Violent launch has to stop

[Alpine]

I went out to the track last night a tried to launch my C6Z. It launched so violently that I yanked it out of 1st twice! Embarrasing. Either way it planted then hopeed and threw me around. It felt like something was about to break. Any rear suspension experience on eliminating wheel hop/violent launches? Stack car btw.

[DennyM]

Thanks for posting!
You might check Ranger's Z06 Launch Techniques - sticky post under quarter mile.
Here's a related discussion thread.
Leaving the lights at what RPM

[No Doubt]

The right tires
The right tire pressure
The right track prep
The right launch rpm
The right clutch operation
The right....

Wheelhop is caused by rapid and repeated traction followed by loss of traction. Think of a torsion spring coiling and uncoiling rapidly. In effect, the cars rearend does the same and the result is wheelhop. If you simply hook and go you won't get wheelhop. If you spin the tires you may get wheelhop. Although you think they're spinning continuously, they're not. The tires are getting traction for a fraction of a second, the rearend winds up like a spring, then lets go. Again, the result is what is known as wheelhop.

There are ways to help reduce the possibility, one of which is rear shocks that help keep the tires in contact with the track. That is, they aid in traction. Remember, if you get traction and keep it you reduce the chances of wheelhop.

In addition, the Corvette rear suspension design and drivetrain is inherently more prone to wheelhop and damage when drag racing since it is not a solid axle design.

Practice also helps...a lot.

[GR8 WHITE]

I never had a violent launch like that, but then again, I am not dumping the clutch at 9000 RPMs and expecting silk smooth launches either.

My understanding o fteh trade is to set it in competition mode, lower rear tire pressure to 15 - 17 psi, start off at a compfortable RPM launch such as 4000 and sllip/feather the clutch. If you slightly bog, tak eit up to 4500 rpms next time. I fyou break loose, take it down a knotch.

What do I know.... My best 60' is 1.9 seconds Hell, I can nearly run faster than that

Good luck, and whatever you do, don't break anything.

(NO DOUBT is the Master)

[robz]

Originally Posted by Alpine

I went out to the track last night a tried to launch my C6Z. It launched so violently that I yanked it out of 1st twice! Embarrasing. Either way it planted then hopeed and threw me around. It felt like something was about to break. Any rear suspension experience on eliminating wheel hop/violent launches? Stack car btw.

Talk to guys like Ranger, Dr.Ron,etc..
I would first start by lowering the tire pressure and getting a little heat in the tires.
Some guys go to the morer extreme and getr qa1 shocks but the proper technique can allow you to overcome some of the hazards.
And most are saying a very fast clutch release is necessary.
Keep in mind anyone can break anytime also.

[Pit Man]

Originally Posted by robz

Talk to guys like Ranger, Dr.Ron,etc..
I would first start by lowering the tire pressure and getting a little heat in the tires.
Some guys go to the morer extreme and getr qa1 shocks but the proper technique can allow you to overcome some of the hazards.
And most are saying a very fast clutch release is necessary.
Keep in mind anyone can break anytime also.

I agree with that...thought I had a bullet proof setup and I am down again after a mild launch on a great RPM differential...BAM,,,drag it on the trailer after one hour of fun !! Listen to these guys..they have been through it all.
Pit

[Alpine]

Ugh, I don't want to slip it. Well thanks guys. Technique aside I think any kind of wheelhop is rear end/suspension related way before it has much to do with technique. It shouldn't matter how high I sidestep it. Hop is not okay, and I was very dissapointed that it launched so violently. I can see tire shake maybe, but not this. It's not as if I can drop the bottom of the fourlink lol.

[MikesZ06]

Originally Posted by Alpine

Ugh, I don't want to slip it. Well thanks guys. Technique aside I think any kind of wheelhop is rear end/suspension related way before it has much to do with technique. It shouldn't matter how high I sidestep it. Hop is not okay, and I was very dissapointed that it launched so violently. I can see tire shake maybe, but not this. It's not as if I can drop the bottom of the fourlink lol.

Not sure I agree with your statement about technique but IRS does create different launch problems then a solid rear end. Yes, the Z does have massive torque down low and requires getting used to on the launch. Others have already mentioned a few things that can help but I still think that personal experimentation can lead to successful launches.

You have to remember, GM did not build this car as a special purpose drag racing car. The Z06 was born out of the necessity of the Corvette C5R racing team to have a roadracing factory production model.
That means WE are the ones trying to make a drag racing monster out of it. Time and patience can make that happen.

Mike

[UVETTYA]

It took me 4 years to figure out how to launch effectively, and I read everything I could about launching. You just have to get a feel for it. I finally watched someone who knew how to launch and the light bulb went on for me.

I used to come out about 4K rpm and dump the clutch, then try to feather the throttle to keep the wheels from spinning and hopping, but that doesn't get you low 60 ft times. Now I come out north of 5K rpm and slip the clutch a little for the first 10 ft or so, and I get consistent low 1.7X 60 ft times and a 1.6X every now and then. It's easier on your drive line when you don't "shock it" and you will get better 60 ft times than just side stepping the clutch. Slower clutch release at first will result in a quicker launch over all. Think about starting out slow and ending up quick.

If you don't think that works, ask (Mike) AZZ061. He was getting 1.9 60 fts just like the rest of us, until I explained this technique to him. Now he gets consistent 1.7X 60 fts too.

Slipping it is hard on your clutch though, so you have to do long cool down times between runs if you're stock, or pony up for a Textralia, add a clutch bleeder and bleed it after every track day and add fresh fluid. If you like to drag race and plan on doing that a lot with your Z, then you might just as well build it for the track before it breaks.