No, YOU'RE not "getting it". So pay attention, you may learn something. No matter how you bolt the powertrain into the car, the crank still rotates. And Newton's 3rd law states that in order to accelerate the crank, you have to exert an equal and opposite force. So you have a twisting torque trying to rotate the car against the crank, lifting the left side wheels and pressing the right side wheels into the ground. Thus you have a higher coefficient of friction on the right side than you do on the left, and if you apply enough force to break traction on both tires, the car will lose traction on the left side first, causing the fishtail. The reason I posted that pic was because it illustrates this very well. Just because the corvette suspension is more sorted out doesn't mean the forces don't still exist.

You can see in these two shots, that even though the vette is launching better than that old impala, the left wheel is higher.

https://cimg6.ibsrv.net/gimg/www.cor...d858f985c9.jpg

https://cimg7.ibsrv.net/gimg/www.cor...baff63e357.jpg

As far as the sidewinder dragsters, you can look those up yourself. Don Garlits was the one I remember as a kid running a top fuel sidewinder. Look him up.

You just posted pictures of 2 c4 vettes, and guess what neither of those 2 cars have? A torque tube :willy::thumbs:

As to your "weight of the crank being enough to exert force to one side of the car or the other to cause frame twist" theory....

then revving the car in my driveway in neutral will show the total force you speak of. :rolleyes:

Further, most people launch at 2-3000 rpm anyway, so the crank has already undergone its acceleration and has already exerted its force on the car, and then everything equalizes again once a steady RPM is reached (but still, this is a tiny force to begin with)

The twist that you are siting in the photographs is on cars that have a conventional drive shaft, and the frame of the car has to prohibit the engine and trans spinning one way, and the rear diff and rear axle spinning the opposite.

It would help your argument if you posted photos of cars with torque tubes , and then showed me THOSE CARS twisting. I'll go grab a snickers while you look for one :lurk:

Please, think about this a little longer this time because i know im correct. You are not.

https://cimg3.ibsrv.net/gimg/www.cor...a6b9cc5554.jpg

well, you are about to have a whole forum of people politely come down on you, because a car with a torque tube cant twist its frame unless the torque tube is also twisting, which they don't do, they are solid or they just snap.

They are made out of barrel woven/rolled carbon fiber these days in the c7z's.. where the whole thing is made from a single strand of carbon fiber that is ran up and back the tube during construction like kite string or fishing line on a spool.

Pretty brittle stuff.. aka no give.

And the reason why torque tubes DO CRACK is because they are FIGHTING TO PREVENT THE CAR FROM TWISTING 1 IOTA DURING THE CAR'S LAUNCH, and cars with enough Torque and Traction sometimes win the war and get the car to twist, and that equals a cracked torque tube.

Post up another smart guy meme, and pretend im the dumb one.
https://cimg5.ibsrv.net/gimg/www.cor...f995fd6a06.jpg
https://cimg6.ibsrv.net/gimg/www.cor...382574c6a6.jpg


https://www.corvetteforum.com/forums...e-cracked.html

I don't think your mind is where it needs to be for learning to occur.

I posted a pic of a car w/a tq tube; a C5. I also posted a pic of a IRS car w/o a tq tube; a C3. Doesn't matter; the tq is resolved w/in the frame of the car, either way.

Who said anything about "the weight of the crank shaft"!? Not me.

Finally, I don't need to look up Don Garlits; know who he is...but far more importantly, I know how well transverse mounted engine work in cars, bikes, snowmobiles and other machinery. Since we as humans, already know that transverse mounted engines work...the burden of proof is on YOU to show how the millions out there running around, "have obstacles" the prevent them from working. :lol: :thumbs:

You are not correct and repeating the same comments over and over about solid rear axle cars, ain't gonna change the facts that pertain to an IRS car. You need to open your head and use your brain. I'm thinking about the "leading a horse to water...." right now. :ack:


.

Read the 4th paragraph/sentence down....

RESOLVING ENGINE TQ THROUGH THE FRAME

From the Engineer:
"A channel section is a very poor conductor of torque. Round sections are used to do that i.e. the round shape of a hollow drive shaft.

One other thing, the rocker beams are vey effective in resolving the torque exerted by the engine and differential through the engine mounts and bat wing as the rails are far apart from the center of the car. The torque gets resolved into a force couple that is extered up and down on each side of the frame rails."

Note from the first sentence, about a round tube for managing tq. Like the tq tube in the C5* cars. :yesnod:

BTW; the two cars that you posted pics of a solid rear axle cars. That's why the left wheel is up higher. Gotta have all your facts right to have credibility and make a point. :thumbs:



.

