86 GT with 438rwhp and TKO trans / spec stage 3.
8.8" rear with Trutrac posi, moser 31 axles, FRPP driveshaft, Steeda L/UCAs.
Everything is brand new and the car vibrates like hell above 85mph. At 75, its perfectly smooth, and by 85, it feels horrible. It's a bit worse under hard acceleration, but it's there at 85 no matter what. I checked it on accel, decel, and in neutral, and it's always there.
It's hard to explain - the vibration comes intense and fades about every second. I've heard other people on here describing the same issue, and now I know what they meant!
Got the driveshaft balanced at Dynotech
Pinion angle is perfect -2.6 deg
Driveshaft runout is .015" in the back and .019" in the front (not sure on the spec)
Brand new tires were just balanced
I don't know what else to look at! Any ideas?
8.8" rear with Trutrac posi, moser 31 axles, FRPP driveshaft, Steeda L/UCAs.
Everything is brand new and the car vibrates like hell above 85mph. At 75, its perfectly smooth, and by 85, it feels horrible. It's a bit worse under hard acceleration, but it's there at 85 no matter what. I checked it on accel, decel, and in neutral, and it's always there.
It's hard to explain - the vibration comes intense and fades about every second. I've heard other people on here describing the same issue, and now I know what they meant!
Got the driveshaft balanced at Dynotech
Pinion angle is perfect -2.6 deg
Driveshaft runout is .015" in the back and .019" in the front (not sure on the spec)
Brand new tires were just balanced
I don't know what else to look at! Any ideas?