Vibration at 100MPH
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Joined: Nov 2013
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Vibration at 100MPH
My 93 corvette has a vibration at 100+ MPH I think it is due to Optisaprk but any input welcome I noticed it recently and other issues like a miss at idle and will replace the cap rotor and wires plugs
Melting Slicks
Joined: Jun 2013
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Bad Tire, Out Of Balance Wheel, Cracked Wheel, Bent Hub, Bent Drive Shaft, Out Of Balance Drive Shaft, Bad U Joint, Worn Motor Or Trans Mounts, Incorrect Tire Pressure.
I Don't Think Its Motor Related Because It Would Happen All The Time Or Certain Rpms.
I Don't Think Its Motor Related Because It Would Happen All The Time Or Certain Rpms.
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OK at 30-35 MPH I get a engine vibe when I throttle up it goes away running at 65-80 MPH no issues after the car is over 90 I start to feel a vibration that seems like it is from the engine if I let off throttle it goes away the Optispark I am installing a new cap rotor wires and plugs on Monday so I should know if that solves the issue after I replace the parts and tune the ECM
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not sure how old are the tires I just bought the car and the tires are not original Goodyear eagle F1 the have little wear this is a "CORVETTE" so driving at 100 MPH is a norm for these car as they are designed to go 165 MPH + I just dropped it off on Wednesday at the dealer to fix a grounding issue and lose rear view mirror the power steering was having an issue but noticed the serpentine belt was the wrong belt not double sided so replace that and cleaned the pulley's solved that issue currently all the car needs is a tune up and TARGA top the original one is warped I live in AZ so I am considering looking for a fiberglass top to replace the Lexan top as they warp here in the hot sun but the vibration concerned me so thank you all for the in put as I may get the tires checked out and put the car up on a lift I planed to remove the center muffler and replace with separate resonators I will keep posting after I due the tune up
Last edited by RWC112; Dec 1, 2013 at 04:57 PM.
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Team Owner
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Vibrations that may be created by tires usually are seen at speeds anywhere from about 40 th as high as 65. Typical issues would be cord separation, out of round, or even imbalance. Sometimes it can be related to a wheel problem.
For the serp belt, '93's used both single and double sided belts. The change was sometime in early part of the production year. Is your car one that used the double-sided belt?
The Opti should not cause a vibration by itself as it turns at 1/2 engine RPM. At that MPH where you feel vibrations, I'll bet the problem is not in the engine.
Corvettes are capable of high speeds, true. But unless you are driving these speeds on a track, it's not a good idea to talk about high speeds on public roads. The Mods take a dim view of that.
For the serp belt, '93's used both single and double sided belts. The change was sometime in early part of the production year. Is your car one that used the double-sided belt?
The Opti should not cause a vibration by itself as it turns at 1/2 engine RPM. At that MPH where you feel vibrations, I'll bet the problem is not in the engine.
Corvettes are capable of high speeds, true. But unless you are driving these speeds on a track, it's not a good idea to talk about high speeds on public roads. The Mods take a dim view of that.
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in AZ the speed limit is 75 MPH and many drive at 90-105 all the time I 10 is built for higher speeds of the 60's when the limit was 95 and many drove 120 I do not subscribe to driving this fast just bought the car and was about the drop it off for the dealer to address issues so I wanted to test the car after I had it for 1 month to see what needed addressing by them
Team Owner
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From: Phila., PA burbs
You'll find a four digit date code on the side of your tire that will tell you when the were made.
It doesn't matter how fast these cars were designed to go................if a tire is out of balance it will cause a vibration whether it's a Corvette or a Kia
It doesn't matter how fast these cars were designed to go................if a tire is out of balance it will cause a vibration whether it's a Corvette or a Kia
Team Owner
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
So rwc, you still haven't answered the question about the tire age.
I'm assuming you have limited mechanical knowledge.
So on the tire there is some little numbers that signify the week and year of manufacture.
If your tires are more than 5-6 years old, no matter how much tread is left, your playing with fire over 75.
I sure hope you don't end up like a lot of others on the C4 section that end up selling because they can no longer justify the maintenance costs.
Good Luck
BTW the center muffler is a CAT
I'm assuming you have limited mechanical knowledge.
