the yokes are welded to the driveshaft tubing, they also need to run equal angles. In the 4x4 truck example, if the front angle was 8 degrees down near the trans, then the rear angle near the axle should be 8 degrees up.
So if your trans ends up longitudinal in the car, and you really can't get it much wrong, then the angles correct, as the pinion shaft is automatically longitudinal.
Correcting the pinion angle for non-stock ride heights requires an aftermarket adjustable torque arm.
And all this is overkill anyway, there's no telling how many trillions of miles have been driven with some measurable error but no ill effects.
To better help illustrate this, If this was a 4x4 truck with a lift, and a multi-link rear suspension, not leaf sprung, with equal-length upper and lower longitudinal links, you'd want the trans angle and pinion angle both at zero, all the angle would be in the driveshaft. But in this example the angle is vertical, so the pinion can be centered.
In our cars, the pinion angle is already horizontal, with any and all of the bolt-in axles, so you don't need any vertical.
But because U-joints are not constant velocity, not only do the need to be in phase when the yokes are welded to the driveshaft tubing, they also need to run equal angles. In the 4x4 truck example, if the front angle was 8 degrees down near the trans, then the rear angle near the axle should be 8 degrees up.
So if your trans ends up longitudinal in the car, and you really can't get it much wrong, then the angles correct, as the pinion shaft is automatically longitudinal.
Correcting the pinion angle for non-stock ride heights requires an aftermarket adjustable torque arm.
And all this is overkill anyway, there's no telling how many trillions of miles have been driven with some measurable error but no ill effects.
12-31-2014, 11:44 AM
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12-31-2014, 11:53 AM
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