Vibration 115-120mph

[jwibbity]

So after being involved in a thread about 4.10 gears and tuning, i was thinking that vibration through the car at the above speed was normal for 4.10's and stock driveshaft.....but apparently alot of other guys are getting past 120, one even to 140ish mph(stock shaft, 3.55's)

so my question is other than a balanced driveshaft what could possibly be loose or wrong in my car causing this vibration??

i thought up until recently i was reaching the critical rotation speed of the stock driveshaft causing vibrations but i seem to be the only guy with 4.10s having this issue

THANKS!!!!

[whitey]

Anything to do with wheels or steering, such as tires out of balance, worn ball joints, steering knuckles, uneven treadwear, tiny unicorns jumping and punching holes in your exhaust, flux capacitor going bad....

[rayjay]

Have the drive shaft balanced or go with a upgrade. When I had the 3.55s I was north of 150, one time, rock solid. I haven't lost my mind since installing the 4.10s.

[martyo]

There was a reason that these cars were speed limited from the factory….

The driveshaft harmonics can cause the vibration you are experiencing. Left unchecked things can go very bad.

[Vortech347]

I usually cruise 90-100 going to Vegas. No issues, 4.10's.

[whitey]

I dont think its the driveshaft, just because there are more common issues that could cause it. Its like saying your engine is misfiring and saying its a fuel injector.

[tbone]

The main reason is the driveshaft. That's the whole reason the police get a special one.

[martyo]

The main reason is the driveshaft. That's the whole reason the police get a special one.

Yep.

There were lengthy discussions about this issue back in the day.

I will see if I can dig it up.

[fireandice9008]

That was the reason the previous owner of mine had a custom one made, I forget by who though. Good for him for spending the $$, I just wouldn't have gone that fast. No clue how fast i'm good to now, but 120 or so is smooth as can be.

[Vortech347]

Yep.

There were lengthy discussions about this issue back in the day.

I will see if I can dig it up.

What is weird is I've done a clean 130 on my GPS with my factory driveshaft and 4.10's. I didn't have any issues at all. I was even listening/feeling to see if there was anything out of whack...

Maybe I got lucky and mine was made on a Monday when the guy was paying attention?

[martyo]

What is weird is I've done a clean 130 on my GPS with my factory driveshaft and 4.10's. I didn't have any issues at all. I was even listening/feeling to see if there was anything out of whack...

Maybe I got lucky and mine was made on a Monday when the guy was paying attention?

One good or one bad does not form an acceptable standard in either direction.

Having witnessed driveshafts coming apart (thankfully only on the dyno) makes me leery of something that will cause one to come apart.

[jwibbity]

eventually i will be getting a decent balanced driveshaft but just wanted to see if other issues could cause this beside the driveshaft? the car has just a **** hair north of 80k and to my knowledge no suspension components have been replaced besides RAS compressor

[MM2004]

Swapping 3.55's with 4.10's will cause the driveshaft to hit critical speed at a lower mph that the stock gears.

The driveshafts in these cars are long, thus a lower critical speed will be achieved than one 2/3rd's the length or 2-piece driveshaft.

I cannot remember what critical speed is on our driveshafts, yet I do recall it was around the 130+/- mph mark?

Which Martin hit the nail on the head with speed limiting these cars.

The Metal Matrix driveshafts are more rigid, and have a much higher critical speed factor that aluminum. That is a known fact.

Mike.

[RF Overlord]

^^^what MM2004 said^^^

Driveline critical speed can be as low as 76 MPH. Here (http://www.tccoa.com/articles/tranny/transmission/page17.shtml)'s a link.

[fastblackmerc]

Short runs at 120+ usually won't cause any problems. It's the sustained 120+ runs that may lead to the transmission tail shaft bearing / seal coming out. I don't think anyone has had a drive shaft self destruct.

I check

Tire balance
Tires are not out of round
Suspension in good shape
Shocks are good
And the most important thing.... the u-joints are OK.

Wouldn't be a bad idea to get the drive shaft balanced.

BTW... for the old-timers, remember Lallycat (sp?), his tail shaft broke, but he was doing sustained high speed runs on a race track IIRC.

[Marauderjack]

Uh......why are you driving 115-120 MPH??:eek:

Those NC boys will put you under the jail!!:bigcry:

[Marauderman]

Swapping 3.55's with 4.10's will cause the driveshaft to hit critical speed at a lower mph that the stock gears.

The driveshafts in these cars are long, thus a lower critical speed will be achieved than one 2/3rd's the length or 2-piece driveshaft.

I cannot remember what critical speed is on our driveshafts, yet I do recall it was around the 130+/- mph mark?

Which Martin hit the nail on the head with speed limiting these cars.

The Metal Matrix driveshafts are more rigid, and have a much higher critical speed factor that aluminum. That is a known fact.

Mike.


Mike is correct--A Metal Metric Harmonic Balanced Shaft will solve the issue-

Stock over 123+ will start showing/ feeling the vibrations--


Short runs at 120+ usually won't cause any problems. It's the sustained 120+ runs that may lead to the transmission tail shaft bearing / seal coming out. I don't think anyone has had a drive shaft self destruct.

