For those of you who know my history, I have dealt with a drone in my car since I dualled out the exhaust, not just with flowmasters, but with side pipes and glasspaks under the car. I recently put in a x-pipe and much of that drone is gone. Now while I am driving at highway speeds, I can hear the engine just purring, but there is still a physically-felt, mechanical feeling vibration wave that I would like to work out. Mild, my wife doesn't notice it unless I point it out, but I can feel it, and am pretty sure it is affecting my u-joints. (all the typical culprits have been worked out...new tailshaft housing, new trans and motor mounts, professionally balanced shaft, new joints, etc) I have caltracs that i run at 1-1/2 turns preload, and up until this past week, I had 2 degree shims to adjust pinion angle. With that setup, the vibe was pretty bad, and pretty loud, and I could even feel it pulling down my engine while it reached its crescendo. Especially when I accelerated and further loaded the leafsprings (further adding pinion angle). Friday, i took off the shims, and took a 90 mile round trip yesterday, and it was WAY nicer. Today, I backed off all the preload, and turned the caltracs 4 turns off the spring, basically removing them completely. I am hoping that there is enough slack that the springs will never touch them and make noise, for the time being. My hypothesis is that I am now back to stock suspension except for the 4th leaf, and I may have the pinion angle back to stock, and I should lose the rest of that vibe. Taking a 60 mile round trip today...will let you know. If this works, I will keep it like this and only put about half that preload on only when I take it to the track (which is RARELY). I live near the Royal Purple 1/4 mile track now, so maybe I will get more chance to run it in the near future. But I also don't want to hear the springs slapping the loose caltracs, and would rather hear the slight vibe instead.
Well...made it worse. Going to add preload a quarter turn at a time and see what happens. But first a crawfish and shrimp boil with family!
Well, I turned it 1/4 on and it helped a bit. I will put another quarter on it and try again. When it is not vibrating, it sure is quiet on the inside. Still loud on the outside, though!
The round spinny thing, sits about a 1/8" off my spring, and I put some rubber hose around it, I kinda like the sound, but I really like how the car raises when you get on it.
