Stock Halfshafts - How much can they take?

[Ninjazx71]

Sorry for another question, but wondering how stout the rear end is on the Gen4's. I know the IRS and LSD are great at putting the power down to the ground on the street and road courses. My question is more about running DR's at the dragstrip. Can this rear end handle hooking up with sticky tires at a prep'd track? I remember on my old "Terminator" the IRS was great and all, except when you get wheel hop. At that point it was choosing to get off the gas, or get ready to just install a solid rear end. Assuming the stock setup on the Gen4's though is probably built a little better than that though... Thoughts?

[Steve M]

From what I've read, the early Gen 4s (early 2008 builds) had the weakest half shafts...they were upgraded for the ACR when it came out later that model year. I'm pretty sure that same upgraded part carried over for the rest of 2008, and all of 2009 and 2010 cars.

That said, they are still likely your next weakest link now that you have a sticky clutch. If I had to place a bet on what would go next if you add sticky tires + a well prepped track, I'd guess it would be them. It's not a cheap proposition to upgrade them, and Gen 4 cars are apparently the most difficult to replace due to how they are secured to the diff. Slowhatch went through this headache when he wanted to swap his ring and pinion from a 3.07 to a 3.55:

http://driveviper.com/forums/threads...ial#post127288

[FrgMstr]

From what I've read, the early Gen 4s (early 2008 builds) had the weakest half shafts...

Is there any way to identify if my 2008 has the weaker or the stronger?

[Steve M]

Is there any way to identify if my 2008 has the weaker or the stronger?

I've not been able to track down that info.

[FrgMstr]

I've not been able to track down that info.

Not the first time I have asked either. My Google-fu is weak!

[Fatboy 18]

My Stock Halfshafts got damaged when a UJ Snapped at the Drag strip! It was my first ever attempt on the Drag strip! Car got 10 ft off the line and BANG!





They were the weakest link on my car! I changed them all thanks to JonB

[Ninjazx71]

My Stock Halfshafts got damaged when a UJ Snapped at the Drag strip! It was my first ever attempt on the Drag strip! Car got 10 ft off the line and BANG!

OUCH! Were you running DR's or stock PS2 type tires? When you changed them, what type did you end up going with?

[Fatboy 18]

Sticky track, no wheel spins prior to launch, I had driven the car to the strip with no problems. Car was running Michelin PS2s, came into Stage, built the revs up to about 3,000 rpm let the stock clutch go on green and Bang!

JonB fixed me up with Unitrax Halfshafts, and a complete set of replacement straps and UJs.
I don't plan on running a Supercharger so went with these ones
http://www.unitrax.biz/?tag=dodge-viper-gts

Full album here
https://www.flickr.com/photos/905823...57633073729716

[Steve-Indy]

Weren't the early half shafts hollow...replaced by solid ones?? The replacements weighed more when I hefted them at the parts counter.

[Fatboy 18]

Weren't the early half shafts hollow...replaced by solid ones?? The replacements weighed more when I hefted them at the parts counter.

Unitrax produced two types of Half shaft ones that look similar to stock which are hollow and can take up to 850 hp then there were the thinner Solid shaft Half shafts which could take over 1000hp
http://www.gounitrax.com/viper.htm

Bottom picture is the stronger one.

[Ninjazx71]

Yeah, I thought I found on Google that they changed from the hollow half shafts to the solid ones part way through the Gen4, but now I can't find where I read it again. Would assume if that was the case, the stronger ones would be the thinner, solid, shafts and the older ones would be the thicker hollow ones. Need to get an eye under the car and take a looksee...

[MalingatorGTS]

While I don't have a Gen3, my Gen2, heads, cam, headers, tune snapped a set of Unitrax on the street with a low RPM uphill launch from a red light. Nothing crazy, but it snapped right in half! They were not at all willing to say it was anything other then "wheel hop." I've had NUMEROUS people who work in the field and others look at it and have all said it was metal failure and not wheel hop!

I didn't ask for a free pair. I didn't ask for anything from Unitax. I was only looking at a snapped halfshaft on a car which doesn't make to max HP the shaft is rated for, on the street and on street tires and asking if there was something the company could do. Other then send it back for a re-build, at full cost, nothing.

I only say this knowing they are seemingly the only game in town, so you don't seem to have much choice in the matter. That said, even good companies have issues. It's how they handle them that matters. I for one will be doing just fine with the stockers back in place!

