Help! Front end lifts at high speed

[eoseitz]

I was wondering if anyone knew of any type of wing or suspension I can buy to keep the front of the car from lifting off the ground after about 120 mph. I just bought the car and found out it does this. Is it normal on a 74 stingray? I have the L82 engine in it and it's slightly modified. It just feels like all control goes away. Kind of like hydroplaning.

 

[6 Shooter]

1978 Front & Rear type spoilers, then head for 200!

BTW - Welcome to the

 

[6880 Mike]

Probably normal. C3s are known to lift the nose at speed; steering will get light. The factory front spoiler helps to keep the nose down and aid cooling.

 

[Hib Halverson]

Yes it's normal...well maybe not lifting the front wheels of the ground at 120....that's a good reason not to drive the car that fast until you fix the problem.

The C3 shape does have aero lift that is significant once you go by 100 mph.

The first thing to do is check ride height. If your car is higher in the front, you're making the problem worse. I'd set the trim heights such that the car has a slight rake. Next make sure the OE front air dam is in place and consider buidling a larger one. Consider adding a small rear deck spoiler. Doing those things should make a noticeable difference.

Lastly, the idea that you can add the 78 front and rear spoilers is a little unrealistic because to do that in the rear you'd have to do major body work. Also, the idea that you can head for 200 mph with a modified L82 is, well...a bit optimistic.

 

[Rex S]

There is a great article in this month's Corvette Fever about the racing Grand Sports doing just that. Bad news is GM never found a way to fix the problem.

 

[eoseitz]

ok. thanks guys. I'm not at all familiar with the car yet. Does the suspension come stock with the ability to set ride height? Also, how would I go about building an air damn? Would it be something I'd make with fiberglass and bolt on, or is there an easier way?

 

[Hib Halverson]

There is a great article in this month's Corvette Fever about the racing Grand Sports doing just that. Bad news is GM never found a way to fix the problem.

Actually, the Grand Sports that lifted were C2s not C3s, but with C2 the problem was even worse.

 

[6880 Mike]

...Also, how would I go about building an air damn? Would it be something I'd make with fiberglass and bolt on, or is there an easier way?...

There's an easier way. All the Corvette parts providers carry the stock chin spoilers and add-on aftermarket spoilers.

 

[Rex S]

Actually, the Grand Sports that lifted were C2s not C3s, but with C2 the problem was even worse.

That's what I thought but the article has 2s&3s both in the pictures.

 

[73shark]

Actually, the Grand Sports that lifted were C2s not C3s, but with C2 the problem was even worse.

I read a Zora quote once where he said that the mid-year design had just enough lift to be a bad airplane.

 

[bucket]

I think it just needs a little more weight over the tires...

 

[Evolution1980]

eoseitz, welcome to the

I had the same issue on my car so here are a couple of things for you to consider...

1) If you have power steering, have the system gone over. Is it somewhat sloppy at normal speeds? Do you have a lot of side-to-side play in the steering wheel while still remaining in a straight line? If so, you likely have worn pieces (worm gear, rag joint, etc). Addressing those will tighten up your steering a little and cut down on the perception of lighter steering at high speeds.

2) There are various alignment configurations you can get the car. Find a shop that's competent in doing 4 wheel thrust alignments on Corvettes. Not just any cars, as our cars are not "just like any other car" to your average shop with highschool greasemonkeys working there. You can have an alignment that favors low speed autocrossing (lots of left-right transitions), one that favors high speed straight line action, or something in the middle. I had my car aligned for high speed straight away speeds and the difference was HUGE! Completely removed the feeling of high speed lift. The car feels completely buttoned down well into the 140+ range.

I also changed over to a rack & pinion which also helped the issue. However, a properly functioning OEM setup shouldn't be that much different play-wise than a new r & p setup.

 

[gmjunkie]

eoseitz, welcome to the



2) There are various alignment configurations you can get the car. Find a shop that's competent in doing 4 wheel thrust alignments on Corvettes. Not just any cars, as our cars are not "just like any other car" to your average shop with highschool greasemonkeys working there. You can have an alignment that favors low speed autocrossing (lots of left-right transitions), one that favors high speed straight line action, or something in the middle. I had my car aligned for high speed straight away speeds and the difference was HUGE! Completely removed the feeling of high speed lift. The car feels completely buttoned down well into the 140+ range.

You'd be surprised what 1 1/2* to 2* more than stock positive caster with 1/4* to 1/2* negative camber will feel like at 140+!!
Oh Wow,somebody filled my front bumper full of lead!!:L:L:L

PS. She will be a little rougher on the tires though,but she will be planted firmly on the road!!