#21  
Old 07-07-2024, 09:27 PM
soupman soupman is offline
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What if I am just cruising in overdrive, no acceleration? Is there any windup then? A few posts ago it was suggested to match the angles so they are parallel. Is this not ideal?

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Old 07-08-2024, 06:51 AM
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Holeshot71 Holeshot71 is offline
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Yes, ideally you want them to match. I missed that you are using an adjustable torque arm. This is more of a problem with older F-body’s with leaf springs as the differential can wind up on acceleration. You could try playing with the angles some and see if you can find the “sweet spot”.

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  #23  
Old 07-08-2024, 10:52 PM
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Quote:
Originally Posted by Holeshot71 View Post
I don’t believe you want the angles to match. The diff will windup some on acceleration. The diff should be 1~2 deg less than the engine/trans. So if your trans is down 3.8 deg the diff should be up ~1.8 to 2.8 deg.
For drag racing, some people will optimize pinion angle for when the driveline is under heavy load during acceleration. But for a street car, they should be equal and opposite numbers, within 1/2 degree of one another.

From the QA1 website:

Quote:
The slope of the transmission output shaft and pinion shaft should be in the same direction. They should also be within ˝° of each other to avoid driveline vibration.

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Old 07-09-2024, 07:55 AM
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I believe the QA1 recommendation should have read as 'in operation', and not a blanket statement.

Every car is different, weight, shocks, springs, and as the suspension articulates, the angles change. It will change just with someone sitting in the car.

I bet if you measure with 200lbs in the driver's seat it will change by at least a 1/2 degree. Or 200lbs in the trunk.

If you are cruising at a steady state mph on a flat road, the suspension is under load, even if it's not a lot. Every dip, hill, or turn, the angle will change too.

So technically, the 'optimum' angle would be a range, and that's why a good 'starting point' is with @ 1-3 degrees pinion down. Try it, and if because of your suspension or driving conditions it isn't optimal, adjust to suit you.


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Old 07-09-2024, 07:57 AM
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Exception to the rule is if you have an independent suspension rear, but that's another story.


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  #26  
Old 07-09-2024, 03:38 PM
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Ok, I will adjust it down a little, maybe a degree to see what happens. Pretty easy to do with the adjustable torque arm. Thanks

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