Front End Bounce
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Joined: Mar 2014
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From: Palm Bay florida
Front End Bounce
Hello everyone, I have this 81 vette that I put a lot of time, money and effort in and now it is race car fast but I have this one problem. Not like you are supposed to do this but when you are traveling down a long stretch of road where nobody is around and get up to an excessive speed sometimes the front of the car will look like it is bouncing as the hood is flexing. The steering is rock solid and the car is smooth as silk but the hood looks like it is flexing sometimes during high speed and when you let off of it, problem goes away. New shocks, ball joints, tie rods, bushings, bearings and tires, and had it professionally aligned. Does anyone know how to fix this or has experienced the same things?
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Rookie guess: Is your car supposed to have a rubber or thick foam seal between the top of the radiator and the hood? If it does not have a seal there the air through the grills could be going over the top of the radiator and is trying to "lift the hood".
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
Last edited by doorgunner; Apr 4, 2016 at 11:59 PM.
Le Mans Master
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From: RI, Now Franklin/Nashville TN
Rookie guess: Is your car supposed to have a rubber or thick foam seal between the top of the radiator and the hood? If it does not have a seal there the air through the grills could be going over the top of the radiator and is trying to "lift the hood".
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
You should change the title of this thread to hood flexing at high speed, NOT front end bounce.
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Joined: Mar 2014
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From: Palm Bay florida
Thread Starter
Advanced
Joined: Mar 2014
Posts: 60
Likes: 1
From: Palm Bay florida
Rookie guess: Is your car supposed to have a rubber or thick foam seal between the top of the radiator and the hood? If it does not have a seal there the air through the grills could be going over the top of the radiator and is trying to "lift the hood".
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
ALSO......let's be clear that the front of the car isn't "FLOATING" at high speeds!
Le Mans Master
Joined: Oct 2007
Posts: 7,451
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From: RI, Now Franklin/Nashville TN
Did you replace the front springs during the rebuild and what spring rating are the springs that are installed? What shocks did you use? Hopefully, Bistein Heavy Duty/Sports or an equivalent high performance shock and NOT a mass market one...
Melting Slicks
Joined: Mar 2008
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From: Meriden CT
Look at the bottom of the radiator core support. If the mounts are loose or rusted thru I suppose its possible for lots of body flex at high speed. Probably see it on a good bump too.
Last edited by SH-60B; Apr 5, 2016 at 11:28 AM.
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Sounds like shocks to me
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From: Palm Bay florida
I put new kyb shocks on the back and the front but kept the original springs
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From: Palm Bay florida
Le Mans Master
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From: RI, Now Franklin/Nashville TN
I would definitely look at those OEM springs and think about changing those KYB's out for some shocks that offer more performance.
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From: Butler Pa
but the hood looks like it is flexing sometimes during high speed and when you let off of it, problem goes away. New shocks, ball joints, tie rods, bushings, bearings and tires, and had it professionally aligned. Does anyone know how to fix this or has experienced the same things?
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From: Palm Bay florida
Le Mans Master
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From: Butler Pa
OK, so the suspension is not shaking? If it was, you would certainly feel it in the steering wheel.
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From: Palm Bay florida
Team Owner
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From: Crossville TN
A '78 C3 with 'stock' front springs is NOT "race ready".
You need to have a qualified mechanic do a thorough check out of the front end suspension and frame to make sure there is not something broken/loose/worn and causing problems. Not doing this and then driving the car at 90+ mph "could be hazardous to your health."
Do you have a front air dam mounted to the lower front valence (as intended by the car's design)? If not, that's another issue...
You need to have a qualified mechanic do a thorough check out of the front end suspension and frame to make sure there is not something broken/loose/worn and causing problems. Not doing this and then driving the car at 90+ mph "could be hazardous to your health."
Do you have a front air dam mounted to the lower front valence (as intended by the car's design)? If not, that's another issue...
Thread Starter
Advanced
Joined: Mar 2014
Posts: 60
Likes: 1
From: Palm Bay florida
A '78 C3 with 'stock' front springs is NOT "race ready".
You need to have a qualified mechanic do a thorough check out of the front end suspension and frame to make sure there is not something broken/loose/worn and causing problems. Not doing this and then driving the car at 90+ mph "could be hazardous to your health."
Do you have a front air dam mounted to the lower front valence (as intended by the car's design)? If not, that's another issue...
You need to have a qualified mechanic do a thorough check out of the front end suspension and frame to make sure there is not something broken/loose/worn and causing problems. Not doing this and then driving the car at 90+ mph "could be hazardous to your health."
Do you have a front air dam mounted to the lower front valence (as intended by the car's design)? If not, that's another issue...