Here's why sidewinder dragsters don't work, for those of you too lazy to look it up: https://www.nhra.com/news/2018/don-g...der-top-fueler which probably explains why they're not used by a single top fuel or funny car today.

And I'm thinking of "You can lead a fool to knowledge but you can't make him think". You guys are claiming that the torque tube and IRS in the vette is a perfect system and zero torque escapes. Wouldn't that require aluminum and steel to be perfectly rigid materials, not to mention the frame to also be perfectly rigid? Which I guess you can pretend it is as long as you're not actually out on the drag strip.

For someone who doesn't 'get" forces and basic physics, you come off pretty damn cocky.

Can you explain to us how "tq escapes"? WTF does that even mean!? Wow...yikes.

If you put a tq wrench on a long extension and apply 100 lb of tq to the extension, you'll twist the extension -like a torsion bar. You're applying 100 lbs of tq to a slightly twisted bar which is connected to a nut that's not turning. Is torque....."escaping"? :lol:

Nice rip-off and reword of my horse/water phrase. :roll eyes:

And FYI, I'd bet that I drag track my cars more than you do...but that ain't necessary to know how a car, structures and basic physics work. You read the link I provided? :toetap:

??? you were not the one i was tango'ing with, it was the other guy. I have no objection to your original posts. Your c5 photo proves my points. I thought you and I were in agreement?

but now I am seeing that we arent, so this is funny...

alright, lets explain this in a way you can imagine...

have you ever seen a c5 rolling torque tube? (its like a rolling chasis, except the frame is absent.

A c5 c6 c7 rolling torque tube... can be driven, you could sit on the torque tube and run throttle controls manually, as long as you mount a gas tank to the thing. You could have subframe at the front and a separate sub frame at the rear, but NO FRAME RAILS CONNECTING THE FRONT AND BACK OF THE CAR.... ONLY THE TORQUE TUBE.

Lets say you take off WOT... and lets say you COULD get grip...

the front axle and the rear half shafts will NOT twist/clock/torque from each other. The torque tube prevents it. If enough torque overcomes the torque tube, it cracks, and now the frame of the car feels the force for the first time.

But assuming it does not crack, the only force you have left is the force of the crank weight and a thin driveshaft which weighs very little.

Again, that "force" of the crank and the drive shaft, can be felt just by putting the trans in neutral and revving the car from 1000rpm to 6500rpm in the blink of an eye.

now, a real car going down a track does not go from 1000 to 6500 in the blink of an eye, so the energy/force is broken up over more time, so its even less force than the force you feel revving your car in neutral.

The frame of the car DOES NOT FEEL TORQUE when a car has a torque tube, not from acceleration at least. Curves and driving, different story.

The back half shafts and the rest of the car only feel a torque which tries to make the car wheelie... there is no barrel roll torque force on the car (except the amount of force you feel when you rev your car in neutral in your driveway... which is next to nothing.)

Any questions class?

You could remove the front axle and ride a wheelie.. and with the engine up in the air in front of you, and no frame in the front of the car at all... the engine will stay level with the rear axle... there is not exerted force, the torque tube STOPS IT FROM OCCURRING...

its like me saying im going to push you really hard, but there is a brick wall in my way... between you and I. I can push on the brick wall as hard as I want, and you on the other side of the brick wall, and you will feel nothing, you never feel my force... unless i break the brick wall, and then you feel my force... just like the cars frame feels no force until the torque tube is broken, then it feels barrel roll direction of torque.

The torque tube stops all barrel roll torque from occurring on the rear of the car, let alone the front. The only force is the crank and drive shaft inertia/momentums as the engine accelerates or decelerates rpm..... the slight force you feel when you rev your car in neutral... that's it.. thats the total force all packed into 1 second when you rev your engine in neutral. And its a tiny/negligible force

So what are you guys talking about right now?!?

The small force does on average cause the one tire to get slightly more grip and the other to break loose first... but once the car has launched, assuming both tires are now "hooked up", then these forces you are speaking about become a moot point.

So, if a person's rear end breaks loose and the car always pulls to one side, that can be changed by the toe and the camber and the caster of the rear wheels.

For instance, if I align the wheel that grips to point to the left, then the car will go left when the other breaks loose. If i align the wheel to the right, the car will go right when the other breaks loose.

Alignment is everything on cars with rigid carbon fiber torque tubes, and the DSC rear alignment settles the car down in a hurry. Which is why im saying, what you guys are talking about has nothing to do with solving the problem, and it CAN and has been solved many times.... with corrected alignment

Sorry, I responded to and quoted some of the wrong posts. My bad.

No, you and I are in complete agreement. W/the tq tube, you're not going to be lifting the left front wheel, and there is no reason why the car should slide one way or the other in a burn out, other than something is broken or out of alignment, or road crown. Just as Tadge suggested.