I check

Tire balance
Tires are not out of round
Suspension in good shape
Shocks are good
And the most important thing.... the u-joints are OK.

Wouldn't be a bad idea to get the drive shaft balanced.

BTW... for the old-timers, remember Lallycat (sp?), his tail shaft broke, but he was doing sustained high speed runs on a race track IIRC.

Correct sir!!!^^^^Alleykat--(sp) was the guy--remember well-

Once over 120 + for just about any continued length will show vibrations --most all old timers changed to the balance one I mentioned and all have been fine as I know---and Martyo is again right on!! as usual!!

[Motorhead350]

Marauder world problems.

LOL

[nh muscle]

sometimesthe the converter will play into vibrations. i can sell you my marauder driveshaft and you can have it balanced then swap it out so you dont lose any down time with your car.

[VMARAUDER]

What is weird is I've done a clean 130 on my GPS with my factory driveshaft and 4.10's. I didn't have any issues at all. I was even listening/feeling to see if there was anything out of whack...

Maybe I got lucky and mine was made on a Monday when the guy was paying attention?

Been at 130 too with no issues since I had my wheels RFB - road force balanced
stock shaft far as I know, though it was re-balanced since I owned the car (4 years)'s
Smooth as a baby's a##
Check suspension thoroughly get the wheels RFB

[MM2004]

While it could be a driveshaft balance issue, keep this in mind...

Once nearing critical speed, the driveshaft begins to distort at the linear center of the tube causing the driveshaft to become "bow" shaped.

This is where it gets ugly and more times than not, the driveshaft will self-destruct from the center outwards. Debris from the driveshaft can punch straight thru a floorboard possibly injuring anyone in the vehicle. Or worse. Death.

Parts left on either end of the driveshaft, bolted to the rear-end or tranny end, will also beat the hell out of the floorpan. In addition, if enough of the rear part of the driveshaft stays in tact at the rear-end side, it can drop down, contact the ground and catapault the vehicle into the air.

How do I know this?

For the past 29 years as an employee for Dana Corporation (Light Vehicle Driveline), I have seen destroyed driveshafts and told stories from the Warranty Dept. that sent chills down my spine.

Be careful out there folks!

Mike.

[martyo]

How do I know this?

For the past 29 years as an employee for Dana Corporation (Light Vehicle Driveline), I have seen destroyed driveshafts and told stories from the Warranty Dept. that sent chills down my spine.

Be careful out there folks!

Mike.

Amen brother Mike!!!

Here is one of countless examples (this one from a lowly V6 car....):

http://www.youtube.com/watch?v=LZXBjVIrR08

[guspech750]

Amen brother Mike!!!

Here is one of countless examples (this one from a lowly V6 car....):

http://www.youtube.com/watch?v=LZXBjVIrR08

Holy crap that is scary.


Sent from The White House on taxpayers dimes.

DTR + 4.10's + Eaton swap = Wreeeeeeeeeeeeeeedom

[martyo]

Holy crap that is scary.



Come hang around the dyno some time and you will see scary! :P

[whitey]

Driveshaft problems? JB Weld it!

[J-MAN]

Amen brother Mike!!!

Here is one of countless examples (this one from a lowly V6 car....):

http://www.youtube.com/watch?v=LZXBjVIrR08


Ouch! I'll bet he took a big bite out of the seat!!

[jwibbity]

just an fyi for anybody wondering about how bad the vibration is, its pretty hard, not a "im going to fast i need to slow down" vibration but a 'im going to vibrate apart on you" vibration

Marty do you guys do all of the suggested checks throughout this thread??,

RoadForce Balance
Car Fixer Specs
Driveshaft Balance
U-Joint Replacement
Complete Suspension Check Out?

im kinda thinking maybe get a MMC driveshaft and rebalance tires to start

I dont plan, :P :P, on going close to 120 anytime soon but dont want my driveshaft destroying itself at some lower speed while cruising plus if we go to another track at marauderville i wanna see how fast i can go and not have to really worry

[jwibbity]

Uh......why are you driving 115-120 MPH??:eek:

Those NC boys will put you under the jail!!:bigcry:

yea these smooth highways have been tempting here.....i cant help myself sometimes

maybe i need to drive my wifes 4 banger more often....

[lji372]

^^^what MM2004 said^^^

Driveline critical speed can be as low as 76 MPH. Here (http://www.tccoa.com/articles/tranny/transmission/page17.shtml)'s a link.

More of us should listen to him ;)

[lji372]

yea these smooth highways have been tempting here.....i cant help myself sometimes

maybe i need to drive my wife more often....


Fixed :D

Almost sorry but could not resist :lol:

[jwibbity]

Fixed :D

Almost sorry but could not resist :lol:
i had a feeling it was coming

o yea thanks for the plug looks sweet under the hood!!!

