Violent Take-Off Shudder
You were 2.4* pinion nose down to the drive shaft. The MP suspension book says 5-7. No wonder is was shaking. Also of note, with the SS springs, the rear segments of the springs are not "supposed" to be wrapped. Only the front segments.
This is correct Rusty. I will add to this. Though the spec is 5-7, this wouldn't have made much of a difference until I put my foot in it. That 5-7 degrees is for the allowance of axle wrap to avoid trashing your ujoints. I think if I would have stepped on it enough with only a 2.4 degrees of pinion angle delta, I would have exploded the ujoint or even worse, the chunk. One thing I do want to highlight from this is the 0 degree delta from the tailshaft to the driveshaft. This can actually be worse than having your pinion angle out of spec. Why? I am still trying to think that through, but its all in rotational kinematics.
Talk to me about the SS springs. Are you referring to the straps that prevent the springs from spreading under acceleration? I haven't had the opportunity to experiment with that yet. I did read somewhere that auto cars like to have them completely unstrapped from the axle back, but stick cars do not. Do you have some wisdom for me on that?
Not sure that was the right fix, just masking the symtoms with the trans angle change.
View attachment 1715739683
Bad driveline angles would have shook in all gears at all speeds.
☆
I disagree with the masking statement. Your 1st gear will impose the biggest angle change due to axle wrap due to the tall gear. I did have a very slight vibration at around 70 mph +, so that suggests that there was a very small difference in drive angle and pinion angle. The car drives very smooth now even at 80 MPH. Also, I want to point out that with such an aggressive clutch, you cannot have differentiating velocities between the tail shaft and the rear end. Differentiating velocities is a result of not having equal and opposite angles between the clutch and the driveline. This will cause the clutch to have a "skipping" affect during acceleration which is the actual definition of "jerk". This was causing the clutch to grab and let go cyclically (Shudder). That explains the entire problem. With that said, though going with less pressure plate pressure and a non-puck type ceramic clutch would have definitely gotten rid of the shuddering, it would not have fixed the fact that you still have differentiating velocities due to bad drive angle. In the end, that still would have resulted in wearing out the clutch faster. Its all dynamics. I hope this helps explain some of the situation. There are quite a few people who have had this exact same problem and was never able to fix it without swapping to a stock style clutch. If your drive angles are perfect, a puck style ceramic disc is very doable and will take much more abuse.
Clutch is NOT the problem. Driveshaft angles matter...especially when you get into a more aggressive clutch. Putting a rag disc back in the car with 550+ hp would have masked the problem...and resulted in the need to pull the trans once again. The OP and I worked through the problem....and got it right....problem solved.
This is why I do business with folks that care about their customers and their reputation. You show me someone who doesn't trust Dan and I will show you someone I wouldn't pee on if they were on fire. Thanks for all the help brother.