.

Tom400CFI is correct.

Per Thomas Gillespie's "Fundamentals of Vehicle Dynamics" :
"Transverse weight shift occurs on all Solid Drive axles, whether on the front or rear of the vehicle. The basic reactions on a rear axle.....The driveshaft into the differential imposes a torque T_d on the axle. ...The chassis may roll compressing and extending springs on opposite sides of the vehicle such that a torque due to suspension roll stiffness, T_s, is produced. Any difference between these two must be absorbed as a difference in weight on the two wheels. ...."

This applies to solid rear axle vehicle not our Corvettes. As Tom400CFI stated, with our cars the Torque imposed into the rear axle is absorbed by a torque tube or by the frame rails on a C2-C4. Say traction is completely lost and the rear tires no longer have a coefficient of friction with the road surface (It's only diminished in the real world not eliminated) the torque produced through the drivetrain is absorbed by the torque/frame rails meaning that there is no effective weight difference applied to the wheels save for the static loading which is generally driver heavy. NOTE: I'm talking about a standstill burnout. The cause of the Yaw is most likely the road surface. When a 0.035G turn effect acts over a period of time the car is going to move unless something acts against it. Generally the forces presented through the tire friction and into the sidewall stop this from happening but once the coefficient of friction is greatly diminished it makes it more "difficult" (Physics people don't hate me for saying that) for the tire to stop the yaw from happening. Say we have an AWD vehicle with LSD front and rear. If they were doing an AWD burnout and "eliminated" (not really the case) the coefficient of friction then they would slide off of the road. In reality, if you can calculate the coefficient of friction of the heated rubber in a kinetic state and you knew your weight at each rear tire you could estimate if the C of F can retain the vehicle through sidewall force. This is actually a much more Dynamic problem that gets deeper than this but that is the basics of it.

Colton @ CSM Performance LLC

Here is some reading for you....

A GOOD READ

another way to think about it is...

if you attached a shopping cart crazy wheel to the bottom of the engine oil pan on a c5-c7.. and only had the torque tube as the only member going forward to the engine, and had the complete rear sub frame and axles and diff...

so you have a trike now basically, with no frame rails of the vehicle to the front of the car....

and you floor the car WOT while the car is in first gear, the engine will stay level side to side in the barrel roll direction.

So if the engine stays level there, how on earth is it exerting force on the frame of the car, as other car makes and models DO since they LACK a torque tube?

Again, its like someone being on the other side of the brick wall, and me pushing on the brick wall, i am exerting a force, but the brick wall is stopping it. Only if I break the brick wall, does the person on the other side feel my force....

Only if the torque tube breaks, does the frame feel any barrel roll torque rotational forces... otherwise there is no extra force on one wheel vs the other, other than the negligible force of the crank and drive shaft inertia/momentum.

What's in a name? The Torque Tube
 

I hate to jump into the middle of this but respectfully, I think there is some misunderstanding of what a torque tube is. It’s not meant to deal with torsion along its axis (although that’s what it sounds like - as in a Chrysler torsion spring). If you look at the three items below:

1. A WIKEPEDIA article:
https://en.wikipedia.org/wiki/Torque_tube
see where it states, “CONSTRUCTION
The "torque" that is referred to in the name is not that of the driveshaft, along the axis of the car, but that applied by the wheels. …”


2. A comparison (crude drawing),
"Hotchkiss drive and Torque tube drive":


3. Best of all, A Youtube with Tadge explaining it on a C7 assembly line. Watch Tadge between 1:32 to 2:25 minutes.
"(MOTO-MAN) Chevy Corvette Stingray C7: Behind the Scenes of it's Design, Engineering & Build - Part One":


The torque tube in cars like C5, 6, &7’s takes on a tremendous amount of torque that is trying to lift the front end of the car by the differential reacting to the rear wheels (as Tadge explains). I don’t believe the torque tube makes any difference as far as “fish-tailing” forces are concerned and also wether there is independent rear suspension or solid. The engine is mounted to the frame, the differential is mounted to the frame or the solid axle which is mounted to the frame thru the suspension(wether there is a torque tube present or not). If the engine is developing torque there is an equal and opposite torque that the engine block is applying to the frame through its mounts. If the wheels are kept from turning (locked for the sake of argument and the engine is still producing torque at zero RPM), then an equal amount of torque is trying to twist the differential, frame, and torque tube (if there is one), leaving a net rolling/rotational force of zero. It doesn’t matter wether there is a torque tube or not. Either there are torsional forces on the torque tube and the frame, or just the frame. If nothing bends or breaks, it’s all the same. When the car is launching and the rear wheels are digging in (or burning), there is less torque trying to twist the rear of the frame (in the same direction as the drive shaft) as large amounts of torque are applied to the rear wheels against the pavement but, the engine block is still applying torque in a counter direction, to the frame, through its mounts, undivided. therefore there is a net rotational force tending to rotate/roll the car clockwise putting more weight on the right side. There are probably hundreds of variables that will vary this effect like transmission and differential gear ratios, suspension, weight distribution, wheel span, center of gravity, etc., but it’s there.