[martyo]

RoadForce Balance
Car Fixer Specs
Driveshaft Balance
U-Joint Replacement
Complete Suspension Check Out?


What we can't do in house, we can get done while we have it!

[lji372]

i had a feeling it was coming

o yea thanks for the plug looks sweet under the hood!!!

Pics or it didn't happen.

Not of the plug :laugh:

I'm glad you like it :beer:

[jwibbity]

What we can't do in house, we can get done while we have it!

ill be contacting you after next week, going to CT for an CNC machine install, but might be coming down to atlanta for a router spindle replacement so i might be able to drop it off to you guys :banana2: :banana2:

[lji372]

What we can't do in house, we can get done while we have it!

Forged internals
Whipple
Nos
Widened wheels
Fuzzy dice
Etc

[tbone]

When you go supercharged, do you have to have a driveshaft loop to race at the track?

[jwibbity]

When you go supercharged, do you have to have a driveshaft loop to race at the track?

like a road course or drag strip??

[Vortech347]

I believe a loop is necessary for any car running drag radials, slicks, or under 12.00. However its a cheap piece of insurance to keep you from pole vaulting. I have one on both my Mustangs.


One good or one bad does not form an acceptable standard in either direction.

Having witnessed driveshafts coming apart (thankfully only on the dyno) makes me leery of something that will cause one to come apart.

No, it doesn't which is why I joked about the monday shaft. Hell the whole reason I did that 130 pull was that I was curious about that specific thing.

That is f'n nuts you've watched one come apart on the dyno. I hope everyone was clear.

[Vortech347]

Double post. oops.

[fastblackmerc]

When you go supercharged, do you have to have a driveshaft loop to race at the track?
I have one on my DD. Cheap insurance.

[martyo]

Forged internals
Whipple
Nos
Widened wheels
Fuzzy dice
Etc

That we can do in house!

[martyo]

That is f'n nuts you've watched one come apart on the dyno. I hope everyone was clear.

recently we had one come apart on a customer-built Fox Body. It beat the ever living crap out of the car, scared the snot out of everyone near the dyno.

As I always say, it is cool to be near the dyno until something lets loose. Then it is way cooler to be at the other end of the shop!

[martyo]

I believe a loop is necessary for any car running drag radials, slicks, or under 12.00. However its a cheap piece of insurance to keep you from pole vaulting. I have one on both my Mustangs.



A very good move!

[88grandmarq]

So after being involved in a thread about 4.10 gears and tuning, i was thinking that vibration through the car at the above speed was normal for 4.10's and stock driveshaft.....but apparently alot of other guys are getting past 120, one even to 140ish mph(stock shaft, 3.55's)

so my question is other than a balanced driveshaft what could possibly be loose or wrong in my car causing this vibration??

i thought up until recently i was reaching the critical rotation speed of the stock driveshaft causing vibrations but i seem to be the only guy with 4.10s having this issue

THANKS!!!!

I rebuilt the Transmission in jwibbity's Marauder last month, while the transmission was out of the car, I found the aftermarket grease-able U-joints were worn out and very loose. Drive shaft was sent out to North Atlanta Drive line for a new OEM style sealed U-joints and a high speed balance. http://drivelineserviceofnorthatlanta .com/

I had the car up to 80-85 MPH and it was smooth as glass. :burn:


http://www.85merk.com/members/eric_s/U_joint.jpg


We also installed a Metco drive shaft safety loop


http://www.85merk.com/members/eric_s/Safety_loop.jpg

[tbone]

Just ordered one up.

[GreekGod]

Did you read the link that was posted? >>>

http://www.tccoa.com/articles/tranny/transmission/page17.shtml

The driveshaft whips in the middle. Nothing to do with balance of the OEM shaft.

One of the best suppliers in the USA:

http://www.dynotechengineering.com/

=====================

[justbob]

While it could be a driveshaft balance issue, keep this in mind...

Once nearing critical speed, the driveshaft begins to distort at the linear center of the tube causing the driveshaft to become "bow" shaped.

This is where it gets ugly and more times than not, the driveshaft will self-destruct from the center outwards. Debris from the driveshaft can punch straight thru a floorboard possibly injuring anyone in the vehicle. Or worse. Death.

Parts left on either end of the driveshaft, bolted to the rear-end or tranny end, will also beat the hell out of the floorpan. In addition, if enough of the rear part of the driveshaft stays in tact at the rear-end side, it can drop down, contact the ground and catapault the vehicle into the air.

How do I know this?

For the past 29 years as an employee for Dana Corporation (Light Vehicle Driveline), I have seen destroyed driveshafts and told stories from the Warranty Dept. that sent chills down my spine.

Be careful out there folks!

Mike.


You should have seen my 1" tall X pipe after mine snapped in half going into third at the track.. :eek:

http://img.tapatalk.com/d/14/05/18/7ube7eda.jpg

The banana remains..

http://img.tapatalk.com/d/14/05/18/epezu4eg.jpg

Walking a quarter mile back...

http://img.tapatalk.com/d/14/05/18/sydysasu.jpg


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
"Since 2004"