20150427_131043.jpg

[Fatboy 18]

While I don't have a Gen3, my Gen2, heads, cam, headers, tune snapped a set of Unitrax on the street with a low RPM uphill launch from a red light. Nothing crazy, but it snapped right in half! They were not at all willing to say it was anything other then "wheel hop." I've had NUMEROUS people who work in the field and others look at it and have all said it was metal failure and not wheel hop!

I didn't ask for a free pair. I didn't ask for anything from Unitax. I was only looking at a snapped halfshaft on a car which doesn't make to max HP the shaft is rated for, on the street and on street tires and asking if there was something the company could do. Other then send it back for a re-build, at full cost, nothing.

I only say this knowing they are seemingly the only game in town, so you don't seem to have much choice in the matter. That said, even good companies have issues. It's how they handle them that matters. I for one will be doing just fine with the stockers back in place!

20150427_131043.jpg

I'm going to update this also about these So called Improved products!
UNITRAX SHAFTS ARE JUNK!

This was the LHS that broke last month


And this is the RHS one that broke Yesterday!


Stock engine on Road tires.

[Fatboy 18]

Ouch!

[steve911]

All 08's and later had the solid shafts. The HP increase and the major Diff change that came in the Gen 4's mandated the change. There's an early '08 in the neighborhood and it has the solid "double hump Shafts"

The nice thing about the Gen 3-4 cars is that they are CV's instead of ujoints like the earlier cars.

[Ninjazx71]

All 08's and later had the solid shafts. The HP increase and the major Diff change that came in the Gen 4's mandated the change. There's an early '08 in the neighborhood and it has the solid "double hump Shafts"

The nice thing about the Gen 3-4 cars is that they are CV's instead of ujoints like the earlier cars.

Ah, beautiful! Still though, will go ahead and run on these until (IF!) something happens and then look into some aftermarket solid ones too... but if these are solid already with CV's, I have to imagine they can stand up to some pretty decent beatings.

[Steve M]

All 08's and later had the solid shafts. The HP increase and the major Diff change that came in the Gen 4's mandated the change. There's an early '08 in the neighborhood and it has the solid "double hump Shafts"

The nice thing about the Gen 3-4 cars is that they are CV's instead of ujoints like the earlier cars.

This makes more sense than what I read, but now I can't find where I read it the first time.

[steve911]

The "double hump" CV shafts are acutally an offshoot of the Comp Coupe program.

These stand up pretty well in the World Challenge Cars behind the sequentials which are notoriously hard on diffs and CV shafts due to the shock load when shifting up and down.

[99RT10]

Mine happened on a nice sunny Sunday afternoon, hammering it 2nd to 3rd:



shaft.jpg


And one short-shaft out of the rearend:

[MalingatorGTS]

Funny, I just got this from a buddy who was told, Unitrax would never snap! Just like they told me..wheel hop..RIGHT!!! He's well under the HP rating for his too!snapped 2.jpg

[Steve M]

Wheel hop seems to be the common denominator here, and the only way around that that I've seen is to run a better set of shocks.

[MalingatorGTS]

Wheel hop seems to be the common denominator here, and the only way around that that I've seen is to run a better set of shocks.

Actually with my broken shaft and my friends broken shaft (2 days old) , neither had wheel hop.

I understand we have performance cars and with that, performance parts break, I get it! That said, when a company say good for 800 hp or 1000 hp and your 600 something car snaps a part in half, on street tires, on the street, there's an issue.

Now, things break. It's how a company deals with you AFTER a part fails makes all the difference. Saying you have NEVER had a failure is ridiculous and in this day and age insulting. Accusing a customer of lying is no way to run a business.

Seems a miracle that I was able to post two pictures just from my tiny corner of the world of "we've never had one break" and yet, here two are.

[Steve M]

Actually with my broken shaft and my friends broken shaft (2 days old) , neither had wheel hop.

I misread what you wrote...I thought you did have wheel hop, but instead it was them accusing you of having it causing the break. My apologies.

[MalingatorGTS]

I misread what you wrote...I thought you did have wheel hop, but instead it was them accusing you of having it causing the break. My apologies.

No need to apologize Steve...they are the ones being poor at dealing with customers!

[Steve M]

No need to apologize Steve...they are the ones being poor at dealing with customers!

I've dealt with companies like that in the past, and it is never good for anyone, especially since they are the only ones in the game that I'm aware of.