So on the tire there is some little numbers that signify the week and year of manufacture.
If your tires are more than 5-6 years old, no matter how much tread is left, your playing with fire over 75.
I sure hope you don't end up like a lot of others on the C4 section that end up selling because they can no longer justify the maintenance costs.
Good Luck
BTW the center muffler is a CAT
Last edited by JrRifleCoach; Dec 2, 2013 at 12:46 AM.
Le Mans Master
Joined: Dec 2006
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From: H-Town Texas
Not on the LT1 cars.
General rule of thumb,
Vibrations that occur at common rpm regardless of wheel speed are typically powertrain related.
Vibrations that occur at common wheelspeed regardless of engine rpm are typically drivetrain/suspension related.
General rule of thumb,
Vibrations that occur at common rpm regardless of wheel speed are typically powertrain related.
Vibrations that occur at common wheelspeed regardless of engine rpm are typically drivetrain/suspension related.
Last edited by lt4obsesses; Dec 2, 2013 at 02:02 AM.
Drifting
Joined: Aug 2010
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I'm experiencing a bad vibration at high rpms since i had the car and it's probably related to the drive shaft unbalanced.In 3thd gear at high rpms,during a launch you can hear the entire car resonating,then going into OD lowering the rpms,it fades down...may be the cranckshaft?
Drifting
Joined: Jul 2004
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From: MA
Why don't you put the car in neutral when you feel the vibration. If the vibration goes away it is probably engine related. If the vibration is still there then you have a lot of possibilities, (tires, u-joints, transmission, differential, etc.).
Goodluck!
Goodluck!
Drifting
Joined: Aug 2010
Posts: 1,704
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For the engine
new harmonic balancer a
new engine mounts
Transmission freshly rebuild
Tires
Fresh brand new
BF Goodrich 255/50ZR16
Suspensions
New Bilstein Z51
I know lot of old thinghs still there ,and vibration goes on...
new harmonic balancer a
new engine mounts
Transmission freshly rebuild
Tires
Fresh brand new
BF Goodrich 255/50ZR16
Suspensions
New Bilstein Z51
I know lot of old thinghs still there ,and vibration goes on...
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
As this thread can attest, there are many things that can cause vibration in these cars. One of the great things about the C4 is the feeback it delivers to the driver.
First, with the car in neutral, see if it is an enging vibration by simply observing how it revs in neutral. However, sometimes of course it happens when the engine is under load, so put it in gear with the brake on and see if it vibrates while gently giving it some gas. The point is to take wheel speed out of the equation.
Then on the road, I have always tried to first vary the rpms at a constant speed. Then to vary the speed at a constant rpm.
Also important is where you feel the vibration.
If the steering wheel is trying to shake itself out of your hands, then it's probably time for new tires and an alignment, and have the rotors checked/surfaced.
If the shifter feels like it's going to shake your hand off, then look at the driveline, u joints, suspension, rear end.
For me, there have been a couple of times where I've had specific vibrations and new tires fixed the issue. Amazing how that happens.
First, with the car in neutral, see if it is an enging vibration by simply observing how it revs in neutral. However, sometimes of course it happens when the engine is under load, so put it in gear with the brake on and see if it vibrates while gently giving it some gas. The point is to take wheel speed out of the equation.
Then on the road, I have always tried to first vary the rpms at a constant speed. Then to vary the speed at a constant rpm.
Also important is where you feel the vibration.
If the steering wheel is trying to shake itself out of your hands, then it's probably time for new tires and an alignment, and have the rotors checked/surfaced.
If the shifter feels like it's going to shake your hand off, then look at the driveline, u joints, suspension, rear end.
For me, there have been a couple of times where I've had specific vibrations and new tires fixed the issue. Amazing how that happens.
Last edited by lt4obsesses; Dec 2, 2013 at 09:15 AM.
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we had a guy at work that seems to think its funny to put some kind of rock or other thing to chalk one tire when you drive over it this will cause the tire to be ruined this may been the issue as when I first drove the car it was fine at all speeds ran smooth then there came a miss at idle and a vibe at a constant rpm I assumed this was the Optispark the guy was caught putting something behind my tire and was remanded then removed the chalk I will have tires checked when I pick up the Corvette today