Okay, tonight, going down a back road, I'm accelerating, and I can't remember the gear, but I'm probably around 80- 100 mph or so, and I lose traction for a split second. Than, on my second pass back down, I'm in 6th gear edging up to about 130 and I lose traction again but it feels much worse than it did before probably b/c I was going faster. This kinda freaked me out as I don't understand what went wrong. New tires (less than 1K miles), and it happened twice going to and from. Now I can't rule out if it was in the same spot of road but I was in different lanes each time. Anybody got any answers to this. Trust me, at 130 mph, when that rear end went sideways a tad, PUCKER FACTOR BIG TIME!!!!!

 

You're doing 130 on a public highway, on a back road that's probably full of interesting uncertaintees, in the dark, and you're worried about losing traction? Uh, I'm no saint, but the real problem here doesn't sound like traction.

 

it's not the smartest thing to do. It's just soooooo smooth I didn't even notice that I was reaching 130........

 

everyone is such a tight *** when it comes to driving faster than the suggested speed. im just glad you do it when little if any cars are on the road.

 

Could it be because your Z06 is lowered and you didnt maintain the proper 1/2" higher in the rear for down force? I've been 170+ in my 01 and never had that happen.

 

My first thought is that you may have lifeted you right foot slightly off the accelorater. This removes the weight from the rear wheels and that feeling of loosing traction. DO NOT LIFT your right foot at those speeds.

6th gear is a high way cruzing gear not a speed gear as you have less control of your car in 6th. 4th and 5th are the speed gears.

Next if a corvette is lowered too much, more then 1 to 1 1/2 inches AND you dont have the required rack the car will loose down force very quickly at speeds above 120 mph. When the front of a vette is lowered more then 1 1/2 in in front there is not enough 'suction' under the car to hold is down.

The rake of your car. When lowereing, do the front first. then Measure the distance from the frame rails to the ground just behind the front jacking puck points. Then measure from the frame rails to the ground beind the rear jacking puck points. the rear must be 4-5 mm high then the front. if not the car does not have the required rake for aerodynamics and the suction to hold the car down at higher speeds.

How is your cars alignment?? normal street alignment is not very good or safe for 'at speed' driving. Check your cars alignment.

Be safe out there.

 

I suggest you try it on another road. Check your tire pressure. What tires are you running?

 

I just did a few 40-140mph pulls on the highway the other day and i didnt feel anything like what you described. My car is lowered (cut bushings in front and 2/3 cut in the rear). I do suggest you not use 6th gear for trying to gain speed, its not designed for that. Believe me, start in 1st or 2nd and run through the gears and you will have more than enough. If you were doing 130 and using 6th gear you must not be using all the RPM's of every gear.

 

does your car have stability or traction control, or something like that?

 

He has a 02 Z06. He has t/c and a/h....standard.

 

Do everything he says!

 

ok....so given that, here was my thoughts (no i don't have a Z06).

On the CTS-V, certain exhaust mods combined with high speeds over 100MPH would somehow trigger our Stabilitrak falsely....causing it to tug on a front brake and jerk the car slightly to the side. It was very rapid but very unsettling and scary. Is this possible in this case?

 

Our vettes (Zo6's) dont do that. I have taken mine to 140 a few time and had no problems.

 

I was in Comp Mode, and I've measured my rake and it seems to be okay. I guess I'll stay out of 6th from now on. I'm running 19" Yokohama tires. I've cut pretty much all bushings up front and the rear is lowered quite a bit. I haven't had the car aligned up since I've lowered it as it's not pulling too bad. I probably need to do that before I try reaching those speeds again although that wasn't a good feeling when it happened so it kinda freaked me out about driving that fast. I put it in Comp mode b/c when I have traction control on, I'm not able to run the rpm's up b/c it seems to stall. I know everyone says when on the track, keep it in comp mode. I didn't plan on going that fast but the fastest I had been in the car was about 120 so I was trying for a little bit more.

 

You may have to put the original bushings back in and raise the car up. Slammed cars do look cool but have extreamly bad handling charcteristics at speed.

If the alignement is 'slighlty off' or not pulling too bad that means it is pulling SOME. At slow speeds that may be ok, but over 80 mph your alignment needs to be exact.

Also what was your tire pressure?? To high a base or cold pressure causes way too high pressure when running. Normally 30-32 psi cold ( before you drive ) which means 38-42 HOT ( pressure just after a hard run.

Remeber roads are crowned to allow rain water to run off. It is normal for a car to pull to the right becuase of the crown. Take your car out to a large flat parking lot and do a few 40 - 5 mph stops and see or feel if the car pull one way or the other.

Something else to think about is that if you car is lowered too much, if you hit a bump the car's suppension can not move up and down like it was disgned to do. The only thing left for the supenssion to do is to move or bounce the car. Supenssions are deisgned by a group of engineers to do a specific task.

I routenly drive at 130 to 150 MPH on a road race tracks only. The alignments and rake must be exact. I use to have my car lowered as much as possible both front and rear. The car was damn unstable over 120 mph that it was scary I raised the car up slightly in front 3/8" from the lowest possible stock setting and almost an inch higher in the rear. Now it is unbelievle stable at 150 mph that I can almost feel the car being sucked down to the asphalt at high speeds. Not quite but almost.

Thx Cpt I am just passing on info I have learned over the years from others on this forum and at the track.

 

Definitely check the above mentioned items. I've been 160+ with no issues and I'm lowered (not hammered, but lowered.) I've scratched 5th gear at 150 mph on the bottle tho!!

 

Just a guess, but the road might have some oil spills in spots, and you happen to hit them.
I think I would go back during the day and check the road.

augydog

 

What rack are you referring to?

 

DOH Sorry fat fingers. I ment rake, the cars rake.

rack? Must have been thinking about her . . . . . . . . .

 

He said rack. That happens to me all the time.