Update 7-17: Dyno Wars - Nationals GTG

[KY_BOB]

I hoping to have KY_BOB help me dial in my tune before we start...played around with it while I was on vacation and didn?t get anywhere.

I'll do what I can. 

 

[Loggie]

I'll do what I can. 

That's why I love ya bro...just a little help is all I need

 

[Chopped_Burban]

three runs three different setups....

First without the bottle
Second with the bottle
Third with a new driveline

and for $80 I might run twice

Sorry Loggie, couldn't help myself

 

[Loggie]

Sorry Loggie, couldn't help myself

I'll make sure the local shop has one available

 

[KY_BOB]

bump


I put mine on a dyno last Saturday.  It made  HP and  torque.

 

[KY_BOB]

OK, so it's no big secret but I'll make you work for it. 

 

[MR.SMITH]

I dont wanna dyno but I will probably swing by to watch this. Should be entertaining. That and I havent hugged Loggie in a year.

 

[Hug_R_Av]

I dont wanna dyno but I will probably swing by to watch this. Should be entertaining. That and I havent hugged Loggie in a year.

 

[Loggie]

OK, so it's no big secret but I'll make you work for it. 

Might need to buy another bottle to catch ya  I can?t wait to see my numbers. 

 

[Loggie]

I dont wanna dyno but I will probably swing by to watch this. Should be entertaining. That and I havent hugged Loggie in a year.

Ya might want to watch out, wife will have been gone for a few months by then

 

[MR.SMITH]

Ya might want to watch out, wife will have been gone for a few months by then

Hey I will be just like your wife. Buy me something and we will talk about it.

 

[MR.SMITH]

Does that mean your coming to the dyno?

 

[Loggie]

Hey I will be just like your wife. Buy me something and we will talk about it.

  yep, just like her

 

[MR.SMITH]

  yep, just like her

Heck if your willing to buy me enough I can let you borrow my wife.

 

[ericb]

  yep, just like her

Except Smitty doesn't scare me.

 

[Chopped_Burban]

You guys are making we want to do  things to the Avalanche. Still thinking about that MagnaCharger.

 

[Zoojelly]

BOOM!!!!

Because of this statement, "The rule sof the event are simple in that everyone will run the same. Period. If someone doesn't like the rules then they don't have to play..." I hereby withdraw my entry....


Loggie, you can pay half of the next man's fee.... 

Flabouy told me if I didn't tell you all what happened today he would ...(the description of actions that caused me to go under a trance with all the inhanced interrigation technices I would have to undergo)....

I got my just modified AV on the dyno today with good and bad news

480 HP  and 450 ft Lb torque broken driveshaft

Everything was going good AV tuned idleing @780 rpm. And on the third dyno run , 125 mph, 4800 rpm, 3rd gear locked in and BOOM right in the middle of the shaft it broke ,

denting my new corsa muff and and tranny hump
Yes I have the Z66 with aluminum driveshaft.

It was very scary,,Should I get the mech to pay for repairs? 75038 miles on my extended warranty that only went to 75,000 miles and the company denied my claim. 

 

[ericb]

Ouch.  Sorry to hear that Zoojelly.  Hope you get it repaired soon.

 

[DamonCollins]

ouch!

 

[Spork_Driver]

Now do you all know why I'm leary about putting my baby on one?

 

[Aries]

Flabouy told me if I didn't tell you all what happened today he would ...(the description of actions that caused me to go under a trance with all the inhanced interrigation technices I would have to undergo)....

I got my just modified AV on the dyno today with good and bad news

480 HP  and 450 ft Lb torque broken driveshaft

Everything was going good AV tuned idleing @780 rpm. And on the third dyno run , 125 mph, 4800 rpm, 3rd gear locked in and BOOM right in the middle of the shaft it broke ,

denting my new corsa muff and and tranny hump
Yes I have the Z66 with aluminum driveshaft.

It was very scary,,Should I get the mech to pay for repairs? 75038 miles on my extended warranty that only went to 75,000 miles and the company denied my claim. 

Well, before everyone goes on a tagent again about driveshafts (again)... I am asuming you HAD a stock drive shaft? If so, I am not surprised it broke. The 2wd Driveshaft is a long azz drive shaft and I am not surpised that you managed to break it at that power level.

