one piece drive shaft balancing

[kiwimanz]

Hi all,
I have installed a baby T5 in my build and have gone with a one piece drive shaft. The drive shaft was built by Drive line Services here in Portland, very reputable shop so I know its good to go. I think my issue is insuring each end of the dive shaft is parallel to one another.
It looks the diff actually points uphill to accommodate the stock two piece, so to offset this I have shimmed down the cross brace to drop the end of the gear box. See video.
https://www.youtube.com/watch?v=gmV4qwLfOMY

I have been running the car up the road and doing mapping but getting heavy vibration from the drive shaft as the speed rises. Anyone have an idea how to sort this out?
Cheers
Linz

[twin turbo]

IT need to be "straight" line from out of gearbox to difflange.

Lift the box back up? The diff is fairly straight since the 2 piece is also "straight" original.

But if allot of vibrstion, IT might be the prop itself...

[whitelx]

Are you using one of the driveshaft adapters on the diff? You want the angles between the diff and trans to be within 3 degrees of each other. I have about 1.5 degrees. The diff isn't really adjustable, so it's a matter of shimming the trans mount or the engine mounts. I ended up pulling my shims out of the trans mount and shimming the engine mounts to get the angles better. I have very little vibration now and the mount I do have I attribute to a work tailshaft bushing. It's an old junkyard trans that makes a ton of noise and there's a lot of movement at the yoke, it's worn out.

I bought one of the magnetic digital angle finders off amazon. I had tried using an analog gauge and wasn't having much luck.Same with my phone, it just wasn't repeatable. The digital angle finder made it quick and easy.

[my8950]

What's a baby T5?

[kiwimanz]

Thanks guys,
I put a 3' straight edge across the diff flange and measured from the ends to the center of the output shaft on the gear box. It was about a 1mm out of square over the distance to me was pretty darn good. I measures the vertical angle of the diff flange and the gear box output shaft and it was too far out so I have shimmed up the back of the gearbox and I'm about .2 deg out of parallel so I think that should be fine. Just need to run it now
Will report back
Cheers
Linz

[DPDISXR4Ti]

First, as a general statement, getting a vibration-free car with a one-piece driveshaft and the Lima 2.3 is always a challenge with this car. I've had better luck with the 8.8 rear-end, but that could be attributable to several things. As mentioned above, I also had best results by shimming the engine up. Also, make sure your spacers on the transmission x-member are unequal (one side spaced down more than the other).

At the end of the day, I stopped measuring angles and just played around until I came up with a combo that was relatively vibration free.

[whitelx]

I had asked about the driveshaft adapter earlier and didn't see a response about it. It may seem trivial, but it's an important question.

I purchased an adapter and had bad vibrations when I installed the 1-piece mustang driveshaft. This was after I had made sure the angles were good. i took the driveshaft out and had the balance checked on it. I made sure they checked before doing any work. The driveshaft was perfect. Then I took the adapter to them. Turns out with everything bolted together as an assembly, the driveshaft was now out of balance. The adapter was not balanced after production. I had the driveshaft and adapter balanced as an assembly (and marked for orientation) and now no more vibrations.