barrok69

Originally Posted by philistine
The stock driveline is a 2pc driveshaft for a reason, the angles

I'm planning on measuring my angles this winter also.

The 2pc driveshaft answer is a simple one. Cost, weight, tolerance and packaging. It is much easier to package a two piece shaft because you can make the diameters smaller over the span of the car and it usually has favorable NVH properties compared to a single piece. The two piece also has better articulation and thus will last longer than a 1 piece over the life of the vehicle. (if designed properly....we all know how crap the V center supports are).

Is this ideal for the aftermarket people... no. but generally the OEM's don't give a **** about that.

The reason ford probably went to the carbon shaft is due to the fact that a 1 piece aluminum one wouldn't fit or meet their specs for power, speed rating and proximity packaging.

A Nissan 370Z also has a carbon shaft stock.

ryridesmotox

I'm pretty sure that FoMoCo did that because the GT500 is capable of 200mph+. That would mean the critical speed of the driveshaft would need to be significantly higher. I believe 50+mph because the stock GT is limited to 155mph +/-... Not saying guys haven't gone faster than that in a GT 5.0 stang. I'm just saying, because Ford builds the 500 with the power to do it, they equip it to do it which is kinda nice. Plus it comes from the FACTORY like that. Its setup and designed to be like that, so proper alignment angles are accounted for. Its not hung in there as a replacement. Just something to consider.

ls1247

iTrader: (2)

point being the 1 piece shaft is a viable option for us....

ryridesmotox

Your issue and the issue others seem to have would indicate that is false. Unless the driveshaft is being produced incorrectly... Which it very well may be.

You always tout the reliability of OEM, yet you went aftermarket and are now floating in a sea of issues with the driveshaft. GM designed it to be a 2 piece. Just saying.

AAIIIC

iTrader: (19)

FWIW, Maximum Motorsports has you do the cross measurements like that when installing their K-member (front cross-member) on a Mustang. (Starts on page 7 with "Squaring the K Member".) However, they tell you to hang the plumb bobs from the suspension pick-up points, rather than from the hubs/brakes. That way the alignment and any bushing flex in the control arms is taken out of the equation and you're only measuring the chassis.

ls1247

iTrader: (2)

If it can work in those platforms it'll work in this one.

As fars as being an authority on what I tout, you aren't.

ls1247

iTrader: (2)

Good info and that's why I started this thread. If I ever bother, the procedure I'd use would be a little more involved than the curiosity measurements I whizzed through the other day....but I still remain confident that while this method may not be accurate enough to square off of, my conclusion is sound.

ls1247

iTrader: (2)

What i might be missing here is whether ford made other changes to the gt500 to accommodate the carbon shafts tendency to transmit harmonics. Wonder if they added dampers or changed transmission/motor mount stiffness??

rjoffe

They may be able to adjust NVH by changing the construction of the carbon fiber. There is all sorts of tricks that can be done by using different layers, resins and layup methods.

54inches

iTrader: (4)

I have talked to several driveshaft shops that believe that the V is too long for a 1 piece.

ryridesmotox

Makes sense. The driveshaft is pretty long as a 1 piece. I wonder if having a more heavy duty joint would make a difference. Like a U-Joint, thinking a big *** pickup. They have pretty long driveshafts as well and many have a single section as long or longer than the V. But I'd like to see some solid data either way

ls1247

iTrader: (2)

I got .025 inches of runout on the front cv last night which would explain all the issues I'm having but if they won't or can't make it right, ill be calling voodoochikn

ls1247

iTrader: (2)

They forgot to include the cv grease caps which also work to center the cvs on the adapters which explains the huge runout.

Great....

Bio248

jesus, man.

i got mine from my parts guy yesterday and it looks like everything is there. so far so good.

54inches

iTrader: (4)

It's not the u-joints, but that would help. it's the length of the shaft and the spinning at high speeds, they come part due to a bending force.

Stay with me here. I believe it starts to become plastic-like and then starts pulling apart. Make sense?

Big trucks don't usually do 200 mph.....

Back to the Subframe connectors.

Someone mentioned high horsepower vehicles. Not a really valid point.

ALOT of uni-body vehicles need them at stock levels; think 2nd, 3rd, 4th gen F-bodys and Fox bodies.....

I have had several that NEVER had more than 250 rwhp and they were starting to show signs of sagging in the doors and unibody.

When the front end hits a pot hole, the front goes up and the back does not move, thus moving the point where it bends between the two subframes.....

Same with the rear.

Joining these two frames eliminates these conditions. Period.

Is this necessary for our Vs, not as much.

I was asked to build them, so we did.

They helped my wheelhop alot in certain normal conditions, notwithstanding sliding sideways when it is wet, off camber situations, wet conditions that change road types. lol

With that said, we wee at the track last weekend and we saw MANY vehicles doing burnouts with wheelhop.

It's common and not just a IRS or CTSV phenomena.

Just my .02.

ls1247

iTrader: (2)

This is reasonably true but is very dependent on how heavy the material being used is. Steel will whip more than aluminum which whips more than carbon.

I personally used an aluminum shaft in an f-body that was 55 inches iirc and it worked fine. Don't expect issues with a 60 inch carbon shaft and the fact that there have been reports of successes with shaft confirms it... People report problems before success all day long.

54inches

iTrader: (4)

Agreed wholeheartedly with your first statement.

When racing the mile, I would rather have a two piece and have failure than a one piece.....I hope I don't have to explain why. lol

ls1247

iTrader: (2)

I just hope the damn thing works. So tired screwing with this thing. Takin 2 vacation days, spent 7 hours in a beat up old truck riding back and forth and now I gotta crawl back under this car.....again.

So to sum it up, nobody has had problems with or noticed that their subframe is shifting under load. Further, after really thinking about it, if I cared to straighten it out, I wouldn't see much movement at all in the pinion shaft angle because the cradle is only moving a half inch at most.

Thanks guys...

Btw....I've heard that a carbon shaft turns to dust when it fails instead of turning into a rotating mass of unhappy metal. Don't know if that's true and I hope I never find out....anybody have any experience with this or is that another thread....

54inches

iTrader: (4)

lol

Well here is my update...the cradle definitely moves.

I pulled the subframe connectors, the cradle and installed the hardest poly bushings available today.

I got 75D Cradle bushings from RevShift; they are not advertised, but you can get any of their bushings in them. Thy are about equal to solid Al.

LOVED THEM!!!!!

I was expecting tons of noise, especially since my backseat is out and my 10" RF blew a few weeks back, but damn if it is still quiet.

With that said, the cradle does move.

I am also suggesting that if someone wants SFCs for their V, then they need to get bushings and install them first.

The rear end feels so good now. The whine in the stock diff is a little more pronounced, but the clunk in the newest diff is horrid.

Still no hop on dryish ground; concrete.....

ryridesmotox

I'm glad I'm not the only one who has a horrific clunk after installing bushings.

The one thing I will say is that, if I'm driving aggressively it seems to be smooth and not clunk at all. If I'm just putsing around it does it pretty bad.