What i don't see in your posting is WHERE the driveshaft broke... Did it break at a u-joint or did you twist it?

honestly, this can't even be a real discussion until you post where and maybe even some pictures of how it broke.

 

[Waz]

Flabouy told me if I didn't tell you all what happened today he would ...(the description of actions that caused me to go under a trance with all the inhanced interrigation technices I would have to undergo)....

I got my just modified AV on the dyno today with good and bad news

480 HP  and 450 ft Lb torque broken driveshaft

Everything was going good AV tuned idleing @780 rpm. And on the third dyno run , 125 mph, 4800 rpm, 3rd gear locked in and BOOM right in the middle of the shaft it broke ,

denting my new corsa muff and and tranny hump
Yes I have the Z66 with aluminum driveshaft.

It was very scary,,Should I get the mech to pay for repairs? 75038 miles on my extended warranty that only went to 75,000 miles and the company denied my claim. 

Well, before everyone goes on a tagent again about driveshafts (again)... I am asuming you HAD a stock drive shaft? If so, I am not surprised it broke. The 2wd Driveshaft is a long azz drive shaft and I am not surpised that you managed to break it at that power level.

What i don't see in your posting is WHERE the driveshaft broke... Did it break at a u-joint or did you twist it?

honestly, this can't even be a real discussion until you post where and maybe even some pictures of how it broke.

Uh, it appears as tho he did say where it broke.

This shouldn't be a problem though since the first post says we will be running in 2nd gear or closest equivalent.
That should keep the RPMs well down below the danger zone for the long 2wd aluminum drive shafts like my brothers. (Mine too but, my AV is staying home for this GTG.)

 

[Aries]

1 - If the drive shaft was truley broken in the middle of it then it was twisted a part with sheer brute force. Then there is no argument, he flat exceeded the power handling range of the drive shaft. Its a very long Aluminium drive shaft for pete sake!


The bottom line is that if think you are making more then 350HP\350TQ at the wheels you need a custom driveshaft or at the very least to have the balanced checked on the factory one. And if your truck is stock you can have the balanced checked on the stock drive shaft for peace of mind.

I will reiterate that when I read many posts on other forums about drive shafts and they all said the same basic thing; that the stock GM drive shafts will only fail at super high RPM if they are out of balance enough to cause a major bowing of the shaft but, you would feel that vibration long before you hit the failure point. 

Drive shafts don?t just ?Explode? at a certain/speciffic RPM, if the vibration is high enough and finds a point of harmonic vibration the u-joint(s) or Slip Yoke with fail. How ever most every drive shaft failure is due to exceeding the power handling capabilities of the build of the drive shaft. In fact even a perfectly balanced drive shaft can still be tore apart by vibration because with enough power you start to twist the drive shaft and cause it deforms the shape and will vibrate.


It was already agreed months ago that we would run the trucks in 2nd gear to avoid any chance of a possible vibration failure so; bringing all this up yet again is nothing but a headache for everyone and it not proving anything special. If you are concerned just find a local drive line shop that can check the balance of your stock drive shaft, this is very cheap to have done. Or buy an extra stock drive shaft off eBay to bring with you, they are about $100.00.

 

[Aries]

Uh, it appears as tho he did say where it broke.

This shouldn't be a problem though since the first post says we will be running in 2nd gear or closest equivalent.
That should keep the RPMs well down below the danger zone for the long 2wd aluminum drive shafts like my brothers. (Mine too but, my AV is staying home for this GTG.)

There is no actual "Danger Zone", there is no speciffic RPM that a drive shaft can/will fail at due to vibrations. And drive shafts don't just "Explode" from centrifical force either. IF there is excesive vibration it can fail at the U-joint(s) or slip yoke but, you would have to reach an RPM where that Harmonic relationship exsist to cause enough vibration force to cause a problem/fail of a part.

In all actuality you are going to feel any vibration before you reach that point. This is why on the dyno I always make a slow pull up to speed to check for any vibration(s) or funny sounds. If you jump on a dyno and just puch it, then the only person to blame is the driver.

There are just not enough cases/examples of Stock vehicles breaking stock drives shafts on a dyno for anyone to be worried about... As for moddified vehicles, well thats another story all together...

 

[Zoojelly]

I believe it is the high rpm of the shaft with 100 mph speed limited removed that causes problems. and my u joint may have been bad but there was no vibration to warn when it blew