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Car Yaws Left on Acceleration

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Old 07-19-08, 12:18 AM
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Car Yaws Left on Acceleration

I just bought an 1987 LX with just only 9K original miles. The car looks new and runs great, but has an unusual handling quirk. When I accelerate hard in the lower gears, the car yaws to the left; correspondingly, it yaws right if I snap off the gas. I have had the wheel alignment checked, and it is within specs.

I know the rear suspension of these cars is set up to vary the suspension geometry during cornering. Is the yaw a characteristic of these cars, or do I have a suspension problem (bushings too soft due to age, perhaps)?

I look forward to being a part of the RX-7 community.
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Old 07-19-08, 02:31 AM
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Yaw, to rotate about a vertical axis; used in naval architecture, navigation, aeronautics and flight dynamics. Rotation about horizontal axes are called pitch and roll.

i had to wikipedia what the **** a yaw is.

john ny
Old 07-19-08, 05:03 AM
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With my very limited knowledge, I will say it is because the engine turns one way really hard causing the car to yaw and when you lift off the gas the engine load lowers lessening the yaw. I just pulled crap out of my *** so don't get at me for being wrong
Old 07-19-08, 08:46 AM
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it does sound like the bushings on one side of the rear suspension acting up. Part of the suspension toe change is due to jounce or droop of the wheel, part is due to side loading. What may be happening is one wheel is toe-ing more due to bad bushings in jounce (when excellerating), pushing the rear end one direction, while in droop (braking, engine braking etc) it twists the opposite direction, pulling the rear end the other way. Definitely take a look back there and make sure everything is nice and snug, and there is not a lot of play.
Old 07-19-08, 08:58 AM
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Originally Posted by dawicka2
Yaw, to rotate about a vertical axis; used in naval architecture, navigation, aeronautics and flight dynamics. Rotation about horizontal axes are called pitch and roll.

i had to wikipedia what the **** a yaw is.

john ny
John,

I used the term Yaw as compared to "pulling to the right/left" to describe this problem as it is different than the effects of torque steer felt on a front wheel drive. Here, the car changes the direction it is heading with no apparent change in the steering angle of the front wheels.

This issue is talked about quite a bit in the 3rd Gen forum, where the problem has been traced back to uneven tire wear or air pressure. My tires are new, and the air pressure is 32PSI all around.

Any help will be much appreciated.
Old 07-19-08, 09:22 AM
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What you are describing is deflection caused by loose or worn parts. Given the low mileage I would check for loose fasteners and then for deteriorated bushings. This is not a normal characteristic.
Old 07-19-08, 09:54 AM
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The *** end of my 87 TII used to "jig" several inches to the right every time I shifted. It was worse the harder you shifted into each gear. The problem lied in the passenger "rear steer" bushing on the hub being shot. I installed DTSS eliminator bushings (also called rear toe eliminator bushings) which 100% cured my problem. As far as I am concerned, this is one of the best mods you can do to the car. The DTSS loses usefulness quickly even when it works functionally. Also a good time to do rear wheel bearings if needed.
Old 07-19-08, 11:37 AM
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Install an adverse yaw compensator in the Feel and Trim assy (F-111 thingamajig).

I had something similar on a turbo car. It was the right rear lateral link that was bent by the previous owner somehow. If you had it aligned you'd think they would have seen that.
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