This part? Correct. Dead on, right.


This part? wrong. How much tq the engine block is still applying torque in a counter direction, to the frame, through its mounts....if you remove the drive shaft from the car? Effectively, none. As tire traction diminishes, tq load on the entire drivetrain does as well...all the way to the clutch plate. The only tq the engine block is applying to the frame through it's mounts, is the reaction to accelerating the crankshaft, flywheel and harmonic damper...which I'm going to go out on a limb and say is essentially meaningless -especially since most of us don't launch a car from 0 RPM.

The tq tube does do double duty as acting like a tq arm under acceleration...but that's not all it does.

I have to correct you so the other guys dont group you with me.

THe torque tube does change fish tailing characteristics for all the reasons all of us explained above.

A car where the frame twists with NO torque tube, it puts more weight on one rear wheel, so the other has less weight and breaks loose first.

if i sat in the passenger seat of your car and you went WOT at 30mph, and I could control with a switch which of your 2 back tires would break loose first, then i could systematically control which way your car would initiate its fish tail, assuming there was no crown in the road and your steering angle was straight, and your alignment symmetrical.

So, yes, torque tubes affect which way a car fish tails more often than not, for that reason.... or more specifically, preventing it from favoring one side.

Disection:
Wiki and vid #1: Here you are comparing a live axle, using a Tq tube...ready for this? That is not connected to the transmission in a way that provides radial stability. IOW, the tq tube you used in your example has some type of "ball and socket" attachment to the trans or frame of the car. The Corvette, the diff is bolted to the trans, rigidly. The trans is bolted to the tq tube, rigidly. The tq tube is bolted to the bell housing, rigidly. The bell housing is bolted to the engine block, rigidly. They're effectively ALL ONE UNIT...just like that in a FWD or for that matter a mid engined car....just spread out more. Any tq that the engine imparts on the diff housing during a launch is immediately resolved, back through the diff case, trans case, tq tube, bell housing and back into the engine block.

Vid #2: Tadge is totally right. The reaction tq to wheel tq is sent down the tq tube, trying to lift the front of the car. He neglected to mention that the reaction tq to engine tq is also resolved through the tq tube. In realty, the first force, wheel reaction tq is sending a BENDING force down the tq tube, trying to bend it as it lifts the front of car. The engine tq is trying to twist it against the diff. That twist is equal and opposite the resistive forces of traction and trying to accelerate the car...so, they effectively cancel each other out.

Actually there was nothing mentioned in the original question about turning left or right. In fact I took it as meaning accelerating in a straight line which way the rear end stepped out. Because honestly I'm not sure how you could compare fishtailing when turning left or right. You're obviously not going to have that back end swing to the right as you're turning right LOL
And the rear does always seem to prefer to kick to the right when accelerating in a straight line from my experience in C5s, 6s, and 7s.

I’m not sure I explained my original question as well as I should have. Maybe, I should have said…

On a totally flat road, turn off TC and StabiliTrak, point the steering wheel straight ahead, put the car in first gear, and, floor the accelerator. Does the car fishtail to the LEFT, -OR-, to the RIGHT, -OR-, does the car go precisely straight ahead, AND, why?

I suppose this is reasonably, easily test-able, but I was looking for an engineer’s perspective to validate my perception that the car will fishtail to the RIGHT (meaning the rear of the car kicks out to the RIGHT). If the road is crowned, you could do the test on "both sides of the crown”.

I had already seen where Tadge said that manual trans C7Z06 and C7ZR1s have different shafts to prevent “power hop”… https://www.corvetteforum.com/forums...and-axles.html #hammerdown

Once you break the rear tires loose, you have no meaningful lateral connection to the road (CSM performance already covered this in post #31). The rear of the car will drift left, right, or not at all depending on the forced acting on the car. The forces would be:
*Gravity -if the road is tiled, crowned...whatever
*Forces exerted on the chassis by the rear tires -if your rear toe alignment were off, or your thrust angle were off, it would be inclined to push the rear of the car in one direction.

If I truly wanted to diagnose this, I'd start by getting a spot-on alignment (factory alignment is almost for sure, not right), then go do some burn outs and ascertain the levelness of the road. In reality though....who GAF? Do a burn out, if the car steps slightly to one side or the other, steer with it, and enjoy the ride....right?


.