Engine angle Pinion angle????????
12-20-2010, 04:51 PM
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Engine angle Pinion angle???????? Could somebody give me a hand with engine angle and pinion angle? Its a drag car that will see some street use it has a four link so I can adjust it and it is a big tire car hope to have 425 to 500 rwhp. The motor is sitting at 4 degrees down the drive shaft is 0 and the pinion is 4 degrees up. I see people on here talking about -2 on the pinion. It might not be pinion angle I'm looking for might just be the engine angle I need for now. Just trying to get the engine at the right angle. Ok, I don't know how so I would like to hear your thoughts. I'm using a motor plate and midplate and having to fab cross member so I would like to do it right the first time for a change. Is there anything else you need to know. Thanks 
12-20-2010, 09:30 PM
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12-20-2010, 09:53 PM
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If the trans output is 4 degrees down,(angle finder on the output shaft shows -4.0), I would put the pinion angle up +3 degrees (angle finder on the pinion +3) so under acceleration when the slack is taken up and the rear rotates upward another 1 degree, both ujoints will be in phase.
The negative 2 degree pinion angle for all cars is one of the worst internet myths around....it's broken a lot of u joints and shafts.
Different planes is not a problem since most are built that way. Goal is to phase the u joints under load.
The negative 2 degree pinion angle for all cars is one of the worst internet myths around....it's broken a lot of u joints and shafts.
Different planes is not a problem since most are built that way. Goal is to phase the u joints under load.
12-22-2010, 01:03 AM
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Thanks Thats what I was hoping to hear. I felt being on different plain shouldn't matter but I didn't know for sure. May I'll still try to get a little closer like -2 on the trans and +1 on the pinion or -3 and +2. Its just that any time I move the motor up I loose room for headers. I think I'll be using straws for header tubes now. Thanks Again
12-22-2010, 11:06 AM
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We have to be careful to express these angles in relative terms. The internet "myth" is not really a myth, it's a generally accepted "magnitude of relative axial misalignment" when comparing the angle created between the pinion's axis and the driveshaft's axis when the car is at race weight. 1-2 degrees of axial misalignment is a good target for a 4-link car, 2-3 degrees for a ladder bar car, and anywhere from 4-8 degrees for a leaf spring car. These guidelines are always referring to the angular displacement between the two. Perhaps the myth is propagated by folks not considering that it's meant to be a relative idea.
About your engine's position? Put it where you need to, and don't worry about the driveline's relative angle with the ground line or horizontal.... aim the driveline at the pinion centerline with the chassis as close to race ride height, with the necessary clearances you need to mount exhaust and accessories to the engine. Of course, avoid left/right axial misalignment of the driveline, and don't mount the motor sky-high! Your short wheelbase, lightweight car should wheelie fine without a high center of gravity.
Best of luck!
About your engine's position? Put it where you need to, and don't worry about the driveline's relative angle with the ground line or horizontal.... aim the driveline at the pinion centerline with the chassis as close to race ride height, with the necessary clearances you need to mount exhaust and accessories to the engine. Of course, avoid left/right axial misalignment of the driveline, and don't mount the motor sky-high! Your short wheelbase, lightweight car should wheelie fine without a high center of gravity.
Best of luck!
12-22-2010, 04:58 PM
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"The internet "myth" is not really a myth, it's a generally accepted "magnitude of relative axial misalignment" when comparing the angle created between the pinion's axis and the driveshaft's axis when the car is at race weight."
That is not the myth. The myth is "all fbods should use a -2.0 degrees down pinion angle for best traction". and that's a true myth if ever there has been one....lol..
That is not the myth. The myth is "all fbods should use a -2.0 degrees down pinion angle for best traction". and that's a true myth if ever there has been one....lol..
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12-23-2010, 03:30 PM
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Ahhh yes, the very old and equally ridiculous notion that pinion angle is an uber-critical launch parameter. In the old days of leaf springs, guys would put a huge amount of pinion angle in their chassis tune to soften the hit on the tires. Still waiting on the physics behind how this applies to modern suspensions!
12-23-2010, 08:38 PM
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Ahhh yes, the very old and equally ridiculous notion that pinion angle is an uber-critical launch parameter. In the old days of leaf springs, guys would put a huge amount of pinion angle in their chassis tune to soften the hit on the tires. Still waiting on the physics behind how this applies to modern suspensions!
