Gdub
08-18-2016, 05:20 AM
I know there are a ton of threads on this and I have read through a ton of them but I finally made sense of a few and figured out my harmonic vibration issue above 70/75! Now the way I did mine is off the wall and never read it anywhere so I wanted to share it. Maybe I got lucky and this isnt the way to do it but whatever.
For a long time I kept moving my pinion and trans around trying to get these damn angles opposite, and had a few issues along the way. One of my issues kinda was I was not on level ground, its pretty level but still had a little bit of a slope. I know this doesnt really matter but still cause me confusion. I wasnt doing the math correctly i guess? I think some times I was reading a positive angle as a negative or vice versa which causes all kinds of headaches. Any way lets get to it.
First ill give you my specs, car is running a triangulated rear 4 link with standard poly rubber bushings, t56 magnum with 0.50 6th, 3" steel ds, energy suspension trans mount, motor is about 300-350hp 360 Mopar, 3:91 gears.
Ok so I leveled out my drive shaft and measured the angles! Yes I know some people might think im crazy but what I have determined was that the angles of the trans and rear end are relative to the ds. so instead of trying to figure out all this math, why not make the ds at 0* and then what ever your trans is sitting at and your rear end is sitting at is your actual angle! This just hit me the other day like a ton of bricks. I searched and searched for someone who did this but never could find any backing so I said screw it and tried it and boom 90 smooth as butter!! What I found out when I made my ds level is my trans was pointed down towards the ground at .7* but my rear end was also pointed down towards the ground as .5*, which I knew was not right. It was mind boggling at first because what I had the car sitting pretty level in my garage, my trans was like 1.9* down and my rear end was pointed up .5* and the ds was going down hill roughly 1.3* from front to rear. Everywhere I looked, this was supposed to be fine, i was within 3*, my angles were opposite and wanted to give some room for pinion to climb. Well I guess i dont have enough power or something but pinion wasnt climbing. So I put the front tires on blocks, jacked up the rear by the axle so suspension was loaded, and kept going untill my ds read 0*. I adjusted my rear end untill it was pointed up .5*, so now the back of the trans is pointed downhill at the floor .7* and rear end is pointed uphill towards the sky at .5* and the ds is sitting at 0*. I dropped the car back down on the ground, made sure my ds was still running down hill from front to rear and it was, took it for a drive and wow its gone!
To me leveling out the ds took the math out of it and your left with your true angles of the trans and rearend. I kept reading how the angles of the rear and trans are Please feel free to correct me or let me know why this shouldnt work or what issues I may run into doing it this way, i wont get but hurt I just hope this might help someone out there fix there vibration. I have been fighting this for about 3 years now.
For a long time I kept moving my pinion and trans around trying to get these damn angles opposite, and had a few issues along the way. One of my issues kinda was I was not on level ground, its pretty level but still had a little bit of a slope. I know this doesnt really matter but still cause me confusion. I wasnt doing the math correctly i guess? I think some times I was reading a positive angle as a negative or vice versa which causes all kinds of headaches. Any way lets get to it.
First ill give you my specs, car is running a triangulated rear 4 link with standard poly rubber bushings, t56 magnum with 0.50 6th, 3" steel ds, energy suspension trans mount, motor is about 300-350hp 360 Mopar, 3:91 gears.
Ok so I leveled out my drive shaft and measured the angles! Yes I know some people might think im crazy but what I have determined was that the angles of the trans and rear end are relative to the ds. so instead of trying to figure out all this math, why not make the ds at 0* and then what ever your trans is sitting at and your rear end is sitting at is your actual angle! This just hit me the other day like a ton of bricks. I searched and searched for someone who did this but never could find any backing so I said screw it and tried it and boom 90 smooth as butter!! What I found out when I made my ds level is my trans was pointed down towards the ground at .7* but my rear end was also pointed down towards the ground as .5*, which I knew was not right. It was mind boggling at first because what I had the car sitting pretty level in my garage, my trans was like 1.9* down and my rear end was pointed up .5* and the ds was going down hill roughly 1.3* from front to rear. Everywhere I looked, this was supposed to be fine, i was within 3*, my angles were opposite and wanted to give some room for pinion to climb. Well I guess i dont have enough power or something but pinion wasnt climbing. So I put the front tires on blocks, jacked up the rear by the axle so suspension was loaded, and kept going untill my ds read 0*. I adjusted my rear end untill it was pointed up .5*, so now the back of the trans is pointed downhill at the floor .7* and rear end is pointed uphill towards the sky at .5* and the ds is sitting at 0*. I dropped the car back down on the ground, made sure my ds was still running down hill from front to rear and it was, took it for a drive and wow its gone!
To me leveling out the ds took the math out of it and your left with your true angles of the trans and rearend. I kept reading how the angles of the rear and trans are Please feel free to correct me or let me know why this shouldnt work or what issues I may run into doing it this way, i wont get but hurt I just hope this might help someone out there fix there vibration. I have been fighting this for about 3 years now.