liquorman

Has anyone noticed front end lift under heavy acceleration. Rolling along at 50 to 60 mph in forth gear then down shift into 3rd then bring it up to 105 to 115 mph very quickly shifting into 4th. I do notice some front end lift anyone else. My car is a z-51 stick with all the extras I don't know if that would make a difference.

SilversledC7

You're joking right?

rotherd31

It's what we get for buying a new model Vette.....something called weight transfer. My guess is that Chevy will correct that problem in the 2015......I plan on taking mine into the dealer this next week and have them check it out as mine is doing the same thing!

BIG Dave

Time for Physics Class 101! Yes, it's completely normal. Newton's Law states, an object at rest tends to stay at rest. When a car accelerates, the vehicle's body remains in place as power from the engine begins to push the car forward. As the wheels accelerate and move forward, the weight of the vehicle shifts to the rear and the front end rises slightly.

Just as a vehicle's weight shifts toward the rear during acceleration, the car's weight shifts forward during braking, forcing the front end down. This forward shift also takes place pursuant to Newton's Law, as a vehicle in motion tends to stay in motion.

JerryU

Assume this may be a joke, but just in case:
Think about all the force on those sticky Z51 tires when you stomp on the throttle. It must be reacted to so GM uses a sold torque tube that connects the rear end to the engine. It tries to lift the engine on that long lever arm! It reduces lift but does not eliminate it. If you had the 4 bar link as in my 8.2 liter, 525 hp street rod with lots of adjustment holes you could move the instant center even further forward creating more lift and transfering more weight to the rear wheels. Even with the 16 inch section width Mickey Thompsons you need all the weight transfer you can get!

KenHorse

I would suggest the addition of wheelie bars.....

W88fixer

Hard to believe the lift is significant but then I don’t have mine yet. Don

B Stead

The car needs stiffer springs to reduce a rear-end dip. Swaybars will not help that situation. But to stay in balance the springs must be stiffer both front and rear.

Now, stiffer springs make a faster reacting car so they do not suit everyone's driving style
.

daytonagary

liquorman

No, I'm not.

liquorman

Again, I'm not joking.

Michael A

Or anti-squat geometry in the rear suspension.

Michael

JerryU

Then the physics lesson by Big Dave and what I mentioned should help understand that every action has an equal and opposite reaction! Must admit on my fast acceleration runs, I'm considering many other things, like the tach and shifting than the small front end lift! Watch some of the drag races where small block Chevys lift the front wheels a couple of feet!

JerryU

Funny, I recall a professor going through what Big Dave outlined and several of us telling him it didn't hold for a '51 Olds! That rear suspension had anti-squat geometry and as I recall both front and rear raised up!! There are some things that can be done but they have other consequences. The small amount of lift with the C7 is not worth sacrificing the other excellent handling characteristics to worry about, in my opinion.

slief

This is NOT an issue with car let alone a first year issue and there is NOTHING for them to fix with regards to front end lift. SMH..

My guess is that you guys are new to Corvettes let alone high powered sports cars. Pretty much any car with this kind of power and traction will do this. The only thing wrong here are the expectations.

FWIW, this is my 3rd Vette including a 2009 Z06 and they all will do this to soem degree under heavy acceleration.

liquorman

You are correct this is my first Corvette. I've been driving a mini van for the last 14 years. Thanks.

Motohead279

liquorman.... how much have you had to drink today?

liquorman

[QUOTE=Motohead279;1587188866]liquorman.... how much have you had to drink today?[/QU

Nothing

slief

That may explain a lot. I've found that mini vans typically have less front end lift than my Vettes largely due to the stiffer rear suspension to accommodate the heavier loads like groceries, bags of dog food, cinder blocks from Home Depot or even our 6 Bull Mastiff's. The stiffer suspension in most mini vans helps mitigate rear end squat. Since most of us don't pack our Bull Mastiffs in the trunk of our Vettes, they gave it softer suspension in the rear than your typical mini van.

If you're really noticing a lot of front end lift under heavy acceleration, there is one thing you can check. While Magnetic Ride control is optional, all C7 Vettes have PSA (Pneumatic-boost Suspension Assist). This system manages dampening and re-bound for the rear suspension and has a huge impact on the amount of squat the car exhibits. Without it, the suspension would feel like a wet noodle when you step on the gas and squat like granny on Ex-Lax.

If you lift the carpet up in the trunk, you will find the PSA pressure reservoir that holds compressed air for the rear suspension. The carpet is tucked under the plastic trim that surrounds the trunk. Simply get a good grip on the carpet and give her a tug and it will pull back.

This system is fed by the power brakes hydro-boost braking system and there is a line running from the front of the car to the rear.
Here is a diagram of the PSA suspension assist system and it's connections to the brakes booster system.


This is the rear suspension PSA system that is located under the trunk area carpet. In the lower part of this picture, you can see the PSA boost reservoir and the left and right shock PSA solenoids above that. The PSA Boost reservoir is depicted as a globe looking thing in the diagram above. In the C7, it's a large black cylindrical tank.


Inspect this system closely for any air leaks. I'd suggest having the car running and if you have a child, have them stand up and sit down repeatedly while standing in the trunk area with the hatch or trunk lid open. The idea is to load and unload the suspension system. You need to listen for air leaks back there so if you have performance exhaust, I'd suggest being in Eco or Tour mode and make sure you exhaust valves are closed. You are listening for a hiss or a shhhhhh sound.

Place your ear near the lines going to and from the booster reservoir shown in the lower part of the above photo. Also there is a small drain valve on the left side of the reservoir that should be closed. If you hear any leaking from that valve, turn it clockwise. That valve is used to drain any water than may build up from condensation in the air. Also, listen for leaks at the pressure connections going to the left and right suspension bypass solenoids as well as the little compressor looking things in the upper part of the picture. If you hear a leak at any of those points, tighten the compression fitting.

Hope that helps!



. .

rcooper

Hell, my wife's Buick Lacrosse does it,also as does my 09 Vett. Just a fact of too much power, and the 4 banger in the Buick is just loaded with it.